RU2823042C1 - Encoder, decoder and corresponding methods to simplify signaling of picture header - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to image encoding and decoding. Disclosed is a method which involves parsing a bit stream to obtain a flag from the header of the picture of the bit stream, wherein the flag indicates whether the current picture is an I-picture. When the flag indicates that the current picture is an I-picture, the syntax element intended for external prediction is logically output as a default value; or, when the flag indicates that the current picture is a P or B picture, obtaining a syntax element intended for external prediction from the picture header.

EFFECT: high efficiency of encoding and decoding.

21 cl, 19 dwg

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to US Provisional Application No. 62/913,730, filed October 10, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

Embodiments of the present application (disclosure) generally relate to the field of picture processing and, more specifically, to simplifying picture header signaling.

BACKGROUND OF THE ART

Video encoding (video encoding and decoding) is used in a wide range of digital video applications, such as digital broadcast television, video transmission over the Internet and mobile networks, real-time conversational applications such as video chat, video conferencing, DVD and Blu-ray discs, systems for collecting and editing video content and video cameras for security applications.

The amount of video data required to present even a relatively short video can be significant, which can lead to difficulties when the data must be streamed or otherwise communicated over a communications network with limited bandwidth. Thus, video data is typically compressed before being transmitted over modern telecommunications networks. Video size can also be an issue when the video is stored on a storage device, as memory resources may be limited. Video compression devices often use software and/or hardware at the source to encode video data before transmission or storage, thereby reducing the amount of data required to represent digital video images. The compressed data is then received by the recipient's video decompressor, which decodes the video data. With limited network resources and ever-increasing demands for higher video quality, simplifying picture header signaling is desirable.

SUMMARY OF THE INVENTION

Embodiments of the present application provide apparatus and methods for encoding and decoding according to independent claims.

The above and other goals are achieved by the invention according to independent claims. Additional forms of implementation are obvious from the dependent claims, description and figures.

According to a first aspect, the invention relates to an encoding method implemented by a decoding device. The method includes parsing a bitstream to obtain a flag from a bitstream picture header, wherein the flag indicates whether the current picture is an I-picture.

When the flag indicates that the current picture is an I-picture, the syntax element intended for external prediction is output as the default value; or when the flag indicates that the current picture is picture P or B, obtaining a syntactic element intended for external prediction from the picture header.

A syntax element intended for external prediction includes one or more of the following elements: pic_log2_diff_min_qt_min_cb_inter_slice, pic_max_mtt_hierarchy_depth_inter_slice, pic_log2_diff_max_bt_min_qt_inter_slice, pic_log2_diff_max_tt_min_qt_inter_slice, pic_cu_qp_ delta_subdiv_inter_slice, pic_cu_chroma_qp_offset_subdiv_inter_slice, pic_temporal_mvp_enabled_flag, mvd_l1_zero_flag, pic_fpel_mmvd_enabled_flag or pic_disable_bdof_dmvr_flag.

According to a second aspect, the invention relates to an encoding method implemented by an encoding device. The method includes determining whether the current picture is an I picture; And

sending the bit stream to the decoding device, wherein the bit stream picture header includes a flag indicating whether the current picture is an I picture; and wherein, when the current picture is an I-picture, the syntactic element for inter-prediction is not signaled in the picture header; or when the current picture is picture P or B, a syntactic element for inter-prediction is signaled in the header of the picture.

The method according to the first aspect of the invention can be carried out by apparatus according to the third aspect of the invention. Additional features and forms of implementation of the method according to the third aspect of the invention correspond to the features and forms of implementation of the equipment according to the first aspect of the invention.

The method according to the second aspect of the invention can be carried out by apparatus according to the fourth aspect of the invention. Additional features and forms of implementation of the method according to the fourth aspect of the invention correspond to the features and forms of implementation of the equipment according to the second aspect of the invention.

According to a fifth aspect, the invention relates to apparatus for decoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the first aspect.

According to a sixth aspect, the invention relates to apparatus for encoding a video stream, including a processor and a memory. The memory stores instructions that cause the processor to execute the method according to the second aspect.

According to a seventh aspect, there is provided a computer-readable medium on which instructions are stored that, when executed, cause operation of one or more processors configured to encode video data. The instructions cause one or more processors to perform a method according to the first or second aspect or any possible embodiment of the first or second aspect.

According to an eighth aspect, the invention relates to a computer program containing program code for performing a method according to the first or second aspect or any possible embodiment of the first or second aspect when executed on a computer.

As discussed above, by indicating whether the current picture is an I-picture in the bitstream picture header, the syntax element for inter-prediction is not signaled in the picture header when the current picture is an I-picture. Thus, embodiments can simplify picture header signaling for all internal pictures, i.e., I picture. Accordingly, signaling overhead costs are reduced.

Details of one or more embodiments are set forth in the accompanying drawings and in the following description. Other features, objects and advantages will be apparent from the description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments, the inventions are described in more detail with reference to the accompanying figures and drawings, in which:

Fig. 1A is a block diagram showing an example of a video encoding system configured to implement embodiments of the invention;

FIG. 1B is a block diagram showing another example of a video encoding system configured to implement embodiments of the invention; FIG.

Fig. 2 is a block diagram showing an example of a video encoder configured to implement embodiments of the invention;

Fig. 3 is a block diagram showing an example of a structure of a video decoder configured to implement embodiments of the invention;

Fig. 4 is a block diagram illustrating an example of encoding equipment or decoding equipment;

Fig. 5 is a block diagram illustrating another example of encoding equipment or decoding equipment;

Fig. 6 is an example of the RBSP syntax for a set of picture parameters;

Fig. 7 is an example of the RBSP picture parameter set syntax;

Fig. 8 is an example of the syntax of a set of adaptation parameters;

Fig. 9 is an example of general slice header syntax;

Fig. 10a is an example of the syntactic structure of an encoding tree unit;

Fig. 10b is an example of picture header syntax;

Fig. 11 is another example of general slice header syntax;

Fig. 12 is a block diagram 1200 illustrating a method implemented by an encoding device;

Fig. 13 shows a block diagram 1300 illustrating a method implemented by a decoding apparatus;

Fig. 14 illustrates the configuration of an encoding device;

Fig. 15 illustrates the configuration of a decoding device;

Fig. 16 is a block diagram showing an exemplary structure of a content delivery system 3100 that implements a content delivery service; And

Fig. 17 is a block diagram showing the structure of an exemplary terminal device.

The following identical reference numerals refer to identical or at least functionally equivalent functions unless explicitly stated otherwise.

IMPLEMENTATION OF THE INVENTION

In the following description, reference is made to the accompanying drawings, which form a part of this disclosure and which show, by way of illustration, specific aspects of embodiments of the invention or specific aspects in which embodiments of the present invention may be used. It is understood that embodiments of the present invention may be used in other aspects and contain structural or logical changes not shown in the figures. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

For example, it will be understood that the disclosure associated with the described method may also apply to a corresponding device or system configured to perform the method, and vice versa. For example, if one or a plurality of specific method steps are described, the corresponding apparatus may include one or a plurality of blocks, such as functional blocks, to perform the one or multiple method steps described (e.g., one block performing one or a plurality of steps, or a plurality of blocks, each of which performs one or more of a plurality of steps), even if such one or more blocks are not explicitly described or illustrated in the figures. On the other hand, for example, if a particular device is described in terms of one or a plurality of blocks, such as functional blocks, the corresponding method may include one step for performing the functionality of the one or multiple blocks (e.g., one step performing the functionality of the one or multiple blocks , or a plurality of steps, each of which performs the functionality of one or more of a plurality of blocks), even if such one or multiple steps are not explicitly described or illustrated in the figures. It is further understood that features of various exemplary embodiments and/or aspects described herein may be combined with each other unless specifically stated otherwise.

Video encoding generally refers to the processing of the sequence of pictures that form a video or video sequence. Instead of the term "picture", the term "frame" or "image" can be used interchangeably in the field of video encoding. Video encoding (or encoding in general) consists of two parts: video encoding and video decoding. Video encoding is performed at the source side and typically involves processing (eg, through compression) of the source video images to reduce the amount of data required to represent the video images (for more efficient storage and/or transmission). Video decoding is performed on the receiver (destination) side and usually contains reverse processing compared to the encoder for reconstructing video images. Embodiments relating to "encoding" of video pictures (or pictures in general) are to be understood as referring to "encoding" or "decoding" video pictures or corresponding video sequences. The combination of an encoding part and a decoding part is also called CODEC (encoding and decoding).

In the case of lossless video encoding, the original video images can be restored, i.e., the restored video images have the same quality as the original video images (provided that no transmission loss or other data loss occurs during storage or transmission). In the case of lossy video encoding, additional compression is performed, for example through quantization, to reduce the amount of data representing video images that cannot be fully reconstructed at the decoder, i.e. the quality of the restored video images is lower or worse compared to the quality of the original video images.

Several video coding standards belong to the group of "hybrid lossy video codecs" (i.e., they combine spatial and temporal prediction in the sample domain and 2D transform coding to apply quantization in the transform domain). Each picture of a video sequence is usually divided into a set of non-overlapping blocks, and encoding is usually done at the block level (block level). In other words, in a video encoder, video is typically processed, that is, encoded, at the block (video block) level, for example using spatial (in-picture) prediction and/or temporal (out-of-picture) prediction to generate a prediction block, the prediction block being subtracted from the current block ( block that is currently being processed/to be processed) to obtain a residual block, the residual block is transformed and this residual block is quantized in the transform domain to reduce the amount of data (compression) to be transmitted, whereas in the decoder, reverse processing compared to the encoder is applied to an encoded or compressed block to reconstruct the current block for presentation. In addition, the encoder duplicates the decoder's processing loop so that they will both generate identical predictions (eg, intra and outer predictions) and/or reconstructions for processing, ie encoding, of subsequent blocks.

In the following embodiments, the video encoding system 10, video encoder 20, and video decoder 30 are described based on FIGS. from 1 to 3.

Fig. 1A is a schematic block diagram illustrating an exemplary encoding system 10, such as video encoding system 10 (or encoding system 10 for short), which may use the techniques of the present application. Video encoder 20 (or encoder 20 for short) and video decoder 30 (or decoder 30 for short) of video encoding system 10 are examples of devices that may be configured to perform methods in accordance with various examples described herein.

As shown in FIG. 1A, encoding system 10 includes a source device 12 configured to provide encoded picture data 21, for example, to a destination device 14 for decoding the encoded picture data 13.

The source device 12 contains an encoder 20 and can additionally, i.e. optionally comprising a picture source 16, a preprocessor (or preprocessing unit) 18, such as a picture preprocessor 18, and a communications interface or communications unit 22.

The picture source 16 may contain or be any type of picture capturing device, such as a camera for capturing a real world picture, and/or any type of picture generating device, such as a computer graphics processor for generating a computer animated picture, or any type of other device for obtaining and /or providing a real-world image, a computer-generated image (e.g., screen content, virtual reality (VR) image), and/or any combination thereof (e.g., augmented reality (AR) image). The source of the picture can be any type of memory or storage that stores any of the above pictures.

In contrast to the preprocessor 18 and the processing performed by the preprocessing unit 18, the picture or picture data 17 may also be referred to as a raw picture or raw picture data 17.

The preprocessor 18 is configured to receive (raw) picture data 17 and perform preprocessing on the picture data 17 to produce a preprocessed picture 19 or preprocessed picture data 19. Preprocessing performed by preprocessor 18 may, for example, comprise cropping, color format conversion (eg, RGB to YCbCr), color correction, or noise reduction. It can be understood that the preprocessing unit 18 may be an optional component.

Video encoder 20 is configured to receive pre-processed picture data 19 and provide encoded picture data 21 (further details will be described below, eg based on FIG. 2).

The communication interface 22 of the source device 12 may be configured to receive encoded picture data 21 and transmit this encoded picture data 21 (or any additional processed version thereof) over the communication channel 13 to another device, such as the destination device 14 or any other device. , for saving or immediate restoration.

The recipient device 14 includes a decoder 30 (eg, video decoder 30) and may additionally, i.e. optionally comprising a communication interface or communication unit 28, a post processor 32 (or post processing unit 32) and a display device 34.

The communication interface 28 of the destination device 14 is configured to receive encoded picture data 21 (or any additional processed version thereof), for example, directly from the source device 12 or from any other source, such as a storage device, for example, an encoded picture data storage device, and providing the encoded picture data 21 to the decoder 30.

The communication interface 22 and the communication interface 28 may be configured to transmit or receive encoded picture data 21 or encoded data 13 through a direct communication link between the source device 12 and the destination device 14, such as a direct wired or wireless connection, or through a network of any type, for example, a wired or wireless network or any combination thereof, or any private and public network, or any combination thereof.

The communications interface 22 may, for example, be configured to package the encoded picture data 21 into an appropriate format, such as packets, and/or process the encoded picture data using any type of transmission encoding or processing for transmission over a communications channel or communications network.

The communication interface 28, which is analogous to the communication interface 22, may, for example, be configured to receive the transmitted data and process the transmission data using any kind of appropriate decoding or transmission processing and/or decompression to obtain the encoded picture data 21.

Both communication interface 22 and communication interface 28 may be configured as unidirectional communication interfaces, as shown by the arrow for communication channel 13 in FIG. 1A pointing from a source device 12 to a destination device 14, or as bidirectional communication interfaces, and may be configured to, for example, send and receive messages, for example, to establish a connection, to confirm and exchange any other information related to communication lines and/or data transmission, such as transmission of encoded picture data.

The decoder 30 is configured to receive encoded picture data 21 and provide decoded picture data 31 or decoded picture 31 (further details will be described below, for example, based on FIG. 3 or FIG. 5.

The post-processor 32 of the recipient device 14 is configured to post-process the decoded picture data 31 (also called recovered picture data), for example, the decoded picture 31, to obtain post-processed picture data 33, for example, the post-processed picture 33. Post-processing performed by block 32 post-processing may comprise, for example, color format conversion (eg, from YCbCr to RGB), color correction, cropping or resampling, or any other processing, for example, to prepare decoded picture data 31 for display, for example, by display device 34.

The display device 34 of the recipient device 14 is configured to receive post-processed picture data 33 for displaying the picture, for example, to a user or viewer. The display device 34 may be or include any type of display for presenting the reconstructed picture, such as an integrated or external display or monitor. The displays may, for example, comprise liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), plasma displays, projectors, micro-LED displays, liquid crystal on silicon (LCoS), digital light processor (DLP), or any other type of display .

Although Fig. 1A illustrates source device 12 and destination device 14 as separate devices, embodiments of the devices may also include both or both functionality, source device 12 or corresponding functionality and destination device 14 or corresponding functionality. In such embodiments, source device 12 or related functionality and destination device 14 or related functionality may be implemented using the same hardware and/or software, or using separate hardware and/or software, or any combination thereof. .

As will be apparent to one skilled in the art from the description, the presence and (precise) separation of functionality of various blocks or functions in source device 12 and/or destination device 14, as shown in FIG. 1A, may vary depending on the actual device and application. .

Encoder 20 (e.g., video encoder 20) or decoder 30 (e.g., video decoder 30) or both the encoder 20 and the decoder 30 may be implemented through a processing circuit as shown in FIG. 1B, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), discrete logic, hardware, dedicated video encoding, or any combination thereof. Encoder 20 may be implemented through processing circuit 46 to implement various modules, as discussed with respect to encoder 20 of FIG. 2 and/or any other encoder system or subsystem described in this document. Decoder 30 may be implemented through processing circuit 46 to implement various modules, as discussed with respect to decoder 30 of FIG. 3 and/or any other decoder system or subsystem described herein. The processing circuit may be configured to perform various operations, which will be described below. As shown in FIG. 5, if the techniques are partially implemented in software, the apparatus may store instructions for the software on a suitable non-transitory computer readable storage medium and may execute the instructions in hardware using one or more processors to execute the techniques of this disclosure. Either of video encoder 20 and video decoder 30 may be integrated as part of a combined encoder/decoder (CODEC) in a single device, for example, as shown in FIG. 1B.

Source device 12 and destination device 14 may include any of a wide range of devices, including any type of portable or desktop devices, such as laptops or notebook computers, mobile phones, smartphones, tablets or tablet computers, cameras, desktop computers, set-top boxes , televisions, display devices, digital media players, game consoles, video streaming devices (such as content service servers or content delivery servers), broadcast receiving device, broadcast transmitting device, or the like, and may use or dispense with any type of operating system. In some cases, source device 12 and destination device 14 may be equipped for wireless communication. Thus, source device 12 and destination device 14 may be wireless communication devices.

In some cases , the video encoding system 10 illustrated in FIG. 1A is an example only, and the methods of the present application can be applied to video encoding settings (such as video encoding or video decoding) that do not necessarily involve transferring any data between encoding and decoding devices. In other examples, data is retrieved from local memory, streamed over a network, or the like. A video encoding device may encode and store data into memory, and/or a video decoding device may retrieve and decode data from memory. In some examples, encoding and decoding are performed by devices that do not communicate with each other, but simply encode data into memory and/or retrieve and decode data from memory.

For convenience of description, embodiments of the present invention are described herein, for example, with reference to High Efficiency Video Coding (HEVC) or Versatile Video Coding (VVC) reference software, a next-generation video encoding standard being developed by the Joint Collaboration on Video Coding (JCT-VC) Expert Group. ITU-T video encoding (VCEG) and ISO/IEC Moving Picture Expert Group (MPEG). One of ordinary skill in the art will understand that embodiments of the present invention are not limited to HEVC or VVC.

Encoder and encoding method

Fig. 2 shows a schematic block diagram of an exemplary video encoder 20 that is configured to implement the methods of the present application. In the example in FIG. 2, video encoder 20 includes an input 201 (or input interface 201), a remainder calculation block 204, a transform processing block 206, a quantization block 208, an inverse quantization block 210 and an inverse transform processing block 212, a restoration block 214, a loop filter block 220, a buffer 230 ( DPB) of decoded pictures, a mode selection unit 260, an entropy encoding unit 270, and an output 272 (or output interface 272). The mode selection block 260 may include an inter prediction block 244, an intra prediction block 254, and a separating block 262. The inter prediction unit 244 may include a motion estimation unit and a motion compensation unit (not shown). The video encoder 20 shown in FIG. 2 may also be called a hybrid video encoder or a video encoder according to a hybrid video codec.

The remainder calculation block 204, transform processing block 206, quantization block 208, mode selection block 260 may relate to the formation of the forward signal path of the encoder 20, while the inverse quantization block 210, inverse transform processing block 212, restoration block 214, buffer 216, contour filter 220, decoded picture buffer (DPB) 230, inter prediction block 244, and intra prediction block 254 may relate to generating a reverse signal path of video encoder 20, wherein the reverse signal path of video encoder 20 corresponds to the signal path of the decoder (see video decoder 30 on Fig. 3). The inverse quantization unit 210, the inverse transform processing unit 212, the restoration unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter prediction unit 244, and the intra prediction unit 254 are also relevant to forming the “on-chip decoder” of the video encoder 20.

Pictures and picture division (pictures and blocks)

Encoder 20 may be configured to receive, for example, through input 201, a picture 17 (or picture data 17), for example, a picture from a sequence of pictures forming a video or video sequence. The received picture or picture data may also be a preprocessed picture 19 (or preprocessed picture data 19). For simplicity, the following description refers to picture 17. Picture 17 may also be referred to as the current picture or the picture to be encoded (particularly in video encoding, to distinguish the current picture from other pictures, for example, previously encoded and/or decoded pictures of the same video sequence, i.e. a video sequence that also contains the current picture).

A (digital) picture is, or can be viewed as, a two-dimensional array or matrix of samples with intensity values. A selection in an array may also be referred to as a pixel (short form of picture element) or pel (picture element). The number of samples in the horizontal and vertical direction (or axis) of the array or picture determines the size and/or resolution of the picture. Three color components are usually used to represent color, i.e. the picture can be presented or include three arrays of samples. In RBG format, or color space, a picture contains a corresponding array of red, green, or blue samples. However, in video encoding, each pixel is typically represented in a luminance and chrominance format or color space, such as YCbCr, which contains a luminance component, denoted Y (sometimes L is also used instead), and two chrominance components (chrominance components), denoted Cb and Cr. The Y component of luminance (or luma for short) represents the brightness or intensity of the gray level (such as in a halftone picture), while the two components Cb and Cr are chrominance (or chrominance for short). chroma) represent components of chromaticity or color information. Accordingly, a picture in YCbCr format contains an array of brightness samples with values (Y) of brightness samples and two arrays of chrominance samples with values (Cb and Cr) of chromaticity. Pictures in RGB format can be converted or converted to YCbCr format and vice versa, the process is also known as color conversion or conversion. If the picture is monochrome, it can only contain an array of brightness samples. Accordingly, a picture can be, for example, an array of luminance samples in a monochrome format or an array of luminance samples and two corresponding arrays of chrominance samples in 4:2:0, 4:2:2 and 4:4:4 color formats.

Embodiments of video encoder 20 may include a picture splitter (not shown in FIG. 2) configured to divide picture 17 into multiple (usually non-overlapping) picture blocks 203. These blocks may also be called root blocks, macroblocks (H.264/AVC) or coding tree blocks (CTB) or coding tree units (CTU) (H.265/HEVC and VVC). The picture division block may be configured to use the same block size for all pictures in a video sequence and a corresponding grid defining the block size, or to vary the block size between pictures or subsets or groups of pictures and divide each picture into appropriate blocks.

In additional embodiments, the video encoder may be configured to receive directly a block 203 of a picture 17, for example, one, more, or all of the blocks forming a picture 17. The picture block 203 may also be referred to as a current picture block or a picture block to be encoded.

Like picture 17, picture block 203 is again, or can be viewed as, a two-dimensional array or matrix of samples with intensity values (sample values), albeit smaller in size than picture 17. In other words, block 203 may contain, for example, a single array of samples (e.g. , a brightness array in the case of a monochrome picture 17 or a brightness or chrominance array in the case of a color picture) or three arrays of samples (for example, brightness and two chrominance arrays in the case of color picture 17) or any other number and/or type of arrays depending on the color used format. The number of samples in the horizontal and vertical direction (or axis) of block 203 determines the size of block 203. Accordingly, the block may, for example, be an MxN array of samples (M-column by N-row) or an MxN array of transform coefficients.

Embodiments of video encoder 20 shown in FIG. 2 may be configured to encode picture 17 block by block, for example, encoding and prediction is performed for each block 203.

Embodiments of video encoder 20, as shown in FIG. 2 may further be configured to divide and/or encode a picture using slices (also referred to as video slices), wherein the picture may be divided into or encoded using one or more slices (usually non-overlapping), and each slice may contain one or more units (for example, CTU).

Embodiments of video encoder 20 shown in FIG. 2 may be further configured to divide and/or encode a picture using groups of tiles (also called video tile groups) and/or tiles (also called video tiles), wherein the picture can be divided into or encoded using one or more groups of tiles (usually non-overlapping), and each group of tiles may contain, for example, one or more blocks (for example, CTU) or one or more tiles, where each tile, for example, may be rectangular in shape and may contain one or more blocks (eg CTU) such as full or partial blocks.

Calculating the remainder

Residual calculation block 204 may be configured to calculate residual block 205 (also referred to as residual 205) based on picture block 203 and prediction block 265 (additional details about prediction block 265 are provided below), for example, by subtracting the sample values of prediction block 265 from the values samples the picture block 203, sample by sample (pixel by pixel), to obtain a residual block 205 in the sample region.

Conversion

Transform processing unit 206 may be configured to apply a transform, such as a discrete cosine transform (DCT) or a discrete sine transform (DST), to the sample values of the residual block 205 to obtain transform coefficients 207 in the transform domain. The transform coefficients 207 may also be referred to as residual transform coefficients and represent the residual block 205 in the transform domain.

Transform processing block 206 may be configured to apply DCT/DST integer approximations, such as the transforms defined for H.265/HEVC. Compared to the orthogonal DCT transform, such integer approximations are usually scaled by some factor. To preserve the norm of the residual block that is processed by the forward and inverse transforms, additional scaling factors are applied as part of the transform process. Scaling factors are typically chosen based on some constraints, e.g., scaling factors are powers of two for shift operations, bit depth of transform factors, tradeoff between accuracy and implementation cost, etc. Specific scaling factors, for example, are specified for inverse transform, e.g. , the inverse transform processing unit 212 (and the corresponding inverse transform, for example, the inverse transform processing unit 312 in the video decoder 30), and the corresponding scaling factors for the forward transform, for example, the transform processing unit 206, can be set appropriately in the encoder 20.

Embodiments of video encoder 20 (respectively transform processing unit 206) may be configured to output transform parameters, such as the type of transform or transforms, for example, directly or encoded or compressed via entropy encoding unit 270, so that, for example, video decoder 30 may receive and use conversion parameters for decoding.

Quantization

The quantization unit 208 may be configured to quantize the transform coefficients 207 to obtain quantized coefficients 209, for example, by applying scalar quantization or vector quantization. Quantized coefficients 209 may also be referred to as quantized transform coefficients 209 or quantized residual coefficients 209.

The quantization process may reduce the bit depth associated with some or all of the transform coefficients 207. For example, an n-bit transform factor may be rounded to an m-bit transform factor during quantization, where n is greater than m. The degree of quantization can be changed by adjusting the quantization parameter (QP). For example, for scalar quantization, different scaling may be applied to achieve finer or coarser quantization. Smaller quantization step sizes correspond to finer quantization, while larger quantization step sizes correspond to coarser quantization. The applicable quantization step size may be specified by the quantization parameter (QP). The quantization parameter may, for example, be an index to a predefined set of applicable quantization step sizes. For example, small quantization parameters may correspond to fine quantization (small quantization step sizes), and large quantization parameters may correspond to coarse quantization (large quantization step sizes), or vice versa. Quantization may include dividing by a quantization step size, and corresponding and/or inverse dequantization, such as by inverse quantization unit 210, may include multiplying by a quantization step size. Embodiments in accordance with some standards, such as HEVC, may be configured to use a quantization parameter to determine the quantization step size. Typically, the quantization step size can be calculated based on the quantization parameter using a fixed point approximation of the equation involving division. Additional scaling factors can be introduced for quantization and dequantization to recover the residual block norm that may have been changed due to the scaling used in the fixed point approximation of the above equation for the quantization step size and the quantization parameter. In one exemplary implementation, inverse transform scaling and dequantization may be combined. Alternatively, customized quantization tables can be used and signaled from encoder to decoder, for example in a bitstream. Quantization is a lossy operation in which losses increase as the size of the quantization steps increases.

Embodiments of video encoder 20 (respectively quantization block 208) may be configured to output quantization parameters (QPs), for example, directly or encoded through entropy encoding block 270, so that, for example, video decoder 30 can receive and apply the quantization parameters for decoding.

Inverse quantization

The inverse quantization block 210 is configured to apply the inverse quantization of the quantization block 208 to the quantized coefficients to obtain the dequantized coefficients 211, for example, by applying an inverse quantization scheme to that applied by the quantization block 208, based on or using the same quantization step size as quantization unit 208. The dequantized coefficients 211 may also be referred to as the dequantized residual coefficients 211 and correspond - although they are typically not identical to the transform coefficients due to quantization loss - to the transform coefficients 207.

Reverse conversion

The inverse transform processing unit 212 is configured to apply an inverse transform relative to the transform applied by the transform processing unit 206, such as an inverse discrete cosine transform (DCT) or an inverse discrete sine transform (DST) or other inverse transforms to obtain the reconstructed residual block 213 (or corresponding dequantized coefficients 213) in the sample area. The reconstructed residual block 213 may also be referred to as a transform block 213.

Recovery

A reconstruction block 214 (e.g., an add block or an adder 214) is configured to add a transform block 213 (i.e., a reconstructed residual block 213) with a prediction block 265 to obtain a reconstructed block 215 in the sample domain, for example, through addition-sample-per-sample sample - sample values of the reconstructed residual block 213 and sample values of the prediction block 265.

Filtration

Loop filter block 220 (or “loop filter” 220 for short) is configured to filter the reconstructed block 215 to obtain a filtered block 221, or more generally to filter the reconstructed samples to obtain filtered samples. The edge filter block, for example, is configured to smooth pixel transitions or otherwise improve video quality . Loop filter block 220 may include one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as a two-way filter, an adaptive loop filter (ALF), anti-aliasing filters, sharpening or joint filters, or any combination of them. Although the loop filter block 220 is shown in FIG. 2 as a loop filter, in other configurations the loop filter block 220 may be implemented as a post-loop filter. Filtered block 221 may also be referred to as filtered reconstructed block 221.

Embodiments of video encoder 20 (respectively, loop filter block 220) may be configured to output loop filter parameters (such as sample-adaptive offset information), for example, directly or encoded through entropy encoding block 270, so that, for example, decoder 30 can receive and apply similar loop filter parameters or corresponding loop filters for decoding.

Buffer of decoded pictures

Decoded picture buffer (DPB) 230 may be a memory that stores reference pictures, or generally reference picture data, for encoding video data by video encoder 20. DPB 230 may be formed by any of a variety of storage devices, such as dynamic random access memory (DRAM). DRAM), including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM), resistive RAM (RRAM), or other types of memory devices. The decoded picture buffer (DPB) 230 may be configured to store one or more filtered blocks 221. The decoded picture buffer 230 may be further configured to store other previously filtered blocks, such as previously reconstructed and filtered blocks 221, of the same current picture. or different pictures, for example, previously restored pictures, and can provide complete previously restored ones, i.e. decoded, pictures (and corresponding reference blocks and samples) and/or partially reconstructed current picture (and corresponding reference blocks and samples), for example, for inter-prediction. Decoded picture buffer (DPB) 230 may also be configured to store one or more unfiltered reconstructed blocks 215, or generally unfiltered reconstructed samples, for example, if reconstructed block 215 is not filtered by loop filter block 220, or any other further processed version of the reconstructed blocks or selections.

Mode selection (separation and prediction)

The mode selecting unit 260 includes a separating unit 262, an inter-prediction unit 244, and an intra-prediction unit 254, and is configured to receive or obtain the original picture data, for example, the original block 203 (the current block 203 of the current picture 17), and the reconstructed picture data, for example, filtered and/or unfiltered reconstructed samples or blocks of the same (current) picture and/or from one or more previously decoded pictures, for example, from decoded picture buffer 230 or other buffers (for example, a line buffer, not shown). The reconstructed picture data is used as reference picture data for prediction, for example, inter-prediction or intra-prediction to obtain a prediction block 265 or a predictor 265.

The mode selector 260 may be configured to determine or select a split for the current block prediction mode (including no split) and a prediction mode (eg, intra or inter prediction mode) and generate a corresponding prediction block 265 that is used to calculate the residual block 205 and to restore the recovered block 215.

Embodiments of mode selector 260 may be configured to select a division and prediction mode (eg, from those supported or available to mode selector 260) that provide the best match, or in other words, the minimum remainder (minimum remainder means best result) compression for transmission or storage), or minimum signaling (minimum signaling means better compression for transmission or storage), or which accounts for or balances both. The mode selector 260 may be configured to determine a division and prediction mode based on rate/distortion optimization (RDO), that is, selecting a prediction mode that provides minimum distortion at a certain rate. Terms such as "best", "minimum", "optimal", etc. in this context do not necessarily refer to the all-encompassing "best", "minimum", "optimal", etc., but may also refer to meeting a selection or termination criterion, such as when a value exceeds or falls below a threshold, or other constraints, potentially leading to "suboptimal selection" but reducing complexity and processing time.

In other words, partitioning unit 262 may be configured to partition block 203 into smaller block sections or sub-blocks (which form blocks again), for example, iteratively using quad-tree partitioning (QT), binary partitioning (BT), or ternary tree partitioning ( TT) or any combination thereof, and performing, for example, prediction for each of the block sections or subblocks, wherein the mode selection comprises selecting a tree structure of the shared block 203, and the prediction modes are applied to each of the block sections or subblocks.

Next, the division (e.g., through partitioner 260) and prediction processing (through inter-prediction block 244 and intra-prediction block 254) performed by the exemplary video encoder 20 are explained in more detail.

Separation

Divider 262 may divide (or split) the current block 203 into smaller sections, such as smaller blocks of square or rectangular size. These smaller blocks (which may also be called subblocks) can be further divided into even smaller sections. This is also called tree partitioning or hierarchical tree partitioning, in which a root block, for example at root level 0 of the tree (hierarchy level 0, depth 0), can be recursively partitioned, for example divided into two or more blocks of the next lower tree level, e.g. , nodes at tree level 1 (hierarchy level 1, depth 1), and these blocks can be again divided into two or more blocks of the next lower level, for example, tree level 2 (hierarchy level 2, depth 2), etc. until the split is completed, for example due to a termination criterion being met, such as reaching the maximum tree depth or minimum block size. Blocks that are not further divided are also called leaf blocks or leaf nodes of a tree. A tree using two partitions is called a binary tree (BT), a tree using three partitions is called a ternary tree (TT), and a tree using four partitions is called a quadtree (QT).

As mentioned earlier, the term "block" as used herein can be a part, particularly a square or rectangular part of a picture. With respect to, for example, HEVC and VVC, a block may be or correspond to a coding tree unit (CTU), a coding unit (CU), a prediction unit (PU) and a transform unit (TU) and/or corresponding blocks, such as a coding tree block ( CTB), coding block (CB), transform block (TB) or prediction block (PB).

For example, a coding tree unit (CTU) may be or contain a CTB of luma samples, two corresponding CTBs of chroma samples of a picture that has three arrays of samples, or a CTB of samples of a monochrome picture or a picture that is encoded using three separate color planes and the syntactic structures used for encoding samples. Accordingly, a code tree block (CTB) may be an N×N block of samples for some value of N, such that dividing a component by the CTB is a division. A coding unit (CU) may be or comprise a luma sample encoding unit, two corresponding chroma sample encoding units of a picture that has three sample arrays, or a monochrome sample encoding unit or a picture that is encoded using three separate color planes and syntactic structures used for encoding samples. Accordingly, a code block (CB) may be an M×N block of samples for some values of M and N, so that dividing the CTB into code blocks is a division.

In embodiments, for example, according to HEVC, a coding tree unit (CTU) can be partitioned into CUs using a quadtree structure designated as a coding tree. The decision of whether to encode a picture region using extra-picture (temporal) or intra-picture (spatial) prediction is made at the CU level. Each CU can be further partitioned into one, two or four PUs according to the PU partition type. Within a single PU, the same prediction process is applied and the relevant information is passed to the PU-based decoder. After obtaining the residual block by applying a prediction process based on the partition type on the PU, the CU can be partitioned into transform units (TUs) according to a different quadtree structure similar to the encoding tree for the CU.

In embodiments, for example, in accordance with the newest video encoding standard currently under development, called Versatile Video Coding (VVC), for example, a combined quadtree and binary tree (QTBT) partitioning is used to divide an encoding block. In a block structure, a QTBT CU can be either square or rectangular in shape. For example, a coding tree unit (CTU) is first divided into a quadtree structure. The leaf nodes of a quadtree are further separated by a binary tree or ternary (or ternary) tree structure. The leaf nodes of the partitioning tree are called encoding units (CUs), and this segmentation is used to process prediction and transformation without any additional partitioning. This means that CU, PU and TU have the same block size in the QTBT encoding block structure. In parallel, a multiple partition, such as a ternary tree partition, can be used in conjunction with the QTBT block structure.

In one example, the mode selector 260 of the video encoder 20 may be configured to perform any combination of the division methods described herein.

As described above, video encoder 20 is configured to determine or select the best or optimal prediction mode from a set of (eg, predefined) prediction modes. The set of prediction modes may comprise, for example, intra prediction modes and/or inter prediction modes.

Internal prediction

The set of intra prediction modes may contain 35 different intra prediction modes, for example, non-directional modes, such as DC (or average) mode and planar mode, or directional modes, for example, as defined in HEVC, or may contain 67 different intra prediction modes, for example , non-directional modes such as DC (or average) mode and planar mode, or directional modes such as those defined for VVC.

The intra prediction block 254 is configured to use reconstructed samples of neighboring blocks of the same current picture to generate an intra prediction block 265 according to the intra prediction mode of the set of intra prediction modes.

The intra prediction block 254 (or more generally the mode selection block 260) is further configured to output intra prediction parameters (or more generally information indicating the selected intra prediction mode for the block) to the entropy encoding block 270 in the form of syntax elements 266 for including a coded picture in the data 21 so that, for example, the video decoder 30 can receive and use the prediction parameters for decoding.

External prediction

The set of (possible) inter-prediction modes depends on the available reference pictures (i.e., previous, at least partially decoded pictures, e.g., stored in DBP 230) and other inter-prediction parameters, e.g., whether the entire reference picture is used or only a portion, e.g. , the search window area around the area of the current block, the reference picture to find the most suitable reference block and/or, for example, whether pixel interpolation is applied, such as half/semi-pel and/or quarter-pel interpolation, or No.

In addition to the above prediction modes, a skip mode and/or a direct mode may be used.

The inter-prediction block 244 may include a motion estimation (ME) block and a motion compensation (MC) block (both not shown in FIG. 2). The motion estimator may be configured to receive or obtain a picture block 203 (current picture block 203 of said current picture 17) and a decoded picture 231, or at least one or a plurality of previously reconstructed blocks, such as reconstructed blocks of one or many different/different previously 231 decoded pictures for motion estimation. For example, the video sequence may contain the current picture and previously decoded pictures 231 or, in other words, the current picture and previously decoded pictures 231 may be part of or form a sequence of pictures making up the video sequence.

The encoder 20 may, for example, be configured to select a reference block from a plurality of reference blocks of the same or different pictures from a plurality of other pictures and provide a reference picture (or reference picture index) and/or an offset (spatial offset) between the position (x, y coordinates ) of the reference block and the position of the current block as inter-prediction parameters to the motion estimation block. This displacement is also called motion vector (MV).

The motion compensation unit is configured to obtain, for example, receiving an inter prediction parameter and performing inter prediction based on or using the inter prediction parameter to obtain an inter prediction unit 265. The motion compensation performed by the motion compensation block may include obtaining or generating a prediction block based on a motion vector/block determined by motion estimation, possibly performing interpolations with sub-pixel accuracy. Interpolation filtering can generate additional pixel samples from known pixel samples, thereby potentially increasing the number of candidate prediction blocks that can be used to encode a picture block. After receiving the motion vector for the PU of the current picture block, the motion compensation unit may determine the location of the prediction block pointed to by the motion vector in one of the reference picture lists.

The motion compensation block may also generate syntax elements associated with video blocks and slices for use by video decoder 30 when decoding picture blocks of a video slice. In addition to or as an alternative to slices and corresponding syntax elements, groups of tiles and/or tiles and corresponding syntax elements may be generated or used.

Entropy coding

The entropy encoding block 270 is configured to employ, for example, an entropy encoding algorithm or scheme (e.g., a variable length coding (VLC) scheme, a context adaptive VLC (CAVLC) scheme, an arithmetic encoding scheme, binarization, a context adaptive binary arithmetic encoding ( CABAC) based on the syntax of context-adaptive binary arithmetic coding (SBAC), probability interval entropy encoding (PIPE), or other entropy encoding method or methodology) or bypass (uncompressed) with respect to quantized coefficients 209, inter-prediction parameters, parameters intra prediction, loop filter parameters, and/or other syntax elements to obtain encoded picture data 21, which may be output via pin 272, for example, in the form of an encoded bitstream 21, so that, for example, video decoder 30 can receive and use these parameters for decoding . The encoded bitstream 21 may be transmitted to video decoder 30 or stored in memory for later transmission or retrieval by video decoder 30.

Other changes to the structure of video encoder 20 may be used to encode the video stream. For example, non-transform encoder 20 may quantize the residual signal directly without transform processing unit 206. In another implementation, encoder 20 may have a quantization unit 208 and an inverse quantization unit 210 combined into a single unit.

Decoder and decoding method

Fig. 3 shows an example of a video decoder 30 that is configured to implement the methods of the present application. Video decoder 30 is configured to receive encoded picture data 21 (e.g., encoded bitstream 21), e.g., encoded by encoder 20, to obtain decoded picture 331. The encoded picture data or bitstream contains information for decoding the encoded picture data, e.g., data that represent picture blocks of an encoded video slice (and/or tiles or groups of tiles) and associated syntactic elements.

In the example in FIG. 3, decoder 30 includes an entropy decoding block 304, an inverse quantization block 310, an inverse transform processing block 312, a recovery block 314 (e.g., adder 314), a loop filter 320, a decoded picture buffer (DPB) 330, a mode applying block 360, a block 344 inter prediction and intra prediction block 354. The inter prediction unit 344 may be or include a motion compensation unit. Video decoder 30 may, in some examples, perform a decoding step that is generally the reverse of the encoding step described with respect to video encoder 100 in FIG. 2.

As described with respect to the encoder 20, the inverse quantization unit 210, the inverse transform processing unit 212, the reconstruction unit 214, the loop filter 220, the decoded picture buffer (DPB) 230, the inter-prediction unit 344, and the intra-prediction unit 354 also relate to forming the “on-chip decoder”. » video encoder 20. Accordingly, the inverse quantization block 310 may be identical in function to the inverse quantization block 110, the inverse transform processing block 312 may be identical in function to the inverse transform processing block 212, the restoration block 314 may be identical in function to the reconstruction block 214, loop filter 320 may be identical in function to loop filter 220, and decoded picture buffer 330 may be identical in function to decoded picture buffer 230. Therefore, the explanations provided for the corresponding blocks and functions of the video encoder 20 apply correspondingly to the corresponding blocks and functions of the video decoder 30.

Entropy Decoding

Entropy decoding module 304 is configured to parse bitstream 21 (or generally encoded picture data 21) and perform, for example, entropy decoding on encoded picture data 21 to obtain, for example, quantized coefficients 309 and/or decoded encoding parameters (not shown in FIG. 3), for example, any or all of the inter prediction parameters (eg, reference picture index and motion vector), intra prediction parameter (eg, index or intra prediction mode), transform parameters, quantization parameters, contour parameters filter and/or other syntactic elements. The entropy decoding unit 304 may be configured to employ decoding algorithms or circuits corresponding to the encoding schemes as described with respect to the entropy encoding unit 270 of the encoder 20. The entropy decoding unit 304 may be further configured to provide inter prediction parameters, an intra prediction parameter, and/or or other syntax elements to block 360 for applying the mode and other parameters to other blocks of decoder 30. Video decoder 30 may receive syntax elements at the video slice level and/or video block level. In addition to or as an alternative to slices and corresponding syntax elements, groups of tiles and/or tiles and corresponding syntax elements may be received and/or used.

Inverse quantization

The inverse quantization unit 310 may be configured to receive quantization parameters (QPs) (or, more generally, information related to inverse quantization) and quantized coefficients from the encoded picture data 21 (e.g., by parsing and/or decoding, e.g., by entropy decoding block 304) and applying, based on the quantization parameters, inverse quantization on the decoded quantized coefficients 309 to obtain dequantized coefficients 311, which may also be referred to as transform coefficients 311. The inverse quantization process may include using a quantization parameter determined by video encoder 20 for each video block in a video slice (or tile or group of tiles) to determine the degree of quantization and, likewise, the degree of inverse quantization to be applied.

Reverse conversion

The inverse transform processing unit 312 may be configured to receive the dequantized coefficients 311, also referred to as transform coefficients 311, and apply a transform to the dequantized coefficients 311 to obtain reconstructed residual blocks 213 in the sample region. The reconstructed residual blocks 213 may also be referred to as transform blocks 313. The conversion may be an inverse transform, such as an inverse DCT, an inverse DST, an integer integer transform, or a conceptually similar inverse transform process. The inverse transform processing unit 312 may be further configured to receive transform parameters or corresponding information from the encoded picture data 21 (e.g., by parsing and/or decoding, e.g., by entropy decoding unit 304) to determine a transform to be applied to dequantized coefficients 311.

Recovery

The reconstruction block 314 (e.g., add block or adder 314) may be configured to add the reconstructed residual block 313 with the prediction block 365 to obtain a reconstructed block 315 in the sample domain, for example, by adding the sample values of the reconstructed residual block 313 and the block sample values 365 predictions.

Filtration

A loop filter module 320 (either in the encoding loop or after the encoding loop) is configured to filter the reconstructed block 315 to produce a filtered block 321, for example, to smooth pixel transitions or otherwise improve video quality. Loop filter block 320 may include one or more loop filters, such as a deblocking filter, a sample adaptive offset (SAO) filter, or one or more other filters, such as a two-way filter, an adaptive loop filter (ALF), anti-aliasing filters, sharpening or joint filters, or any combination of them. Although the loop filter block 320 is shown in FIG. 3 as a loop filter, in other configurations the loop filter block 320 may be implemented as a post-loop filter.

Buffer of decoded pictures

The decoded video picture blocks 321 are then stored in a decoded picture buffer 330, which stores the decoded pictures 331 as reference pictures for subsequent motion compensation for other pictures and/or for output or display.

The decoder 30 is configured to output the decoded picture 311, for example, through an output 312 for presentation or viewing to a user.

Prediction

The inter prediction block 344 may be identical to the inter prediction block 244 (in particular, the motion compensation block), and the intra prediction block 354 may be identical to the inter prediction block 254 in function, and makes splitting or splitting decisions and performs prediction based on the splitting parameters and /or prediction or corresponding information received from the encoded picture data 21 (eg, by parsing and/or decoding, eg, by entropy decoding unit 304). The mode application block 360 may be configured to perform prediction (intra or inter prediction) for each block based on the reconstructed pictures, blocks, or corresponding samples (filtered or unfiltered) to obtain a prediction block 365.

When a video slice is encoded as an intra-encoded (I) slice, an intra prediction block 354 of a mode applying block 360 is configured to generate a prediction block 365 for a picture block of the current video slice based on the signaled intra prediction mode and data from previously decoded current picture blocks. When a video picture is encoded as an outer-encoded (i.e., B or P) slice, an inter-prediction block 344 (e.g., a motion compensation block) of the mode applying block 360 is configured to generate prediction blocks 365 for the video block of the current video slice based on motion vectors and other syntax elements. , received from the entropy decoding unit 304. For inter-prediction, prediction blocks may be created from one of the reference pictures within one of the reference picture lists. Video decoder 30 may construct reference picture lists, List 0 and List 1, using default construction methods based on reference pictures stored in DPB 330. The same or similar may be used for or through embodiments using tile groups (e.g., video tile groups ) and/or tiles (eg, video tiles) in addition to or alternatively to slices (eg, video slices), for example, video may be encoded using groups of I, P or B tiles and/or tiles.

The mode applying unit 360 is configured to determine prediction information for a video block of the current video slice by parsing motion vectors or related information and other syntax elements, and uses the prediction information to create prediction blocks for the current video block to be decoded. For example, mode apply block 360 uses some of the received syntax elements to determine the prediction mode (e.g., intra or inter prediction) used to encode video blocks of a video slice, type of inter prediction slice (e.g., B-slice, P-slice, or GPB slice) , construction information for one or more reference picture lists for the slice, motion vectors for each outer-coded video block of the slice, inter-prediction status for each outer-coded video block of the slice, and other information for decoding the video blocks in the current video slice. The same or similar may apply to or through embodiments using tile groups (eg, video tile groups) and/or tiles (eg, video tiles) in addition to or alternatively to slices (eg, video slices), for example, video may be encoded with using groups of I, P or B tiles and/or tiles.

Embodiments of video decoder 30, as shown in FIG. 3 may be configured to split and/or decode a picture using slices (also referred to as video slices), wherein the picture may be divided into or encoded using one or more slices (usually non-overlapping), and each slice may contain one or more blocks (for example, CTU).

Embodiments of video decoder 30 shown in FIG. 3 may be configured to divide and/or decode a picture using groups of tiles (also called video tile groups) and/or tiles (also called video tiles), wherein the picture can be divided into or decoded using one or more groups tiles (usually non-overlapping), and each group of tiles may contain, for example, one or more blocks (for example, CTU) or one or more tiles, where each tile, for example, can be rectangular in shape and can contain one or more blocks (for example , CTU) such as full or partial blocks.

Other embodiments of the video decoder 30 may be used to decode the encoded picture data 21. For example, decoder 30 may produce an output video stream without loop filtering block 320. For example, the non-transform decoder 30 may perform inverse quantization of the residual signal directly without detransforming processing unit 312 for some blocks or frames. In another implementation, video decoder 30 may have an inverse quantization block 310 and an inverse transform processing block 312 combined into one block.

It should be understood that in the encoder 20 and decoder 30, the result of processing of some current stage may be further processed and then output to the next stage. For example, after interpolation filtering, motion vector acquisition, or contour filtering, an additional operation such as Clip or offset may be performed on the result of the interpolation filtering, motion vector acquisition, or contour filtering processing.

It should be noted that additional operations may be applied to the resulting current block motion vectors (including, but not limited to, affine mode checkpoint motion vectors, affine mode subblock motion vectors, planar mode motion vectors, ATMVP mode motion vectors, temporary motion vectors, and the like). For example, the value of a motion vector is limited to a predefined range according to its representing bit. If the representing bit of the motion vector is bitDepth, then the range is -2^(bitDepth-1) ~ 2^(bitDepth-1)-1, where "^" means exponentiation. For example, if bitDepth is set to 16, the range is -32768 ~ 32767; if bitDepth is set to 18, the range is -131072~131071. For example, the value of the resulting motion vector (for example, the MV of four 4x4 subblocks in one 8x8 block) is limited so that the maximum difference between the entire parts of the MV of four 4x4 subblocks does not exceed N pixels, for example, is no more than 1 pixel . Here are two ways to constrain the motion vector according to bitDepth.

Method 1: Removing MSB (Most Significant Bit) Overflow via Streaming Operations

where mvx represents the horizontal component of the motion vector of the image block or sub-block, mvy represents the vertical component of the motion vector of the image block or sub-block, and ux and uy indicate an intermediate value;

For example, if the value of mvx is -32769, after applying formulas (1) and (2), the resulting value is 32767. In a computing system, decimal numbers are stored as two's complement. The two's complement of -32769 is 1,0111,1111,1111,1111 (17 bits), then the MSB is discarded, so the resulting two's complement is 0111,1111,1111,1111 (decimal is 32767), which is the same as the output from the application of formulas (1) and (2).

Operations can be applied during the summation of mvp and mvd, as shown in formulas (5) to (8).

Method 2: Remove MSB overflow by truncating the value

where vx represents the horizontal component of the motion vector of the image block or sub-block, vy represents the vertical component of the motion vector of the image block or sub-block; x, y and z respectively correspond to the three input values of the MV clipping process, and the definition of the Clip3 function is as follows:

Fig. 4 is a schematic diagram of a video encoding apparatus 400 according to an embodiment of the present disclosure. Video encoding apparatus 400 is suitable for implementing the disclosed embodiments that are described herein. In an embodiment, video encoding device 400 may be a decoder, such as video decoder 30 of FIG. 1A, or an encoder such as video encoder 20 of FIG. 1A.

The video encoding device 400 includes input ports 410 (or input ports 410) and receiver (Rx) blocks 420 for receiving data; a processor, logical unit, or central processing unit (CPU) 430 for processing data; transmitter (Tx) blocks 440 and output ports 450 (or output ports 450) for data transmission; and a memory 460 for storing data. Video encoding device 400 may also include optical-to-electrical (OE) components and electrical-to-optical (EO) components connected to input ports 410, receiver blocks 420, transmitter blocks 440, and output ports 450 to provide optical or optical input or output. electrical signals.

The processor 430 is implemented in hardware and software. Processor 430 may be implemented as one or more CPU chips, cores (eg, a multi-core processor), FPGA, ASIC, and DSP. Processor 430 communicates with input ports 410, receiver units 420, transmitter units 440, output ports 450, and memory 460. Processor 430 includes an encoding module 470. Encoding module 470 implements the disclosed embodiments described above. For example, encoding module 470 implements, processes, prepares, or provides various encoding operations. Therefore, the inclusion of the encoding module 470 provides a significant improvement in the functionality of the video encoding device 400 and allows the video encoding device 400 to be transformed into a different state. Alternatively, encoding module 470 is implemented as instructions stored in memory 460 and executed by processor 430.

Memory 460 may include one or more disks, tape drives, and solid-state drives and may be used as an overflow storage device for storing programs when such programs are selected for execution and for storing instructions and data that are read during execution of the programs. Memory 460 may be, for example, volatile and/or non-volatile and may be read only memory (ROM), random access memory (RAM), ternary memory associative memory (TCAM), and/or static random access memory (SRAM).

Fig. 5 is a simplified block diagram of hardware 500 that can be used as one or both of source device 12 and destination device 14 of FIG. 1 according to an exemplary embodiment .

The processor 502 in the hardware 500 may be a central processing unit. Alternatively, processor 502 may be any other type of device or plurality of devices capable of manipulating or processing information that currently exists or will be developed in the future. Although the disclosed implementations may be practiced with a single processor, as shown, for example, with processor 502, speed and efficiency benefits may be achieved by using more than one processor.

Memory 504 in device 500 may be read-only memory (ROM) or random access memory (RAM) in some implementation. Memory 504 may be any other suitable type of storage device. Memory 504 may include code and data 506 accessed by processor 502 using bus 512. Memory 504 may further include an operating system 508 and application programs 510, wherein application programs 510 include at least one program which allows the processor 502 to perform the methods described herein. For example, application programs 510 may include applications 1 through N, which further include a video encoding application that performs the methods described herein.

The apparatus 500 may also include one or more output devices, such as a display 518. The display 518 may be, in one example, a touch-sensitive display that combines a display with a touch element capable of sensing touch inputs. Display 518 may be coupled to processor 502 via bus 512.

Although depicted here as a single bus, bus 512 of apparatus 500 may be composed of multiple buses. In addition, secondary storage 514 may be directly coupled to other components of hardware 500 or may be accessible via a network and may comprise a single plug-in unit, such as a memory card, or multiple units, such as multiple memory cards. Thus, the apparatus 500 can be implemented in a wide variety of configurations.

Parameter Sets

The parameter sets in modern codecs are fundamentally similar and pursue the same basic design goals, namely data rate efficiency, error tolerance, and provision of system-level interfaces. In HEVC (H.265), there is a hierarchy of parameter sets, including a video parameter set (VPS), a sequence parameter set (SPS), and a picture parameter set (PPS), which are similar to their counterparts in AVC and VVC. Each slice references one active PPS, SPS and VPS to access information used to decode the slice. The PPS contains information that applies to all slices in a picture, and therefore all slices in a picture must belong to the same PPS. Slices in different pictures can also refer to the same PPS. Likewise, the SPS contains information that applies to all pictures in the same coded/decoded video sequence.

Although the PPS may vary for individual pictures, typically many or all of the pictures in a video sequence to be encoded/decoded are assigned to the same PPS. Reusing parameter sets is bitrate efficient because it avoids sending shared information multiple times. It is also loss-tolerant because it allows the contents of the parameter set to be carried over a more reliable external communication channel or repeated frequently in the bitstream to ensure that it is not lost.

In HEVC, to identify for a given slice the active parameter set at each level of the parameter set type hierarchy, each slice header contains a PPS identifier that refers to a specific PPS. Inside the PPS is an identifier that refers to a specific SPS. In turn, inside the SPS there is an identifier that refers to a specific VPS.

A parameter set is activated when the current encoded slice to be decoded references this parameter set. All active parameter sets must be available to the decoder the first time they are accessed. Parameter sets can be sent within or outside the range, and can also be sent repeatedly.

The parameter sets can be obtained in any order.

These features of parameter sets provide increased error tolerance by eliminating some of the loss of parameter sets in the network. In addition, the use of parameter sets allows a single slice to be decoded even if another slice in the same picture suffers network loss, compared to if a picture header containing the same information is present in a subset of the picture slices.

Picture Parameter Set (PPS)

PPS contains parameters that can change for different pictures in the same encoded video sequence. However, multiple pictures can belong to the same PPS, even with different slice encoding types (I, P and B). Including these parameters in picture parameter sets rather than in the slice header can improve data rate efficiency and provide error tolerance for more reliable PPS transmission.

The PPS contains the PPS ID as well as the reference SPS index. The remaining parameters describe the encoding tools used in slices that are specific to PPS. Encoding tools can be enabled or disabled, including tiles, weighted prediction, sign data hiding, temporal motion vector prediction, etc. Encoding tool parameters signaled in PPS include number of reference indexes, quantization start parameter (QP), and offsets Chroma QP. Encoding tool parameters can also be signaled to the PPS, such as deblocking filter controls, tile configurations, and scaling list data. An example PPS is shown in FIG. 6 and 7, in accordance with the document “Versatile Video Coding (Draft 6) of Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11 (available under http:/ /phenix.it-sudparis.eu/jvet/, document no: Document: JVET-O2001-vE).

In fig. 7 shows a PPS section. In this figure, the syntax element Constant_slice_header_params_enabled_flag (constant_slice_header_params_enabled_flag) indicates whether there are constant parameters in the PPS. When the value of Constant_slice_header_params_enabled_flag is 1, additional syntax elements such as pps_temporal_mvp_enabled_idc (730) are included in the PPS. pps_temporal_mvp_enabled_idc is a syntax element that can be present in PPS that controls the application of temporal motion vector prediction and specifies the following:

If the value of the syntax element is 1, then MV temporal prediction is disabled in slices that reference the referenced PPS.

If the value of the syntax element is 2, then MV temporal prediction is enabled in the slices that reference the referenced PPS.

If the value of the syntax element is 0, then a second syntax element is included in the slice header to control the application of MV temporal prediction to the slice. According to the prior art (JVET-O2001-vE), a pps_temporal_mvp_enabled_idc value of 0 indicates that the slice_temporal_mvp_enabled_flag syntax element is present in the header of slices with slice_type not equal to I slices referencing the PPS. pps_temporal_mvp_enabled_idc equal to 1 or 2 indicates that slice_temporal_mvp_enabled_flag is not present in the header of slices referencing the PPS. pps_temporal_mvp_enabled_idc equal to 3 reserved for future use by ITU-T | ISO/IEC.

Figure 7 shows another example, which is the dep_quant_enabled_flag (720). A pps_dep_quant_enabled_idc value of 0 indicates that the dep_quant_enabled_flag syntax element is present in the header of slices referencing the PPS. pps_dep_quant_enabled_idc equal to 1 or 2 indicates that the dep_quant_enabled_flag syntax element is not present in the header of slices referencing the PPS. pps_dep_quant_enabled_idc equal to 3 reserved for future use by ITU-T | ISO/IEC. When the dep_quant_enabled_flag controls the use of dependent quantization on a slice, a value of zero corresponds to disabling dependent quantization, and a value of 1 corresponds to enabling dependent quantization. When pps_dep_quant_enabled_idc is not zero, the dep_quant_enabled_flag is not included in the slice header, but is instead inferred to be pps_dep_quant_enabled_idc - 1.

The syntax elements that are included in PPS when Constant_slice_header_params_enabled_flag is set to true are shown in Figure 1. 7. Syntax elements define default values that are included in PPS when Constant_slice_header_params_enabled_flag is set to true, and have the following common property:

Each syntax element in PPS has a corresponding syntax element in the slice header. For example, pps_dep_quant_enabled_idc is a syntax element in PPS, and dep_quant_enabled_flag is the corresponding syntax element in the slice header.

If the syntax element in PPS has a null value, then the equivalent of the slice header is present (included) in the slice header. Otherwise, the slice header syntax element is not present in the slice header.

If a syntax element in the PPS has a value other than zero, then the value of the corresponding syntax element in the slice header is output according to the value of the syntax element in the PPS. For example, if the value of pps_dep_quant_enabled_idc is 1, it is logically concluded that the value of dep_quant_enabled_idc is equal to pps_dep_quant_enabled_idc - 1=0.

In VVC and HEVC formats, sections of the same video picture (slices, tiles, subpictures, bricks, etc.) must refer to the same set of picture parameters. This is a requirement of the encoding standard because PPS may include parameters that apply to the entire picture. For example, the syntax elements enclosed in square bracket (610) describe how the picture is divided into several tile sections as follows:

tile_cols_width_minus1 specifies the width of each tile in CTB units when the image is evenly divided into tiles.

tile_rows_height_minus1 specifies the height of each tile in CTB units when the image is evenly divided into tiles.

num_tile_columns_minus1 indicates the number of tile columns in the image.

num_tile_rows_minus1 indicates the number of rows of tiles in the image.

The PPS-related picture is divided into several tile parts, which are specified according to the syntax elements above. If two slices of the same image refer to 2 different PPS, this can cause a conflict situation, since each PPS can specify different types of image tiles. Therefore, it is prohibited for 2 slices (or even 2 sections of a picture) to refer to 2 different PPS.

VVC defines various mechanisms for dividing a picture, they are called slices, tiles, bricks and subpictures. As used herein, a picture section is a general term to refer to any of the slices, tiles, bricks, or subpictures. A picture section usually refers to a portion of a frame that is encoded independently of other parts of the same picture.

Set of adaptation parameters

In modern video codecs, a bitstream consists of a sequence of data blocks called network abstraction layer (NAL) blocks. Some NAL blocks contain parameter sets that carry high-level information regarding the entire encoded video sequence or a subset of pictures within it. Other NAL blocks carry encoded samples in the form of slices belonging to one of the different picture types. An adaptation parameter set (APS) is a set of parameters that is used to encapsulate ALF filter control data (eg, filter coefficients).

Fig. 8 illustrates a set of adaptation parameters in accordance with the document “Versatile Video Coding (Draft 6) of Joint Video Experts Team (JVET) of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC 29/WG 11 (available under http: //phenix.it-sudparis.eu/jvet/, document no: Document: JVET-O2001-vE).

Slice title

The slice segment header contains the index of the reference PPS. The slice segment header contains data identifying the starting address of the slice. Some parameters are included only in the first segment of the slice, including the slice type (I, P or B), the picture output flag, etc. The presence of some encoding tool parameters in the slice header if the tools were included in SPS or PPS, including inclusion SAO separately for luma and chrominance, enabling the deblocking filter operation for slices, and the initial value of the slice quantization parameter (QP). The deblocking filter parameters can be present either in the slice segment header or in the PPS.

Coded slice

Each encoded slice typically consists of a slice header followed by slice data. The slice header carries control information for the slice, and the slice data carries the encoded samples. In fig. 9 and 11 show the slice header according to JVET-O2001-vE. In addition, Fig. 10a shows the syntactic structure of an encoding tree unit that is part of the slice data.

Each slice is independent of other slices in the sense that the information contained in a slice is encoded without any dependence on data from other slices within the same picture.

Picture title

A picture header (PH) is a syntactic structure containing syntactic elements that apply to all slices of the encoded picture. In fig. 10b shows an example of a picture header according to the document JVET-P1006 (http://phenix.it-sudparis.eu/jvet/doc_end_user/documents/16_Geneva/wg11/JVET-P1006-v2.zip). For example, pic_temporal_mvp_enabled_flag determines whether temporal motion vector predictors can be used for external prediction for all slices associated with the picture title. If pic_temporal_mvp_enabled_flag is 0, the syntax elements of the slices associated with the picture header must be constrained such that the temporal motion vector predictor is not used when decoding the slices. Otherwise (pic_temporal_mvp_enabled_flag is equal to 1), temporal motion vector predictors may be used when decoding the slices associated with the picture title.

The picture title is for all types of pictures, i.e. I-picture, P-picture and B-picture. The I picture contains only the intra prediction block, while the P or B picture contains the intra prediction block. The difference between pictures P and B is that picture B can contain an inter-prediction block with bi-directional prediction, while picture P only allows uni-directional inter-prediction. Note that pictures P or B may also have intra-prediction blocks.

There are quite a few syntactic elements in the picture header that are only applicable for external prediction, namely only for P- and B-pictures. These elements are not necessary for I-pictures.

Embodiments of this invention propose to introduce a flag indicating whether the current picture is an I-picture or not. When the current picture is an I-picture, all syntactic elements intended for external prediction are not signaled in the picture header, but are output to a default value.

In one example, the proposed flag is called ph_all_intra_flag. The use of this flag is illustrated as follows.

partition_constraints_override_flag equal to 1 indicates that the partition constraint parameters are present in the image header. partition_constraints_override_flag equal to 0 indicates that the partition constraint parameters are not present in the image header. If it is missing, the value of partition_constraints_override_flag is inferred to be 0.

pic_log2_diff_min_qt_min_cb_intra_slice_luma specifies the difference between the base 2 logarithm of the minimum size in luminance samples of a leaf luminance block resulting from a quadtree partition of the CTU, and the base 2 logarithm of the minimum size of the encoding block in luminance samples for a luminance CU in slices with slice_type equal to 2 (I) associated with the title of the picture. The value of pic_log2_diff_min_qt_min_cb_intra_slice_luma must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_min_qt_min_cb_luma is equal to sps_log2_diff_min_qt_min_cb_intra_slice_luma.

pic_log2_diff_min_qt_min_cb_inter_slice defines the difference between the base 2 logarithm of the minimum size in luminance samples of a leaf luminance block resulting from a quadtree partition of the CTU, and the base 2 logarithm of the minimum size of luminance encoding block in luminance samples for a luminance CU in slices with slice_type equal to 0 (B) or 1 (P) associated with the title of the picture. The value of pic_log2_diff_min_qt_min_cb_inter_slice must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_min_qt_min_cb_luma is equal to sps_log2_diff_min_qt_min_cb_inter_slice.

pic_max_mtt_hierarchy_depth_inter_slice defines the maximum hierarchy depth for encoding blocks obtained as a result of a multi-type tree split of some quadtree leaf into slices with slice_type equal to 0 (B) or 1 (P) associated with the picture title. The value of pic_max_mtt_hierarchy_depth_inter_slice must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, the value of pic_max_mtt_hierarchy_depth_inter_slice is inferred to be equal to sps_max_mtt_hierarchy_depth_inter_slice.

pic_max_mtt_hierarchy_depth_intra_slice_luma defines the maximum hierarchy depth for encoding blocks resulting from a multi-type tree split of some quadtree leaf into slices with slice_type equal to 2 (I) associated with the picture title. The value of pic_max_mtt_hierarchy_depth_intra_slice_luma must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, it is logically concluded that the value of pic_max_mtt_hierarchy_depth_intra_slice_luma is equal to sps_max_mtt_hierarchy_depth_intra_slice_luma.

pic_log2_diff_max_bt_min_qt_intra_slice_luma defines the difference between the base-2 logarithm of the maximum size (width or height) in the luma samples of a luma encoding block that can be divided using a binary slice, and the minimum size (width or height) in the luma samples of a luma leaf block resulting from a CTU split quadtree into slices with slice_type equal to 2 (I), associated with the image title. The value of pic_log2_diff_max_bt_min_qt_intra_slice_luma must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeIntraY inclusive. If it is missing, it is logically deduced that the value of pic_log2_diff_max_bt_min_qt_intra_slice_luma is equal to sps_log2_diff_max_bt_min_qt_intra_slice_luma.

pic_log2_diff_max_tt_min_qt_intra_slice_luma defines the difference between the base-2 logarithm of the maximum size (width or height) in the luma samples of a luma encoding block that can be split using a ternary slice, and the minimum size (width or height) in the luma samples of a leaf luma block resulting from a CTU split quadtree into slices with slice_type equal to 2 (I), associated with the image title. The value of pic_log2_diff_max_tt_min_qt_intra_slice_luma must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeIntraY inclusive. If it is missing, it is logically deduced that the value of pic_log2_diff_max_tt_min_qt_intra_slice_luma is equal to sps_log2_diff_max_tt_min_qt_intra_slice_luma.

pic_log2_diff_max_bt_min_qt_inter_slice defines the difference between the base-2 logarithm of the maximum size (width or height) in the luminance samples of a luminance encoding block that can be sliced using binary slicing, and the minimum size (width or height) in luminance samples of a leaf luminance block resulting from the split CTU for slices with slice_type equal to 0 (B) or 1 (P) associated with the image title. The value of pic_log2_diff_max_bt_min_qt_inter_slice must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeInterY inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_max_bt_min_qt_inter_slice is equal to sps_log2_diff_max_bt_min_qt_inter_slice.

pic_log2_diff_max_tt_min_qt_inter_slice defines the difference between the base-2 logarithm of the maximum size (width or height) in the luma samples of a luma encoding block that can be split using a ternary split, and the minimum size (width or height) in the luma samples of a leaf luma block resulting from the split CTU quadtree into slices with slice_type equal to 0 (B) or 1 (P) associated with the picture title. The value of pic_log2_diff_max_tt_min_qt_inter_slice must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeInterY inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_max_tt_min_qt_inter_slice is equal to sps_log2_diff_max_tt_min_qt_inter_slice.

pic_log2_diff_min_qt_min_cb_intra_slice_chroma defines the difference between the base 2 logarithm of the minimum size in luminance samples of a leaf chroma block obtained by splitting a chrominance CTU quadtree with treeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum size of the encoding block in luminance samples for a chrominance CU with treeType equal to DUAL _TREE_CHROMA , in slices with slice_type equal to 2 (I) associated with the image title. The value of pic_log2_diff_min_qt_min_cb_intra_slice_chroma must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_min_qt_min_cb_intra_slice_chroma is equal to sps_log2_diff_min_qt_min_cb_intra_slice_chroma.

pic_max_mtt_hierarchy_depth_intra_slice_chroma defines the maximum hierarchy depth for chroma encoding blocks, resulting from a multi-type tree splitting of a chroma quadtree leaf with treeType equal to DUAL_TREE_CHROMA into slices with slice_type equal to 2 (I) associated with the picture title. The value of pic_max_mtt_hierarchy_depth_intra_slice_chroma must be in the range from 0 to CtbLog2SizeY - MinCbLog2SizeY inclusive. If it is missing, it is logically concluded that the value of pic_max_mtt_hierarchy_depth_intra_slice_chroma is equal to sps_max_mtt_hierarchy_depth_intra_slice_chroma.

pic_log2_diff_max_bt_min_qt_intra_slice_chroma defines the difference between the base-2 logarithm of the maximum size (width or height) in the luminance samples of a chroma block that can be sliced using binary slicing, and the minimum size (width or height) in the luminance samples of a leaf chroma block resulting from the slice Chromaticity CTU per quadtree with treeType equal to DUAL_TREE_CHROMA, per slice with slice_type equal to 2 (I), associated with the picture title. The value of pic_log2_diff_max_bt_min_qt_intra_slice_chroma must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeIntraC inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_max_bt_min_qt_intra_slice_chroma is equal to sps_log2_diff_max_bt_min_qt_intra_slice_chroma.

pic_log2_diff_max_tt_min_qt_intra_slice_chroma defines the difference between the base-2 logarithm of the maximum size (width or height) in the luminance samples of a chroma block that can be sliced using a ternary slice, and the minimum size (width or height) in the luminance samples of a leaf chroma block resulting from the slice Chromaticity CTU per quadtree with treeType equal to DUAL_TREE_CHROMA, per slice with slice_type equal to 2 (I), associated with the picture title. The value of pic_log2_diff_max_tt_min_qt_intra_slice_chroma must be in the range from 0 to CtbLog2SizeY - MinQtLog2SizeIntraC inclusive. If it is missing, it is logically concluded that the value of pic_log2_diff_max_tt_min_qt_intra_slice_chroma is equal to sps_log2_diff_max_tt_min_qt_intra_slice_chroma.

pic_cu_qp_delta_subdiv_intra_slice defines the maximum cbSubdiv value of the encoding blocks in the inner slice that carry cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of pic_cu_qp_delta_subdiv_intra_slice must be in the range 0 to 2 * ( CtbLog2SizeY − MinQtLog2SizeIntraY+pic_max_mtt_hierarchy_depth_intra_slice_luma ) inclusive.

If it is missing, it is logically concluded that the value of pic_cu_qp_delta_subdiv_intra_slice is 0.

pic_cu_qp_delta_subdiv_inter_slice defines the maximum cbSubdiv value for encoding blocks in the outer slice that carry cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of pic_cu_qp_delta_subdiv_inter_slice must be in the range from 0 to 2 * (CtbLog2SizeY − MinQtLog2SizeInterY+pic_max_mtt_hierarchy_depth_inter_slice) inclusive.

If it is missing, it is logically concluded that the value of pic_cu_qp_delta_subdiv_inter_slice is 0.

pic_cu_chroma_qp_offset_subdiv_intra_slice defines the maximum cbSubdiv value of the encoding blocks in the internal slice that pass cu_chroma_qp_offset_flag. The value of pic_cu_chroma_qp_offset_subdiv_intra_slice must be in the range 0 to 2 * ( CtbLog2SizeY − MinQtLog2SizeIntraY+pic_max_mtt_hierarchy_depth_intra_slice_luma ) inclusive.

If it is missing, the value of pic_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be 0.

pic_cu_chroma_qp_offset_subdiv_inter_slice defines the maximum cbSubdiv value of the encoding blocks in the internal slice that pass cu_chroma_qp_offset_flag. The value of pic_cu_chroma_qp_offset_subdiv_inter_slice must be in the range 0 to 2 * (CtbLog2SizeY − MinQtLog2SizeInterY+pic_max_mtt_hierarchy_depth_inter_slice) inclusive.

If it is missing, the value of pic_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be 0.

pic_temporal_mvp_enabled_flag indicates whether temporal motion vector predictors can be used for external prediction for slices associated with the picture title. If pic_temporal_mvp_enabled_flag is 0, the syntax elements of the slices associated with the picture title must be constrained such that the temporal motion vector predictor is not used when decoding the slices. Otherwise (pic_temporal_mvp_enabled_flag is equal to 1), temporal motion vector predictors can be used when decoding slices associated with the picture title.

When pic_temporal_mvp_enabled_flag is not present, the following applies:

If sps_temporal_mvp_enabled_flag is 0, it is inferred that pic_temporal_mvp_enabled_flag is 0.

Otherwise (sps_temporal_mvp_enabled_flag is equal to 1), it is logically deduced that the value of pic_temporal_mvp_enabled_flag is equal to pps_temporal_mvp_enabled_idc - 1.

mvd_l1_zero_flag equal to 1 specifies that the syntax structure mvd_coding( x0, y0, 1 ) is not parsed syntactically, and MvdL1[ x0 ][ y0 ][ compIdx ] and MvdL1[ x0 ][ y0 ][ cpIdx ][ compIdx ] are set to 0 for compIdx=0..1 and cpIdx=0..2. mvd_l1_zero_flag equal to 0 indicates that the syntactic structure mvd_coding( x0, y0, 1 ) is parsed syntactically. If it is missing, it is logically concluded that the value of mvd_l1_zero_flag is equal to pps_mvd_l1_zero_idc - 1.

pic_six_minus_max_num_merge_cand specifies the maximum number of merge motion vector prediction (MVP) candidates supported in the slices associated with a picture title, subtracted from 6. The maximum number of MVP merge candidates, MaxNumMergeCand, is obtained as follows:

MaxNumMergeCand=6 - picsix_minus_max_num_merge_cand (7 111)

The MaxNumMergeCand value must be between 1 and 6, inclusive. If it is missing, it is logically concluded that the value of pic_six_minus_max_num_merge_cand is equal to pps_six_minus_max_num_merge_cand_plus1-1.

pic_five_minus_max_num_subblock_merge_cand specifies the maximum number of subblock-based merge motion vector prediction candidates supported in a slice, subtracted from 5.

When pic_five_minus_max_num_subblock_merge_cand is missing, the following applies:

If sps_affine_enabled_flag is 0, it is logically deduced that the value of pic_five_minus_max_num_subblock_merge_cand is 5 - (sps_sbtmvp_enabled_flag  &&  pic_temporal_mvp_enabled_flag ).

Otherwise (sps_affine_enabled_flag is equal to 1), it is logically deduced that the value of pic_five_minus_max_num_subblock_merge_cand is equal to pps_five_minus_max_num_subblock_merge_cand_plus1-1.

The maximum number of subblock-based merge MVP candidates, MaxNumSubblockMergeCand, is obtained as follows:

MaxNumSubblockMergeCand=5 - pic_five_minus_max_num_subblock_merge_cand (7 112)

The MaxNumSubblockMergeCand value must be between 0 and 5, inclusive.

pic_fpel_mmvd_enabled_flag equal to 1 specifies that the motion vector difference fusion mode uses integer sampling precision in the slices associated with the picture title. A pic_fpel_mmvd_enabled_flag value of 0 indicates that the motion vector difference fusion mode can use fractional sampling precision in the slices associated with the picture title. If it is missing, the value of pic_fpel_mmvd_enabled_flag is inferred to be 0.

pic_disable_bdof_dmvr_flag equal to 1 specifies that neither bidirectional outer bidirectional optical flow prediction nor outer bidirectional decoder motion vector refinement prediction is enabled in the slices associated with the picture header. pic_disable_bdof_dmvr_flag equal to 0 specifies that bidirectional inter-prediction of bi-directional optical flow or external bi-directional decoder motion vector refinement prediction may or may not be enabled in the slices associated with the picture header. If it is missing, the value of pic_disable_bdof_dmvr_flag is inferred to be 0.

pic_max_num_merge_cand_minus_max_num_triangle_cand specifies the maximum number of triangular merge mode candidates supported in the slices associated with the pictur header subtracted from MaxNumMergeCand.

If pic_max_num_merge_cand_minus_max_num_triangle_cand is missing and sps_triangle_enabled_flag is 1 and MaxNumMergeCand is greater than or equal to 2, the logical conclusion is that pic_max_num_merge_cand_minus_max_num_triangle_cand is equal to pps_max_num_merge_cand_minus_max_num_triangle_cand_plus1 −1.

The maximum number of triangular merge mode candidates, MaxNumTriangleMergeCand, is obtained as follows:

MaxNumTriangleMergeCand=MaxNumMergeCand - pic_max_num_merge_cand_minus_max_num_triangle_cand (7 113)

When pic_max_num_merge_cand_minus_max_num_triangle_cand is present, the MaxNumTriangleMergeCand value must be in the range 2 to MaxNumMergeCand, inclusive.

When pic_max_num_merge_cand_minus_max_num_triangle_cand is missing and (sps_triangle_enabled_flag is 0 or MaxNumMergeCand is less than 2), MaxNumTriangleMergeCand is set to 0.

When MaxNumTriangleMergeCand is 0, triangle merging mode is not allowed for slices associated with the image title.

pic_six_minus_max_num_ibc_merge_cand defines the maximum number of IBC merge block vector prediction (BVP) candidates supported in the slices associated with the picture header, subtracted from 6. The maximum number of IBC merge BVP candidates, MaxNumIbcMergeCand, is defined as follows:

MaxNumIbcMergeCand=6 - pic_six_minus_max_num_ibc_merge_cand (7 114)

The MaxNumIbcMergeCand value must be between 1 and 6, inclusive.

It should be noted that the ph_all_intra_flag may be signaled anywhere before the first place where it will control the syntax element related to the interprediction, that is, pic_log2_diff_min_qt_min_cb_inter_slice. It should be noted that there are one or more places where ph_all_intra_flag may be removed (ie, control only a subset of syntax elements of embodiments of the present invention). As another example, the use of this flag is illustrated as follows.

In particular, the following methods and embodiments implemented by the encoding apparatus are provided. The encoding device may be video encoder 20 of FIG. 1A or encoder 20 of FIG. 2.

According to embodiment 1200 (see FIG. 12), the device determines whether the current picture is an I picture at step 1201.

Since the I-picture contains only an intra-prediction block, there is no need to signal the syntax element intended for inter-prediction in the bitstream picture header. Thus, when the current picture is an I-picture, the syntactic element intended for inter-prediction is not signaled in the picture header. At step 1203, the device sends the bitstream to the decoder, where the bitstream picture header includes a flag that is used to indicate whether the current picture is an I-picture. In this situation, the flag indicates that the current picture is an I-picture. The syntactic element intended for external prediction is not signaled in the picture header. When the current picture is an I-picture, the syntactic element intended for external prediction is output to the default value.

When the current picture is not an I picture, that is, the current picture is a P or B picture, the device obtains a syntax element for inter-prediction at step 1205. As described above, the syntax element for inter-prediction includes one or more of the following elements: pic_log2_diff_min_qt_min_cb_inter_slice, pic_max_mtt_hierarchy_depth_inter_slice, pic_log2_diff_max_bt_min_qt_inter_slice, pic_log2_diff_max_tt_min_qt_inter_slice, pic_cu_qp_delta_subdiv_inter_slice, pic_cu_chroma_ qp_offset_subdiv_inter_slice, pic_temporal_mvp_enabled_flag, mvd_l1_zero_flag, pic_fpel_mmvd_enabled_flag or pic_disable_bdof_dmvr_flag.

At step 1207, the device sends the bit stream to the decoding device. The bitstream picture header includes not only a flag that is used to indicate whether the current picture is an I-picture, but also a syntax element for inter-prediction. In this situation, the flag indicates that the current picture is not an I-picture.

For example, the flag is called ph_all_intra_flag. The ph_all_intra_flag is properly signaled anywhere before the first position controlling a syntax element intended for inter prediction. The use of this flag is shown as described above.

The following methods and embodiments implemented by the decoding apparatus are provided. The decoding device may be the video decoder 30 of FIG. 1A or decoder 30 of FIG. 3. According to embodiment 1300 (see FIG. 13), the device receives a bitstream and parses the bitstream to obtain a flag from the bitstream picture header at step 1301, where the flag indicates whether the current picture is an I-picture.

For example, the flag is called ph_all_intra_flag. The ph_all_intra_flag is properly signaled anywhere before the first position controlling a syntax element intended for inter prediction. The use of this flag is shown as described above.

The device determines whether the current picture is an I picture based on the flag at step 1303.

When the current picture is an I-picture, the inter-prediction syntax element is not signaled in the picture header, the inter-prediction syntax element is output to a default value in step 1305.

When the current picture is not an I picture, that is, the current picture is a P or B picture, the device obtains an inter-prediction syntax element from the bitstream picture header at step 1307. As described above, the inter-prediction syntax element includes in itself one or more of the following elements: pic_log2_diff_min_qt_min_cb_inter_slice, pic_max_mtt_hierarchy_depth_inter_slice, pic_log2_diff_max_bt_min_qt_inter_slice, pic_log2_diff_max_tt_min_qt_inter_slice, pic_cu_qp_delta_subdiv_inter_slice, cu_chroma_qp_offset_subdiv_inter_slice, pic_temporal_mvp_enabled_flag, mvd_l1_zero_flag, pic_fpel_mmvd_enabled_flag or pic_disable_bdof_dmvr_flag.

In FIG. 14 illustrates embodiments of device 1400. Device 1400 may be the video encoder 20 of FIG. 1A or encoder 20 of FIG. 2. Apparatus 1400 may be used to implement embodiment 1200 and other embodiments described above.

The device 1400 according to the present disclosure includes a determining block 1401, a receiving block 1402, and a signaling block 1403. The determination unit 1401 is configured to determine whether the current picture is an I picture.

The receiving unit 1402 is configured to receive a syntax element for inter-prediction when the current picture is not an I picture, i.e. P- or B-picture. As described above, a syntax element for inter-prediction includes one or more of the following elements: pic_log2_diff_min_qt_min_cb_inter_slice, pic_max_mtt_hierarchy_depth_inter_slice, pic_log2_diff_max_bt_min_qt_inter_slice, pic_log2_diff_max_tt_min_qt_inter_slice, cu_qp_delta_subdiv_inter_slice, pic_cu_chroma_qp_offset_subdiv_inter_slice, pic_temporal_mvp_enabled_flag, mvd_l1_zero_flag, pic_fpel_mmvd_enabled_flag or pic_disable_bdof_dmvr_flag.

When the current picture is an I-picture, the syntactic element intended for external prediction is output to the default value.

The signaling unit 1403 is configured to send the bit stream to the decoding device, where the bit stream picture header includes a flag that is used to indicate whether the current picture is an I picture.

The bitstream picture header further includes a syntax element for inter-prediction when the current picture is not an I-picture. Since the I-picture contains only an intra-prediction block, there is no need to signal the syntax element intended for inter-prediction in the bitstream picture header.

For example, the flag is called ph_all_intra_flag. The ph_all_intra_flag flag is appropriately signaled anywhere before the first place controlling a syntax element intended for inter prediction. The use of this flag is shown as described above.

Fig. 15 illustrates embodiments of device 1500. Device 1500 may be the video decoder 30 of FIG. 1A or decoder 30 in FIG. 3. Apparatus 1500 may be used to implement embodiment 1300 and other embodiments described above.

The device 1500 includes a receiving unit 1501 and a determining unit 1502. The receiving unit 1501 is configured to parse the bit stream to obtain a flag from the bit stream picture header, where the flag indicates whether the current picture is an I picture. For example, the flag is called ph_all_intra_flag.

The determination unit 1502 is configured to determine whether the current picture is an I picture based on the flag.

The obtaining unit 1501 is further configured to obtain a syntax element for inter-prediction from the picture header when the flag indicates that the current picture is not an I-picture, i.e. P- or B-picture. When the current picture is an I-picture, the syntax element for inter-prediction is not signaled in the picture header, the syntax element for inter-prediction is output with a default value.

In addition, the following embodiments are provided herein.

Option 1 implementation. An encoding method implemented by a decoding device, containing:

bitstream parsing; And

obtaining a flag from the bitstream picture header, where the flag indicates whether the current picture is an I-picture.

Option 2 implementation. The method as in Embodiment 1, in which, when the current picture is an I-picture, a syntax element intended for inter-prediction is output as a default value.

Option 3 implementation. The method of Embodiment 1 or 2, wherein the flag is carried in PBSP picture header syntax.

Option 4 implementation. The method as in any one of embodiments 1 to 3, wherein the flag is named ph_all_intra_flag.

Option 5 implementation. The method of embodiment 4, wherein the flag is used as follows:

Option 6 implementation. The method according to embodiment 4 or 5, in which the flag is used as follows:

Option 7 implementation. The method as in any one of embodiments 4-6, wherein the flag is used as follows:

Embodiment 8. The method as in any one of embodiments 4 to 7, wherein the flag is used as follows:

Option 9 implementation. The method as in any one of embodiments 1 to 8, wherein the I picture contains only an intra prediction block, while the P or B picture contains an inter prediction block.

Embodiment 10. An encoding method implemented by an encoding device, containing:

signaling a flag to the bitstream picture header, wherein the flag indicates whether the current picture is an I-picture; And

sending a bit stream.

Embodiment 11. The method of Embodiment 10, in which, when the current picture is an I-picture, all syntax elements intended for inter-prediction are not signaled in the picture header.

Embodiment 12. The method as in Embodiment 10 or 11, wherein when the current picture is an I-picture, a syntax element intended for inter-prediction is output as a default value.

Embodiment 13. The method as in any one of embodiments 10-12, wherein the flag is signaled in PBSP picture header syntax.

Embodiment 14. The method as in any one of embodiments 10-13, wherein the flag is named ph_all_intra_flag.

Embodiment 15. The method of Embodiment 14, wherein the ph_all_intra_flag is suitably signaled anywhere before the first position controlling a syntax element related to inter prediction.

Embodiment 16. The method of embodiment 14 or 15, wherein the flag is used as follows:

Embodiment 17. The method as in any one of embodiments 14-16, wherein the flag is used as follows:

Embodiment 18. The method as in any one of embodiments 14-17, wherein the flag is used as follows:

Embodiment 19. The method as in any one of embodiments 14-18, wherein the flag is used as follows:

As discussed above, by indicating whether the current picture is an I-picture in the bitstream picture header, the syntax element for inter-prediction is not signaled in the picture header when the current picture is an I-picture. Thus, embodiments can simplify picture header signaling for all internal pictures, i.e., I-picture. Signaling costs are reduced accordingly.

The term "receive" may refer to receiving (for example, explicitly, as a corresponding parameter from another object/device or module in the same device, for example, for a decoder by parsing a bitstream) and/or retrieving (for example, which may also treated as an implicit technique, for example for a decoder by parsing other information/parameters from the bitstream and extracting the corresponding information or parameter from such other information/parameters).

The following will be an explanation of the applications of the encoding method as well as the decoding method as shown in the above-mentioned embodiments and the system using them.

Fig. 16 is a block diagram showing a content delivery system 3100 for implementing a content distribution service. This content delivery system 3100 includes a capture device 3102, a terminal device 3106, and optionally includes a display 3126. The capture device 3102 communicates with the terminal device 3106 via a communication line 3104. The communication link may include a communication channel 13 described above. Communication link 3104 includes, but is not limited to, WIFI, Ethernet, cable, wireless (3G/4G/5G), USB, or any combination thereof, or the like.

The capture device 3102 generates data and can encode the data using the encoding method shown in the above embodiments. Alternatively, capture device 3102 may distribute data to a streaming server (not shown in the Figures), and the server encodes the data and transmits the encoded data to terminal device 3106. Capture device 3102 includes, but is not limited to, a camera, smartphone, or a tablet, computer or laptop, video conferencing system, PDA, vehicle-mounted device, or a combination of any of these, or the like. For example, capture device 3102 may include source device 12 described above. When the data includes video, the video encoder 20 included in the capture device 3102 may actually perform video encoding processing. When the data includes audio (ie, speech), an audio encoder included in the capture device 3102 may actually perform audio encoding processing. For some practical scenarios, capture device 3102 distributes encoded video and audio data by multiplexing them together. For other practical scenarios, such as in a video conferencing system, encoded audio data and encoded video data are not multiplexed. The capture device 3102 distributes the encoded audio data and the encoded video data to the terminal device 3106 separately.

In the content delivery system 3100, the terminal device 310 receives and reproduces encoded data. Terminal device 3106 may be a device capable of receiving and retrieving data, such as a smartphone or tablet 3108, computer or laptop 3110, network video recorder (NVR)/digital video recorder (DVR) 3112, television 3114, set-top box (STB) 3116, video conferencing system 3118 , a video surveillance system 3120, a personal digital assistant (PDA) 3122, a vehicle-mounted device 3124, or a combination thereof, or the like, capable of decoding the above encoded data. For example, terminal device 3106 may include receiver device 14 described above. When the encoded data includes video, the video decoder 30 included in the terminal device is given priority to perform video decoding. When the encoded data includes audio, an audio decoder included in the terminal device is given priority to perform audio decoding processing.

For a terminal device with its own display, such as a smartphone or tablet 3108, a computer or laptop 3110, a network video recorder (NVR)/digital video recorder (DVR) 3112, a television 3114, a personal digital assistant (PDA) 3122, or a vehicle-mounted device 3124, terminal the device can transmit decoded data to its display. For a non-display terminal device, such as the STB 3116, video conferencing system 3118, or video surveillance system 3120, it communicates with an external display 3126 to receive and display the decoded data.

When each device in this system performs encoding or decoding, a picture encoding device or a picture decoding device may be used, as shown in the above embodiments.

Fig. 17 is a diagram showing the structure of an exemplary terminal device 3106. After the terminal device 3106 receives a stream from the capture device 3102, a protocol processing unit 3202 analyzes the transmission protocol of the stream. The protocol includes, but is not limited to, Real Time Streaming Protocol (RTSP), Hypertext Transfer Protocol (HTTP), HTTP Live Streaming Protocol (HLS), MPEG-DASH, Real Time Transport Protocol (RTP), Exchange Protocol real-time messaging (RTMP) or any combination thereof, or the like.

After the protocol processing unit 3202 processes the stream, a stream file is generated. The file is output to a demultiplexing block 3204. A demultiplexer 3204 may separate the multiplexed data into encoded audio data and encoded video data. As described above, in other practical scenarios, such as in a video conferencing system, encoded audio data and encoded video data are not multiplexed. In this situation, the encoded data is transmitted to the video decoder 3206 and audio decoder 3208 without using the demultiplexer 3204.

Through the demultiplexing processing, a video elementary stream (ES), an audio ES, and optionally subtitles are generated. The video decoder 3206, which includes the video decoder 30 described in the above embodiments, decodes the ES video using the decoding method as shown in the above embodiments to generate a video frame and supplies this data to the synchronization unit 3212. Audio decoder 3208 decodes the audio ES to generate an audio frame and supplies this data to synchronization block 3212. Alternatively, the video frame may be stored in a buffer (not shown in FIG. 21) before being supplied to synchronization block 3212. Likewise, an audio frame may be stored in a buffer (not shown in FIG. 21) before being supplied to synchronization block 3212.

The synchronization unit 3212 synchronizes the video frame and the audio frame and supplies the video/audio to the video/audio display 3214. For example, the synchronization unit 3212 synchronizes the presentation of video and audio information. Information may be encoded in syntax using timestamps relating to the presentation of the encoded audio and video data, as well as timestamps relating to the delivery of the data stream itself.

If subtitles are included in the stream, subtitle decoder 3210 decodes the subtitles and synchronizes them with the video frame and audio frame and transmits the video/audio/subtitles to the video/audio/subtitle display 3216.

The present invention is not limited to the above system, and either the picture encoding device or the picture decoding device in the above embodiments may be included in another system, such as an automobile system.

The mathematical operators used in this application are similar to those used in the C programming language. However, the results of integer division and arithmetic shift operations are defined more precisely, and additional operations such as exponentiation and real-valued division are also defined. Numbering and counting conventions specify starting at 0, for example, "first" is equivalent to 0, "second" is equivalent to 1, etc.

Arithmetic operators

The following arithmetic operators are defined as follows:

Logical operators

The following logical operators are defined as follows:

x && y

x || y Boolean logical "or" for x and y

! Boolean logical "not"

x?y:z If x is TRUE or not 0, the value of y is calculated; otherwise, the z value is calculated.

Relational operators

The following relational operators are defined as follows:

> More

>= Greater than or equal to

< Less

<= Less than or equal to

== Equal

!= Not equal

When a comparison operator is applied to a syntax element or variable that is assigned the value "na" (not applicable), the value "na" is treated as a separate value for the syntax element or variable. The value "na" is not considered equal to any other value.

Bit operators

The following bitwise operators are defined as follows:

& bit "and". When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

| bit or. When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

^ exclusive or. When operating on integer arguments, operates on the two's complement representation of an integer value. When working on a binary argument that contains fewer bits than another argument, the shorter argument is expanded by adding more significant bits equal to 0.

x >> y Arithmetic right shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. The bits shifted to the most significant bits (MSB) by a right shift have a value equal to the MSB of x before the shift operation.

x << y Arithmetic left shift of the two's complement integer representation of x by y binary digits. This function is defined only for non-negative integer values of y. Bits shifted to the least significant bits (LSB) by left shifting have a value of 0.

Assignment Operators

The following arithmetic operators are defined as follows:

= assignment operator

+ + Increment, i.e. x+ + is equivalent to x = x+ 1; when used in an array index, evaluates to the value of the variable before the increment operation.

− − Decrease, i.e. x− − is equivalent to x = x - 1; when used in an array index, evaluates the value of the variable before the decrement operation.

+=Increment by the specified amount, i.e. x += 3 is equivalent to x=x+3, and x += (−3) is equivalent to x=x + (−3).

−=Decrease by the specified amount, i.e. x −= 3 is equivalent to x=x − 3, and x −= (−3) is equivalent to x=x − (−3).

Range designation

The following notation is used to indicate a range of values:

x=y..z x takes integer values from y to z, inclusive, where x, y and z are integers and z is greater than y.

Mathematical functions

The following mathematical functions are defined:

Asin(x) is a trigonometric inverse sine function operating on an argument x that ranges from −1.0 to 1.0 inclusive, with an output value ranging from −π ÷ 2 to π ÷ 2 inclusive, in units of radians.

Atan( x ) is a trigonometric arctangent function operating on an argument x, with an output value ranging from −π÷2 to π÷2 inclusive, in units of radians.

Ceil( x ) smallest integer greater than or equal to x

Clip1Y( x )=Clip3( 0, ( 1 << BitDepthY ) − 1, x )

Clip1C( x )=Clip3( 0, ( 1 << BitDepthC ) − 1, x )

Cos( x ) is a trigonometric cosine function that operates on x in units of radians.

Floor( x ) is the largest integer less than or equal to x.

Ln( x ) natural logarithm of x (logarithm to base e, where e is the base constant of the natural logarithm 2.718 281 828...).

Log2( x ) logarithm of x to base 2.

Log10( x ) is the logarithm of x to base 10.

Round( x )=Sign( x ) * Floor( Abs( x ) + 0.5)

Sin( x ) is a trigonometric sine function that operates on x in units of radians.

Sqrt( x )=

Swap( x, y )=( y, x )

Tan( x ) is a trigonometric tangent function that operates on x in units of radians.

Order of priority of operations

When the order of precedence in an expression is not explicitly specified using parentheses, the following rules apply:

Operations with higher priority are evaluated before any operation with lower priority.

Operations with the same priority are evaluated sequentially from left to right.

The table below lists the priority of operations from highest to lowest; a higher position in the table indicates higher priority.

For those operators that are also used in the C programming language, the order of precedence used in this description is the same as in the C programming language.

Table: Operation priority from highest (at the top of the table) to lowest (at the bottom of the table)

Text description of logical operations

The text contains a definition of logical operations, which would be described mathematically in the following form:

if ( condition 0 ) definition 0

else if( condition 1)

definition 1...

else /* informative comment on the remaining condition */ definition n

can be described as follows:

... as below / ... the following applies:

- if condition 0, definition 0

- Otherwise, if condition 1, definition 1

- ...

- Otherwise (informative comment on the remaining condition), definition n.

Each "if...else, if...else,..." definition in the text is introduced with the words "...as below" or "...the following applies" followed immediately by "if..." . The final condition "if...else, if...else..." can always be "otherwise..." Alternating definitions of "if...else if...else,..." can be identified by comparison "...as stated below" or "...the following applies" followed by a final "otherwise,...".

The text contains a definition of logical operations, which would be described mathematically in the following form:

if( condition 0a && condition 0b ) definition 0

else if ( condition 1a | | condition 1b ) definition 1 ... else definition n

can be described as follows:

... as below / ... the following applies:

- If all of the following conditions are true, definition 0:

- condition 0a

- condition 0b

- Else, if one or more of the following conditions are true, Definition 1:

- condition 1a

- condition 1b

- ...

- Otherwise, the definition of n

The text contains a definition of logical operations, which would be described mathematically in the following form:

if (condition 0) definition 0 if (condition 1) definition 1

can be described as follows:

When condition is 0, definition is 0

When condition 1, definition 1

Although embodiments of the present invention have been primarily described in terms of video encoding, it should be noted that embodiments of encoding system 10, encoder 20, and decoder 30 (and thus system 10), as well as other embodiments described herein, may also be configured to process or encode a still picture, i.e. processing or encoding a single picture independently of any preceding or subsequent picture, as in video encoding. In general, only inter prediction (encoder) and 344 (decoder) blocks 244 may not be available if the encoding for picture processing is limited to a single picture 17. All other functionality (also referred to as tools or technologies) of video encoder 20 and video decoder 30 may equally used for still picture processing, such as residual computation 204/304, transform 206, quantization 208, inverse quantization 210/310, (inverse) transform 212/312, division 262/362, intra prediction 254/354 and/or loop filtering 220, 320 and entropy encoding 270 and entropy decoding 304.

Embodiments of, for example, encoder 20 and decoder 30, as well as the functions described herein, for example, with respect to encoder 20 and decoder 30 may be implemented by hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a computer-readable medium or transmitted through a communication medium in the form of one or more instructions or code and executed by a hardware processing unit. Computer-readable media may include computer-readable media that corresponds to a tangible medium, such as a storage medium, or a communication medium, including any medium that enables transmission of a computer program from one location to another, such as according to a communications protocol. Thus, computer-readable media may typically correspond to (1) tangible computer-readable storage media that are non-transitory, or (2) a communication medium such as a signal or carrier wave. Storage media can be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, code and/or data structures for implementing the techniques described in this disclosure. The computer program product may include computer-readable media.

By way of example, and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other media that can used to store desired program code in the form of instructions or data structures and can be accessed by a computer. Additionally, any connection is properly referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave communications, then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, radio and microwave communications are included in the definition of media. However, it should be understood that computer readable and storage media do not include connections, carrier waves, signals, or other short-lived media, but are instead directed to long-term, tangible storage media. The disk and disc used in this document include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where discs ) typically reproduce data magnetically, while discs (discs) reproduce data optically using lasers. Combinations of the above should also be included in the scope of computer readable media.

The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Accordingly, the term “processor” as used herein can refer to any of the above structure or any other structure suitable for implementing the techniques described herein. Additionally, in some aspects, the functionality described herein may be provided within specialized hardware and/or software modules configured for encoding and decoding, or included in a combination codec. In addition, the techniques may be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide variety of devices or hardware components, including a wireless telephone, an integrated circuit (IC), or a set of ICs (eg, a chipset). This disclosure describes various components, modules, or blocks to highlight functional aspects of devices configured to implement the disclosed technologies, but not necessarily required to be implemented by different hardware units. Rather, as described above, the various blocks may be combined into a codec hardware block or provided by a collection of interacting hardware blocks, including one or more processors as described above, together with suitable software and/or firmware.

Claims (55)

1. A decoding method implemented by a decoding device, containing: parsing (1301) the bitstream to obtain a first flag from the bitstream picture header, the first flag indicating whether the current picture is an I-picture; when the first flag indicates that the current picture is an I-picture, the inter-prediction syntax element is not signaled in the picture header and is logically inferred to be equal to the value of the inter-prediction syntax element in the bitstream sequence parameter set (SPS) (1305) ; or, when the first flag indicates that the current picture is a picture P or B, and the second flag indicates that the section constraint parameters are present in the picture header, obtaining (1307) a syntax element intended for inter-prediction from the picture header, wherein the second flag represents is partition_constraints_override_flag. 2. The method according to claim 1, characterized in that the syntactic element intended for external prediction includes pic_log2_diff_min_qt_min_cb_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_min_qt_min_cb_inter_slice determines the difference between the base 2 logarithm of the minimum size in luminance samples of the luminance leaf block resulting from the quadtree split of the encoding tree unit (CTU), and the base 2 logarithm the minimum luminance coding block size in luminance samples for luminance coding units (CU) in slices with a P or B picture associated with the picture header; or Moreover, when the first flag indicates that the current picture is an I-picture, the value of pic_log2_diff_min_qt_min_cb_luma is logically output to be equal to sps_log2_diff_min_qt_min_cb_inter_slice. 3. The method according to claim 1 or 2, wherein the syntax element for inter-prediction further includes pic_max_mtt_hierarchy_depth_inter_slice, in this case, when the first flag indicates that the current picture is picture P or B, pic_max_mtt_hierarchy_depth_inter_slice indicates the maximum hierarchy depth for encoding blocks, obtained as a result of a multi-type splitting of a certain quadtree leaf into slices; or however, when the first flag indicates that the current picture is an I-picture, the value of pic_max_mtt_hierarchy_depth_inter_slice is logically output to be equal to sps_max_mtt_hierarchy_depth_inter_slice. 4. The method of claim 3, wherein when pic_max_mtt_hierarchy_depth_inter_slice is not equal to 0, the syntax element for inter-prediction further includes pic_log2_diff_max_bt_min_qt_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_max_bt_min_qt_inter_slice indicates the difference between the base 2 logarithm of the maximum size (width or height) in the luminance samples of the luminance encoding block, which can be sliced using binary slicing, and the logarithm of base 2 of the minimum size (width or height) in the brightness samples of the leaf luma block obtained by splitting the quadtree of some CTU into slices; or Moreover, when the first flag indicates that the current picture is picture I, the value of pic_log2_diff_max_bt_min_qt_inter_slice is logically output equal to sps_log2_diff_max_bt_min_qt_inter_slice. 5. The method as claimed in claim 3 or 4, wherein when pic_max_mtt_hierarchy_depth_inter_slice is not equal to 0, the syntax element for inter-prediction further includes pic_log2_diff_max_tt_min_qt_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_max_tt_min_qt_inter_slice indicates the difference between the base 2 logarithm of the maximum size (width or height) in the luminance samples of a luminance encoding block that can be split using ternary slicing, and the logarithm of base 2 of the minimum size (width or height) in the brightness samples of the leaf luma block obtained by splitting the quadtree of some CTU into slices; or Moreover, when the first flag indicates that the current picture is picture I, the value of pic_log2_diff_max_tt_min_qt_inter_slice is logically output equal to sps_log2_diff_max_tt_min_qt_inter_slice. 6. Method according to any one of paragraphs. 1-5, wherein the syntax element for inter-prediction further includes pic_cu_qp_delta_subdiv_inter_slice, in this case, when the first flag indicates that the current picture is a P or B picture, pic_cu_qp_delta_subdiv_inter_slice indicates the maximum value cbSubdiv of encoding blocks, which in the external slice transmit cu_qp_delta_abs and cu_qp_delta_sign_flag; or however, when the first flag indicates that the current picture is picture I, it is logically inferred that the value of pic_cu_qp_delta_subdiv_inter_slice is 0. 7. Method according to any one of paragraphs. 1-6, wherein the syntax element for inter-prediction further includes pic_cu_chroma_qp_offset_subdiv_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_cu_chroma_qp_offset_subdiv_inter_slice indicates the maximum cbSubdiv value of encoding blocks in the outer slice that transmit cu_chroma_qp_offset_flag; or however, when the first flag indicates that the current picture is picture I, it is logically inferred that the value of pic_cu_chroma_qp_offset_subdiv_inter_slice is 0. 8. Method according to any one of paragraphs. 1-7, wherein the syntax element for inter-prediction further includes pic_cu_chroma_qp_offset_subdiv_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_cu_chroma_qp_offset_subdiv_inter_slice indicates the maximum cbSubdiv value of encoding blocks in the outer slice that transmit cu_chroma_qp_offset_flag; or however, when the first flag indicates that the current picture is picture I, it is logically inferred that the value of pic_cu_chroma_qp_offset_subdiv_inter_slice is 0. 9. Method according to any one of paragraphs. 1-8, wherein the syntax element for inter-prediction further includes pic_temporal_mvp_enabled_flag, wherein, when the first flag indicates that the current picture is a P or B picture, pic_temporal_mvp_enabled_flag indicates whether temporal motion vector predictors can be used for inter-prediction for slices associated with the picture header; or however, when the first flag indicates that the current picture is an I-picture, if sps_temporal_mvp_enabled_flag is equal to 0, the value of pic_temporal_mvp_enabled_flag is logically output equal to 0, otherwise if sps_temporal_mvp_enabled_flag is equal to 1, it is logically concluded that the value of pic_temporal_mvp_enabled_flag is equal to pps_temporal_mvp_enabled_idc - 1. 10. Method according to any one of paragraphs. 1-9, characterized in that the first flag is carried in the PBSP syntax of the picture header. 11. Method according to any one of paragraphs. 1-10, characterized in that the first flag is called ph_all_intra_flag. 12. The method according to claim 11, characterized in that the first flag is used as follows: 13. Method according to any one of paragraphs. 1-12, characterized in that a certain I picture contains only an intra prediction block, while a P or B picture contains an inter prediction block. 14. A decoder (30) comprising a processing circuit for performing the method according to any one of claims. 1-13. 15. Decoder containing: one or more processors; And a non-transitory computer-readable medium coupled to the processors and storing a program for execution by one or more processors to cause the one or more processors to execute the method of any one of claims. 1-13. 16. A decoding device (1500), comprising: an acquisition unit (1501) configured to parse the bitstream to obtain a first flag from the bitstream picture header, wherein the first flag indicates whether the current picture is an I-picture; a determination unit (1502), configured to determine whether the current picture is an I picture based on the first flag; an obtaining unit (1501) further configured to obtain a syntax element for inter-prediction from the picture header when the first flag indicates that the current picture is a P or B picture and the second flag indicates that the section limit parameters are present in the picture header , where the second flag is partition_constraints_override_flag; wherein the first flag indicates that the current picture is an I-picture, the inter-prediction syntax element is not signaled in the picture header and is logically derived equal to the value of the inter-prediction syntax element in the sequence parameter set (SPS) of the bitstream. 17. The apparatus of claim 16, wherein the syntax element for inter-prediction includes pic_log2_diff_min_qt_min_cb_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_min_qt_min_cb_inter_slice specifies the difference between the base 2 logarithm of the minimum size in luminance samples of a leaf luminance block resulting from a quadtree split of the encoding tree unit (CTU), and the base 2 logarithm the minimum luminance coding block size in luminance samples for luminance coding units (CU) in slices with a P or B picture associated with the picture header; or Moreover, when the first flag indicates that the current picture is an I-picture, the value of pic_log2_diff_min_qt_min_cb_luma is logically output to be equal to sps_log2_diff_min_qt_min_cb_inter_slice. 18. The apparatus of claim 16 or 17, wherein the syntax element for inter-prediction further includes pic_max_mtt_hierarchy_depth_inter_slice, in this case, when the first flag indicates that the current picture is picture P or B, pic_max_mtt_hierarchy_depth_inter_slice indicates the maximum hierarchy depth for encoding blocks obtained as a result of a multi-type splitting of the quadtree leaf tree into slices; or however, when the first flag indicates that the current picture is an I-picture, the value of pic_max_mtt_hierarchy_depth_inter_slice is logically output to be equal to sps_max_mtt_hierarchy_depth_inter_slice. 19. The apparatus of claim 18, wherein when pic_max_mtt_hierarchy_depth_inter_slice is not equal to 0, the syntax element for inter-prediction further includes pic_log2_diff_max_bt_min_qt_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_max_bt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum size (width or height) in the luminance samples of a luminance encoding block that can be sliced using binary slicing, and the logarithm of base 2 of the minimum size (width or height) in the brightness samples of the leaf luma block obtained by splitting the CTU quadtree into slices; or Moreover, when the first flag indicates that the current picture is picture I, the value of pic_log2_diff_max_bt_min_qt_inter_slice is logically output equal to sps_log2_diff_max_bt_min_qt_inter_slice. 20. The apparatus of claim 18 or 19, wherein when pic_max_mtt_hierarchy_depth_inter_slice is not equal to 0, the syntax element for inter-prediction further includes pic_log2_diff_max_tt_min_qt_inter_slice, wherein, when the first flag indicates that the current picture is a P or B picture, pic_log2_diff_max_tt_min_qt_inter_slice indicates the difference between the base 2 logarithm of the maximum size (width or height) in the luminance samples of a luminance encoding block that can be split using ternary slicing, and the logarithm of base 2 of the minimum size (width or height) in the brightness samples of the leaf luma block obtained by splitting the CTU quadtree into slices; or Moreover, when the first flag indicates that the current picture is picture I, the value of pic_log2_diff_max_tt_min_qt_inter_slice is logically output equal to sps_log2_diff_max_tt_min_qt_inter_slice. 21. The device according to any one of paragraphs. 18-20, in which the I picture contains only an intra prediction block, while the P or B picture contains an inter prediction block.