WO2012098866A1

WO2012098866A1 - Video encoding method and video decoding method

Info

Publication number: WO2012098866A1
Application number: PCT/JP2012/000262
Authority: WO
Inventors: 敏康杉尾; 西　孝啓; 陽司柴原; 寿郎笹井
Original assignee: パナソニック株式会社
Priority date: 2011-01-18
Filing date: 2012-01-18
Publication date: 2012-07-26

Abstract

Provided are a video encoding method and a video decoding method capable of deriving a motion vector that is optimal for a picture to be encoded, and also capable of improving encoding efficiency. A video encoding device (100) comprising: a reference picture list management unit (111) for assigning a reference picture index to a reference picture and creating a reference picture list together with a display order or the like; a skip mode prediction direction determination unit (112) for determining the prediction direction of a skip mode of a block to be encoded, by using a reference picture list (1) and a reference picture list (2); and an inter-prediction controller (109) for performing a cost comparison of a motion vector detection mode, a direct mode, and the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction established by the skip mode prediction direction determination unit (112), and determining a more efficient inter-prediction mode.

Description

Video encoding method and video decoding method

The present invention relates to a moving image coding method for coding an input image in units of blocks using inter-frame prediction that refers to an encoded picture, and to decode a bit stream in units of blocks using inter-frame prediction. The present invention relates to a moving picture decoding method.

In the moving image encoding process, in general, the amount of information is compressed using redundancy in the spatial direction and temporal direction of a moving image. In general, as a method of using redundancy in the spatial direction, conversion to the frequency domain is used, and as a method of using redundancy in the temporal direction, inter-picture prediction (hereinafter referred to as inter prediction) encoding is used. Processing is used. In the inter prediction encoding process, when a certain picture is encoded, an encoded picture that is ahead or behind in the display time order with respect to the encoding target picture is used as a reference picture. Then, a motion vector is detected by detecting the motion of the encoding target picture with respect to the reference picture. By taking the difference between the predicted image data obtained by performing motion compensation based on the detected motion vector and the image data of the encoding target picture, redundancy in the time direction is removed. Here, in motion detection, a difference value between a coding target block in a coded picture and a block in a reference picture is calculated, and a block in the reference picture having the smallest difference value is set as a reference block. Then, a motion vector is detected using the encoding target block and the reference block.

, H. already standardized. In a moving picture coding system called H.264 (see, for example, Non-Patent Document 1), three types of picture types, i.e., an I picture, a P picture, and a B picture, are used to compress the information amount. An I picture is a picture that does not perform inter prediction encoding processing, that is, performs intra prediction (hereinafter referred to as intra prediction) encoding processing. A P picture is a picture that is subjected to inter prediction encoding with reference to one already encoded picture in front of or behind the current picture in display time order. The B picture is a picture that performs inter prediction encoding with reference to two already encoded pictures that are in front of or behind the encoding target picture in display time order.

In inter prediction encoding, a reference picture list for specifying a reference picture is generated. The reference picture list is a list in which a reference picture index is assigned to an encoded reference picture that is referred to in inter prediction. For example, since B picture can be encoded with reference to two pictures, two reference picture lists (L0, L1) are held. FIG. 1A is a diagram for explaining reference picture index assignment to reference pictures, and FIGS. 1B and 1C are diagrams illustrating examples of reference picture lists in B pictures.

FIG. 1A assumes a case where, for example, reference picture 3, reference picture 2, reference picture 1, and encoding target picture are arranged in the order of display. In this case, the reference picture list 1 (L0) is an example of the reference picture list in the prediction direction 1 in the bi-directional prediction, and the reference picture in the display order 2 is set to the value “0” of the reference picture index 1 as shown in FIG. 1B. 1. Reference picture 2 in display order 1 is assigned to value “1” of reference picture index 1, and reference picture 3 in display order 0 is assigned to value “2” in reference picture index 1. That is, the reference picture index is assigned to the encoding target picture in the order of time in display order. On the other hand, the reference picture list 2 (L1) is an example of the reference picture list in the prediction direction 2 in the bi-directional prediction, and the reference picture 2 in the display order 1 is set to the value “0” of the reference picture index 2 as shown in FIG. 1C. The reference picture 1 in the display order 2 is assigned to the value “1” of the reference picture index 2, and the reference picture 3 in the display order 0 is assigned to the value “2” of the reference picture index 2. In this way, it is possible to assign different reference picture indexes for each reference picture for each prediction direction (

reference pictures

1 and 2 shown in FIG. 1A), or to assign the same reference picture index (see FIG. 1A). Reference picture 3) shown.

H. In the moving picture coding method called H.264, as the inter prediction coding mode of each coding target block in the B picture, the difference value between the prediction image data and the coding target block and the prediction image data generation are used. The motion vector detection mode that encodes the motion vector, and only the difference value of the image data are encoded, the direct mode that predicts the motion vector from the peripheral blocks, and the difference value and motion vector of the image data are not encoded. There is a skip mode in which a predicted image at a position indicated by a motion vector predicted from a peripheral block or the like is a decoded image as it is.

The motion vector detection mode for the B picture includes two-way prediction in which a prediction image is generated with reference to two already-encoded pictures ahead or behind the current picture as a prediction direction, and forward or backward. The one-way prediction for generating the predicted image with reference to one already encoded picture in (1) can be selected.

On the other hand, in the B picture skip mode and direct mode, the prediction direction of the block to be encoded is determined according to the prediction mode of the neighboring blocks and the like. A specific example will be described with reference to FIG. In FIG. 2, the encoded block adjacent to the left of the encoding target block is adjacent block A, the encoded block adjacent above the encoding target block is adjacent block B, and the encoded block adjacent to the upper right of the encoding target block is Is an adjacent block C.

In FIG. 2, the adjacent block A is bi-directional prediction, and has a motion vector MvL0_A in the prediction direction 1 and a motion vector MvL1_A in the prediction direction 2. Here, MvL0 is a motion vector that refers to the reference picture specified by the reference picture list 1 (L0), and MvL1 is a motion vector that refers to the reference picture specified by the reference picture list (L1). Adjacent block B is unidirectional prediction and has motion vector MvL0_B in prediction direction 1. Also, the adjacent block C is unidirectional prediction and has a motion vector MvL0_C in the prediction direction 1. Also, here, the motion vectors MvL0_A, MvL0_B, and MvL0_C of each adjacent block refer to the same reference picture RefIdxL0, and MvL1_A refers to the reference picture RefIdxL1.

Assuming that the reference pictures in the prediction direction 1 and the prediction direction 2 in the skip mode and the direct mode of the encoding target block are RefIdxL0 and RefIdxL1, respectively, the prediction directions in the skip mode and the direct mode are RefIdxL0 and RefIdxL1 in any one of the adjacent blocks. If there is a bi-directional prediction that refers to, bi-directional prediction. In the case of FIG. 2, since the adjacent block A satisfies the above condition, bi-directional prediction is selected as the prediction direction of the encoding target block.

However, in the conventional method for determining the prediction direction in the skip mode and the direct mode, for example, although the detection accuracy of the prediction direction 1 motion vector MvL1_A in the adjacent block A in FIG. Further, the predicted image in the skip mode and the direct mode deteriorates, resulting in a problem that the encoding efficiency is deteriorated.

An object of the present invention is to solve the above-described problem, and a moving picture coding method and a moving picture that can derive a motion vector most suitable for a picture to be coded and improve coding efficiency. An object is to provide a decryption method.

In order to achieve the above object, a moving picture coding method according to the present invention includes at least two reference picture lists for at least one reference picture different from a coding target picture including a coding target block. And a coding method for encoding the target block by assigning an index for the reference picture, wherein the index allocation method for the reference picture is the same in the two or more reference picture lists. The same reference picture list determination step for determining whether or not, and a prediction direction switching step for switching a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result; including.

Also, the moving picture coding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the coding target picture including the coding target block, to perform the reference. A moving picture encoding method for encoding an encoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists Same reference picture list determination step, and based on the determination result, a prediction direction flag addition step for adding a prediction direction flag indicating a prediction direction when the encoding target block is encoded in a predetermined encoding mode And including.

Also, the moving picture coding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the coding target picture including the coding target block, to perform the reference. A moving picture encoding method for encoding an encoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists Based on the same reference picture list determination step, a prediction direction switching step of switching a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result, and the determination result The encoding target block determined by encoding in a predetermined encoding mode It includes a header information adding step of adding the prediction direction flag indicating the measurement direction in the header information.

Also, the moving picture coding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the coding target picture including the coding target block, to perform the reference. A moving picture encoding method for encoding an encoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists Whether to add, for each encoding target block, a prediction direction flag for encoding the encoding target block in a predetermined encoding mode based on the same reference picture list determination step for determining Prediction direction addition flag addition step for adding a prediction direction addition flag indicating whether or not to header information , Based on the prediction direction additional flags, including the step of encoding the encoding target block in a predetermined coding mode.

Also, the moving picture coding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the coding target picture including the coding target block, to perform the reference. A moving picture encoding method for encoding an encoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists The same reference picture list determination step, and a prediction direction fixing flag indicating whether or not to fix the prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result. Based on the header information addition step to be added to the header information and the prediction direction fixed flag, the code The current block; and a coding step of coding at the predetermined coding mode.

Also, the moving picture coding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the coding target picture including the coding target block, to perform the reference. A moving picture encoding method for encoding an encoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists The same reference picture list determination step, and a prediction direction fixing flag indicating whether or not to fix the prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result; With header information for adding a first prediction direction flag indicating the fixed prediction direction to the header information A method, based on the prediction direction fixing flag and the first prediction direction flag, including an encoding step of encoding the encoding target block in the predetermined encoding mode.

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A moving picture decoding method for decoding an decoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists And a prediction direction switching step of switching a prediction direction when decoding the decoding target block in a predetermined decoding mode based on the determination result.

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A moving picture decoding method for decoding an decoding target block by assigning an index to a picture, wherein whether or not the index allocation method for the reference picture is the same in the two or more reference picture lists Same reference picture list determination step, and based on the determination result, a prediction direction flag decoding step for decoding a prediction direction flag indicating a prediction direction when decoding the decoding target block in a predetermined decoding mode And including.

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A moving picture decoding method for decoding a decoding target block by assigning an index to a picture, wherein a header of a prediction direction flag indicating a prediction direction when the decoding target block is decoded in a predetermined decoding mode Decoding from the information, and decoding the block to be decoded in a predetermined decoding mode based on the decoded prediction direction flag.

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A video decoding method for decoding the decoding target block by assigning an index to a picture, wherein a prediction direction flag indicating a prediction direction when decoding the decoding target block in a predetermined decoding mode is Decoding a flag indicating whether or not added for each decoding target block from header information; and decoding the decoding target block in a predetermined decoding mode based on the flag. .

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A moving picture decoding method for decoding a decoding target block by assigning an index to a picture, and whether or not to fix a prediction direction when decoding the decoding target block in a predetermined decoding mode. Decoding a prediction direction fixed flag to be expressed from the bit stream, and decoding the block to be decoded in the predetermined decoding mode based on the prediction direction fixed flag.

Also, the moving picture decoding method according to the present invention uses the at least two reference picture lists for at least one reference picture different from the decoding target picture including the decoding target block, to perform the reference. A moving picture decoding method for decoding a decoding target block by assigning an index to a picture, and whether or not to fix a prediction direction when decoding the decoding target block in a predetermined decoding mode. The prediction direction fixed flag to be expressed, the step of decoding the fixed first prediction direction flag from the bitstream, and the decoding target block based on the prediction direction fixed flag and the first prediction direction flag. Decoding in the decoding mode.

Note that the present invention can be realized not only as such a moving image encoding method and a moving image decoding method, but also including the characteristic steps included in such a moving image encoding method and a moving image decoding method. It can also be realized as a moving picture encoding apparatus and a moving picture decoding apparatus as means, or as a program for causing a computer to execute these steps. Such a program can be realized as a recording medium such as a computer-readable CD-ROM, or can be realized as information, data, or a signal indicating the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet.

According to the present invention, it is possible to derive a motion vector and a reference picture that are most suitable for a picture to be coded, and to improve coding efficiency.

FIG. 1A is a diagram for explaining assignment of a reference picture index to a reference picture. FIG. 1B is a diagram illustrating an example of a reference picture list in a B picture. FIG. 1C is a diagram illustrating an example of a reference picture list in a B picture. FIG. 2 is a diagram illustrating the relationship between the encoding target block, adjacent blocks, and motion vectors of adjacent blocks. FIG. 3 is a block diagram showing a configuration of an embodiment of a moving picture coding apparatus using the moving picture coding method according to the present invention. FIG. 4 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 5 is a flowchart showing a flow of determining the skip mode prediction direction in the skip mode prediction direction determination unit. FIG. 6 is a flowchart illustrating the inter prediction mode determination flow in the inter prediction control unit 109. FIG. 7 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode. FIG. 8 is a flowchart showing a processing flow for calculating the cost CostDirect in the direct mode. FIG. 9 is a diagram illustrating the relationship between the encoding target block, the adjacent block, and the motion vector of the adjacent block. FIG. 10 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode. FIG. 11A is a diagram illustrating an example of a motion vector predictor candidate. FIG. 11B is a diagram illustrating an example of a code table used when the motion vector predictor index is variable length encoded. FIG. 12 is a diagram illustrating the relationship between the encoding target block and adjacent blocks. FIG. 13 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 14 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 15 is a flowchart illustrating a determination flow of a skip mode prediction direction addition flag in the skip mode prediction direction addition determination unit. FIG. 16 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode. FIG. 17 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 18 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 19 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 20 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 21 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. FIG. 22 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 23 is a diagram illustrating an example of the syntax of a bitstream in the video decoding method according to the present invention. FIG. 24 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. FIG. 25 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 26 is a diagram showing an example of bitstream syntax in the video decoding method according to the present invention. FIG. 27 is a block diagram showing a configuration of an embodiment of a video decoding device using the video decoding method according to the present invention. FIG. 28 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 29A is a diagram illustrating an example of a bitstream syntax in the video decoding method according to the present invention. FIG. 29B is a diagram illustrating an example of a bitstream syntax in the video decoding method according to the present invention. FIG. 30 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. FIG. 31 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 32A is a diagram illustrating an example of a bitstream syntax in the video decoding method according to the present invention. FIG. 32B is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. FIG. 33 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 34 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 35 is a flowchart illustrating a direct mode prediction direction determination flow in the direct mode prediction direction determination unit. FIG. 36 is a flowchart illustrating a determination flow of the inter prediction mode in the inter prediction control unit. FIG. 37 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode. FIG. 38 is a flowchart showing a processing flow for calculating the cost CostDirect in the direct mode. FIG. 39 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode. FIG. 40 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 41 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 42 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. FIG. 43 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 44 is a block diagram showing a configuration of an embodiment of a video decoding device using the video decoding method according to the present invention. FIG. 45 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 46 is a diagram showing an example of bitstream syntax in the video decoding method according to the present invention. FIG. 47 is a block diagram showing a configuration of an embodiment of a video decoding apparatus using the video decoding method according to the present invention. FIG. 48 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 49A is a diagram showing an example of bitstream syntax in the video decoding method according to the present invention. FIG. 49B is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. FIG. 50 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. FIG. 51 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 52A is a diagram showing an example of bitstream syntax in the video decoding method according to the present invention. FIG. 52B is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. FIG. 53 is a block diagram showing a configuration of an embodiment of a video encoding device using the video encoding method according to the present invention. FIG. 54 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. FIG. 55 is a flowchart illustrating a merge mode prediction direction determination flow in the merge mode prediction direction determination unit. FIG. 56 is a flowchart illustrating a determination flow of the inter prediction mode in the inter prediction control unit. FIG. 57 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode. FIG. 58 is a flowchart showing the processing flow for calculating the cost CostMerge in the merge mode. FIG. 59 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode. FIG. 60 is a block diagram showing a configuration of an embodiment of a video decoding apparatus using the video decoding method according to the present invention. FIG. 61 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention. FIG. 62 is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. FIG. 63 is an overall configuration diagram of a content supply system that implements a content distribution service. FIG. 64 is an overall configuration diagram of a digital broadcasting system. FIG. 65 is a block diagram illustrating a configuration example of a television. FIG. 66 is a block diagram illustrating a configuration example of an information reproducing / recording unit that reads and writes information from and on a recording medium that is an optical disk. FIG. 67 is a diagram illustrating a structure example of a recording medium that is an optical disk. FIG. 68A is a diagram illustrating an example of a mobile phone. FIG. 68B is a block diagram illustrating a configuration example of a mobile phone. FIG. 69 shows a structure of multiplexed data. FIG. 70 is a diagram schematically showing how each stream is multiplexed in the multiplexed data. FIG. 71 is a diagram showing in more detail how the video stream is stored in the PES packet sequence. FIG. 72 is a diagram showing the structure of TS packets and source packets in multiplexed data. FIG. 73 is a diagram showing a data structure of the PMT. FIG. 74 shows an internal structure of multiplexed data information. FIG. 75 shows the internal structure of stream attribute information. FIG. 76 is a diagram showing steps for identifying video data. FIG. 77 is a block diagram illustrating a configuration example of an integrated circuit that implements the moving picture coding method and the moving picture decoding method according to each embodiment. FIG. 78 is a diagram showing a configuration for switching drive frequencies. FIG. 79 is a diagram showing steps for identifying video data and switching between driving frequencies. FIG. 80 is a diagram showing an example of a look-up table in which video data standards are associated with drive frequencies. FIG. 81A is a diagram illustrating an example of a configuration for sharing a module of a signal processing unit. FIG. 81B is a diagram illustrating another example of a configuration for sharing a module of a signal processing unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the moving picture coding system, a coding mode called a merge mode can be selected as an inter prediction mode for each coding target block in a B picture or a P picture. In the merge mode, a motion vector or a reference picture index is copied from an adjacent block of the encoding target block, and the encoding target block is encoded. At this time, the motion vector and the reference picture index can be selected by attaching the index of the adjacent block used for copying to the bit stream.

For example, in the case of FIG. 2, the temporal prediction motion obtained using the motion vectors and reference picture indexes of adjacent blocks A, B, and C and the co-located block as the motion vector and reference picture index of the encoding target block. The motion vector and reference picture index of the block to be encoded are selected from the motion vector and reference picture index in the vector mode with the highest encoding efficiency. Then, a merge index representing the selected adjacent block is attached to the bitstream. For example, when the adjacent block A is selected, the encoding target block is encoded using the prediction direction 1 motion vector MvL0_A, the prediction direction 2 motion vector MvL1_A of the adjacent block A, and the reference picture index of the reference picture referenced by each motion vector. By attaching only the merge index indicating that the adjacent block A is used to the bitstream, the information amount of the motion vector and the reference picture index can be reduced. Details of the merge mode can be referred to Non-Patent Document 2, for example.

However, in the merge mode prediction direction determination method, for example, when adjacent A in FIG. 2 is used as a copy source, bi-directional prediction is always performed even though the detection accuracy of the prediction direction 1 motion vector MvL1_A in the adjacent block A is poor. Since it is selected, the prediction image in the merge mode deteriorates, resulting in a problem that the encoding efficiency is deteriorated.

(Embodiment 1)
FIG. 3 is a block diagram showing a configuration of an embodiment of a moving picture coding apparatus using the moving picture coding method according to the present invention.

As illustrated in FIG. 3, the moving image encoding apparatus 100 includes an orthogonal transform unit 101, a quantization unit 102, an inverse quantization unit 103, an inverse orthogonal transform unit 104, a block memory 105, a frame memory 106, an intra prediction unit 107, An inter prediction unit 108, an inter prediction control unit 109, a picture type determination unit 110, a reference picture list management unit 111, a skip mode prediction direction determination unit 112, and a variable length coding unit 113 are provided.

The orthogonal transform unit 101 transforms prediction image data generated as described later and prediction error data between an input image sequence from an image region to a frequency region. The quantization unit 102 performs a quantization process on the prediction error data converted into the frequency domain. The inverse quantization unit 103 performs inverse quantization processing on the prediction error data quantized by the quantization unit 102. The inverse orthogonal transform unit 104 performs transform from the frequency domain to the image domain on the prediction error data subjected to the inverse quantization process. The block memory 105 stores the decoded image obtained from the predicted image data and the prediction error data subjected to the inverse quantization process in units of blocks. The frame memory 106 stores the decoded image in units of frames. The picture type determination unit 110 determines which of the I picture, B picture, and P picture is used to encode the input image sequence, and generates picture type information. The intra prediction unit 107 uses the decoded image in units of blocks stored in the block memory 105 to generate predicted image data based on intra prediction of the encoding target block. The inter prediction unit 108 generates predicted image data by inter prediction of the encoding target block, using the decoded image in units of frames stored in the frame memory 106.

The inter prediction control unit 109 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a skip mode. The cost comparison of the skip mode which produces | generates a prediction image using the prediction motion vector produced | generated according to the prediction direction determined by the prediction direction determination part 112 is performed, and more efficient inter prediction mode is determined.

The reference picture list management unit 111 assigns a reference picture index to an encoded reference picture that is referred to in inter prediction, and creates a reference picture list together with a display order and the like.

In this embodiment, the reference picture is managed in the reference picture index and the display order. However, the reference picture may be managed in the reference picture index and the encoding order.

The skip mode prediction direction determination unit 112 uses the reference picture list 1 and the reference picture list 2 created by the reference picture list management unit 111 to determine the prediction direction of the skip mode of the encoding target block by a method described later. .

The variable length encoding unit 113 generates a bitstream by performing variable length encoding processing on the quantized prediction error data, inter prediction mode, inter prediction direction flag, skip flag, and picture type information. .

FIG. 4 is a flowchart showing an outline of the processing flow of the moving picture encoding method according to the present invention.

The skip mode prediction direction determination unit 112 determines a prediction direction when the block to be encoded is encoded in the skip mode (step S101). The inter prediction control unit 109 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a skip mode. The cost comparison of the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction determined by the prediction direction determination unit 112 is performed, and a more efficient inter prediction mode is determined (step S102). The cost calculation method will be described later. Next, the inter prediction control unit 109 determines whether or not the determined inter prediction mode is a skip mode (step S103). As a result of this determination, if the inter prediction mode is the skip mode (Yes in step S103), the inter prediction control unit 109 generates a predicted image in the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block (step S104). On the other hand, as a result of the determination, if the inter prediction mode is not the skip mode (No in step S103), the inter prediction control unit 109 performs inter prediction according to the determined inter prediction mode, generates predicted image data, and skip flag. Is set to 0. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. Further, the inter prediction control unit 109 outputs an inter prediction mode and an inter prediction direction flag indicating whether the motion vector detection mode or the direct mode is associated with the bit stream of the encoding target block to the variable length encoding unit 113. (Step S105).

FIG. 5 is a flowchart showing a determination flow of the skip mode prediction direction in the skip mode prediction direction determination unit 112.

In general, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, motion vectors in the prediction direction 1 and the prediction direction 2 are selected in the two-way prediction. In the direction prediction, only the motion vector in the prediction direction 1 may be used, and the motion vector in the prediction direction 2 may decrease as a whole. For example, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the unidirectional prediction using the reference picture list 2 is prohibited, thereby encoding the inter prediction direction flag code. Coding efficiency can be improved by reducing the amount. In this case, since only the motion vector in the prediction direction 1 is used in the unidirectional prediction, the motion vector in the prediction direction 2 is reduced as a whole. In this case, when bi-directional prediction is selected as the prediction direction of the skip mode, there is a tendency that there are few motion vectors in the prediction direction 2 of the adjacent blocks that can be used for generation of the prediction motion vector in the prediction direction 2. There is a possibility that the accuracy of the predicted motion vector will be low. Therefore, when the reference picture index allocation for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the encoding efficiency is improved by fixing the prediction direction of the skip mode to unidirectional prediction. be able to.

The skip mode prediction direction determination unit 112 uses the reference picture list 1 and the reference picture list 2 to determine whether or not the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2. Determination is made (step S201). For example, the display order of the reference picture indicated by each reference picture index 1 is obtained from the reference picture list 1, and compared with the display order of the reference picture indicated by each reference picture index 2 from the reference picture list 2. It can be determined that they are the same. As a result of this determination, if the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 (Yes in step S201), the skip mode prediction direction determination unit 112 determines the skip mode. A prediction direction flag is set to one direction prediction (step S202). On the other hand, when the reference picture index assignment for each reference picture is not the same in reference picture list 1 and reference picture list 2 (No in step S201), skip mode prediction direction determination unit 112 sets a skip mode prediction direction flag. Two-way prediction is set (step S203).

In the present embodiment, it is determined in step S201 whether the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 using the display order. You may determine using order etc.

Further, in this embodiment, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the prediction direction of the skip mode is fixed to one direction. When the reference picture indicated by the reference picture index 1 in the prediction direction 1 in the skip mode of the encoding target block and the reference picture indicated by the reference picture index 2 in the prediction direction 2 are the same picture, the prediction direction in the skip mode is set to one direction. It may be fixed. For example, the display order of the reference picture indicated by the reference picture index 1 is obtained from the reference picture list 1 and is compared with the display order of the reference picture indicated by the reference picture index 2 from the reference picture list 2. it can. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, encoding efficiency can be improved by fixing the prediction direction of the skip mode to one-way prediction.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two previously encoded pictures whose encoding target picture is ahead, the prediction direction of the skip mode is fixed to uni-directional prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, or the prediction direction 1 reference in the skip mode of the encoding target block In some cases, the reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 are the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, encoding efficiency can be improved by fixing the prediction direction of the skip mode to one-way prediction.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two already encoded pictures that are behind the encoding target picture, the prediction direction of the skip mode is fixed to unidirectional prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, and the reference in the prediction direction 1 in the skip mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, encoding efficiency can be improved by fixing the prediction direction of the skip mode to one-way prediction.

FIG. 6 is a flowchart showing the determination flow of the inter prediction mode in the inter prediction control unit 109.

The inter prediction control unit 109 calculates a cost CostInter in a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result by a method described later (step S301). The inter prediction control unit 109 generates a prediction vector using a motion vector of an adjacent block or the like, and calculates a cost CostDirect in a direct mode for generating a prediction image using the prediction vector by a method described later (step S302). The inter prediction control unit 109 calculates the cost CostSkip of the skip mode for generating a predicted image according to the method described later according to the skip mode prediction direction flag determined by the skip mode prediction direction determination unit 112 (step S303). The inter prediction control unit 109 compares the cost CostInter of the motion vector detection mode, the cost CostDirect of the direct mode, and the cost CostSkip of the skip mode, and determines whether or not the cost CostInter of the motion vector detection mode is the minimum (Step S304). ). If the cost CostInter of the motion vector detection mode is the minimum as a result of this determination (Yes in step S304), the inter prediction control unit 109 determines the inter prediction mode as the motion vector detection mode, and sets the inter prediction mode as the motion vector detection mode. (Step S305). On the other hand, if the cost CostInter of the motion vector detection mode is not the minimum (No in step S304), the inter prediction control unit 109 compares the cost CostDirect of the direct mode with the cost CostSkip of the skip mode, and the cost CostDirect of the direct mode is It is determined whether it is small (step S306). If the cost CostDirect of the direct mode is small as a result of this determination (Yes in step S306), the inter prediction control unit 109 determines the inter prediction mode to the direct mode, and sets the inter prediction mode information to the direct mode (step S307). ). On the other hand, if the cost CostDirect of the direct mode is not small (No in step S306), the inter prediction control unit 109 sets the inter prediction mode to the skip mode and sets the skip mode in the inter prediction mode information (step S308).

Next, a method for calculating the cost CostInter in the motion vector detection mode in step S301 in FIG. 6 will be described in detail with reference to FIG. FIG. 7 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode.

The inter prediction control unit 109 performs motion detection on the reference picture 1 indicated by the reference picture index 1 in the prediction direction 1 and the reference picture 2 indicated by the reference picture index 2 in the prediction direction 2, and motion vectors for the respective reference pictures 1 and motion vector 2 are generated (step S401). Here, in motion detection, a difference value between a coding target block in a coded picture and a block in a reference picture is calculated, and a block in the reference picture having the smallest difference value is set as a reference block. Then, a motion vector is obtained from the encoding target block position and the reference block position. Next, the inter prediction control unit 109 generates a prediction image in the prediction direction 1 using the obtained motion vector 1, and calculates the cost CostInterUni1 using, for example, the following equation 1 of the RD optimization model. (Step S402).

In Equation 1, D represents encoding distortion, a pixel value obtained by encoding and decoding a block to be encoded using a prediction image generated with a certain motion vector, and an original pixel value of the block to be encoded The sum of absolute differences is used. R represents the amount of generated code, and the amount of code necessary for encoding the motion vector used for predictive image generation is used. Λ is Lagrange's undetermined multiplier. Next, the inter prediction control unit 109 generates a prediction image in the prediction direction 2 using the obtained motion vector 2, and calculates the cost CostInterUni2 from Equation 1 (Step S403). Next, the inter prediction control unit 109 generates a prediction image in two directions using the obtained motion vector 1 and motion vector 2, and calculates the cost CostInterBi from Equation 1 (step S404). Here, the bi-directional predicted image is, for example, a bi-directional predicted image obtained by performing addition averaging for each pixel of the predicted image obtained from the motion vector 1 and the predicted image obtained from the motion vector 2. The inter prediction control unit 109 compares the values of the cost CostInterUni1, the cost CostInterUni2, and the cost CostInterBi, and determines whether or not the cost CostInterBi is minimum (step S405). If the cost CostInterBi is the minimum as a result of this determination (Yes in step S405), the inter prediction control unit 109 determines the prediction direction of the motion vector detection mode to be bi-directional prediction, and uses the cost CostInterBi as the cost of the motion vector detection mode. Set to CostInter (step S406). On the other hand, if the cost CostInterBi is not minimum (No in step S405), the cost CostInterUni1 and the cost CostInterUni2 are compared to determine whether or not the value of the cost CostInterUni1 is small (step S407). If the value of cost CostInterUni1 is small as a result of this determination (Yes in step S407), the inter prediction control unit 109 determines the motion vector detection mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostInterUni1 as the motion vector detection mode. To the cost CostInter (step S408). On the other hand, if the value of cost CostInterUni1 is not small (No in step S407), the inter prediction control unit 109 determines the motion vector detection mode as one-way prediction 2 in the prediction direction 2, and sets the cost CostInterUni2 as the cost of the motion vector detection mode. Set to CostInter (step S409).

In addition, in this Embodiment, the addition average for every pixel was performed at the time of the prediction image generation | occurrence | production of 2 directions, However A weighted addition average etc. may be performed.

Next, the direct cost cost direct calculation method in step S302 in FIG. 6 will be described in detail with reference to FIG. FIG. 8 is a flowchart showing a processing flow for calculating the cost CostDirect in the direct mode.

The inter prediction control unit 109 calculates the direct vector 1 in the prediction direction 1 and the direct vector 2 in the prediction direction 2 (step S501). Here, the direct vector is calculated using, for example, a motion vector of an adjacent block. A specific example will be described with reference to FIG.

FIG. 9 is a diagram showing the relationship between the encoding target block, adjacent blocks, and motion vectors of adjacent blocks. In FIG. 9, the encoded block adjacent to the left of the encoding target block is adjacent block A, the encoded block adjacent above the encoding target block is adjacent block B, and the encoded block adjacent to the upper right of the encoding target block. Is an adjacent block C.

In FIG. 9, the adjacent block A is bi-directional prediction, and has a motion vector MvL0_A in the prediction direction 1 with respect to the reference picture indicated by the reference picture index RefIdxL0_A in the prediction direction 1, and the reference picture index RefIdxL1_A in the prediction direction 2 is The reference picture shown has a motion vector MvL1_A in the prediction direction 2. The adjacent block B is unidirectionally predicted and has a motion vector MvL0_B in the prediction direction 1 with respect to the reference picture indicated by the reference picture index RefIdxL0_B in the prediction direction 1. Also, the adjacent block C is unidirectional prediction, and has a motion vector MvL0_C in the prediction direction 1 with respect to the reference picture indicated by the reference picture index in the prediction direction 1.

In calculating the direct vector, first, the values of the reference picture index RefIdxL0 in the prediction direction 1 and the reference picture index RefIdxL1 in the prediction direction 2 of the encoding target block are determined. For example, in the direct mode, it is conceivable to always use the reference picture index RefIdxL0 and the reference picture index RefIdxL1 having the value “0”.

In this embodiment, the value “0” is always used as the reference picture index value of the encoding target block in the direct mode. However, the reference picture index value of the adjacent block or the like is referred to more frequently in the adjacent block. A reference picture index indicating the reference picture may be calculated. For example, in FIG. 9, when the possible values of each reference picture index are “0” or “1”, the median value of RefIdxL0_A, RefIdxL0_B, and RefIdxL0_C is used as the reference picture index RefIdxL0 in the prediction direction 1 of the current block. It can be calculated from (RefIdxL0_A, RefIdxL0_B, RefIdxL0_C). Here, the intermediate value is derived as in the following formulas 2 to 4.

The coding efficiency can be improved by improving the prediction accuracy of the direct vector by making the reference picture index of the block to be coded a reference picture index indicating a reference picture that has been referred to more frequently by neighboring blocks. In this example, an example in which a reference picture index indicating a reference picture that has been referred to more frequently in an adjacent block is obtained using an intermediate value is not necessarily limited thereto. For example, it may be calculated by checking the same relationship between the reference picture indexes of adjacent blocks. If the reference picture index values of adjacent blocks are all different, the reference picture index that represents the reference picture that is closest to the encoding target picture in the display order among the reference pictures indicated by each reference picture index is encoded. The reference picture index of the conversion target block may be used.

In addition, as a reference picture index value of the encoding target block in the direct mode, a reference picture index indicating a reference picture that is the closest in display order to the encoding target picture among reference pictures referenced in adjacent blocks is assigned. Also good. For example, in the case of FIG. 9, the reference picture index RefIdxL0 in the prediction direction 1 of the encoding target block is calculated from the minimum value Min (RefIdxL0_A, RefIdxL0_B, RefIdxL0_C) of RefIdxL0_A, RefIdxL0_B, and RefIdxL0_C. Here, the minimum value is derived as shown in Equation 5 below.

In general, a reference picture that is closer to the encoding target picture in display order is more likely to be assigned a smaller reference picture index value. Therefore, by obtaining the minimum value, the closest distance in display order to the encoding target picture is obtained. A reference picture index indicating a reference picture can be calculated. Note that the display order of each reference picture may be obtained from the reference picture index of the adjacent block and the reference picture list, and the reference picture index indicating the reference picture closest to the encoding target picture may be calculated.

The direct vector is calculated from the calculated reference picture index of the encoding target block, the motion vector of the adjacent block, and the reference picture index. For example, it is calculated from median values (MvL0_A, MvL0_B, MvL0_C) of MvL0_A, MvL0_B, and MvL0_C that are motion vectors of adjacent blocks. The direct vector 1 in the prediction direction 1 is calculated from Equation 2 using the motion vector in the prediction direction 1 of the adjacent block. Further, the direct vector 2 in the prediction direction 2 is calculated from Equation 2 using the motion vector in the prediction direction 2 of the adjacent block. Here, when the value of the reference picture index of the current block is different from the value of the reference picture index of the adjacent block, the intermediate value may be calculated using the motion vector of the adjacent block as the motion vector of the value “0”.

Also, if there is no adjacent block having the same reference picture index value as the reference picture index value of the encoding target block, a motion vector having a value “0” or the like may be used as the direct vector.

Next, the inter prediction control unit 109 generates a prediction image in two directions using the obtained direct vector 1 and direct vector 2, and calculates the cost CostDirectBi from Equation 1 (step S502). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image. The inter prediction control unit 109 generates a prediction image in the prediction direction 1 using the obtained direct vector 1, and calculates the cost CostDirectUni1 from Equation 1 (step S503). The inter prediction control unit 109 generates a prediction image in the prediction direction 2 using the obtained direct vector 2, and calculates the cost CostDirectUni2 from Equation 1 (step S504). Next, the inter prediction control unit 109 compares the values of the cost CostDirectUni1, the cost CostDirectUni2, and the cost CostDirectBi, and determines whether or not the cost CostDirectBi is the minimum (step S505). If the cost CostDirectBi is the minimum as a result of this determination (Yes in step S505), the inter prediction control unit 109 determines the prediction direction of the direct mode to be bi-directional prediction, and sets the cost CostDirctBi to the cost CostDirect of the direct mode. (Step S506). On the other hand, if the cost CostDirectBi is not the minimum (No in step S505), the inter prediction control unit 109 compares the cost CostDirectUni1 and the cost CostDirectUni2, and determines whether or not the value of the cost CostDirectUni1 is small (step S507). If the value of cost CostDirectUni1 is small as a result of this determination (Yes in step S507), the inter prediction control unit 109 determines the direct mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostDirectUni1 as the cost CostDirect in the direct mode. It sets (step S508). On the other hand, if the value of cost CostDirectUni1 is not small (No in step S507), the inter prediction control unit 109 determines the direct mode as one-way prediction 2 in the prediction direction 2, and sets the cost and CostDirectUni2 as the cost CostDirect of the direct mode. (Step S509).

Next, a method for calculating the cost CostSkip in step S303 in FIG. 6 will be described in detail with reference to FIG. FIG. 10 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode.

The inter prediction control unit 109 determines whether or not the skip mode prediction direction flag determined by the skip mode prediction direction determination unit 112 is unidirectional prediction (step S601). As a result of this determination, if the skip mode prediction direction flag is unidirectional prediction (Yes in step S601), the inter prediction control unit 109 uses the direct vector 1 obtained in step S501 of FIG. 8 to predict the prediction direction 1. An image is generated, and the cost CostSkip of the skip mode is calculated from Equation 1 (step S602). On the other hand, if the skip mode prediction direction flag is not unidirectional prediction (No in step S601), the inter prediction control unit 109 uses the direct vector 1 and the direct vector 2 obtained in step S501 of FIG. A predicted image is generated, and the cost CostSkip in the skip mode is calculated from Equation 1 (step S603). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image.

In the present embodiment, when the skip mode prediction direction flag is unidirectional prediction, an example of generating a prediction image of unidirectional prediction using the direct vector 1 has been described. A prediction image for unidirectional prediction may be generated using the vector 2.

In the present embodiment, as an example of calculating a direct vector, an example of calculating an intermediate value Median (MvL0_A, MvL0_B, MvL0_C) of MvL0_A, MvL0_B, and MvL0_C has been described, but is not limited to this calculation method. For example, a predicted motion vector having the smallest Cost is selected as a direct vector used for encoding from a plurality of predicted motion vector candidates, and a predicted motion vector index representing the selected predicted motion vector is attached to the bitstream. I do not care. Here, Cost is calculated using Equation 1, for example. In this way, by selecting a direct vector used for encoding from a plurality of candidates, it is possible to derive a direct vector having a smaller Cost. FIG. 11A is a diagram illustrating an example of a motion vector predictor candidate. The predicted motion vector index value is “0” for a value corresponding to Median (MvL0_A, MvL0_B, MvL0_C), “1” for a value corresponding to the motion vector MvL0_A, and “2” for a value corresponding to MvL0_B. The value corresponding to MvL0_C is “3”. The method of assigning the motion vector predictor index is not limited to this example. FIG. 11B shows an example of a code table used when the motion vector predictor index corresponding to the motion vector predictor candidate having the smallest Cost is subjected to variable length coding. Codes with short code lengths are assigned in ascending order of predicted motion vector index values. Therefore, it is possible to improve the encoding efficiency by reducing the value of the motion vector predictor index corresponding to a motion vector predictor candidate that is likely to have good prediction accuracy.

Also, in the present embodiment, an example is shown in which the reference picture index and motion vector of adjacent block A, adjacent block B, and adjacent block C in FIG. However, this is not necessarily the case. For example, as shown in FIG. 12, an adjacent block D or an adjacent block E may be used. For example, since the reference picture index in the prediction direction 1 of the adjacent block C is different from the reference picture index in the prediction direction 1 of the encoding target block, when the motion vector in the prediction direction 1 of the adjacent block C is not used, It is conceivable to use the adjacent block D or the adjacent block E instead. Also in this case, the motion vector of the adjacent block D or the adjacent block E is used depending on whether the reference picture index in the prediction direction 1 of the adjacent block D or the adjacent block E matches the reference picture index of the encoding target block. You can decide whether or not.

As described above, according to the present embodiment, when determining the prediction direction of the skip mode, it is possible to select the optimal prediction direction for the block to be encoded, so that the encoding efficiency can be improved. Become. In particular, when the reference picture index allocation for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the quality of the predicted image is improved by selecting the one-way prediction regardless of the prediction direction of the adjacent block. And encoding efficiency can be improved.

(Embodiment 2)
FIG. 13 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. The moving picture coding apparatus 200 according to the present embodiment newly includes a skip mode prediction direction addition determination unit instead of the skip mode prediction direction determination unit according to the first embodiment. When the skip mode prediction direction addition flag is on, the configuration is different from that of the first embodiment in that the inter prediction direction is attached to each encoding target block even in the skip mode. In addition, about the structure similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The skip mode prediction direction addition determination unit 201 uses the reference picture lists 1 and 2 created by the reference picture list management unit 111 to set the inter prediction direction for each encoding target block even in the skip mode by a method described later. It is determined whether to accompany it.

FIG. 14 is a flowchart showing an outline of the processing flow of the moving picture encoding method according to the present invention.

The skip mode prediction direction addition determination unit 201 determines whether or not to add a prediction direction when the encoding target block is encoded in the skip mode, and turns on the skip mode prediction direction addition flag when adding. (Step S701). The inter prediction control unit 109 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a skip mode. The cost comparison of the skip mode which produces | generates a prediction image using the prediction motion vector produced | generated according to the prediction direction added by the prediction direction addition determination part 201 is performed, and more efficient inter prediction mode is determined (step S702). Here, Formula 1 etc. are utilized for the cost calculation method. Next, the inter prediction control unit 109 determines whether or not the determined inter prediction mode is a skip mode (step S703). If the inter prediction mode is the skip mode as a result of this determination (Yes in step S703), the inter prediction control unit 109 determines whether or not the skip mode prediction direction addition flag is on (step S704). If the result of this determination is that the skip mode prediction direction addition flag is on (Yes in step S704), the inter prediction control unit 109 generates a predicted image in skip mode and sets the skip flag to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. Further, the inter prediction control unit 109 outputs the inter prediction direction flag in the skip mode to the variable length coding unit 113 in order to accompany the bit stream (step S705). On the other hand, if the inter prediction mode is not the skip mode (No in step S704), a predicted image in the skip mode is generated and the skip flag is set to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block (step S706). If the result of determination in step S703 is that the skip mode prediction direction addition flag is not on (No in step S703), the inter prediction control unit 109 performs inter prediction according to the determined inter prediction mode to generate predicted image data. The skip flag is set to 0. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. Further, the inter prediction control unit 109 outputs an inter prediction mode and an inter prediction direction flag indicating whether the motion vector detection mode or the direct mode is associated with the bit stream of the encoding target block to the variable length encoding unit 113. (Step S707).

FIG. 15 is a flowchart showing a determination flow of the skip mode prediction direction addition flag in the skip mode prediction direction addition determination unit 201.

In general, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, motion vectors in the prediction direction 1 and the prediction direction 2 are selected in the two-way prediction. In the direction prediction, only the motion vector in the prediction direction 1 may be used, and the motion vector in the prediction direction 2 may decrease as a whole. For example, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the unidirectional prediction using the reference picture list 2 is prohibited, thereby encoding the inter prediction direction flag code. Coding efficiency can be improved by reducing the amount. In this case, since only the motion vector in the prediction direction 1 is used in the unidirectional prediction, the motion vector in the prediction direction 2 is reduced as a whole. In this case, when bi-directional prediction is selected as the prediction direction of the skip mode, there is a tendency that there are few motion vectors in the prediction direction 2 of the adjacent blocks that can be used for generation of the prediction motion vector in the prediction direction 2. There is a possibility that the accuracy of the predicted motion vector will be low. Therefore, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the prediction direction vector of the prediction direction 2 is obtained by attaching the prediction direction of the skip mode to the stream. When the accuracy is low, one-way prediction can be selected, and when the accuracy of the prediction motion vector in the prediction direction 2 is high, bi-directional prediction can be selected, and the coding efficiency can be improved.

The skip mode prediction direction addition determination unit 201 uses the reference picture list 1 and the reference picture list 2 to determine whether the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2. (Step S801). For example, the display order of the reference picture indicated by each reference picture index 1 is obtained from the reference picture list 1, and compared with the display order of the reference picture indicated by each reference picture index 2 from the reference picture list 2. It can be determined that they are the same. As a result of this determination, if the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2 (Yes in step S801), the skip mode prediction direction addition determination unit 201 determines the skip mode. Is set to ON (step S802). On the other hand, if the reference picture index assignment for each reference picture is not the same in the reference picture list 1 and the reference picture list 2 (No in step S801), the skip mode prediction direction addition determination unit 201 determines the prediction direction of the skip mode. The additional flag is set to off (step S803).

In the present embodiment, it is determined in step S801 whether the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 using the display order. You may determine using order etc.

Also, in this embodiment, when the reference picture index assignment to each reference picture is the same in reference picture list 1 and reference picture list 2, the skip direction prediction direction addition flag is turned on. When the reference picture indicated by the reference picture index 1 in the prediction direction 1 in the skip mode of the block and the reference picture indicated by the reference picture index 2 in the prediction direction 2 are the same picture, the prediction direction addition flag in the skip mode is turned on. It may be. For example, the display order of the reference picture indicated by the reference picture index 1 is obtained from the reference picture list 1 and is compared with the display order of the reference picture indicated by the reference picture index 2 from the reference picture list 2. it can. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, by attaching the prediction direction of the skip mode to the stream, when the accuracy of the prediction motion vector of the prediction direction 2 is low, the one-way prediction is selected, and the prediction motion vector of the prediction direction 2 is selected. When the accuracy is high, bi-directional prediction can be selected, and coding efficiency can be improved.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two previously encoded pictures whose encoding target picture is ahead, the prediction direction of the skip mode is fixed to uni-directional prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, or the prediction direction 1 reference in the skip mode of the encoding target block In some cases, the reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 are the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, by attaching the prediction direction of the skip mode to the stream, when the accuracy of the prediction motion vector of the prediction direction 2 is low, the one-way prediction is selected, and the prediction motion vector of the prediction direction 2 is selected. When the accuracy is high, bi-directional prediction can be selected, and coding efficiency can be improved.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two already encoded pictures that are behind the encoding target picture, the prediction direction of the skip mode is fixed to unidirectional prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, and the reference in the prediction direction 1 in the skip mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 is reduced, by attaching the prediction direction of the skip mode to the stream, when the accuracy of the prediction motion vector of the prediction direction 2 is low, the one-way prediction is selected, and the prediction motion vector of the prediction direction 2 is selected. When the accuracy is high, bi-directional prediction can be selected, and coding efficiency can be improved.

Next, a method for calculating the cost CostSkip in the skip mode in the present embodiment will be described in detail with reference to FIG. FIG. 16 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode. Note that the determination flow of the inter prediction mode, the cost CostInter of the motion vector detection mode, and the calculation method of the cost CostDirect of the direct mode are the same as those in FIG. 6, FIG. 7, and FIG. To do.

Inter prediction control section 109 calculates direct vector 1 in prediction direction 1 and direct vector 2 in prediction direction 2 by the method described in the first embodiment. Then, using the obtained direct vector 1 and direct vector 2, a predicted image in two directions is generated, and the cost CostSkipBi is calculated from Equation 1 (step S901). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image. Next, the inter prediction control unit 109 determines whether or not the skip mode prediction direction addition flag is on (step S902). As a result of this determination, if the skip mode prediction direction addition flag is on (Yes in step S902), the inter prediction control unit 109 generates a prediction image in the prediction direction 1 using the direct vector 1, and its cost. CostSkipUni1 is calculated from Equation 1 (step S903). The inter prediction control unit 109 generates a prediction image in the prediction direction 2 using the direct vector 2, and calculates the cost CostSkipUni2 from Equation 1 (step S904). The inter prediction control unit 109 compares the values of the cost CostSkipUni1, the cost CostSkipUni2, and the cost CostSkipBi, and determines whether or not the cost CostSkipUni1 is the minimum (step S905). If the cost CostSkipUni1 is the minimum as a result of this determination (Yes in step S905), the inter prediction control unit 109 determines the skip mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostSkipUni1 as the cost CostSkip in the skip mode. Setting is made (step S906). On the other hand, if the cost CostSkipUni1 is not the minimum (No in step S905), the cost CostSkipUni2 and the cost CostSkipBi are compared to determine whether the value of the cost CostSkipUni2 is small (step S907). If the cost CostSkipUni2 value is small as a result of this determination (Yes in step S907), the inter prediction control unit 109 determines the skip mode as one-way prediction 2 in the prediction direction 2, and sets the cost CostSkipUni2 as the cost CostSkip in the skip mode. Setting is made (step S908). On the other hand, if the value of cost CostSkipUni2 is not small (No in step S907), and if the skip mode prediction direction addition flag is not on in the determination in step S902 (No in step S902), the inter prediction control unit 109 sets the skip mode. The bi-directional prediction is determined, and the cost CostSkipBi is set to the cost CostSkip in the skip mode (step S909).

As described above, according to the present embodiment, when determining the prediction direction of the skip mode, it is possible to select the optimal prediction direction for the block to be encoded, so that the encoding efficiency can be improved. Become. In particular, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the prediction direction is attached to the bitstream even in the skip mode regardless of the prediction direction of adjacent blocks. By selecting the optimal prediction direction for the block to be encoded, the quality of the predicted image can be improved and the encoding efficiency can be improved.

(Embodiment 3)
FIG. 17 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. The moving picture coding apparatus 300 according to the present embodiment includes header information (for example, H.264) that adds a skip mode prediction direction flag generated by a skip mode prediction direction determination unit to a bitstream for each processing unit such as a picture. The configuration differs from that of the first embodiment in that it is attached to a picture parameter set, a slice header, and the like. In addition, about the structure similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The skip mode prediction direction determination unit 301 determines the prediction mode of the skip mode of the block to be encoded, and sets a skip mode prediction direction flag, as in the first embodiment. Also, the skip mode prediction direction determination unit 301 adds the set skip mode prediction direction flag to the inter prediction control unit 109 and outputs the flag to the variable length coding unit 302.

The variable length coding unit 302 performs variable length coding processing on the quantized prediction error data, inter prediction mode, inter prediction direction flag, skip flag, picture type information, and skip mode prediction direction flag. A bit stream is generated.

FIG. 18 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention.

The skip mode prediction direction determination unit 301 determines a prediction direction when the block to be encoded is encoded in the skip mode, and a variable length encoding unit to attach the determined skip mode prediction direction flag to the picture header or the like It outputs to 302 (step S1001). Here, the method for determining the prediction direction of the skip mode is the same as the flow of FIG. 5 of the first embodiment. The inter prediction control unit 109 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a skip mode. The cost comparison of the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction determined by the prediction direction determination unit 301 is performed, and a more efficient inter prediction mode is determined (step S1002). Here, Formula 1 etc. are utilized for the cost calculation method. Next, the inter prediction control unit 109 determines whether or not the determined inter prediction mode is a skip mode (step S1003). As a result of this determination, if the inter prediction mode is the skip mode (Yes in step S1003), the inter prediction control unit 109 generates a predicted image in the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 302 in order to accompany the bit stream of the coding target block (step S1004). On the other hand, as a result of this determination, if the inter prediction mode is not the skip mode (No in step S1003), the inter prediction control unit 109 performs inter prediction according to the determined inter prediction mode, generates predicted image data, and skip flag. Is set to 0. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 302 in order to accompany the bit stream of the coding target block. Further, the inter prediction control unit 109 outputs an inter prediction mode and an inter prediction direction flag indicating whether the motion vector detection mode or the direct mode is associated with the bit stream of the encoding target block to the variable length encoding unit 302. (Step S1005). In addition, since the inter prediction mode determination method etc. are the same as that of Embodiment 1, description is abbreviate | omitted.

Thus, according to the present embodiment, since the skip mode prediction direction flag is explicitly added to the picture header or the like, the skip mode prediction direction can be flexibly switched for each picture. It is possible to improve the efficiency.

(Embodiment 4)
FIG. 19 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. The moving picture coding apparatus 400 according to the present embodiment includes header information (for example, H.264) that adds a skip mode prediction direction addition flag generated by the skip mode prediction direction addition determination unit to a bitstream for each processing unit such as a picture. H.264 picture parameter set, slice header, etc.) is different from the third embodiment. In addition, about the structure similar to Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The skip mode prediction direction addition determination unit 401 determines whether or not the inter prediction direction is attached to each encoding target block even in the skip mode as in the third embodiment, and sets a skip mode prediction direction addition flag. . Further, the skip mode prediction direction addition determination unit 401 adds the set skip mode prediction direction addition flag to the inter prediction control unit 109 and outputs the flag to the variable length coding unit 402.

The variable length coding unit 402 performs variable length coding processing on the quantized prediction error data, inter prediction mode, inter prediction direction flag, skip flag, picture type information, and skip mode prediction direction addition flag. Thus, a bit stream is generated.

FIG. 20 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention.

The skip mode prediction direction addition determination unit 401 determines whether or not to add a prediction direction when the encoding target block is encoded in the skip mode, and when adding, sets the skip mode prediction direction addition flag to ON. To do. Then, the skip mode prediction direction addition determination unit 401 outputs the set skip mode prediction direction addition flag to the variable length coding unit 402 in order to accompany the picture header or the like (step S1101). Here, the prediction direction addition determination method is the same as that in FIG. 15 of the second embodiment. The inter prediction control unit 109 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a skip mode. The cost comparison of the skip mode which produces | generates a predicted image using the prediction motion vector produced | generated according to the prediction direction added by the prediction direction addition determination part 401 is performed, and more efficient inter prediction mode is determined (step S1102). Here, Formula 1 etc. are utilized for the cost calculation method. Next, the inter prediction control unit 109 determines whether or not the determined inter prediction mode is the skip mode (step S1103). If the inter prediction mode is the skip mode as a result of this determination (Yes in step S1103), the inter prediction control unit 109 determines whether or not the skip mode prediction direction addition flag is on (step S1104). If the result of this determination is that the skip mode prediction direction addition flag is on (Yes in step S1104), the inter prediction control unit 109 generates a predicted image in skip mode and sets the skip flag to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. In addition, the inter prediction control unit 109 outputs the inter prediction direction flag in the skip mode to the variable length coding unit 113 in order to accompany the bit stream (step S1105). On the other hand, if the inter prediction mode is not the skip mode (No in step S1104), a predicted image in the skip mode is generated and the skip flag is set to 1. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 402 in order to accompany the bit stream of the coding target block (step S1106). If the result of determination in step S1103 is that the skip mode prediction direction addition flag is not on (No in step S1103), the inter prediction control unit 109 performs inter prediction according to the determined inter prediction mode, and generates predicted image data. The skip flag is set to 0. Then, the inter prediction control unit 109 outputs the skip flag to the variable length coding unit 402 so as to accompany the bit stream of the coding target block. In addition, the inter prediction control unit 109 outputs an inter prediction mode and an inter prediction direction flag indicating whether the motion vector detection mode or the direct mode is associated with the bit stream of the encoding target block to the variable length encoding unit 402. (Step S1107). In addition, since the inter prediction mode determination method etc. are the same as that of Embodiment 2, description is abbreviate | omitted.

Thus, according to the present embodiment, since the skip mode prediction direction addition flag is explicitly added to the picture header or the like, whether to add the prediction mode of the skip mode can be flexibly switched for each picture. As a result, encoding efficiency can be improved.

(Embodiment 5)
FIG. 21 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention.

As shown in FIG. 21, the moving picture decoding apparatus 500 includes a variable length decoding unit 501, an inverse quantization unit 502, an inverse orthogonal transform unit 503, a block memory 504, a frame memory 505, an intra prediction unit 506, and an inter prediction unit. 507, an inter prediction control unit 508, a reference picture list management unit 509, and a skip mode prediction direction determination unit 510.

The variable length decoding unit 501 performs a variable length decoding process on the input bitstream, and performs the picture type information, the inter prediction mode, the inter prediction direction, the skip flag, and the quantized coefficient that has been subjected to the variable length decoding process. Is generated. The inverse quantization unit 502 performs inverse quantization processing on the quantized coefficients that have been subjected to variable length decoding processing. The inverse orthogonal transform unit 503 transforms the orthogonal transform coefficient that has been subjected to the inverse quantization process from the frequency domain to the image domain to obtain prediction error image data. The block memory 504 stores prediction error image data and an image sequence generated by adding the prediction image data in units of blocks. The frame memory 505 stores the image sequence in units of frames. The intra prediction unit 506 generates predicted image data of the decoding target block by performing intra prediction using the block-by-block image sequence stored in the block memory 504. The inter prediction unit 507 generates predicted image data of the decoding target block by performing inter prediction using the frame-by-frame image sequence stored in the frame memory 505. The inter prediction control unit 508 controls the motion vector and the prediction image data generation method in the inter prediction according to the inter prediction mode, the inter prediction direction flag, and the skip flag.

The reference picture list management unit 509 assigns a reference picture index to an encoded reference picture that is referred to in inter prediction, and creates a reference picture list together with a display order and the like. Since B picture can be encoded with reference to two pictures, it holds two reference picture lists.

The skip mode prediction direction determination unit 510 uses the reference picture list 1 and the reference picture list 2 created by the reference picture list management unit 509 to determine the prediction direction of the skip mode of the encoding target block. Note that the flow for determining the skip mode prediction direction flag is the same as that in FIG.

Finally, a decoded image sequence is generated by adding the decoded prediction error image data and the prediction image data.

FIG. 22 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 508 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 501 is 1 (step S1201). If the result of this determination is that the skip flag is 1 (Yes in step S1201), the inter prediction control unit 508 determines whether or not the skip mode prediction direction flag decoded by the variable length decoding unit 501 is one-way prediction. Is determined (step S1202). If the result of this determination is that the skip mode prediction direction flag is unidirectional prediction (Yes in step S1202), the inter prediction control unit 508 calculates the direct vector 1 by the same method as in step S501 in FIG. A predicted image is generated (step S1203). On the other hand, if the skip mode prediction direction flag is not unidirectional prediction (No in step S1202), the inter prediction control unit 508 calculates the direct vector 1 and the direct vector 2 by the same method as step S501 in FIG. A direction prediction image is generated (step S1204). On the other hand, if the skip flag is not 1 in the determination in step S1201, that is, if it is not the skip mode (No in step S1201), the inter prediction control unit 508 indicates that the inter prediction mode decoded by the variable length decoding unit 501 is a motion vector. It is determined whether or not the detection mode is set (step S1205). As a result of this determination, if the inter prediction mode is the motion vector detection mode (Yes in step S1205), the inter prediction control unit 508 uses the inter prediction direction flag and the motion vector decoded by the variable length decoding unit 501. A predicted image is generated (step S1206). On the other hand, if the inter prediction mode is not the motion vector detection mode, that is, if it is the direct mode (No in step S1205), the inter prediction control unit 508 uses the same method as step S501 in FIG. 8 according to the inter prediction direction flag. To calculate the direct vector 1 and the direct vector 2, and generate a predicted image (step S1208).

In the present embodiment, in step S1203 in FIG. 22, the unidirectional prediction image in the skip mode is generated using the direct vector 1, but the direct vector 2 is used together with the moving image encoding method. A direction prediction image may be generated.

FIG. 23 is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. In FIG. 23, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag.

In this embodiment, the direct vector is calculated by the same method as in step S501 in FIG. 8, but a candidate list composed of a plurality of motion vector predictor candidates is created as shown in FIG. 11A. A prediction motion vector index may be extracted from the stream, and a prediction motion vector candidate indicated by the prediction motion vector index among prediction motion vector candidates in the candidate list may be used as a direct vector for decoding.

Thus, according to the present embodiment, when the reference picture index assignment to each reference picture is the same in reference picture list 1 and reference picture list 2, one-way prediction is performed regardless of the prediction direction of adjacent blocks. By selecting, it becomes possible to appropriately decode a bit stream with improved encoding efficiency.

(Embodiment 6)
FIG. 24 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. The moving picture decoding apparatus 600 according to the present embodiment newly includes a skip mode prediction direction addition determination unit instead of the skip mode prediction direction determination unit according to the fifth embodiment. When the skip mode prediction direction addition flag is on, the configuration is different from that of the fifth embodiment in that a bitstream with an inter prediction direction associated with each encoding target block can be decoded even in the skip mode. In addition, about the structure similar to Embodiment 5, the same code | symbol is attached | subjected and description is abbreviate | omitted. The skip mode prediction direction addition determination flow is the same as that in FIG.

The skip mode prediction direction addition determination unit 601 uses the reference picture lists 1 and 2 created by the reference picture list management unit 509 to set the inter prediction direction for each encoding target block even in the skip mode using the method described later. It is determined whether to accompany it.

FIG. 25 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 603 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 602 is 1 (step S1301). As a result of this determination, if the skip flag is 1 (Yes in step S1301), the inter prediction control unit 603 determines whether or not the skip mode prediction direction addition flag decoded by the variable length decoding unit 602 is on. Determination is made (step S1302). If the result of this determination is that the skip mode prediction direction addition flag is on (Yes in step S1302), the variable length decoding unit 602 decodes the inter prediction direction flag. Then, the inter prediction control unit 603 calculates at least one of the direct vector 1 and the direct vector 2 according to the decoded inter prediction direction flag, and generates a prediction image in one direction or two directions (step S1303). On the other hand, if the skip mode prediction direction addition flag is not on (No in step S1302), the inter prediction control unit 603 calculates the direct vector 1 and the direct vector 2 to generate a bi-directional prediction image (step S1304). On the other hand, if the skip flag is not 1 in the determination in step S1301, that is, if it is not the skip mode (No in step S1301), the inter prediction control unit 603 determines that the inter prediction mode decoded by the variable length decoding unit 602 is a motion vector. It is determined whether or not the detection mode is set (step S1305). As a result of this determination, if the inter prediction mode is the motion vector detection mode (Yes in step S1305), the inter prediction control unit 603 uses the inter prediction direction flag and the motion vector decoded by the variable length decoding unit 602. A predicted image is generated (step S1306). On the other hand, if the inter prediction mode is not the motion vector detection mode, that is, if it is the direct mode (No in step S1305), the inter prediction control unit 603 calculates the direct vector 1 and the direct vector 2 according to the inter prediction direction flag. Then, a predicted image is generated (step S1307).

FIG. 26 is a diagram showing an example of the bitstream syntax in the moving picture decoding method according to the present invention. In FIG. 26, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag.

As described above, according to the present embodiment, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, even in the skip mode regardless of the prediction direction of adjacent blocks. By attaching the prediction direction to the bitstream, it is possible to appropriately decode the bitstream with improved encoding efficiency.

(Embodiment 7)
FIG. 27 is a block diagram showing a configuration of an embodiment of a video decoding device using the video decoding method according to the present invention. The moving picture decoding apparatus 700 according to the present embodiment includes header information (for example, H.264) that gives the skip mode prediction direction flag generated by the skip mode prediction direction determination unit to the bitstream for each processing unit such as a picture. The configuration is different from that of the fifth embodiment in that a bitstream attached to a picture parameter set or a slice header can be decoded. In addition, about the structure similar to Embodiment 5, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 28 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 702 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 701 is 1 (step S1401). If the result of this determination is that the skip flag is 1 (Yes in step S1401), the inter prediction control unit 702 determines whether or not the skip mode prediction direction flag decoded from the bitstream by the variable length decoding unit 701 is one-way prediction. Is determined (step S1402). As a result of this determination, if the skip mode prediction direction flag is unidirectional prediction (Yes in step S1402), the inter prediction control unit 702 calculates the direct vector 1 and generates a unidirectional prediction image (step S1403). On the other hand, if the skip mode prediction direction flag is not unidirectional prediction (No in step S1402), the inter prediction control unit 702 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S1404). . On the other hand, if the skip flag is not 1 in the determination in step S1401, that is, if it is not the skip mode (No in step S1401), the inter prediction control unit 702 indicates that the inter prediction mode decoded by the variable length decoding unit 701 is a motion vector. It is determined whether or not the detection mode is set (step S1405). If the inter prediction mode is the motion vector detection mode as a result of this determination (Yes in step S1405), the inter prediction control unit 702 uses the inter prediction direction flag and the motion vector decoded by the variable length decoding unit 701. A predicted image is generated (step S1406). On the other hand, if the inter prediction mode is not the motion vector detection mode, that is, if it is the direct mode (No in step S1405), the inter prediction control unit 702 calculates the direct vector 1 and the direct vector 2 according to the inter prediction direction flag. Then, a predicted image is generated (step S1408).

In this embodiment, in step S1403 in FIG. 28, the one-way predicted image in the skip mode is generated using the direct vector 1, but the direct vector 2 is used together with the moving image encoding method. A direction prediction image may be generated.

FIG. 29A and FIG. 29B are diagrams illustrating an example of the bitstream syntax in the moving picture decoding method according to the present invention. 29A and 29B, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag. Further, skip_pred_idc added to the picture header or the like represents a skip flag prediction direction flag.

Thus, according to the present embodiment, the coding efficiency is improved by flexibly switching the prediction direction of the skip mode for each picture by explicitly adding the skip mode prediction direction flag to the picture header or the like. It is possible to appropriately decode the generated bit stream.

(Embodiment 8)
FIG. 30 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. The moving picture decoding apparatus 800 according to the present embodiment includes header information (for example, H.264) that adds a skip mode prediction direction addition flag generated by the skip mode prediction direction addition determination unit to a bitstream for each processing unit such as a picture. H.264 picture parameter set, slice header, etc.), and the bit stream can be decoded. In addition, about the structure similar to Embodiment 5, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 31 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 802 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 801 is 1 (step S1501). If the result of this determination is that the skip flag is 1 (Yes in step S1501), the inter prediction control unit 802 determines whether the skip mode prediction direction addition flag decoded from the bitstream by the variable length decoding unit 801 is on. It is determined whether or not (step S1502). If the result of this determination is that the skip mode prediction direction addition flag is on (Yes in step S1502), the inter prediction control unit 802 decodes the inter prediction direction flag, and determines the direct vector 1 according to the decoded inter prediction direction. At least one of the direct vectors 2 is calculated, and a prediction image in one direction or two directions is generated (step S1503). On the other hand, if the skip mode prediction direction addition flag is not on (No in step S1502), the inter prediction control unit 802 calculates a direct vector 1 and a direct vector 2 to generate a bi-directional prediction image (step S1504). On the other hand, if the skip flag is not 1 in the determination in step S1501, that is, if it is not the skip mode (No in step S1501), the inter prediction control unit 802 indicates that the inter prediction mode decoded by the variable length decoding unit 801 is a motion vector. It is determined whether or not the detection mode is set (step S1505). As a result of the determination, if the inter prediction mode is the motion vector detection mode (Yes in step S1505), the inter prediction control unit 802 uses the inter prediction direction flag and the motion vector decoded by the variable length decoding unit 801. A predicted image is generated (step S1506). On the other hand, if the inter prediction mode is not the motion vector detection mode, that is, if it is the direct mode (No in step S1505), the inter prediction control unit 802 calculates the direct vector 1 and the direct vector 2 according to the inter prediction direction flag. Then, a predicted image is generated (step S1507).

32A and 32B are diagrams showing an example of the syntax of the bitstream in the moving picture decoding method according to the present invention. 32A and 32B, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag. Further, skip_add_dir added to the picture header or the like represents a skip flag prediction direction addition flag.

As described above, according to the present embodiment, whether or not to add the prediction direction of the skip mode can be flexibly switched for each picture by explicitly adding the skip mode prediction direction addition flag to the picture header or the like. Thus, it becomes possible to appropriately decode the bit stream with improved encoding efficiency.

(Embodiment 9)
FIG. 33 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention.

As shown in FIG. 33, the moving picture coding apparatus 900 includes an orthogonal transform unit 101, a quantization unit 102, an inverse quantization unit 103, an inverse orthogonal transform unit 104, a block memory 105, a frame memory 106, an intra prediction unit 107, An inter prediction unit 108, an inter prediction control unit 902, a picture type determination unit 110, a reference picture list management unit 111, a direct mode prediction direction determination unit 901, and a variable length encoding unit 113 are provided.

The reference picture list management unit 111 assigns a reference picture index to an encoded reference picture that is referred to in inter prediction, and creates a reference picture list together with a display order and the like. Since B picture can be encoded with reference to two pictures, it holds two reference picture lists. In this embodiment, the reference picture is managed in the reference picture index and the display order. However, the reference picture may be managed in the reference picture index and the encoding order.

The direct mode prediction direction determination unit 901 uses the reference picture lists 1 and 2 created by the reference picture list management unit 111 to determine the direct mode prediction direction of the block to be encoded by a method described later.

FIG. 34 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention.

The direct mode prediction direction determination unit 901 determines a prediction direction when the encoding target block is encoded in the direct mode (step S1601). The inter prediction control unit 902 includes a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result, a direct mode for generating a predicted image using a predicted motion vector generated from an adjacent block, and a direct mode. The cost comparison of the skip mode for generating a prediction image using the prediction motion vector generated according to the prediction direction determined by the prediction direction determination unit 901 is performed, and a more efficient inter prediction mode is determined (step S1602). The cost calculation method will be described later. Next, the inter prediction control unit 902 determines whether or not the determined inter prediction mode is a skip mode (step S1603). As a result of this determination, if the inter prediction mode is the skip mode (Yes in step S1603), the inter prediction control unit 902 generates a predicted image in the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block (step S1604). On the other hand, as a result of this determination, if the inter prediction mode is not the skip mode (No in step S1603), the inter prediction control unit 902 indicates that the determined inter prediction mode is the direct mode and the direct mode prediction direction determined by the method described later. It is determined whether or not the fixed flag is on (step S1605). As a result of this determination, if the inter prediction mode is the direct mode and the direct mode prediction direction fixed flag is on (Yes in step S1605), the inter prediction control unit 902 generates a direct mode bi-directional prediction image and skips it. Set the flag to 0. Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. Also, the inter prediction control unit 902 outputs an inter prediction mode indicating the motion vector detection mode or the direct mode to the variable length coding unit 113 so as to accompany the bit stream of the coding target block (step S1606). On the other hand, if the inter prediction mode is the direct mode and the direct mode prediction direction fixed flag is not on (No in step S1605), the inter prediction is performed according to the determined inter prediction mode, predictive image data is generated, and the skip flag is set to 0. And Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 113 in order to accompany the bit stream of the coding target block. In addition, the inter prediction control unit 902 includes an inter prediction mode indicating whether the motion vector detection mode or the direct mode, and a one-way prediction in which the inter prediction direction is the prediction direction 1, or a one-way prediction in the prediction direction 2, or a prediction direction. An inter prediction direction flag indicating whether or not bi-directional prediction using 1 and prediction direction 2 is output to the variable-length encoding unit 113 in order to accompany the bit stream of the encoding target block (step S1608).

FIG. 35 is a flowchart showing a flow of determining the direct mode prediction direction in the direct mode prediction direction determination unit.

In general, when the reference picture index allocation to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the cost of the two-way prediction and the one-way prediction tends to be relatively close, and thus either By fixing to one prediction direction, it is not necessary to accompany the inter prediction direction flag for each encoding target block. In the present embodiment, the following description will be given using an example in which prediction is fixed to bi-directional prediction that can generate a prediction image with relatively little noise due to the influence of addition averaging or the like. In the case of an image with little influence of noise or the like, it may be fixed to unidirectional prediction from the viewpoint of processing amount.

The direct mode prediction direction determination unit 901 uses the reference picture lists 1 and 2 to determine whether or not the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 ( Step S1701). For example, the display order of the reference picture indicated by each reference picture index 1 is obtained from the reference picture list 1, and compared with the display order of the reference picture indicated by each reference picture index 2 from the reference picture list 2. It can be determined that they are the same. As a result of this determination, if the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 (Yes in step S1701), the direct mode prediction direction determination unit 901 determines the direct mode. Is determined to be bi-directional prediction, and the direct mode prediction direction fixed flag is set to ON (step S1702). On the other hand, if the reference picture index assignment to each reference picture is not the same in the reference picture list 1 and the reference picture list 2 (No in step S1701), the direct mode prediction direction fixed flag is set to off (step S1703). .

In this embodiment, it is determined in step S1701 whether the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 using the display order. You may determine using order etc.

Also, in this embodiment, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the direct mode prediction direction is determined to be bi-directional prediction, and the direct mode prediction is performed. The direction fixed flag is set to ON, but the reference picture indicated by the reference picture index 1 in the prediction direction 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 in the direct mode of the current block are the same picture In this case, the direct mode prediction direction may be determined to be bi-directional prediction, and the direct mode prediction direction fixed flag may be set to ON. For example, the display order of the reference picture indicated by the reference picture index 1 is obtained from the reference picture list 1 and is compared with the display order of the reference picture indicated by the reference picture index 2 from the reference picture list 2. it can. Even in such a case, the costs of the bi-directional prediction and the uni-directional prediction tend to be relatively close. Therefore, the inter-prediction direction flag is attached to each encoding target block by fixing to one of the prediction directions. This is unnecessary, and the encoding efficiency can be improved.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two previously encoded pictures whose encoding target picture is ahead, the direct mode prediction direction is determined to be bi-directional prediction, and the direct mode You may make it set a prediction direction fixed flag to ON. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, or the reference in the prediction direction 1 in the direct mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the costs of the bi-directional prediction and the uni-directional prediction tend to be relatively close. Therefore, the inter-prediction direction flag is attached to each encoding target block by fixing to one of the prediction directions. This is unnecessary, and the encoding efficiency can be improved.

Further, in the case of a B picture that generates a bi-directional prediction image with reference to two already encoded pictures that are behind the current picture to be encoded, the direct mode prediction direction is determined to be bi-directional prediction, and the direct mode You may make it set a prediction direction fixed flag to ON. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, or the reference in the prediction direction 1 in the direct mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the costs of the bi-directional prediction and the uni-directional prediction tend to be relatively close. Therefore, the inter-prediction direction flag is attached to each encoding target block by fixing to one of the prediction directions. This is unnecessary, and the encoding efficiency can be improved.

FIG. 36 is a flowchart showing the determination flow of the inter prediction mode in the inter prediction control unit.

The inter prediction control unit 902 calculates a cost CostInter in a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result by a method described later (step S1801). The inter prediction control unit 902 generates a prediction vector using a motion vector such as an adjacent block in accordance with the direct mode prediction direction fixed flag determined by the direct mode prediction direction determination unit 901, and generates a prediction image using the prediction vector. The cost CostDirect of the direct mode to be calculated is calculated by the method described later (step S1802). The inter prediction control unit 902 calculates the cost CostSkip in the skip mode in which the predicted image at the position indicated by the motion vector predicted from the peripheral block or the like is the decoded image as it is (step S1803). The inter prediction control unit 902 compares the cost CostInter of the motion vector detection mode, the cost CostDirect of the direct mode, and the cost CostSkip of the skip mode, and determines whether or not the cost CostInter of the motion vector detection mode is the minimum (step S1804). ). If the cost CostInter of the motion vector detection mode is the minimum as a result of this determination (Yes in step S1804), the inter prediction control unit 902 determines the inter prediction mode as the motion vector detection mode, and sets the inter prediction mode to the motion vector detection mode. (Step S1805). On the other hand, if the cost CostInter of the motion vector detection mode is not minimum (No in step S1804), the inter prediction control unit 902 compares the cost CostDirect of the direct mode with the cost CostSkip of the skip mode, and whether the cost CostDirect of the direct mode is small. It is determined whether or not (step S1806). If the cost CostDirect of the direct mode is small as a result of this determination (Yes in step S1806), the inter prediction control unit 902 determines the inter prediction mode to be the direct mode, and sets the inter prediction mode to the direct mode (step S1807). . On the other hand, if the cost CostDirect of the direct mode is not small, the inter prediction control unit 902 sets the inter prediction mode to the skip mode and sets the skip mode to the inter prediction mode (step S1808).

Next, a method for calculating the cost CostInter in the motion vector detection mode in step S1801 in FIG. 36 will be described in detail with reference to FIG. FIG. 37 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode.

The inter prediction control unit 902 performs motion detection on the reference picture 1 indicated by the reference picture index 1 in the prediction direction 1 and the reference picture 2 indicated by the reference picture index 2 in the prediction direction 2, and the motion vector for each reference picture 1 and motion vector 2 are generated (step S1901). Here, in motion detection, a difference value between a coding target block in a coded picture and a block in a reference picture is calculated, and a block in the reference picture having the smallest difference value is set as a reference block. Then, a motion vector is obtained from the encoding target block position and the reference block position. Next, the inter prediction control unit 902 generates a prediction image in the prediction direction 1 using the obtained motion vector 1, and calculates the cost CostInterUni1 by, for example, Equation 1 of the RD optimization model (step S1). S1902).

The inter prediction control unit 902 generates a prediction image in the prediction direction 2 using the motion vector 2, and calculates the cost CostInterUni2 from Equation 1 (step S1903). The inter prediction control unit 902 generates a prediction image in two directions using the obtained motion vector 1 and motion vector 2, and calculates the cost CostInterBi from Equation 1 (step S1904). Here, the bi-directional predicted image is, for example, a bi-directional predicted image obtained by performing addition averaging for each pixel of the predicted image obtained from the motion vector 1 and the predicted image obtained from the motion vector 2. Next, the inter prediction control unit 902 compares the values of the cost CostInterUni1, the cost CostInterUni2, and the cost CostInterBi, and determines whether or not the cost CostInterBi is the minimum (step S1905). If the cost CostInterBi is the minimum as a result of this determination (Yes in step S1905), the inter prediction control unit 902 determines the prediction direction of the motion vector detection mode to be bi-directional prediction, and uses the cost CostInterBi as the cost of the motion vector detection mode. Set to CostInter (step S1906). On the other hand, if the cost CostInterBi is not minimum (No in step S1905), the inter prediction control unit 902 compares the cost CostInterUni1 and the cost CostInterUni2 and determines whether or not the value of the cost CostInterUni1 is small (step S1907). If the cost CostInterUni1 value is small as a result of this determination (Yes in step S1907), the inter prediction control unit 902 determines the motion vector detection mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostInterUni1 as the motion vector detection mode. To the cost CostInter (step S1908). On the other hand, if the value of cost CostInterUni1 is not small (No in step S1907), inter prediction control section 902 determines the motion vector detection mode as one-way prediction 2 in prediction direction 2, and uses cost CostInterUni2 as the cost of motion vector detection mode. Set to CostInter (step S1909).

Next, the direct cost cost direct calculation method in step S1802 in FIG. 36 will be described in detail with reference to FIG. FIG. 38 is a flowchart showing a processing flow for calculating the cost CostDirect in the direct mode.

The inter prediction control unit 902 calculates the direct vector 1 in the prediction direction 1 and the direct vector 2 in the prediction direction 2 (step S2001). Here, the direct vector is calculated, for example, by the method described in step S501 of FIG. 8 of the first embodiment. The inter prediction control unit 902 generates a prediction image in two directions using the obtained direct vector 1 and direct vector 2, and calculates the cost CostDirectBi from Equation 1 (step S2002). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image. Next, the inter prediction control unit 902 determines whether or not the direct mode prediction direction fixed flag is off (step S2003). If the direct mode prediction direction fixed flag is OFF as a result of this determination (Yes in step S2003), the inter prediction control unit 902 generates a prediction image in the prediction direction 1 using the direct vector 1, and its cost CostDirectUni1. Is calculated from Equation 1 (step S2004). The inter prediction control unit 902 generates a prediction image in the prediction direction 2 using the obtained direct vector 2, and calculates the cost CostDirectUni2 from Equation 1 (step S2005). Next, the inter prediction control unit 902 compares the values of the cost CostDirectUni1, the cost CostDirectUni2, and the cost CostDirectBi, and determines whether or not the cost CostDirectBi is the minimum (step S2006). If the cost CostDirectBi is the minimum as a result of this determination (Yes in step S2006), the inter prediction control unit 902 determines the prediction direction of the direct mode to be bi-directional prediction, and sets the cost CostDirctBi to the cost CostDirect of the direct mode. (Step S2007). On the other hand, if the cost CostDirectBi is not minimum (No in step S2006), the inter prediction control unit 902 compares the cost CostDirectUni1 and the cost CostDirectUni2, and determines whether or not the value of the cost CostDirectUni1 is small (step S2008). If the cost CostDirectUni1 value is small as a result of this determination (Yes in step S2008), the inter prediction control unit 902 determines the direct mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostDirectUni1 as the cost CostDirect in the direct mode. Setting is performed (step S2009). On the other hand, if the value of cost CostDirectUni1 is not small (No in step S2008), inter prediction control section 902 determines direct mode as unidirectional prediction 2 in prediction direction 2, and sets cost CostDirectUni2 as cost CostDirect in the direct mode. (Step S2010). In the determination in step S2003, if the direct prediction direction fixed flag is on (No in step S2003), the inter prediction control unit 902 determines the prediction direction of the direct mode to be bi-directional prediction, and directs the cost CostDirctBi directly. The mode cost is set to CostDirect (step S2007).

Next, a method for calculating the cost CostSkip in the skip mode in step S1803 in FIG. 36 will be described in detail with reference to FIG. FIG. 39 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode.

The inter prediction control unit 902 calculates the direct vector 1 in the prediction direction 1 and the direct vector 2 in the prediction direction 2 (step S2101). Here, the direct vector is calculated, for example, by the method described in step S501 of FIG. 8 of the first embodiment. Next, the inter prediction control unit 902 generates a prediction image in two directions using the direct vector 1 and the direct vector 2, and calculates the cost CostSkip of the skip mode from Equation 1 (step S2102). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image.

Thus, according to the present embodiment, when determining the prediction direction of the direct mode, the optimal prediction direction for the encoding target block is selected and attached to the bitstream regardless of the prediction direction of the neighboring blocks. As a result, the quality of the prediction image in the direct mode can be improved, and the encoding efficiency can be improved.

In addition, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the cost of the two-way prediction and the one-way prediction tends to be relatively close. The prediction direction is fixed to bi-directional prediction that can generate a prediction image with relatively little noise. As a result, it is not necessary to always associate the prediction direction flag in the direct mode for each block to be encoded, and it is possible to improve the encoding efficiency by suppressing the amount of extra information.

(Embodiment 10)
FIG. 40 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. The moving picture coding apparatus 1000 according to the present embodiment includes header information (for example, H.264) that adds a direct mode prediction direction fixed flag generated by the direct mode prediction direction determination unit to a bitstream for each processing unit such as a picture. The configuration differs from that of the ninth embodiment in that it is attached to the picture parameter set, slice header, and the like. In addition, about the structure similar to Embodiment 9, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The direct mode prediction direction determination unit 1001 determines the direct mode prediction direction of the current block using the reference picture lists 1 and 2 as in the first embodiment. Also, the direct mode prediction direction determination unit 1001 adds the set direct mode prediction direction fixed flag to the inter prediction control unit 902 and outputs the flag to the variable length coding unit 1002.

The variable length coding unit 1002 performs variable length coding processing on the quantized prediction error data, inter prediction mode, inter prediction direction flag, skip flag, picture type information, and direct mode prediction direction fixed flag. Thus, a bit stream is generated.

FIG. 41 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention.

The direct mode prediction direction determination unit 1001 determines a prediction direction when encoding the current block in the direct mode, and performs variable length encoding so that the determined direct mode prediction direction fixed flag is attached to the picture header or the like. The data is output to the unit 1002 (step S2201). Here, the method for determining the prediction direction in the direct mode is the same as the flow in FIG. 35 of the ninth embodiment. The inter prediction control unit 902 includes a motion vector detection mode for generating a prediction image using a motion vector based on a motion detection result, a direct mode for generating a prediction image using a prediction motion vector generated from an adjacent block, and a direct mode. The cost comparison of the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction determined by the prediction direction determination unit 1001 is performed, and a more efficient inter prediction mode is determined (step S2202). Here, Formula 1 etc. are utilized for the cost calculation method. Next, the inter prediction control unit 902 determines whether or not the determined inter prediction mode is a skip mode (step S2203). As a result of this determination, if the inter prediction mode is the skip mode (Yes in step S2203), the inter prediction control unit 902 generates a predicted image in the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 1002 to accompany the bit stream of the coding target block (step S2204). On the other hand, as a result of this determination, if the inter prediction mode is not the skip mode (No in step S2203), the inter prediction control unit 902 determines whether the determined inter prediction mode is the direct mode and the direct prediction direction fixed flag is on. It is determined whether or not (step S2205). As a result of this determination, if the inter prediction mode is the direct mode and the direct prediction direction fixed flag is on (Yes in step S2205), the inter prediction control unit 902 generates a direct mode bi-directional prediction image, and skip flag Is set to 0. Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 1002 in order to accompany the bit stream of the coding target block. Also, the inter prediction mode indicating whether the motion vector detection mode or the direct mode is output to the variable length coding unit 1002 in order to accompany the bit stream of the block to be coded (step S2206). On the other hand, as a result of this determination, if the inter prediction mode is the direct mode and the direct prediction direction fixed flag is not on (No in step S2205), the inter prediction control unit 902 performs inter prediction according to the determined inter prediction mode, Predictive image data is generated and the skip flag is set to 0. Then, the inter prediction control unit 902 outputs the skip flag to the variable length coding unit 1002 to accompany the bit stream of the coding target block. In addition, the inter prediction control unit 902 includes an inter prediction mode indicating whether the motion vector detection mode or the direct mode, and one-way prediction in which the inter prediction direction is the prediction direction 1, or one-way prediction in the prediction direction 2, or a prediction direction. An inter prediction direction flag indicating whether or not bi-directional prediction using 1 and prediction direction 2 is output to the variable-length encoding unit 1002 to accompany the bit stream of the encoding target block (step S2207). Note that the inter prediction mode determination method and the like are the same as those in Embodiment 9, and thus the description thereof is omitted.

As described above, according to the present embodiment, since the direct mode prediction direction fixed flag is explicitly given to the picture header or the like, whether or not the direct mode prediction direction is fixed to bi-directional prediction is determined for each picture. It becomes possible to switch flexibly and improve the coding efficiency.

(Embodiment 11)
FIG. 42 is a block diagram showing a configuration of an embodiment of a video encoding apparatus using the video encoding method according to the present invention. The moving image encoding apparatus 1100 according to the present embodiment includes a header that adds the direct mode prediction direction flag generated by the direct mode prediction direction determination unit and the direct mode prediction direction fixed flag to the bitstream for each processing unit such as a picture. The configuration is different from that of the ninth embodiment in that it is attached to information (for example, H.264 picture parameter set and slice header). In addition, about the structure similar to Embodiment 9, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 43 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention.

The direct mode prediction direction determination unit 1101 determines the prediction direction when the encoding target block is encoded in the direct mode, and attaches the determined direct mode prediction direction fixed flag and the direct prediction direction flag to the picture header or the like. Therefore, the data is output to the variable length coding unit 1102 (step S2301). Here, the method for determining the prediction direction in the direct mode is the same as the flow in FIG. 35 of the ninth embodiment. The inter prediction control unit 1103 includes a motion vector detection mode for generating a prediction image using a motion vector based on a motion detection result, a direct mode for generating a prediction image using a prediction motion vector generated from an adjacent block, and a direct mode. The cost comparison of the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction determined by the prediction direction determination unit 1101 is performed, and a more efficient inter prediction mode is determined (step S2302). Here, Formula 1 etc. are utilized for the cost calculation method. The inter prediction control unit 1103 determines whether or not the determined inter prediction mode is the skip mode (step S2303). As a result of this determination, if the inter prediction mode is the skip mode (Yes in step S2303), the inter prediction control unit 1103 generates a predicted image of the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 1103 outputs the skip flag to the variable length coding unit 1102 in order to accompany the bit stream of the coding target block (step S2304). On the other hand, if the inter prediction mode is not the skip mode as a result of this determination, the inter prediction control unit 1103 determines whether or not the determined inter prediction mode is the direct mode and the direct prediction direction fixed flag is on ( Step S2305). As a result of this determination, if the inter prediction mode is the direct mode and the direct prediction direction fixed flag is on (Yes in step S2305), the inter prediction control unit 1103 generates a prediction image according to the determined direct mode prediction direction. The skip flag is set to 0. Then, the inter prediction control unit 1103 outputs the skip flag to the variable length coding unit 1102 to accompany the bit stream of the coding target block. Further, the inter prediction control unit 1103 outputs an inter prediction mode indicating the motion vector detection mode or the direct mode to the variable length coding unit 1102 in order to accompany the bit stream of the coding target block (step S2306). On the other hand, if the inter prediction mode is the direct mode and the direct prediction direction fixed flag is not on (No in step S2305), the inter prediction control unit 1103 performs inter prediction according to the determined inter prediction mode, and generates predicted image data. The skip flag is set to 0. Then, the inter prediction control unit 1103 outputs the skip flag to the variable length coding unit 1102 to accompany the bit stream of the coding target block. Also, the inter prediction control unit 1103 outputs an inter prediction mode and an inter prediction direction flag indicating whether the motion vector detection mode or the direct mode is attached to the variable length coding unit 1102 so as to accompany the bit stream of the coding target block. (Step S2307). Note that the inter prediction mode determination method and the like are the same as those in Embodiment 9, and thus the description thereof is omitted.

Thus, according to the present embodiment, the direct mode prediction direction fixed flag and the direct prediction direction flag are explicitly added to the picture header or the like, so that the direct mode prediction direction is fixed to a certain prediction direction. Whether or not can be flexibly switched for each picture, and the encoding efficiency can be improved.

(Embodiment 12)
FIG. 44 is a block diagram showing a configuration of an embodiment of a video decoding device using the video decoding method according to the present invention.

As shown in FIG. 44, the moving picture decoding apparatus 1200 includes a variable length decoding unit 501, an inverse quantization unit 502, an inverse orthogonal transform unit 503, a block memory 504, a frame memory 505, an intra prediction unit 506, and an inter prediction unit. 507, an inter prediction control unit 1202, a reference picture list management unit 509, and a direct mode prediction direction determination unit 1201.

The variable length decoding unit 501 performs variable length decoding processing on the input bitstream, and performs quantization on which picture type information, inter prediction mode, inter prediction direction flag, skip flag, and variable length decoding processing are performed. Generate coefficients. The inverse quantization unit 502 performs inverse quantization processing on the quantized coefficients that have been subjected to variable length decoding processing. The inverse orthogonal transform unit 503 transforms the orthogonal transform coefficient that has been subjected to the inverse quantization process from the frequency domain to the image domain to obtain prediction error image data. The block memory 504 stores prediction error image data and an image sequence generated by adding the prediction image data in units of blocks. The frame memory 505 stores the image sequence in units of frames. The intra prediction unit 506 generates predicted image data of the decoding target block by performing intra prediction using the block-by-block image sequence stored in the block memory 504. The inter prediction unit 507 generates predicted image data of the decoding target block by performing inter prediction using the frame-by-frame image sequence stored in the frame memory 505. The inter prediction control unit 1202 controls the motion vector and the prediction image data generation method in the inter prediction according to the inter prediction mode, the inter prediction direction, and the skip flag.

The direct mode prediction direction determination unit 1201 uses the reference picture lists 1 and 2 created by the reference picture list management unit 509 to determine the direct mode prediction direction of the encoding target block, and sets a direct mode prediction direction fixed flag. Set. Note that the determination flow of the direct mode prediction direction fixed flag is the same as that in FIG.

FIG. 45 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 1202 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 501 is 1 (step S2401). If the skip flag is 1 as a result of this determination (Yes in step S2401), the inter prediction control unit 1202 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S2402). Here, the direct vector is calculated, for example, by the method described in step S501 of FIG. 8 of the first embodiment. On the other hand, if the skip flag is not 1, that is, if it is not the skip mode (No in step S2401), the inter prediction control unit 1202 determines whether or not the inter prediction mode decoded by the variable length decoding unit 501 is the direct mode. Is determined (step S2403). If the inter prediction mode is the direct mode as a result of this determination (Yes in step S2403), the inter prediction control unit 1202 determines whether or not the direct mode prediction direction fixed flag is on (step S2404). As a result of this determination, if the direct mode prediction direction fixed flag is on (Yes in step S2404), the inter prediction control unit 1202 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S2404). S2405). On the other hand, if the direct mode prediction direction fixed flag is not on (No in step S2404), the inter prediction control unit 1202 direct vector 1, direct vector 2 according to the inter prediction direction decoded by the variable length decoding unit 501. Is calculated and a predicted image is generated (step S2406). On the other hand, as a result of the determination in step S2403, if the inter prediction mode is not the direct mode, that is, if it is the motion vector detection mode (No in step S2403), the inter prediction direction and the motion vector decoded by the variable length decoding unit 501 are used. The prediction image is generated using the prediction image (step S2407). In this embodiment, if the direct mode prediction direction fixed flag is turned on in step S2405, a bidirectional prediction image is generated. However, for example, a unidirectional prediction image is generated in accordance with the encoding method. You may make it.

FIG. 46 is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. In FIG. 46, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag.

Thus, according to the present embodiment, when determining the prediction direction of the direct mode, the optimal prediction direction for the encoding target block is selected and attached to the bitstream regardless of the prediction direction of the neighboring blocks. As a result, it becomes possible to appropriately decode the bit stream with improved encoding efficiency.

Also, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the direct mode prediction direction is fixed to bi-directional prediction, and the direct mode prediction direction flag is set to bit stream. Therefore, it is possible to appropriately decode a bit stream in which the amount of extra information is suppressed and the encoding efficiency is improved.

(Embodiment 13)
FIG. 47 is a block diagram showing a configuration of an embodiment of a video decoding apparatus using the video decoding method according to the present invention. The moving picture decoding apparatus 1300 according to the present embodiment includes header information (for example, H.264) that adds a direct mode prediction direction fixed flag generated by the direct mode prediction direction determination unit to a bitstream for each processing unit such as a picture. The configuration is different from that of the twelfth embodiment in that the bitstream attached to the picture parameter set, slice header, etc.) can be decoded. In addition, about the structure similar to Embodiment 12, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 48 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 1302 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 1301 is 1 (step S2501). As a result of this determination, if the skip flag is 1 (Yes in step S2501), the inter prediction control unit 1302 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S2502). On the other hand, if the skip flag is not 1, that is, if it is not the skip mode (No in step S2501), the inter prediction control unit 1302 determines whether or not the inter prediction mode decoded by the variable length decoding unit 1301 is the direct mode. Is determined (step S2503). If the inter prediction mode is the direct mode as a result of this determination (Yes in step S2503), the inter prediction control unit 1302 has the direct mode prediction direction fixed flag decoded from the bitstream by the variable length decoding unit 1301 turned on. It is determined whether or not there is (step S2504). If the direct mode prediction direction fixed flag is on as a result of this determination (Yes in step S2504), the inter prediction control unit 1302 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step) S2505). On the other hand, if the direct mode prediction direction fixed flag is not on (No in step S2504), the inter prediction control unit 1302 determines the direct vector 1 and the direct vector according to the inter prediction direction flag decoded by the variable length decoding unit 1301. 2 is calculated and a predicted image is generated (step S2506). On the other hand, as a result of the determination in step S2503, if the inter prediction mode is not the direct mode, that is, if it is the motion vector detection mode (No in step S2503), the inter prediction control unit 1302 is decoded by the variable length decoding unit 1301. A prediction image is generated using the inter prediction direction flag and the motion vector (step S2507). In this embodiment, if the direct mode prediction direction fixed flag is turned on in step S2505, a bi-directional prediction image is generated. However, in accordance with the encoding method, for example, a uni-directional prediction image is generated. You may make it.

49A and 49B are diagrams showing an example of the syntax of the bitstream in the moving picture decoding method according to the present invention. 49A and 49B, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag. Also, fixed_direct_pred added to the picture header or the like represents a direct mode prediction direction fixed flag.

Thus, according to the present embodiment, whether or not the direct mode prediction direction is fixed to the bi-directional prediction by explicitly assigning the direct mode prediction direction fixed flag to the picture header or the like is determined for each picture. It is possible to appropriately decode a bit stream with improved encoding efficiency by switching to a flexible manner.

(Embodiment 14)
FIG. 50 is a block diagram showing a configuration of an embodiment of a moving picture decoding apparatus using the moving picture decoding method according to the present invention. In moving picture decoding apparatus 1400 according to the present embodiment, the direct prediction direction flag generated by the direct mode prediction direction determination unit and the direct mode prediction direction fixed flag are added to the bitstream for each processing unit such as a picture. The configuration is different from that of the twelfth embodiment in that a bitstream attached to header information (for example, H.264 picture parameter set, slice header, etc.) can be decoded. In addition, about the structure similar to Embodiment 12, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 51 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 1402 determines whether or not the skip flag decoded from the bitstream by the variable length decoding unit 1401 is 1 (step S2601). If the skip flag is 1 as a result of this determination (Yes in step S2601), the inter prediction control unit 1402 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S2602). On the other hand, if the skip flag is not 1, that is, if it is not the skip mode (No in step S2601), the inter prediction control unit 1402 determines whether or not the inter prediction mode decoded by the variable length decoding unit 1401 is the direct mode. Is determined (step S2603). As a result of this determination, if the inter prediction mode is the direct mode (Yes in step S2603), the inter prediction control unit 1402 has the direct mode prediction direction fixed flag decoded from the bitstream by the variable length decoding unit 1401 turned on. It is determined whether or not there is (step S2604). As a result of this determination, if the direct mode prediction direction fixed flag is on (Yes in step S2604), the inter prediction control unit 1402 responds to the direct mode prediction flag decoded from the bitstream by the variable length decoding unit 1401. The direct vector 1 and the direct vector 2 are calculated, and a predicted image is generated (step S2605). On the other hand, if the direct mode prediction direction fixed flag is not on, the inter prediction control unit 1402 calculates the direct vector 1 and the direct vector 2 according to the inter prediction direction flag decoded by the variable length decoding unit 1401, and performs prediction. An image is generated (step S2606). On the other hand, as a result of the determination in step S2603, if the inter prediction mode is not the direct mode, that is, if it is the motion vector detection mode (No in step S2603), the inter prediction control unit 1402 is decoded by the variable length decoding unit 1401. A prediction image is generated using the inter prediction direction flag and the motion vector (step S2607).

52A and 52B are diagrams showing an example of the syntax of the bitstream in the moving picture decoding method according to the present invention. 52A and 52B, skip_flag represents a skip flag, pred_mode represents an inter prediction mode, and inter_pred_idc represents an inter prediction direction flag. Further, fixed_direct_pred added to a picture header or the like represents a direct mode prediction direction fixed flag, and direct_pred_idc represents a direct prediction direction flag.

As described above, according to the present embodiment, the direct mode prediction direction fixed flag and the direct prediction direction flag are explicitly added to the picture header or the like, so that the direct mode prediction direction is fixed to a certain prediction direction. It is possible to appropriately decode a bitstream with improved coding efficiency by flexibly switching whether or not to perform each picture.

(Embodiment 15)
In this embodiment, a case where Embodiment 1 and Embodiment 9 are combined will be described. In the first embodiment, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the encoding is performed by fixing the prediction direction of the skip mode to unidirectional prediction. An example of improving efficiency was given.

Also, in Embodiment 9, when the reference picture index assignment for each reference picture is the same in reference picture list 1 and reference picture list 2, the costs of direct mode bi-directional prediction and uni-directional prediction are relatively close. Therefore, by fixing the prediction direction of the direct mode to either one of the two-way prediction or the one-way prediction, there is no need to always attach the prediction mode flag of the direct mode for each encoding target block. An example of improving the coding efficiency by suppressing the amount of extra information has been shown.

When the first embodiment and the ninth embodiment are combined, if the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the prediction direction of the skip mode is set to one-way prediction. By fixing, skip mode encoding efficiency can be improved. On the other hand, some coding target blocks whose bi-directional prediction costs are lower than those in the unidirectional prediction in the skip mode are encoded as the bi-directional prediction in the direct mode. Therefore, by fixing the direct mode prediction direction to bi-directional prediction, it is not necessary to always include more direct mode prediction direction flags for each encoding target block, and the amount of extra information is suppressed. Thus, encoding efficiency can be improved.

(Embodiment 16)
FIG. 53 is a block diagram showing a configuration of an embodiment of a video encoding device using the video encoding method according to the present invention.

As shown in FIG. 53, the moving image encoding apparatus 1500 includes an orthogonal transform unit 101, a quantization unit 102, an inverse quantization unit 103, an inverse orthogonal transform unit 104, a block memory 105, a frame memory 106, an intra prediction unit 107, An inter prediction unit 108, an inter prediction control unit 1502, a picture type determination unit 110, a reference picture list management unit 111, a merge mode prediction direction determination unit 1501, and a variable length encoding unit 113 are provided.

The orthogonal transform unit 101 transforms prediction image data generated as described later and prediction error data between an input image sequence from an image region to a frequency region. The quantization unit 102 performs a quantization process on the prediction error data converted into the frequency domain. The inverse quantization unit 103 performs inverse quantization processing on the prediction error data quantized by the quantization unit 102. The inverse orthogonal transform unit 104 performs transform from the frequency domain to the image domain on the prediction error data subjected to the inverse quantization process. The block memory 105 stores the decoded image obtained from the prediction image data and the prediction error data subjected to the inverse quantization process in units of blocks, and the frame memory 106 stores the decoded image in units of frames. The picture type determination unit 110 determines which of the I picture, B picture, and P picture is used to encode the input image sequence, and generates picture type information. The intra prediction unit 107 uses the decoded image in units of blocks stored in the block memory 105 to generate predicted image data based on intra prediction of the encoding target block. The inter prediction unit 108 generates predicted image data by inter prediction of the encoding target block, using the decoded image in units of frames stored in the frame memory 106.

The reference picture list management unit 110 assigns a reference picture index to an encoded reference picture to be referred to in inter prediction, and creates a reference picture list together with a display order and the like. Since B picture can be encoded with reference to two pictures, it holds two reference picture lists. In this embodiment, the reference picture is managed in the reference picture index and the display order. However, the reference picture may be managed in the reference picture index and the encoding order.

The merge mode prediction direction determination unit 1501 uses the reference picture lists 1 and 2 created by the reference picture list management unit 110 to determine the prediction direction of the merge mode of the block to be encoded by a method described later.

FIG. 54 is a flowchart showing an outline of the processing flow of the moving picture coding method according to the present invention. The merge mode prediction direction determination unit 1501 determines a prediction direction when the encoding target block is encoded in the merge mode (step S2701). The inter prediction control unit 1502 includes a motion vector detection mode that generates a predicted image using a motion vector based on a motion detection result, a merge mode that generates a predicted image using a predicted motion vector such as an adjacent block, and a merge mode prediction direction. The cost comparison of the skip mode for generating a predicted image using the predicted motion vector generated according to the prediction direction determined by the determination unit 1501 is performed, and a more efficient inter prediction mode is determined (step S2702). The cost calculation method will be described later. Next, the inter prediction control unit 1502 determines whether or not the inter prediction mode determined in step S2702 is the skip mode (step S2703). If the result of this determination is true (Yes in step S2703), the inter prediction control unit 1502 generates a predicted image in the skip mode and sets the skip flag to 1. Then, the inter prediction control unit 1502 outputs the skip flag to the variable length coding unit 113 to accompany the bit stream of the coding target block (step S2704). If the determination result is false (No in step S2703), the inter prediction control unit 1502 determines whether or not the determined inter prediction mode is the merge mode (step S2705). If the result of this determination is true (Yes in step S2705), the inter prediction control unit 1502 generates a merge mode prediction image according to the merge mode prediction direction fixed flag obtained by the method described later, and skip flag Is set to 0. Then, the inter prediction control unit 1502 outputs the skip flag to the variable length encoding unit 113 in order to accompany the bit stream of the encoding target block. Also, the inter prediction control unit 1502 associates the inter prediction mode indicating the motion vector detection mode or the merge mode and the adjacent block information used for merging obtained by the method described later with the bit stream of the encoding target block. Therefore, the data is output to the variable length coding unit 113 (step S2706). On the other hand, if the determination result in step S2705 is false (No in step S2705), the inter prediction control unit 1502 generates predicted image data in the motion vector detection mode, and sets the skip flag to 0. Then, the inter prediction control unit 1502 outputs the skip flag to the variable length encoding unit 113 in order to accompany the bit stream of the encoding target block. In addition, the inter prediction control unit 1502 includes an inter prediction mode indicating the motion vector detection mode or the merge mode, and one-way prediction in which the inter prediction direction is the prediction direction 1, or one-way prediction in the prediction direction 2, or a prediction direction. An inter prediction direction flag indicating whether or not bi-directional prediction using 1 and prediction direction 2 is output to the variable length encoding unit 113 in order to accompany the bit stream of the encoding target block (step S2707).

FIG. 55 is a flowchart showing a merge mode prediction direction determination flow in the merge mode prediction direction determination unit 1501. In general, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, motion vectors in the prediction direction 1 and the prediction direction 2 are selected in the two-way prediction. In the direction prediction, only the motion vector in the prediction direction 1 may be used, and the motion vector in the prediction direction 2 may decrease as a whole. For example, when the reference picture index assignment for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the unidirectional prediction using the reference picture list 2 is prohibited, thereby encoding the inter prediction direction flag code. Coding efficiency can be improved by reducing the amount. In this case, since only the motion vector in the prediction direction 1 is used in the one-way prediction, the motion vector in the prediction direction 2 is reduced as a whole, and the accuracy of the prediction motion vector in the prediction direction 2 may be lowered. Therefore, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the encoding efficiency is improved by fixing the prediction direction of the merge mode to one-way prediction. be able to.

The merge mode prediction direction determination unit 1501 uses the reference picture list 1 and the reference picture list 2 to determine whether or not the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2. Determination is made (step S2801). For example, the display order of the reference picture indicated by each reference picture index 1 is obtained from the reference picture list 1, and compared with the display order of the reference picture indicated by each reference picture index 2 from the reference picture list 2. It can be determined that they are the same. As a result of this determination, if the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2 (Yes in step S2801), the merge mode prediction direction determination unit 1501 determines the merge mode. Is determined to be one-way prediction, and the merge mode prediction direction fixed flag is set to ON (step S2802). On the other hand, if the reference picture index assignment for each reference picture is not the same in reference picture list 1 and reference picture list 2 (No in step S2801), the merge mode prediction direction fixed flag is set to OFF (step S2803). .

In the present embodiment, it is determined in step S2801 whether or not the reference picture index allocation to each reference picture is the same in the reference picture list 1 and the reference picture list 2 using the display order. You may judge using.

In this embodiment, in step S2801, when the reference picture index assignment to each reference picture is the same in the reference picture list 1 and the reference picture list 2, the prediction direction of the merge mode is determined to be one-way prediction. Although the merge mode prediction direction fixed flag is set to ON, the reference picture indicated by the reference picture index 1 in the prediction direction 1 and the reference indicated by the reference picture index 2 in the prediction direction 2 in the merge mode of the encoding target block. When the pictures are the same picture, the merge mode prediction direction may be determined to be bi-directional prediction, and the merge mode prediction direction fixed flag may be set to ON. For example, the display order of the reference picture indicated by the reference picture index 1 is obtained from the reference picture list 1 and is compared with the display order of the reference picture indicated by the reference picture index 2 from the reference picture list 2. it can. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 decreases, encoding efficiency can be improved by fixing the prediction direction of merge mode to 1 direction prediction.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two previously encoded pictures whose encoding target picture is ahead, the prediction direction of the merge mode is fixed to one-way prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, or the reference in the prediction direction 1 in the merge mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 decreases, encoding efficiency can be improved by fixing the prediction direction of merge mode to 1 direction prediction.

In addition, in the case of a B picture that generates a bi-directional prediction image with reference to two already-encoded pictures that are behind the encoding target picture, the prediction direction of the merge mode is fixed to one-way prediction. Also good. In such a B picture, the reference picture index assignment to each reference picture may be the same in the reference picture list 1 and the reference picture list 2, and the reference in the prediction direction 1 in the skip mode of the encoding target block The reference picture indicated by the picture index 1 and the reference picture indicated by the reference picture index 2 in the prediction direction 2 may be the same picture. Even in such a case, the motion vector in the prediction direction 1 and the prediction direction 2 is selected in the two-way prediction, but only the motion vector in the prediction direction 1 may be used in the one-way prediction. Since the motion vector of 2 decreases, encoding efficiency can be improved by fixing the prediction direction of merge mode to 1 direction prediction.

FIG. 56 is a flowchart showing an inter prediction mode determination flow in the inter prediction control unit 1502.

The inter prediction control unit 1502 calculates a cost CostInter of a motion vector detection mode for generating a predicted image using a motion vector based on a motion detection result by a method described later (step S2901). Next, the inter prediction control unit 1502 generates a prediction vector using a motion vector such as an adjacent block, and calculates a cost CostMerge in a merge mode in which a prediction image is generated using the prediction vector by a method described later (step S2902). The inter prediction control unit 1502 calculates a cost CostSkip of a skip mode for generating a predicted image according to the determined skip mode prediction direction flag by a method described later (step S2903). The inter prediction control unit 1502 compares the cost CostInter of the motion vector detection mode, the cost CostMerge of the merge mode, and the cost CostSkip of the skip mode, and determines whether or not the cost CostInter of the motion vector detection mode is the minimum (step S2904). If the cost CostInter of the motion vector detection mode is the minimum as a result of this determination (Yes in step S2904), the inter prediction control unit 1502 determines the inter prediction mode as the motion vector detection mode, and detects the inter prediction mode as a motion vector. The mode is set (step S2905). On the other hand, if the cost CostInter in the motion vector detection mode is not the minimum as a result of the determination in step S2904 (No in step S2904), the inter prediction control unit 1502 compares the cost CostMerge in the merge mode with the cost CostSkip in the skip mode. It is determined whether or not the cost CostMerge in the merge mode is small (step S2906). If the result of this determination is that the cost CostMerge in the merge mode is small (Yes in step S2906), the inter prediction control unit 1502 determines the inter prediction mode as the merge mode, and sets the inter prediction mode as the merge mode (step S2907). . On the other hand, if the determination in step S2906 is false (No in step S2906), the inter prediction control unit 1502 sets the inter prediction mode to the skip mode and sets the skip mode to the inter prediction mode (step S2908).

Next, a method for calculating the cost CostInter in the motion vector detection mode in step S2901 in FIG. 56 will be described in detail with reference to FIG. FIG. 57 is a flowchart showing a processing flow for calculating the cost CostInter in the motion vector detection mode.

The inter prediction control unit 1502 performs motion detection on the reference picture 1 indicated by the reference picture index 1 in the prediction direction 1 and the reference picture 2 indicated by the reference picture index 2 in the prediction direction 2, and the motion vector for each reference picture 1 and motion vector 2 are generated (step S3001). Here, in motion detection, a difference value between a coding target block in a coded picture and a block in a reference picture is calculated, and a block in the reference picture having the smallest difference value is set as a reference block. Then, a motion vector is obtained from the encoding target block position and the reference block position. Next, the inter prediction control unit 1502 uses the obtained motion vector 1 to generate a prediction image in the prediction direction 1, and calculates the cost CostInterUni1 using, for example, the above equation 1 of the RD optimization model ( Step S3002). The inter prediction control unit 1502 generates a prediction image in the prediction direction 2 using the obtained motion vector 2, and calculates the cost CostInterUni2 from Equation 1 (step S3003). The inter prediction control unit 1502 generates a prediction image in two directions using the obtained motion vector 1 and motion vector 2, and calculates the cost CostInterBi from Equation 1 above (step S3004). Here, the bi-directional predicted image is, for example, a bi-directional predicted image obtained by performing addition averaging for each pixel of the predicted image obtained from the motion vector 1 and the predicted image obtained from the motion vector 2. Next, the inter prediction control unit 1502 compares the values of the cost CostInterUni1, the cost CostInterUni2, and the cost CostInterBi, and determines whether or not the cost CostInterBi is the minimum (step S3005). If the cost CostInterBi is the minimum as a result of this determination (Yes in step S3005), the inter prediction control unit 1502 determines the prediction direction of the motion vector detection mode to be bi-directional prediction, and uses the cost CostInterBi as the cost of the motion vector detection mode. Set to CostInter (step S3006). On the other hand, if the cost CostInterBi is not minimum as a result of the determination in step S3005 (No in step S3005), the inter prediction control unit 1502 compares the cost CostInterUni1 and the cost CostInterUni2 and determines whether the cost CostInterUni1 is small ( Step S3007). If the cost CostInterUni1 value is small as a result of this determination (Yes in step S3007), the inter prediction control unit 1502 determines the motion vector detection mode as one-way prediction 1 in the prediction direction 1, and sets the cost CostInterUni1 as the motion vector detection mode. Cost CostInter (step S3008). On the other hand, if the determination in step S3007 is false (No in step S3007), the inter prediction control unit 1502 determines the motion vector detection mode as one-way prediction 2 in the prediction direction 2, and sets the cost CostInterUni2 as the motion vector detection mode. The cost is set to CostInter (step S3009).

Next, the method of calculating the cost CostMerge in the merge mode in step S2902 in FIG. FIG. 58 is a flowchart showing the processing flow for calculating the cost CostMerge in the merge mode.

The inter prediction control unit 1502 determines the left adjacent block A, the upper adjacent block B, and the upper right adjacent block C of the encoding target block (step S3101). For example, the block to which the left adjacent pixel of the pixel at the upper left position of the encoding target block belongs is the left adjacent block A, the block to which the upper adjacent pixel of the pixel at the upper left position belongs is the upper adjacent block B, the most A block to which a pixel on the upper right side of the pixel at the upper right position belongs is assumed to be an upper right block C. Then, the following processing (step S3102 to step S3109) is repeated for each adjacent block N (= AorBorC). The inter prediction control unit 1502 determines the reference picture index of the encoding target block (step S3102). For example, the reference picture index of the adjacent block N is set. Next, the inter prediction control unit 1502 determines whether or not the merge mode prediction direction fixed flag is on (step S3103). As a result of this determination, if the merge mode prediction direction fixed flag is on (Yes in step S3103), the inter prediction control unit 1502 generates a one-way prediction image using the motion vector in the prediction direction 1 of the adjacent block N. Then, the cost TmpCostMerge is calculated from the above equation 1 (step S3104). Next, the inter prediction control unit 1502 determines whether or not the cost TmpCostMerge is smaller than the cost CostMerge (step S3105). If the cost TmpCostMerge is small as a result of this determination, the inter prediction control unit 1502 copies the cost TmpCostMerge to the cost CostMerge and updates the information MinN of the neighboring block that generated the minimum cost (step S3106). On the other hand, if the result of determination in step S3103 is that the merge mode prediction direction fixed flag is off (No in step S3103), the inter prediction control unit 1502 determines whether or not the prediction direction of the adjacent block N is bi-directional prediction. Determination is made (step S3107). If the result of this determination is bi-directional prediction (Yes in step S3107), the inter prediction control unit 1502 generates a bi-directional prediction image using the motion vectors in the prediction direction 1 and the prediction direction 2 of the adjacent block N. The cost TmpCostMerge is calculated from the above equation 1 (step S3108). On the other hand, if the result of determination in step S3107 is not bi-directional prediction (No in step S3107), the inter prediction control unit 1502 uses the motion vector in the prediction direction 1 or prediction direction 2 of the adjacent block N to perform one-way prediction. An image is generated, and its cost TmpCostMerge is calculated from the above equation 1 (step S3109). By performing the processing from step S3102 to step S3109 for each adjacent block, the merge mode cost MergeCost and the adjacent block information MinN used for the merge that generated the minimum cost are calculated.

In the present embodiment, the reference picture index of the adjacent block is used as the reference picture index value of the encoding target block in the merge mode. A reference picture index indicating the referenced reference picture may be calculated. For example, in FIG. 9, when the possible values of each reference picture index are “0” or “1”, the median value of RefIdxL0_A, RefIdxL0_B, and RefIdxL0_C is used as the reference picture index RefIdxL0 in the prediction direction 1 of the current block. It can be calculated from (RefIdxL0_A, RefIdxL0_B, RefIdxL0_C). Here, the intermediate value is derived from Equation 2 above.

In this way, the reference picture index of the block to be encoded is a reference picture index that indicates a reference picture that has been referred to more frequently in adjacent blocks, thereby improving the prediction accuracy of vectors used in the merge mode, thereby improving the encoding efficiency. Can be improved. In this example, an example in which a reference picture index indicating a reference picture that has been referred to more frequently in an adjacent block is obtained using an intermediate value is not necessarily limited thereto. For example, it may be calculated by checking the same relationship between the reference picture indexes of adjacent blocks. If the reference picture index values of adjacent blocks are all different, the reference picture index that represents the reference picture that is closest to the encoding target picture in the display order among the reference pictures indicated by each reference picture index is encoded. The reference picture index of the conversion target block may be used.

In addition, as a reference picture index value of an encoding target block in the merge mode, a reference picture index indicating a reference picture that is closest to the encoding target picture in display order among reference pictures referenced in adjacent blocks is assigned. Also good. For example, in the example shown in FIG. 9, the reference picture index RefIdxL0 in the prediction direction 1 of the encoding target block is calculated from the minimum value Min (RefIdxL0_A, RefIdxL0_B, RefIdxL0_C) of RefIdxL0_A, RefIdxL0_B, and RefIdxL0_C. Here, the minimum value is derived from Equation 5.

The reference picture index is a reference picture index that indicates a reference picture that has been referenced more frequently in the adjacent block, or a reference picture that is closest to the current picture in the display order among the reference pictures that are referenced in the adjacent block. When the reference picture index shown is used, the motion vector used in the merge mode may be scaled according to the distance to the reference picture indicated by the determined reference picture index.

Next, a method for calculating the cost CostSkip in step S2903 in FIG. 56 will be described in detail with reference to FIG. FIG. 59 is a flowchart showing a processing flow for calculating the cost CostSkip in the skip mode.

Inter prediction control unit 1502 calculates direct vector 1 in prediction direction 1 and direct vector 2 in prediction direction 2 (step S3201). Here, the direct vector is calculated, for example, by the method described in step S501 of FIG. 8 of the first embodiment. Next, the inter prediction control unit 1502 generates a prediction image in two directions using the direct vector 1 and the direct vector 2, and calculates the cost CostSkip of the skip mode from the above equation 1 (step S3202). Here, the predicted image in two directions is, for example, a prediction image obtained from the direct vector 1 and a predicted image obtained from the direct vector 2 that is obtained by performing averaging for each pixel as the two-way predicted image.

In the present embodiment, when the merge mode prediction direction fixed flag is turned on, an example of generating a prediction image in the prediction direction 1 has been described. However, a prediction image in the prediction direction 2 is generated throughout the embodiment. You may make it.

In this embodiment, as an example of calculating a direct vector, an example in which an intermediate value Median (MvL0_A, MvL0_B, MvL0_C) of MvL0_A, MvL0_B, and MvL0_C is described is not limited to this calculation method. For example, a predicted motion vector having the smallest Cost is selected as a direct vector used for encoding from a plurality of predicted motion vector candidates, and a predicted motion vector index representing the selected predicted motion vector is attached to the bitstream. I do not care. Here, Cost is calculated using, for example, Equation 1 above. In this way, by selecting a direct vector used for encoding from a plurality of candidates, it is possible to derive a direct vector having a smaller Cost. FIG. 11A shows an example of a motion vector predictor candidate. The predicted motion vector index value is “0” for a value corresponding to Median (MvL0_A, MvL0_B, MvL0_C), “1” for a value corresponding to the motion vector MvL0_A, and “2” for a value corresponding to MvL0_B. The value corresponding to MvL0_C is “3”. The method of assigning the motion vector predictor index is not limited to this example. FIG. 11B shows an example of a code table used when the motion vector predictor index corresponding to the motion vector predictor candidate having the smallest Cost is subjected to variable length coding. Codes with short code lengths are assigned in ascending order of predicted motion vector index values. Therefore, it is possible to improve the encoding efficiency by reducing the value of the motion vector predictor index corresponding to a motion vector predictor candidate that is likely to have good prediction accuracy.

Further, in the present embodiment, the reference picture index of the block to be encoded and the reference picture index and motion vector of adjacent block A, adjacent block B, and adjacent block C in FIG. 9 are used in calculating the adjacent block used for merging. Although an example has been shown, the present invention is not necessarily limited thereto. For example, as shown in FIG. 12, an adjacent block D or an adjacent block E may be used.

As described above, according to the present embodiment, when determining the prediction direction of the merge mode, the optimal prediction direction for the encoding target block is selected and attached to the bitstream regardless of the prediction direction of the neighboring blocks. As a result, the quality of the prediction image in the merge mode can be improved, and the encoding efficiency can be improved. In particular, when the reference picture index allocation for each reference picture is the same in the reference picture list 1 and the reference picture list 2, the quality of the predicted image is improved by selecting the one-way prediction regardless of the prediction direction of the adjacent block. And encoding efficiency can be improved.

(Embodiment 17)
FIG. 60 is a block diagram showing a configuration of an embodiment of a video decoding apparatus using the video decoding method according to the present invention.

As illustrated in FIG. 60, the moving picture decoding apparatus 1600 includes a variable length decoding unit 501, an inverse quantization unit 502, an inverse orthogonal transform unit 503, a block memory 504, a frame memory 505, an intra prediction unit 506, and an inter prediction unit. 507, an inter prediction control unit 1602, a reference picture list management unit 509, and a merge mode prediction direction determination unit 1601.

The variable length decoding unit 501 performs variable length decoding processing on the input bitstream, and performs quantization on which picture type information, inter prediction mode, inter prediction direction flag, skip flag, and variable length decoding processing are performed. Generate coefficients. The inverse quantization unit 502 performs inverse quantization processing on the quantized coefficients that have been subjected to variable length decoding processing. The inverse orthogonal transform unit 503 transforms the orthogonal transform coefficient that has been subjected to the inverse quantization process from the frequency domain to the image domain to obtain prediction error image data. The block memory 504 stores prediction error image data and an image sequence generated by adding the prediction image data in units of blocks. The frame memory 505 stores the image sequence generated by adding the predicted image data in units of frames. The intra prediction unit 506 generates predicted image data of the decoding target block by performing intra prediction using the block-by-block image sequence stored in the block memory 504. The inter prediction unit 507 generates predicted image data of the decoding target block by performing inter prediction using the frame-by-frame image sequence stored in the frame memory 505. The inter prediction control unit 1602 controls the motion vector and the prediction image data generation method in the inter prediction according to the inter prediction mode, the inter prediction direction, and the skip flag.

The reference picture list management unit 509 assigns a reference picture index to a decoded reference picture to be referred to in inter prediction, and creates a reference picture list together with a display order and the like. Since the B picture is decoded with reference to two pictures, it holds two reference picture lists.

In the present embodiment, the reference pictures are managed in the reference picture index and the display order. However, the reference pictures may be managed in the reference picture index and the decoding order.

The merge mode prediction direction determination unit 1601 determines the merge mode prediction direction of the decoding target block using the reference picture list 1 and the reference picture list 2 created by the reference picture list management unit 509, and merge mode prediction direction Set a fixed flag. Note that the flow for determining the merge mode prediction direction fixed flag is the same as that in FIG.

FIG. 61 is a flowchart showing an outline of the processing flow of the moving picture decoding method according to the present invention.

The inter prediction control unit 1602 determines whether or not the skip flag decoded from the bitstream is 1 (step S3301). As a result of this determination, if the skip flag is 1 (Yes in step S3301), the inter prediction control unit 1602 calculates the direct vector 1 and the direct vector 2, and generates a bi-directional prediction image (step S3302). Here, the direct vector is calculated, for example, by the method described in step S501 of FIG. 8 of the first embodiment. On the other hand, as a result of the determination, if the skip flag is not 1 (No in step S3301), that is, if it is not the skip mode, the inter prediction control unit 1602 determines whether or not the decoded prediction mode is the merge mode. (Step S3303). If the prediction mode is the merge mode as a result of this determination (Yes in step S3303), the inter prediction control unit 1602 determines whether or not the merge mode prediction direction fixed flag is on (step S3304). As a result of this determination, if the merge mode prediction direction fixed flag is on, the inter prediction control unit 1602 decodes adjacent block information used for merging, and performs one-way prediction using a motion vector in the prediction direction 1 of the adjacent block. An image is generated (step S3305). On the other hand, if the result of determination is that the merge mode prediction direction fixed flag is off (No in step S3304), the neighboring block information used for merging is decoded, and prediction direction 1 or prediction direction is determined according to the prediction direction of the adjacent block. A predicted image is generated using at least one motion vector of 2 (step S3306). As a result of the determination in step S3303, if the prediction mode is not the merge mode (No in step S3303), that is, if it is the motion vector detection mode, a predicted image is generated using the decoded inter prediction direction and motion vector. (Step S3307).

In this embodiment, if the merge mode prediction direction fixed flag is turned on in step S3305, a one-way prediction image of prediction direction 1 is generated. Two one-way predicted images may be generated.

FIG. 62 is a diagram showing an example of the bitstream syntax in the video decoding method according to the present invention. In FIG. 62, skip_flag is a skip flag, pred_mode is an inter prediction mode, inter_pred_idc is an inter prediction direction flag, and merge_idx is a flag indicating adjacent block information used for merging.

Thus, according to the present embodiment, when the reference picture index assignment to each reference picture is the same in reference picture list 1 and reference picture list 2, in the merge mode, regardless of the prediction direction of adjacent blocks. By selecting unidirectional prediction, it is possible to appropriately decode a bitstream with improved encoding efficiency.

(Embodiment 18)
By recording a program for realizing the configuration of the moving image encoding method (image encoding method) or the moving image decoding method (image decoding method) shown in each of the above embodiments on a storage medium, each of the above embodiments It is possible to easily execute the processing shown in the form in the independent computer system. The storage medium may be any medium that can record a program, such as a magnetic disk, an optical disk, a magneto-optical disk, an IC card, and a semiconductor memory.

Furthermore, application examples of the moving picture coding method (picture coding method) and the moving picture decoding method (picture decoding method) shown in the above embodiments and a system using the same will be described. The system has an image encoding / decoding device including an image encoding device using an image encoding method and an image decoding device using an image decoding method. Other configurations in the system can be appropriately changed according to circumstances.

FIG. 63 is a diagram showing an overall configuration of a content supply system ex100 that realizes a content distribution service. A communication service providing area is divided into desired sizes, and base stations ex106, ex107, ex108, ex109, and ex110, which are fixed wireless stations, are installed in each cell.

This content supply system ex100 includes a computer ex111, a PDA (Personal Digital Assistant) ex112, a camera ex113, a mobile phone ex114, a game machine ex115 via the Internet ex101, the Internet service provider ex102, the telephone network ex104, and the base stations ex106 to ex110. Etc. are connected.

However, the content supply system ex100 is not limited to the configuration as shown in FIG. 63, and any element may be combined and connected. In addition, each device may be directly connected to the telephone network ex104 without going from the base station ex106, which is a fixed wireless station, to ex110. In addition, the devices may be directly connected to each other via short-range wireless or the like.

The camera ex113 is a device that can shoot moving images such as a digital video camera, and the camera ex116 is a device that can shoot still images and movies such as a digital camera. Also, the mobile phone ex114 is a GSM (registered trademark: Global System for Mobile Communications) system, a CDMA (Code Division Multiple Access) system, a W-CDMA (Wideband-Code Division Multiple Access) system, or an LTE (Long Terminal Evolution) system. HSPA (High-Speed-Packet-Access) mobile phone, PHS (Personal-Handyphone-System), etc.

In the content supply system ex100, the camera ex113 and the like are connected to the streaming server ex103 through the base station ex109 and the telephone network ex104, thereby enabling live distribution and the like. In live distribution, the content (for example, music live video) captured by the user using the camera ex113 is encoded as described in the above embodiments (that is, the image encoding of the present invention). Function as a device) and transmit to the streaming server ex103. On the other hand, the streaming server ex103 stream-distributes the content data transmitted to the requested client. Examples of the client include a computer ex111, a PDA ex112, a camera ex113, a mobile phone ex114, and a game machine ex115 that can decode the encoded data. Each device that receives the distributed data decodes the received data and reproduces it (that is, functions as the image decoding device of the present invention).

Note that the captured data may be encoded by the camera ex113, the streaming server ex103 that performs data transmission processing, or may be shared with each other. Similarly, the decryption processing of the distributed data may be performed by the client, the streaming server ex103, or may be performed in common with each other. In addition to the camera ex113, still images and / or moving image data captured by the camera ex116 may be transmitted to the streaming server ex103 via the computer ex111. The encoding process in this case may be performed by any of the camera ex116, the computer ex111, and the streaming server ex103, or may be performed in a shared manner.

Further, these encoding / decoding processes are generally performed in the computer ex111 and the LSI ex500 included in each device. The LSI ex500 may be configured as a single chip or a plurality of chips. It should be noted that moving image encoding / decoding software is incorporated into some recording medium (CD-ROM, flexible disk, hard disk, etc.) that can be read by the computer ex111, etc., and encoding / decoding processing is performed using the software. May be. Furthermore, when the mobile phone ex114 is equipped with a camera, moving image data acquired by the camera may be transmitted. The moving image data at this time is data encoded by the LSI ex500 included in the mobile phone ex114.

Further, the streaming server ex103 may be a plurality of servers or a plurality of computers, and may process, record, and distribute data in a distributed manner.

As described above, in the content supply system ex100, the encoded data can be received and reproduced by the client. Thus, in the content supply system ex100, the information transmitted by the user can be received, decrypted and reproduced by the client in real time, and personal broadcasting can be realized even for a user who does not have special rights or facilities.

In addition to the example of the content supply system ex100, as shown in FIG. 64, the digital broadcast system ex200 also includes at least the video encoding device (video encoding device) or video decoding of each of the above embodiments. Any of the devices (image decoding devices) can be incorporated. Specifically, in the broadcast station ex201, multiplexed data obtained by multiplexing music data and the like on video data is transmitted to a communication or satellite ex202 via radio waves. This video data is data encoded by the moving image encoding method described in the above embodiments (that is, data encoded by the image encoding apparatus of the present invention). Receiving this, the broadcasting satellite ex202 transmits a radio wave for broadcasting, and this radio wave is received by a home antenna ex204 capable of receiving satellite broadcasting. The received multiplexed data is decoded and reproduced by an apparatus such as the television (receiver) ex300 or the set top box (STB) ex217 (that is, functions as the image decoding apparatus of the present invention).

Also, a reader / recorder ex218 that reads and decodes multiplexed data recorded on a recording medium ex215 such as a DVD or a BD, or encodes a video signal on the recording medium ex215 and, in some cases, multiplexes and writes it with a music signal. It is possible to mount the moving picture decoding apparatus or moving picture encoding apparatus described in the above embodiments. In this case, the reproduced video signal is displayed on the monitor ex219, and the video signal can be reproduced in another device or system using the recording medium ex215 on which the multiplexed data is recorded. Alternatively, a moving picture decoding apparatus may be mounted in a set-top box ex217 connected to a cable ex203 for cable television or an antenna ex204 for satellite / terrestrial broadcasting and displayed on the monitor ex219 of the television. At this time, the moving picture decoding apparatus may be incorporated in the television instead of the set top box.

FIG. 65 is a diagram illustrating a television (receiver) ex300 that uses the video decoding method and the video encoding method described in each of the above embodiments. The television ex300 obtains or outputs multiplexed data in which audio data is multiplexed with video data via the antenna ex204 or the cable ex203 that receives the broadcast, and demodulates the received multiplexed data. Alternatively, the modulation / demodulation unit ex302 that modulates multiplexed data to be transmitted to the outside, and the demodulated multiplexed data is separated into video data and audio data, or the video data and audio data encoded by the signal processing unit ex306 Is provided with a multiplexing / demultiplexing unit ex303.

Further, the television ex300 decodes each of the audio data and the video data, or encodes the respective information, the audio signal processing unit ex304, the video signal processing unit ex305 (function as the image encoding device or the image decoding device of the present invention). ), A speaker ex307 for outputting the decoded audio signal, and an output unit ex309 having a display unit ex308 such as a display for displaying the decoded video signal. Furthermore, the television ex300 includes an interface unit ex317 including an operation input unit ex312 that receives an input of a user operation. Furthermore, the television ex300 includes a control unit ex310 that performs overall control of each unit, and a power supply circuit unit ex311 that supplies power to each unit. In addition to the operation input unit ex312, the interface unit ex317 includes a bridge unit ex313 connected to an external device such as a reader / recorder ex218, a recording unit ex216 such as an SD card, and an external recording unit such as a hard disk. A driver ex315 for connecting to a medium, a modem ex316 for connecting to a telephone network, and the like may be included. Note that the recording medium ex216 is capable of electrically recording information by using a nonvolatile / volatile semiconductor memory element to be stored. Each part of the television ex300 is connected to each other via a synchronous bus.

First, a configuration in which the television ex300 decodes and reproduces multiplexed data acquired from the outside by the antenna ex204 and the like will be described. The television ex300 receives a user operation from the remote controller ex220 or the like, and demultiplexes the multiplexed data demodulated by the modulation / demodulation unit ex302 by the multiplexing / demultiplexing unit ex303 based on the control of the control unit ex310 having a CPU or the like. Furthermore, in the television ex300, the separated audio data is decoded by the audio signal processing unit ex304, and the separated video data is decoded by the video signal processing unit ex305 using the decoding method described in each of the above embodiments. The decoded audio signal and video signal are output from the output unit ex309 to the outside. At the time of output, these signals may be temporarily stored in the buffers ex318, ex319, etc. so that the audio signal and the video signal are reproduced in synchronization. Also, the television ex300 may read multiplexed data from recording media ex215 and ex216 such as a magnetic / optical disk and an SD card, not from broadcasting. Next, a configuration in which the television ex300 encodes an audio signal or a video signal and transmits the signal to the outside or to a recording medium will be described. The television ex300 receives a user operation from the remote controller ex220 and the like, encodes an audio signal with the audio signal processing unit ex304, and converts the video signal with the video signal processing unit ex305 based on the control of the control unit ex310. Encoding is performed using the encoding method described in (1). The encoded audio signal and video signal are multiplexed by the multiplexing / demultiplexing unit ex303 and output to the outside. When multiplexing, these signals may be temporarily stored in the buffers ex320, ex321, etc. so that the audio signal and the video signal are synchronized. Note that a plurality of buffers ex318, ex319, ex320, and ex321 may be provided as illustrated, or one or more buffers may be shared. Further, in addition to the illustrated example, data may be stored in the buffer as a buffer material that prevents system overflow and underflow, for example, between the modulation / demodulation unit ex302 and the multiplexing / demultiplexing unit ex303.

In addition to acquiring audio data and video data from broadcasts, recording media, and the like, the television ex300 has a configuration for receiving AV input of a microphone and a camera, and performs encoding processing on the data acquired from them. Also good. Here, the television ex300 has been described as a configuration capable of the above-described encoding processing, multiplexing, and external output, but these processing cannot be performed, and only the above-described reception, decoding processing, and external output are possible. It may be a configuration.

In addition, when reading or writing multiplexed data from a recording medium by the reader / recorder ex218, the decoding process or the encoding process may be performed by either the television ex300 or the reader / recorder ex218, The reader / recorder ex218 may share with each other.

As an example, FIG. 66 shows a configuration of the information reproducing / recording unit ex400 when data is read from or written to an optical disk. The information reproducing / recording unit ex400 includes elements ex401, ex402, ex403, ex404, ex405, ex406, and ex407 described below. The optical head ex401 irradiates a laser spot on the recording surface of the recording medium ex215 that is an optical disk to write information, and detects reflected light from the recording surface of the recording medium ex215 to read the information. The modulation recording unit ex402 electrically drives a semiconductor laser built in the optical head ex401 and modulates the laser beam according to the recording data. The reproduction demodulator ex403 amplifies the reproduction signal obtained by electrically detecting the reflected light from the recording surface by the photodetector built in the optical head ex401, separates and demodulates the signal component recorded on the recording medium ex215, and is necessary To play back information. The buffer ex404 temporarily holds information to be recorded on the recording medium ex215 and information reproduced from the recording medium ex215. The disk motor ex405 rotates the recording medium ex215. The servo controller ex406 moves the optical head ex401 to a predetermined information track while controlling the rotational drive of the disk motor ex405, and performs a laser spot tracking process. The system control unit ex407 controls the entire information reproduction / recording unit ex400. In the reading and writing processes described above, the system control unit ex407 uses various kinds of information held in the buffer ex404, and generates and adds new information as necessary, and the modulation recording unit ex402, the reproduction demodulation unit This is realized by recording / reproducing information through the optical head ex401 while operating the ex403 and the servo control unit ex406 in a coordinated manner. The system control unit ex407 is composed of, for example, a microprocessor, and executes these processes by executing a read / write program.

In the above, the optical head ex401 has been described as irradiating a laser spot. However, a configuration in which higher-density recording is performed using near-field light may be used.

FIG. 67 shows a schematic diagram of a recording medium ex215 that is an optical disk. Guide grooves (grooves) are formed in a spiral shape on the recording surface of the recording medium ex215, and address information indicating the absolute position on the disc is recorded in advance on the information track ex230 by changing the shape of the groove. This address information includes information for specifying the position of the recording block ex231 that is a unit for recording data, and the recording block is specified by reproducing the information track ex230 and reading the address information in a recording or reproducing apparatus. Can do. Further, the recording medium ex215 includes a data recording area ex233, an inner peripheral area ex232, and an outer peripheral area ex234. The area used for recording user data is the data recording area ex233, and the inner circumference area ex232 and the outer circumference area ex234 arranged on the inner or outer circumference of the data recording area ex233 are used for specific purposes other than user data recording. Used. The information reproducing / recording unit ex400 reads / writes encoded audio data, video data, or multiplexed data obtained by multiplexing these data with respect to the data recording area ex233 of the recording medium ex215.

In the above description, an optical disk such as a single-layer DVD or BD has been described as an example. However, the present invention is not limited to these, and an optical disk having a multilayer structure and capable of recording other than the surface may be used. Also, an optical disc with a multi-dimensional recording / reproducing structure, such as recording information using light of different wavelengths in the same place on the disc, or recording different layers of information from various angles. It may be.

Also, in the digital broadcasting system ex200, the car ex210 having the antenna ex205 can receive data from the satellite ex202 and the like, and the moving image can be reproduced on a display device such as the car navigation ex211 that the car ex210 has. Note that the configuration of the car navigation ex211 may be, for example, a configuration in which a GPS receiving unit is added in the configuration illustrated in FIG. 65, and the same may be considered for the computer ex111, the mobile phone ex114, and the like.

FIG. 68A is a diagram showing the mobile phone ex114 using the moving picture decoding method and the moving picture encoding method described in the above embodiment. The mobile phone ex114 includes an antenna ex350 for transmitting and receiving radio waves to and from the base station ex110, a camera unit ex365 capable of capturing video and still images, a video captured by the camera unit ex365, a video received by the antenna ex350, and the like Is provided with a display unit ex358 such as a liquid crystal display for displaying the decrypted data. The mobile phone ex114 further includes a main body unit having an operation key unit ex366, an audio output unit ex357 such as a speaker for outputting audio, an audio input unit ex356 such as a microphone for inputting audio, a captured video, In the memory unit ex367 for storing encoded data or decoded data such as still images, recorded audio, received video, still images, mails, or the like, or an interface unit with a recording medium for storing data A slot ex364 is provided.

Furthermore, a configuration example of the mobile phone ex114 will be described with reference to FIG. 68B. The mobile phone ex114 has a power supply circuit part ex361, an operation input control part ex362, and a video signal processing part ex355 with respect to a main control part ex360 that comprehensively controls each part of the main body including the display part ex358 and the operation key part ex366. , A camera interface unit ex363, an LCD (Liquid Crystal Display) control unit ex359, a modulation / demodulation unit ex352, a multiplexing / demultiplexing unit ex353, an audio signal processing unit ex354, a slot unit ex364, and a memory unit ex367 are connected to each other via a bus ex370. ing.

When the end of call and the power key are turned on by a user operation, the power supply circuit unit ex361 starts up the mobile phone ex114 in an operable state by supplying power from the battery pack to each unit.

The cellular phone ex114 converts the audio signal collected by the audio input unit ex356 in the voice call mode into a digital audio signal by the audio signal processing unit ex354 based on the control of the main control unit ex360 having a CPU, a ROM, a RAM, and the like. Then, this is subjected to spectrum spread processing by the modulation / demodulation unit ex352, digital-analog conversion processing and frequency conversion processing are performed by the transmission / reception unit ex351, and then transmitted via the antenna ex350. The mobile phone ex114 also amplifies the received data received via the antenna ex350 in the voice call mode, performs frequency conversion processing and analog-digital conversion processing, performs spectrum despreading processing by the modulation / demodulation unit ex352, and performs voice signal processing unit After being converted into an analog audio signal by ex354, this is output from the audio output unit ex357.

Further, when an e-mail is transmitted in the data communication mode, the text data of the e-mail input by operating the operation key unit ex366 of the main unit is sent to the main control unit ex360 via the operation input control unit ex362. The main control unit ex360 performs spread spectrum processing on the text data in the modulation / demodulation unit ex352, performs digital analog conversion processing and frequency conversion processing in the transmission / reception unit ex351, and then transmits the text data to the base station ex110 via the antenna ex350. . In the case of receiving an e-mail, almost the reverse process is performed on the received data and output to the display unit ex358.

When transmitting video, still images, or video and audio in the data communication mode, the video signal processing unit ex355 compresses the video signal supplied from the camera unit ex365 by the moving image encoding method described in the above embodiments. Encode (that is, function as the image encoding apparatus of the present invention), and send the encoded video data to the multiplexing / demultiplexing unit ex353. The audio signal processing unit ex354 encodes the audio signal picked up by the audio input unit ex356 while the camera unit ex365 images a video, a still image, etc., and sends the encoded audio data to the multiplexing / separating unit ex353. To do.

The multiplexing / demultiplexing unit ex353 multiplexes the encoded video data supplied from the video signal processing unit ex355 and the encoded audio data supplied from the audio signal processing unit ex354 by a predetermined method, and is obtained as a result. The multiplexed data is subjected to spread spectrum processing by the modulation / demodulation unit (modulation / demodulation circuit unit) ex352, digital-analog conversion processing and frequency conversion processing by the transmission / reception unit ex351, and then transmitted via the antenna ex350.

Decode multiplexed data received via antenna ex350 when receiving video file data linked to a homepage, etc. in data communication mode, or when receiving e-mail with video and / or audio attached Therefore, the multiplexing / separating unit ex353 separates the multiplexed data into a video data bit stream and an audio data bit stream, and performs video signal processing on the video data encoded via the synchronization bus ex370. The encoded audio data is supplied to the audio signal processing unit ex354 while being supplied to the unit ex355. The video signal processing unit ex355 decodes the video signal by decoding using the video decoding method corresponding to the video encoding method shown in each of the above embodiments (that is, functions as the image decoding device of the present invention). For example, video and still images included in the moving image file linked to the home page are displayed from the display unit ex358 via the LCD control unit ex359. The audio signal processing unit ex354 decodes the audio signal, and the audio is output from the audio output unit ex357.

In addition to the transmission / reception type terminal having both the encoder and the decoder, the terminal such as the mobile phone ex114 is referred to as a transmission terminal having only an encoder and a receiving terminal having only a decoder. There are three possible mounting formats. Furthermore, in the digital broadcasting system ex200, it has been described that multiplexed data in which music data or the like is multiplexed with video data is received and transmitted, but data in which character data or the like related to video is multiplexed in addition to audio data It may be video data itself instead of multiplexed data.

As described above, the moving picture encoding method or the moving picture decoding method shown in each of the above embodiments can be used in any of the above-described devices / systems. The described effect can be obtained.

Further, the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.

(Embodiment 19)
The moving picture coding method or apparatus shown in the above embodiments and the moving picture coding method or apparatus compliant with different standards such as MPEG-2, MPEG4-AVC, and VC-1 are appropriately switched as necessary. Thus, it is also possible to generate video data.

Here, when a plurality of pieces of video data conforming to different standards are generated, it is necessary to select a decoding method corresponding to each standard when decoding. However, since it is impossible to identify which standard the video data to be decoded complies with, there arises a problem that an appropriate decoding method cannot be selected.

In order to solve this problem, multiplexed data obtained by multiplexing audio data or the like with video data is configured to include identification information indicating which standard the video data conforms to. A specific configuration of multiplexed data including video data generated by the moving picture encoding method or apparatus shown in the above embodiments will be described below. The multiplexed data is a digital stream in the MPEG-2 transport stream format.

FIG. 69 is a diagram showing a structure of multiplexed data. As shown in FIG. 69, multiplexed data is obtained by multiplexing one or more of a video stream, an audio stream, a presentation graphics stream (PG), and an interactive graphics stream. The video stream indicates the main video and sub-video of the movie, the audio stream (IG) indicates the main audio portion of the movie and the sub-audio mixed with the main audio, and the presentation graphics stream indicates the subtitles of the movie. Here, the main video indicates a normal video displayed on the screen, and the sub-video is a video displayed on a small screen in the main video. The interactive graphics stream indicates an interactive screen created by arranging GUI components on the screen. The video stream is encoded by the moving image encoding method or apparatus shown in the above embodiments, or the moving image encoding method or apparatus conforming to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1. ing. The audio stream is encoded by a method such as Dolby AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, or linear PCM.

Each stream included in the multiplexed data is identified by PID. For example, 0x1011 for video streams used for movie images, 0x1100 to 0x111F for audio streams, 0x1200 to 0x121F for presentation graphics, 0x1400 to 0x141F for interactive graphics streams, 0x1B00 to 0x1B1F are assigned to video streams used for sub-pictures, and 0x1A00 to 0x1A1F are assigned to audio streams used for sub-audio mixed with the main audio.

FIG. 70 is a diagram schematically showing how multiplexed data is multiplexed. First, a video stream ex235 composed of a plurality of video frames and an audio stream ex238 composed of a plurality of audio frames are converted into PES packet sequences ex236 and ex239, respectively, and converted into TS packets ex237 and ex240. Similarly, the data of the presentation graphics stream ex241 and interactive graphics ex244 are converted into PES packet sequences ex242 and ex245, respectively, and further converted into TS packets ex243 and ex246. The multiplexed data ex247 is configured by multiplexing these TS packets into one stream.

FIG. 71 shows in more detail how the video stream is stored in the PES packet sequence. The first row in FIG. 71 shows a video frame sequence of the video stream. The second level shows a PES packet sequence. As shown by arrows yy1, yy2, yy3, and yy4 in FIG. 71, a plurality of video presentation units in a video stream are divided into pictures, B pictures, and P pictures, and are stored in the payload of the PES packet. . Each PES packet has a PES header, and a PTS (Presentation Time-Stamp) that is a display time of a picture and a DTS (Decoding Time-Stamp) that is a decoding time of a picture are stored in the PES header.

FIG. 72 shows the format of TS packets that are finally written in the multiplexed data. The TS packet is a 188-byte fixed-length packet composed of a 4-byte TS header having information such as a PID for identifying a stream and a 184-byte TS payload for storing data. The PES packet is divided and stored in the TS payload. The In the case of a BD-ROM, a 4-byte TP_Extra_Header is added to a TS packet, forms a 192-byte source packet, and is written in multiplexed data. In TP_Extra_Header, information such as ATS (Arrival_Time_Stamp) is described. ATS indicates the transfer start time of the TS packet to the PID filter of the decoder. Source packets are arranged in the multiplexed data as shown in the lower part of FIG. 72, and the number incremented from the head of the multiplexed data is called SPN (source packet number).

In addition, TS packets included in the multiplexed data include PAT (Program Association Table), PMT (Program Map Table), PCR (Program Clock Reference), and the like in addition to each stream such as video / audio / caption. PAT indicates what the PID of the PMT used in the multiplexed data is, and the PID of the PAT itself is registered as 0. The PMT has the PID of each stream such as video / audio / subtitles included in the multiplexed data and the attribute information of the stream corresponding to each PID, and has various descriptors related to the multiplexed data. The descriptor includes copy control information for instructing permission / non-permission of copying of multiplexed data. In order to synchronize the ATC (Arrival Time Clock), which is the ATS time axis, and the STC (System Time Clock), which is the PTS / DTS time axis, the PCR corresponds to the ATS in which the PCR packet is transferred to the decoder. Contains STC time information.

FIG. 73 is a diagram for explaining the data structure of the PMT in detail. A PMT header describing the length of data included in the PMT is arranged at the head of the PMT. After that, a plurality of descriptors related to multiplexed data are arranged. The copy control information and the like are described as descriptors. After the descriptor, a plurality of pieces of stream information regarding each stream included in the multiplexed data are arranged. The stream information includes a stream descriptor in which a stream type, a stream PID, and stream attribute information (frame rate, aspect ratio, etc.) are described to identify a compression codec of the stream. There are as many stream descriptors as the number of streams existing in the multiplexed data.

When recording on a recording medium or the like, the multiplexed data is recorded together with the multiplexed data information file.

As shown in FIG. 74, the multiplexed data information file is management information of multiplexed data, has a one-to-one correspondence with the multiplexed data, and includes multiplexed data information, stream attribute information, and an entry map.

As shown in FIG. 74, the multiplexed data information includes a system rate, a reproduction start time, and a reproduction end time. The system rate indicates a maximum transfer rate of multiplexed data to a PID filter of a system target decoder described later. The ATS interval included in the multiplexed data is set to be equal to or less than the system rate. The playback start time is the PTS of the first video frame of the multiplexed data, and the playback end time is set by adding the playback interval for one frame to the PTS of the video frame at the end of the multiplexed data.

In the stream attribute information, as shown in FIG. 75, attribute information about each stream included in the multiplexed data is registered for each PID. The attribute information has different information for each video stream, audio stream, presentation graphics stream, and interactive graphics stream. The video stream attribute information includes the compression codec used to compress the video stream, the resolution of the individual picture data constituting the video stream, the aspect ratio, and the frame rate. It has information such as how much it is. The audio stream attribute information includes the compression codec used to compress the audio stream, the number of channels included in the audio stream, the language supported, and the sampling frequency. With information. These pieces of information are used for initialization of the decoder before the player reproduces it.

In this embodiment, among the multiplexed data, the stream type included in the PMT is used. Also, when multiplexed data is recorded on the recording medium, video stream attribute information included in the multiplexed data information is used. Specifically, in the video encoding method or apparatus shown in each of the above embodiments, the video encoding shown in each of the above embodiments for the stream type or video stream attribute information included in the PMT. There is provided a step or means for setting unique information indicating that the video data is generated by the method or apparatus. With this configuration, it is possible to discriminate between video data generated by the moving picture encoding method or apparatus described in the above embodiments and video data compliant with other standards.

FIG. 76 shows the steps of the moving picture decoding method according to the present embodiment. In step exS100, the stream type included in the PMT or the video stream attribute information included in the multiplexed data information is acquired from the multiplexed data. Next, in step exS101, it is determined whether or not the stream type or the video stream attribute information indicates multiplexed data generated by the moving picture encoding method or apparatus described in the above embodiments. To do. When it is determined that the stream type or the video stream attribute information is generated by the moving image encoding method or apparatus described in the above embodiments, in step exS102, the above embodiments are performed. Decoding is performed by the moving picture decoding method shown in the form. If the stream type or video stream attribute information indicates that it conforms to a standard such as conventional MPEG-2, MPEG4-AVC, or VC-1, in step exS103, the conventional information Decoding is performed by a moving image decoding method compliant with the standard.

In this way, by setting a new unique value in the stream type or video stream attribute information, whether or not decoding is possible with the moving picture decoding method or apparatus described in each of the above embodiments is performed. Judgment can be made. Therefore, even when multiplexed data conforming to different standards is input, an appropriate decoding method or apparatus can be selected, and therefore decoding can be performed without causing an error. In addition, the moving picture encoding method or apparatus or the moving picture decoding method or apparatus described in this embodiment can be used in any of the above-described devices and systems.

(Embodiment 20)
The moving picture encoding method and apparatus and moving picture decoding method and apparatus described in the above embodiments are typically realized by an LSI that is an integrated circuit. As an example, FIG. 77 shows a configuration of LSI ex500 that is made into one chip. The LSI ex500 includes elements ex501, ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 described below, and each element is connected via a bus ex510. The power supply circuit unit ex505 is activated to an operable state by supplying power to each unit when the power supply is on.

For example, when performing the encoding process, the LSI ex500 performs the microphone ex117 and the camera ex113 by the AV I / O ex509 based on the control of the control unit ex501 including the CPU ex502, the memory controller ex503, the stream controller ex504, the drive frequency control unit ex512, and the like. The AV signal is input from the above. The input AV signal is temporarily stored in an external memory ex511 such as SDRAM. Based on the control of the control unit ex501, the accumulated data is divided into a plurality of times as appropriate according to the processing amount and the processing speed and sent to the signal processing unit ex507, and the signal processing unit ex507 encodes an audio signal and / or video. Signal encoding is performed. Here, the encoding process of the video signal is the encoding process described in the above embodiments. The signal processing unit ex507 further performs processing such as multiplexing the encoded audio data and the encoded video data according to circumstances, and outputs the result from the stream I / Oex 506 to the outside. The output multiplexed data is transmitted to the base station ex107 or written to the recording medium ex215. It should be noted that data should be temporarily stored in the buffer ex508 so as to be synchronized when multiplexing.

In the above description, the memory ex511 is described as an external configuration of the LSI ex500. However, a configuration included in the LSI ex500 may be used. The number of buffers ex508 is not limited to one, and a plurality of buffers may be provided. The LSI ex500 may be made into one chip or a plurality of chips.

In the above description, the control unit ex501 includes the CPU ex502, the memory controller ex503, the stream controller ex504, the drive frequency control unit ex512, and the like, but the configuration of the control unit ex501 is not limited to this configuration. For example, the signal processing unit ex507 may further include a CPU. By providing a CPU also in the signal processing unit ex507, the processing speed can be further improved. As another example, the CPU ex502 may be configured to include a signal processing unit ex507 or, for example, an audio signal processing unit that is a part of the signal processing unit ex507. In such a case, the control unit ex501 is configured to include a signal processing unit ex507 or a CPU ex502 having a part thereof.

In addition, although it was set as LSI here, it may be called IC, system LSI, super LSI, and ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of progress in semiconductor technology or other derived technology, it is naturally possible to integrate functional blocks using this technology. Biotechnology can be applied.

(Embodiment 21)
When decoding the video data generated by the moving picture encoding method or apparatus shown in the above embodiments, the video data conforming to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1 is decoded. It is conceivable that the amount of processing increases compared to the case. Therefore, in LSI ex500, it is necessary to set a driving frequency higher than the driving frequency of CPU ex502 when decoding video data compliant with the conventional standard. However, when the drive frequency is increased, there is a problem that power consumption increases.

In order to solve this problem, moving picture decoding devices such as the television ex300 and LSI ex500 are configured to identify which standard the video data conforms to and switch the driving frequency in accordance with the standard. FIG. 78 shows a configuration ex800 in the present embodiment. The drive frequency switching unit ex803 sets the drive frequency high when the video data is generated by the moving image encoding method or apparatus described in the above embodiments. Then, the decoding processing unit ex801 that executes the moving picture decoding method described in each of the above embodiments is instructed to decode the video data. On the other hand, when the video data is video data compliant with the conventional standard, compared to the case where the video data is generated by the moving picture encoding method or apparatus shown in the above embodiments, Set the drive frequency low. Then, it instructs the decoding processing unit ex802 compliant with the conventional standard to decode the video data.

More specifically, the drive frequency switching unit ex803 includes a CPU ex502 and a drive frequency control unit ex512 in FIG. Also, the decoding processing unit ex801 that executes the moving picture decoding method shown in each of the above embodiments and the decoding processing unit ex802 that complies with the conventional standard correspond to the signal processing unit ex507 in FIG. The CPU ex502 identifies which standard the video data conforms to. Then, based on the signal from the CPU ex502, the drive frequency control unit ex512 sets the drive frequency. Further, based on the signal from the CPU ex502, the signal processing unit ex507 decodes the video data. Here, for example, the identification information described in the nineteenth embodiment may be used for identifying the video data. The identification information is not limited to that described in the nineteenth embodiment, and any information that can identify which standard the video data conforms to may be used. For example, it is possible to identify which standard the video data conforms to based on an external signal that identifies whether the video data is used for a television or a disk. In some cases, identification may be performed based on such an external signal. In addition, the selection of the driving frequency in the CPU ex502 may be performed based on, for example, a lookup table in which video data standards and driving frequencies are associated with each other as shown in FIG. The look-up table is stored in the buffer ex508 or the internal memory of the LSI, and the CPU ex502 can select the drive frequency by referring to the look-up table.

FIG. 79 shows steps for executing the method of the present embodiment. First, in step exS200, the signal processing unit ex507 acquires identification information from the multiplexed data. Next, in step exS201, the CPU ex502 identifies whether the video data is generated by the encoding method or apparatus described in each of the above embodiments based on the identification information. When the video data is generated by the encoding method or apparatus shown in the above embodiments, in step exS202, the CPU ex502 sends a signal for setting the drive frequency high to the drive frequency control unit ex512. Then, the drive frequency control unit ex512 sets a high drive frequency. On the other hand, if it indicates that the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1, in step exS203, the CPU ex502 drives the signal for setting the drive frequency low. This is sent to the frequency control unit ex512. Then, in the drive frequency control unit ex512, the drive frequency is set to be lower than that in the case where the video data is generated by the encoding method or apparatus described in the above embodiments.

Furthermore, the power saving effect can be further enhanced by changing the voltage applied to the LSI ex500 or the device including the LSI ex500 in conjunction with the switching of the driving frequency. For example, when the drive frequency is set low, it is conceivable that the voltage applied to the LSI ex500 or the device including the LSI ex500 is set low as compared with the case where the drive frequency is set high.

In addition, the setting method of the driving frequency may be set to a high driving frequency when the processing amount at the time of decoding is large, and to a low driving frequency when the processing amount at the time of decoding is small. It is not limited to the method. For example, the amount of processing for decoding video data compliant with the MPEG4-AVC standard is larger than the amount of processing for decoding video data generated by the moving picture encoding method or apparatus described in the above embodiments. It is conceivable that the setting of the driving frequency is reversed to that in the case described above.

Furthermore, the method for setting the drive frequency is not limited to the configuration in which the drive frequency is lowered. For example, when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in the above embodiments, the voltage applied to the LSIex500 or the apparatus including the LSIex500 is set high. However, when it is shown that the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, VC-1, etc., it is also possible to set the voltage applied to the LSIex500 or the device including the LSIex500 low. It is done. As another example, when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in the above embodiments, the driving of the CPU ex502 is stopped. If the video data conforms to the standards such as MPEG-2, MPEG4-AVC, VC-1, etc., the CPU ex502 is temporarily stopped because there is room in processing. Is also possible. Even when the identification information indicates that the video data is generated by the moving image encoding method or apparatus described in each of the above embodiments, if there is a margin for processing, the CPU ex502 is temporarily driven. It can also be stopped. In this case, it is conceivable to set the stop time shorter than in the case where the video data conforms to the conventional standards such as MPEG-2, MPEG4-AVC, and VC-1.

Thus, it is possible to save power by switching the drive frequency according to the standard to which the video data conforms. In addition, when the battery is used to drive the LSI ex500 or the device including the LSI ex500, it is possible to extend the life of the battery with power saving.

(Embodiment 22)
A plurality of video data that conforms to different standards may be input to the above-described devices and systems such as a television and a mobile phone. As described above, the signal processing unit ex507 of the LSI ex500 needs to support a plurality of standards in order to be able to decode even when a plurality of video data complying with different standards is input. However, when the signal processing unit ex507 corresponding to each standard is used individually, there is a problem that the circuit scale of the LSI ex500 increases and the cost increases.

In order to solve this problem, a decoding processing unit for executing the moving picture decoding method shown in each of the above embodiments and a decoding conforming to a standard such as MPEG-2, MPEG4-AVC, or VC-1 The processing unit is partly shared. An example of this configuration is shown as ex900 in FIG. 81A. For example, the moving picture decoding method shown in each of the above embodiments and the moving picture decoding method compliant with the MPEG4-AVC standard are processed in processes such as entropy coding, inverse quantization, deblocking filter, and motion compensation. Some contents are common. For the common processing content, the decoding processing unit ex902 corresponding to the MPEG4-AVC standard is shared, and for the other processing content unique to the present invention not corresponding to the MPEG4-AVC standard, the dedicated decoding processing unit ex901 is used. Configuration is conceivable. Regarding the sharing of the decoding processing unit, regarding the common processing content, the decoding processing unit for executing the moving picture decoding method described in each of the above embodiments is shared, and the processing content specific to the MPEG4-AVC standard As for, a configuration using a dedicated decoding processing unit may be used.

Further, ex1000 in FIG. 81B shows another example in which processing is partially shared. In this example, a dedicated decoding processing unit ex1001 corresponding to processing content unique to the present invention, a dedicated decoding processing unit ex1002 corresponding to processing content specific to other conventional standards, and a moving picture decoding method of the present invention A common decoding processing unit ex1003 corresponding to processing contents common to other conventional video decoding methods is used. Here, the dedicated decoding processing units ex1001 and ex1002 are not necessarily specialized in the processing content specific to the present invention or other conventional standards, and may be capable of executing other general-purpose processing. Also, the configuration of the present embodiment can be implemented by LSI ex500.

As described above, by sharing the decoding processing unit with respect to the processing contents common to the moving picture decoding method of the present invention and the moving picture decoding method of the conventional standard, the circuit scale of the LSI is reduced, and the cost is reduced. It is possible to reduce.

The moving picture encoding method and the moving picture decoding method according to the present invention can be applied to any multimedia data, and can improve the compression rate. For example, a mobile phone, a DVD device, a personal computer, etc. It is useful as a moving image encoding method and a moving image decoding method in storage, transmission, communication, etc.

DESCRIPTION OF SYMBOLS 100 Moving image encoder 101 Orthogonal transformation part 102 Quantization part 103 Inverse quantization part 104 Inverse orthogonal transformation part 105 Block memory 106 Frame memory 107 Intra prediction part 108 Inter prediction part 109 Inter prediction control part 110 Picture type determination part 111 See Picture list management unit 112 Skip mode prediction direction determination unit 113 Variable length coding unit 500 Video decoding device 501 Variable length decoding unit 502 Inverse quantization unit 503 Inverse orthogonal transformation unit 504 Block memory 505 Frame memory 506 Intra prediction unit 507 Inter prediction unit 508 Inter prediction control unit 509 Reference picture list management unit 510 Skip mode prediction direction determination unit

Claims

Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A prediction direction switching step for switching a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result;
A moving picture encoding method including:
The predetermined encoding mode is a skip mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the skip mode is set to one-way prediction in which encoding is performed with reference to one reference picture,
The moving image according to claim 1, wherein if the result of the same reference picture list determination is false, the prediction direction in the skip mode is set to bi-directional prediction in which encoding is performed by referring to at least two reference pictures. Image coding method.
The predetermined encoding mode is a direct mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the direct mode is set to bi-directional prediction in which encoding is performed with reference to at least two reference pictures.
If the result of the same reference picture determination is false, the prediction direction of the block to be encoded is selected from the two-way prediction and the one-way prediction in which encoding is performed with reference to one reference picture. The moving image encoding method according to claim 1, wherein a prediction direction flag representing the prediction direction is added to a bitstream.
The predetermined encoding mode is a merge mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the merge mode is set to one-way prediction in which encoding is performed with reference to one reference picture,
The moving picture encoding method according to claim 1, wherein if the result of the same reference picture list determination is false, the prediction direction in the merge mode is determined from an adjacent block of the encoding target block.
The predetermined encoding mode is a skip mode, a direct mode, or a merge mode,
The moving picture coding according to claim 1, wherein the reference picture referred to by the encoding target block is set to the reference picture that is referred to most frequently among the reference pictures referenced by adjacent blocks of the encoding target block. Method.
The predetermined encoding mode is a skip mode, a direct mode, or a merge mode,
The moving image according to claim 1, wherein the index value of the reference picture referred to by the encoding target block is set to an intermediate value of the index value of the reference picture referenced by an adjacent block of the encoding target block. Encoding method.
The predetermined encoding mode is a skip mode, a direct mode, or a merge mode,
The reference picture referred to by the encoding target block is set to the reference picture that is closest to the encoding target picture in display order among the reference pictures referenced by blocks adjacent to the encoding target block. Item 8. A moving image encoding method according to Item 1.
The predetermined encoding mode is a skip mode, a direct mode, or a merge mode,
The moving picture according to claim 1, wherein the index value of the reference picture referred to by the encoding target block is set to a minimum value of the index value of the reference picture referred to by an adjacent block of the encoding target block. Encoding method.
Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A prediction direction flag adding step of adding a prediction direction flag representing a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result;
A moving picture encoding method including:
The predetermined encoding mode is a skip mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the prediction direction flag adding step,
If the result of the same reference picture list determination is false, the prediction direction of the skip mode is set to bi-directional prediction in which encoding is performed with reference to at least two reference pictures.
If the result of the same reference picture list determination is true, in addition to the two-way prediction, in the prediction direction of the skip mode, add one-way prediction that performs coding with reference to one reference picture, The video encoding method according to claim 9, wherein the prediction direction flag indicating the prediction direction used for encoding the block to be encoded is added to a bitstream.
Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A prediction direction switching step for switching a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result;
A header information adding step of adding to the header information a prediction direction flag indicating the prediction direction when the encoding target block determined based on the determination result is encoded in a predetermined encoding mode;
A moving picture encoding method including:
The predetermined encoding mode is a skip mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the skip mode is set to one-way prediction in which encoding is performed with reference to one reference picture,
If the result of the same reference picture list determination is false, the prediction direction of the skip mode is set to bi-directional prediction in which encoding is performed with reference to at least two reference pictures.
In the header information adding step,
The moving picture encoding method according to claim 11, wherein a prediction direction flag indicating the prediction direction of the skip mode determined based on the same reference picture list determination result is added to header information.
Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
Based on the determination result, a prediction direction addition flag indicating whether or not to add a prediction direction flag when the encoding target block is encoded in a predetermined encoding mode for each encoding target block is used as header information. A prediction direction addition flag addition step to be added;
Encoding the encoding target block in a predetermined encoding mode based on the prediction direction addition flag;
A moving picture encoding method including:
The predetermined encoding mode is a skip mode;
When the prediction direction addition flag added to the header information is off, the encoding target block is encoded using bi-directional prediction that references at least two reference pictures.
When the prediction direction addition flag added to the header information is on, in addition to the bi-directional prediction, unidirectional prediction is performed by referring to one reference picture, and finally the encoding target The moving picture coding method according to claim 13, wherein the prediction direction flag indicating the prediction direction used for coding a block is added to a bitstream.
Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A header information adding step of adding to the header information a prediction direction fixing flag indicating whether or not to fix a prediction direction when the encoding target block is encoded in a predetermined encoding mode based on the determination result;
An encoding step of encoding the encoding target block in the predetermined encoding mode based on the prediction direction fixed flag;
A moving picture encoding method including:
The predetermined encoding mode is a direct mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the header information adding step,
If the result of the same reference picture list determination is true, the prediction direction fixed flag is turned on and added to the header information. If the result of the same reference picture determination is false, the prediction direction fixed flag is turned off. To the header information,
In the encoding step,
When the prediction direction fixed flag is on, the prediction direction is set to bi-directional prediction that refers to at least two reference pictures.
When the prediction direction fixed flag is off, the prediction direction of the coding target block is selected from the two-way prediction and the one-way prediction that performs coding with reference to the reference picture, and the selected prediction direction is selected. The moving image encoding method according to claim 15, wherein a prediction direction flag indicating a prediction direction is added to the bitstream.
Using at least two or more reference picture lists, at least one reference picture list different from the encoding target picture including the encoding target block is used to assign an index to the reference picture and code the encoding target block A moving image encoding method for
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
Based on the determination result, a prediction direction fixing flag indicating whether or not to fix a prediction direction when the encoding target block is encoded in a predetermined encoding mode, and a first indicating the fixed prediction direction A header information adding step of adding a prediction direction flag to the header information;
An encoding step of encoding the block to be encoded in the predetermined encoding mode based on the prediction direction fixed flag and the first prediction direction flag;
A moving picture encoding method including:
The predetermined encoding mode is a direct mode;
In the same reference picture list determination step,
It is determined whether the index allocation method for the reference picture that can be referred to by the encoding target picture is the same in the first reference picture list and the second reference picture list included in the encoding target picture. And
In the header information adding step,
If the result of the same reference picture list determination is true, the prediction direction fixed flag is turned on and added to the header information, and further, a first prediction direction flag representing the fixed prediction direction is added to the header information. Add
If the result of the same reference picture determination is false, turn off the prediction direction fixed flag and add to the header information,
In the encoding step,
When the prediction direction fixed flag is on, the first prediction direction flag is set to the prediction direction of the encoding target block,
When the prediction direction fixed flag is off, the prediction direction of the coding target block is selected from the two-way prediction and the one-way prediction that performs coding with reference to the reference picture, and the selected prediction direction is selected. The moving image encoding method according to claim 17, wherein a prediction direction flag indicating a prediction direction is added to the bitstream.
The determination in the same reference picture list determination step using the display order or the encoding order of the reference pictures to which the index is assigned in the reference picture list. A video encoding method.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A prediction direction switching step of switching a prediction direction when decoding the block to be decoded in a predetermined decoding mode based on the determination result;
A moving picture decoding method including:
The predetermined decoding mode is a skip mode;
In the same reference picture list determination step,
It is determined whether or not the index allocation method for the reference picture that can be referred to by the decoding target picture is the same in the first reference picture list and the second reference picture list included in the decoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the skip mode is set to one-way prediction for decoding with reference to one reference picture,
The moving image according to claim 20, wherein if the result of the same reference picture list determination is false, the prediction direction of the skip mode is set to bi-directional prediction in which decoding is performed with reference to at least two reference pictures. Image decoding method.
The predetermined decoding mode is a direct mode;
In the same reference picture list determination step,
It is determined whether or not the index allocation method for the reference picture that can be referred to by the decoding target picture is the same in the first reference picture list and the second reference picture list included in the decoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the direct mode is set to bi-directional prediction in which decoding is performed with reference to at least two reference pictures.
If the same reference picture list determination result is false, the direct mode prediction direction flag is decoded from a bitstream, and the decoding target block is decoded based on the decoded prediction direction flag. 20. The moving picture decoding method according to 20.
The predetermined decoding mode is a merge mode;
In the same reference picture list determination step,
It is determined whether or not the index allocation method for the reference picture that can be referred to by the decoding target picture is the same in the first reference picture list and the second reference picture list included in the decoding target picture. And
In the prediction direction switching step,
If the result of the same reference picture list determination is true, the prediction direction of the merge mode is set to one-way prediction for decoding with reference to one reference picture,
The moving picture decoding method according to claim 20, wherein if the result of the same reference picture list determination is false, the prediction direction in the merge mode is set to a prediction direction obtained from an adjacent block of the decoding target block.
The predetermined decoding mode is a skip mode or a direct mode,
The moving picture decoding according to claim 20, wherein the reference picture referred to by the decoding target block is set to the reference picture referenced most frequently among the reference pictures referenced by adjacent blocks of the decoding target block. Method.
The predetermined decoding mode is a skip mode or a direct mode,
The moving image according to claim 20, wherein the index value of the reference picture referred to by the decoding target block is set to an intermediate value of the index value of the reference picture referred to by an adjacent block of the decoding target block. Decryption method.
The predetermined decoding mode is a skip mode or a direct mode,
The reference picture referred to by the decoding target block is set to the reference picture that is closest to the decoding target picture in display order among the reference pictures referenced by blocks adjacent to the decoding target block. Item 20. The moving picture decoding method according to Item 20.
The predetermined decoding mode is a skip mode or a direct mode,
The moving picture according to claim 20, wherein the index value of the reference picture referred to by the decoding target block is set to a minimum value of the index value of the reference picture referred to by an adjacent block of the decoding target block. Decryption method.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
In the two or more reference picture lists, the same reference picture list determination step of determining whether or not the index allocation method for the reference pictures is the same;
A prediction direction flag decoding step of decoding a prediction direction flag indicating a prediction direction when decoding the decoding target block in a predetermined decoding mode based on the determination result;
A moving picture decoding method including:
The predetermined decoding mode is a skip mode;
In the same reference picture list determination step,
It is determined whether or not the index allocation method for the reference picture that can be referred to by the decoding target picture is the same in the first reference picture list and the second reference picture list included in the decoding target picture. And
In the prediction direction flag decoding step,
If the result of the same reference picture list determination is false, the prediction direction of the skip mode is set to bi-directional prediction for decoding with reference to at least two reference pictures,
If the same reference picture list determination result is true, the prediction direction flag in the skip mode is decoded from a bitstream, and the decoding target block is decoded based on the decoded prediction direction flag. Item 29. The moving picture decoding method according to Item 28.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
Decoding a prediction direction flag indicating a prediction direction when decoding the decoding target block in a predetermined decoding mode from header information;
Decoding the decoding target block in a predetermined decoding mode based on the decoded prediction direction flag;
A moving picture decoding method including:
The predetermined decoding mode is a skip mode;
When the prediction direction flag decoded from the header information is unidirectional prediction, the decoding target block is decoded with reference to one reference picture,
The video decoding method according to claim 30, wherein when the prediction direction flag decoded from the header information is bi-directional prediction, the decoding target block is decoded with reference to at least two reference pictures.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
Decoding a flag indicating whether or not a prediction direction flag indicating a prediction direction has been added for each decoding target block when decoding the decoding target block in a predetermined decoding mode; and
Decoding the block to be decoded in a predetermined decoding mode based on the flag;
A moving picture decoding method including:
The predetermined decoding mode is a skip mode;
When the flag decoded from the header is OFF, the decoding target block is decoded using bi-directional prediction that refers to at least two reference pictures.
The moving image according to claim 32, wherein when the flag decoded from the header information is on, the prediction direction is decoded from a bitstream, and the block to be decoded is decoded based on the previous prediction direction decoded in the previous period. Decryption method.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
Decoding a prediction direction fixing flag indicating whether or not to fix a prediction direction when decoding the decoding target block in a predetermined decoding mode from a bitstream;
Decoding the block to be decoded in the predetermined decoding mode based on the prediction direction fixed flag;
A moving picture decoding method including:
The predetermined decoding mode is a direct mode;
If the decoded prediction direction fixed flag is on, the prediction direction is set to bi-directional prediction referring to at least two or more reference pictures,
The decoded prediction direction flag is decoded from the bitstream when the decoded prediction direction fixed flag is off, and the decoding target block is decoded based on the decoded prediction direction flag. 34. The moving picture decoding method according to 34.
Using at least two or more reference picture lists, at least one reference picture list different from the decoding target picture including the decoding target block is used to assign an index to the reference picture and decode the decoding target block A moving picture decoding method
Decoding a prediction direction fixing flag indicating whether or not to fix a prediction direction when decoding the decoding target block in a predetermined decoding mode, and decoding the fixed first prediction direction flag from a bitstream; ,
Decoding the block to be decoded in the predetermined decoding mode based on the prediction direction fixed flag and the first prediction direction flag;
A moving picture decoding method including:
The predetermined decoding mode is a direct mode;
When the decoded prediction direction fixed flag is on, the first prediction direction flag is decoded from the bitstream, and the decoded first prediction direction flag is set as the prediction direction of the decoding target block. ,
When the prediction direction fixed flag is off, the second prediction direction flag in the direct mode is decoded from the bitstream, and the decoding target block is decoded based on the decoded second prediction direction. The video decoding method according to claim 36, wherein the video decoding method is performed.
The determination in the same reference picture list determination step using the display order or decoding order of the reference pictures to which the index is assigned in the reference picture list. Video decoding method.