JP2010028516A - Video distribution system, video distribution apparatus, video receiving device, video distribution method, video receiving method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten waiting time until displaying video images when starting distributing video contents without notifying a video distribution apparatus of a utilization situation of a buffer from a video receiving device in a video distribution system for distributing layer-coded contents. <P>SOLUTION: A distribution data amount detection means 106 detects the amount of basic layer data to be distributed. A distribution speed determination means 106 determines a distribution bit rate of the basic layer data to a value greater than an encode bit rate until the distribution data amount detected by the distribution data amount detection means 107 reaches a target amount after distribution start. Furthermore, after the data amount reaches the target amount, distribution bit rates of the basic layer data and respective extension layer data are determined to values corresponding to the encode bit rates of the signals thereof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a video distribution technology that distributes hierarchically encoded video content, and more particularly to a video distribution technology that can reduce the waiting time until video is played back when video content distribution starts.

  With the spread of communication services such as FTTH, an environment in which high-speed and high-quality networks can be used in offices and homes is being prepared. In addition, a distribution service for HD (High Definition) video content based on a broadband network has been started in part. However, in the Internet, wireless LAN, mobile phone network, etc., the available network bandwidth varies depending on the situation. In video receivers, it is common to buffer video data in order to prevent video pauses and disturbances caused by fluctuations in the network usable bandwidth. However, due to this buffering, there is a delay from the start of video playback until the video is actually displayed. Since the reduction in response time due to this buffering delay causes user stress, it is important to reduce the playback delay in the video distribution service.

  An example of a technique for solving such a problem is described in Patent Document 1. The technique described in Patent Document 1 receives a video distribution device that distributes video content that is hierarchically encoded into base layer data and enhancement layer data, and receives and reproduces the video content distributed from the video distribution device. And a video receiver. Here, the base layer data is data that guarantees a minimum image quality, and an image can be reproduced by itself. The enhancement layer data is positioned above the base layer data and is decoded together with the base layer data, thereby improving the image quality.

  The video receiving device includes a base layer buffer and an extended layer buffer for storing the basic layer data and the extended layer data distributed from the video distribution device. During video playback, the free capacity of both buffers ( (Buffer usage status) is notified to the video distribution apparatus. On the other hand, if the video distribution device determines that the free space of the base layer buffer is greater than or equal to the first predetermined value based on the notification from the video reception device, the video distribution device transmits the base layer data based on the encoded bit rate. When the distribution is performed at a fast distribution bit rate, and it is determined that the free capacity of the base layer buffer is less than the first predetermined value and the free capacity of the extension layer buffer is greater than or equal to the second predetermined value, Layer data and enhancement layer data are transmitted at a distribution bit rate corresponding to the encoded bit rate.

  Here, the free capacity of the base layer buffer that is first notified to the video distribution apparatus by the video receiving apparatus is equal to or larger than the first predetermined value (since no data is accumulated in the base layer buffer). ) At the start of video content distribution, the video distribution apparatus distributes the base layer data at a distribution bit rate faster than the encoding bit rate. As a result, the buffering is completed in a short time, and the waiting time until the video content is reproduced can be shortened.

JP 2004-297117 A

  However, the technology described in Patent Document 1 notifies the video distribution device of the buffer usage status from the video reception device, and the video distribution device is based on the buffer usage status notified from the video reception device. Since the distribution bit rates of the layer data and the enhancement layer data are determined, there is a problem that a means for transmitting and receiving the buffer usage status must be implemented in the video reception device and the video distribution device, and communication traffic The problem of increasing arises.

(Object of invention)
Accordingly, an object of the present invention is to provide a video that can reduce the waiting time until video is played back when video content distribution starts without the video receiving device notifying the video distribution device of the buffer usage status. To provide a distribution system.

The video distribution system according to the present invention includes:
A video distribution device that distributes video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers, and a video reception device that receives the video content distributed from the video distribution device;
The video distribution device includes:
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
Distribution speed determination means for determining a distribution bit rate of each of the basic signal and the extension signal of each layer, wherein the distribution data of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content Distribution speed determining means for determining a distribution bit rate of the basic signal to a value larger than an encoding bit rate of the basic signal until the amount reaches a first target amount;
A distribution unit that distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit;
The video receiver is
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
Decoding means for decoding the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount.

The first video distribution apparatus according to the present invention is:
A video distribution device that distributes video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers,
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
The distribution bit rate of the basic signal is set to the encoding bit rate of the basic signal until the distribution data amount of the basic signal detected by the distribution data amount detecting means from the start of distribution of the video content reaches a first target amount. A delivery speed determining means for determining a larger value than
A distribution unit that distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit.

A first video receiving device according to the present invention includes:
(A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. A video receiving apparatus for receiving the video content,
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
Decoding means for decoding the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount.

A first video distribution method according to the present invention includes:
A video distribution method for distributing video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers,
Distribution data amount detection means detects the distribution data amount of the basic signal,
The distribution rate determining means for determining the distribution bit rate of each of the basic signal and the extended signal of each layer is the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content. Until the first target amount is reached, the delivery bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal;
The distribution unit distributes the basic signal and the extension signal of each layer according to the distribution bit rate of each of the basic signal and the extension signal of each layer determined by the distribution speed determining unit.

A first video receiving method according to the present invention includes:
(A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. A video receiving method for receiving the video content,
The receiving unit receives the basic signal distributed from the video distribution device and the extended signal of each layer,
Buffering means buffers the basic signal received by the receiving unit and the extension signal of each layer,
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
The decoding means decodes the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount.

The first program according to the present invention is:
A program for causing a computer to function as a video distribution device that distributes video content hierarchically encoded into a basic signal and an extension signal of one or more layers,
The computer,
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
The distribution bit rate of the basic signal is set to the basic signal from the start of the distribution of the video content until the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount. Distribution speed determination means that determines a value larger than the encoding bit rate,
The basic signal and the extension signal of each layer are functioned as a distribution unit that distributes the basic signal and the extension signal of each layer according to the distribution bit rate of each of the basic signal and the extension signal of each layer determined by the distribution speed determining means.

The second program according to the present invention is:
(A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. The video receiving apparatus for receiving the video content to a program for realizing a computer,
The computer,
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
After the accumulated amount of the basic signal detected by the buffer amount detecting means reaches the first target amount, the buffering means functions as a decoding means for decoding the basic signal buffered. program.

  According to the present invention, it is possible to reduce the waiting time until the video is reproduced at the start of the distribution of the video content without notifying the video distribution device of the use status of the buffer from the video reception device. Obtainable.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

[First embodiment of the present invention]
In this embodiment, the video content is played back at the start of the distribution of the video content (sometimes referred to simply as content) without notifying the video distribution device of the buffer usage status (such as free space) from the video reception device. In order to reduce the waiting time until the video content is distributed, the video distribution device detects the distribution data amount of the basic layer data, and until the basic layer data distribution amount reaches the target amount from the start of the distribution of the video content. The distribution bit rate of the base layer data is made faster than the encoding bit rate.

  Referring to FIG. 1, a video distribution system 10 according to a first embodiment of the present invention includes a video distribution device 100 that distributes scalable content, and a video reception device 200 that receives and displays the scalable content, They are connected to each other via a network 300.

  In the present embodiment, the Internet is assumed as the network 300. However, the network 300 is not limited to this, and is not limited to this, but NGN (Next Generation Network), wireless LAN (Local Area Network), mobile phone network, USB (Universal Serial Bus) ) And PCI (Peripheral Component Interconnect) buses may be used to connect devices. The video distribution apparatus 100 is assumed to be a PC server, but may be a hard disk recorder or the like. The video receiving apparatus 200 is assumed to be a PC, but may be a mobile phone, a PDA, a television or a game machine that can be connected to a network.

  Next, the configuration of the video distribution device 100 will be described. Referring to the functional block diagram of FIG. 2, the video distribution apparatus 100 includes a scalable content storage unit 101, a content reading unit 102, a packetizing unit 103, a sending unit 104, a content information management unit 105, and a distribution speed determining unit. 106, distribution data amount detection means 107, and usable bandwidth designation means 108, and a content reading means 102, packetizing means 103, and sending means 104 constitute a distribution unit. Each of these means operates as follows. Here, for ease of explanation, the audio data processing and error processing are omitted.

  The scalable content storage unit 101 is a storage medium such as a disk in which video content encoded using a scalable codec (hierarchically encoded video content) is stored. In the present embodiment, video content is assumed to be composed of a base layer and two enhancement layers (first enhancement layer and second enhancement layer) as shown in content information 400 in FIG. The base layer is a bit stream of the lowest layer (sometimes simply referred to as a stream). When only the base layer is decoded, only a minimum image quality is guaranteed. The first enhancement layer is a bit stream located above the base layer. By decoding the first enhancement layer together with the base layer, an image quality higher than the result of decoding only the base layer can be obtained. The second enhancement layer is a bit stream located above the first enhancement layer. By decoding the second enhancement layer together with the base layer and the first enhancement layer, the base layer, the first enhancement layer, It is possible to obtain an image quality that is higher than the result of decoding together.

  The video content is set with a bit rate (encoding bit rate) for each layer during encoding. Referring to FIG. 4, for example, in the content file 411 whose content file name is NEWS.SVC, the encoding bit rate 421 of the base layer is 1 Mbps, the encoding bit rate 422 of the first enhancement layer is 1 Mbps, and the encoding of the second enhancement layer is performed. Bit rate 423 is encoded as 2Mbps. The setting of the encoding bit rate of each base layer and each enhancement layer, the number of divisions of layers, and the like are examples and other values may be used.

  In this embodiment, it is assumed that video content is compressed with an SNR scalable setting using an H.264 / SVC (Scalable Video Coding) encoder. The codec to be used is an example, and other scalable codecs may be used. The present invention is effective not only for H.264 / SVC but also for MPEG-2 and MPEG-4 scalable profiles. In addition, the present invention is not limited to SNR scalable settings, but is effective even in spatial scalable settings, temporal scalable settings, and the like.

  The content information management unit 105 is a unit that reads the content information 400 stored in the scalable content storage unit 101 and provides it to the distribution speed determination unit 106 as necessary. In the present embodiment, it is assumed that the source of the content information 400 is stored in the scalable content storage unit 101, but may be stored in another storage unit. Further, a message sent from an encoder that created scalable content may be used as the source of content information 400.

  The content reading unit 102 is a unit that reads the stream of each layer from the scalable content storage unit 101 at a specified rate. The content reading means 102 receives designation from the distribution speed determining means 106 regarding which content file stored in the scalable content storage means 101 is read when reading, and the read bit rate of each layer.

  The packetizing means 103 is a means for packetizing the HAL.264 / SVC NAL unit read by the content reading means 102 for transmission to the network 300. In this embodiment, the packetization method is changed to an Internet Engineering Task Force (IETF) draft-ietf-avt-rtp-svc-08 RTP (Real-time Transport Protocol) packet format based on “RTP Payload Format for SVC Video”. However, other packetization formats such as the ISO / IEC 13818-1 MPEG-2 TS system may be used as long as packetization is possible for each layer.

  The sending means 104 is means for sending a packet to the network 300. In the present embodiment, processing for sending a UDP / IP format packet from the network interface card to the Internet is performed.

  The usable bandwidth designating means 108 is a means for designating an upper limit value of the network bandwidth that can be used for the distribution of the current video content. In the present embodiment, it is assumed that the measurement result of the network bandwidth by means not shown is designated, but the network bandwidth requested to be secured to the NGN network or numerical designation via the user interface may be used.

  The distribution data amount detection unit 107 is a unit that detects the distribution data amount of each layer by accumulating the data size of the stream of each layer read by the content reading unit 102. Note that the distribution data amount detection means 107 used in the present embodiment only needs to be capable of detecting at least the distribution data amount of the base layer.

  The distribution speed determination unit 106 acquires the basic layer distribution data amount detected by the distribution data amount detection unit 107, the bit rate information of each layer of content acquired from the content information management unit 105, and the available bandwidth designation unit 108. It is means for determining the distribution bit rate of the stream of each layer based on the available network bandwidth information.

  More specifically, the distribution speed determination unit 106 determines that the distribution data amount of the base layer detected by the distribution data amount detection unit 107 from the start of video content distribution is the first target amount (stable in the video reception device 200). The amount of available network bandwidth is larger than the base layer encoding bit rate until the data reaches the base layer data amount that needs to be buffered for playback. Thus, the distribution bit rate of the base layer is increased from the encoding bit rate within a range not exceeding the available network bandwidth, and the distribution bit rate of the higher enhancement layer is decreased accordingly. In this embodiment, the distribution bit rate of the base layer is made the same as the available network bandwidth, and the distribution bit rates of the first and second enhancement layers are set to 0. The layer for which the distribution bit rate is 0 is not read by the content reading means 102, and the distribution processing for the layer is stopped. When the available network bandwidth is smaller than the base layer encoding bit rate, the distribution bit rates of the base layer and the first and second enhancement layers are all set to 0, and the distribution process is not performed. When the available network bandwidth and the base layer encoding bit rate are equal, the base layer distribution bit rate is set to the same value as the available network bandwidth.

  In addition, after the basic layer distribution data amount detected by the distribution data amount detection unit 107 reaches the first target amount (normal distribution state), the distribution speed determination unit 106 distributes the basic layer distribution bit rate. Is returned to the encoding bit rate acquired from the content information management means 105, and the difference band (residual band) is used for the distribution of other enhancement layers. When the remaining bandwidth is allocated to the enhancement layer, the bandwidth corresponding to the encoding bit rate of that layer is preferentially allocated from the lower enhancement layer within the range where the sum of the distribution bit rates of the enhancement layer does not exceed the remaining bandwidth. .

  The video distribution apparatus 100 can be realized by a computer. In that case, for example, the following is performed. A recording medium such as a disk or a semiconductor memory on which a program for causing a computer to function as the video distribution device 100 is recorded is prepared, and the computer is caused to read the program. The computer can use the content reading means 102, the packetizing means 103, the content information managing means 105, the delivery speed determining means 106, the delivery data amount detecting means 107, and the like on the own computer by controlling its own operation according to the read program. Band specifying means 108 is realized.

  Next, the configuration of the video reception device 200 will be described. Referring to FIG. 3, video receiving apparatus 200 of the present embodiment includes receiving means 201, depacketizing means 202, buffering means 203, decoding means 204, display means 205, and buffer amount detecting means 206. The receiving unit 201 and the depacketizing unit 202 constitute a receiving unit.

  The receiving unit 201 is a unit that receives a video stream transmitted from the video delivery device 100 connected via the network 300. In the present embodiment, receiving means 201 connected to the Internet performs processing for receiving RTP packets. The packet arriving at the receiving means 201 is immediately sent to the depacketizing means 202.

  The depacketizing means 202 is means for acquiring a video stream from the packet received by the receiving means 201. In the present embodiment, processing for acquiring H.264 / SVC data stored in the payload of the RTP packet is performed. At this time, the time information such as the RTP time stamp existing in the RTP packet header is added to the H.264 / SVC data after depacketization in a form not shown. This time information is used as reference information when determining the timing of decoding and display.

  Buffering means 203 is means for buffering the received video stream in preparation for decoding and playback processing. By buffering, packet arrival jitter generated in the network is absorbed. Packet buffering is performed at the timing when the depacketizing means 202 outputs H.264 / SVC data.

  The buffer amount detection unit 206 is a unit that detects the amount of data buffered in the buffering unit 203 for each layer at a fixed period and notifies the decoding unit 204 of the detection result.

  The decoding means 204 is means for decoding a video stream and obtaining a bitmap video. The decoding unit 204 receives the notification of the buffering amount for each layer from the buffer amount detecting unit 206, and starts the decoding process when it is determined that a sufficient amount of buffering has been completed. The decoding unit 204 obtains H.264 / SVC data for one picture from the buffering unit 203. The header of the NAL unit constituting the acquired H.264 / SVC data includes an ID indicating which layer the NAL unit belongs to. The decoding means 204 performs the decoding process for each layer based on this ID.

  Here, an example of a method for determining a decoding target layer in the decoding unit 204 will be described.

The decoding unit 204 performs the following processing every time the accumulation amount of each layer is notified from the buffer amount detection unit 206.
(A) By searching from the base layer, which is the lowest layer, toward the upper layer, the lowest layer among the layers in which the notified accumulation amount is less than the target buffering amount is searched. At this time, for a layer that has already been determined to be a decoding target layer, even if the accumulated amount is less than the target buffering amount, the accumulated amount is the target buffering amount as long as the notified accumulated amount is not 0. A search is performed assuming that the above is true. When the notified accumulation amount is 0, the decision to set the layer as a decoding target layer is invalidated. In addition, when there is a layer that is determined to be a decoding target layer among layers higher than the layer, the determination for the layer is also invalidated. The target buffering amount is the amount of data that needs to be buffered for stable reproduction, and is determined for each layer.
(B) When a layer whose accumulated amount is less than the target buffering amount cannot be searched in a (when the accumulated amount of all layers is equal to or larger than the target buffer amount), all layers are set as decoding target layers. To end the process.
(C) When a layer whose accumulated amount is less than the target buffering amount in a can be searched, it is determined that each layer from the base layer to the layer one layer lower than the searched layer is set as a decoding target layer, and the processing is performed. finish. In addition, when the layer searched in a is a basic layer, there is no decoding target layer.

  If the accumulation amount of each layer notified from the buffer amount detection means 206 is as shown in FIG. 5, the following determination is made. In the process (a) described above, the second enhancement layer is searched for as the lowest layer among the layers whose accumulation amount is less than the target buffering amount. Thereafter, by the above-described process (c), the layers from the base layer to the first enhancement layer (one layer lower than the searched second enhancement layer) are determined as decoding target layers.

  Further, when the accumulation amount of each layer notified from the buffer amount detection means 206 is as shown in FIG. 6, the following determination is performed. In the process (a) described above, the first enhancement layer is searched for as the lowest layer among the layers whose accumulation amount is less than the target buffering amount. Thereafter, the base layer (one layer lower than the searched first enhancement layer) is determined as a decoding target layer by the above-described process (b).

  By the above determination, it is possible to select the highest quality video from video quality that can be stably decoded. In this example, all the extended layers that exist continuously from the basic layer of the input H.264 / SVC data to the upper side have been described as targets of decoding, but from among the layers that can be separately decoded, You may comprise so that the means of designating the hierarchy of the enhancement layer made into the decoding object from a user may be provided.

  The display unit 205 is a unit that receives the bitmap video output from the decoding unit 204 and displays it on a bitmap display device mounted on the video reception device 200 or sends it to a video display device connected to the video reception device 200. . The display unit 205 holds a system clock therein and implements video display according to time information added to the bitmap video, thereby realizing video display at a constant frame rate. In this embodiment, descriptions of the bitmap display device and the video display device are omitted. In this embodiment, the display unit 205 holds the system clock. However, the decoding unit 204 may hold the system clock, and the display unit 205 may passively display an image.

  Next, the overall operation of the present embodiment will be described with reference to the sequence diagram of FIG. In the present embodiment, the content having the file name NEWS.SVC is distributed in the pattern shown in FIG. Further, it is assumed that the buffering amount of the base layer necessary for realizing stable reproduction by the video reception device 200 is data for one second. Further, the description will be made assuming that 4 Mbps is designated as a result of the network bandwidth measurement as the network bandwidth that can be used for video content distribution.

  First, video distribution apparatus 100 accepts distribution request message 701 from video reception apparatus 200 (step ST7001). In the present embodiment, it is assumed that RFC (Request For Comments) 2326 RTSP (Real Time Streaming Protocol) is used, but other communication protocols capable of requesting reproduction may be used. This message includes NEWS.SVC, which is a file name indicating video content desired to be distributed.

  Based on the file name NEWS.SVC, the content information management unit 105 searches the content information 400 (see FIG. 4) stored in the scalable content storage unit 101 and acquires the layer configuration information of the video content desired to be distributed. (Step ST7002). In the present embodiment, the base layer encoding bit rate “1 Mbps”, the first enhancement layer encoding bit rate “1 Mbps”, and the second enhancement layer encoding bit rate “2 Mbps” are acquired as the layer configuration information.

  Subsequently, the delivery speed determining means 106 that has acquired the layer configuration information from the content information managing means 105 determines the delivery bit rate (initial delivery bit rate) of each layer in order to perform initial delivery settings (step ST7003). ). As described above, in this embodiment, when the available network bandwidth is larger than the base layer encoding bits, the base layer distribution bit rate is set to the same value as the available network bandwidth (4 Mbps in this embodiment). Since the delivery bits of the first and second enhancement layers are set to 0, the initial delivery bit rate of the base layer is determined to be 4 Mbps, and the initial delivery bit rates of the first and second enhancement layers are both determined to be 0 Mbps.

  Thereafter, distribution speed determining means 106 sets the distribution bit rate of each layer determined in step ST7003 in content reading means 102 (step ST7004). Thus, since the video content distribution preparation in video distribution apparatus 100 is completed, video distribution apparatus 100 transmits distribution response message 702 to video reception apparatus 200 (step ST7005).

  Thereafter, video distribution apparatus 100 starts distributing video content (step ST7006). That is, the content reading unit 102 reads a base layer stream (base layer data) from the content file 411 at a bit rate of 4 Mbps, packetizes it with the packetizing unit 103, and transmits the packet from the sending unit 104 to the video receiving device 200.

  In video receiving apparatus 200, receiving means 201 receives a packet sent from video distributing apparatus 100, and depacketizing means 202 extracts base layer data from the packet and stores it in buffering 203 (step ST7007). The buffering state (buffering amount for each layer) is detected by the buffer amount detecting means 206 (step ST7008). In this embodiment, since the base layer is delivered at the initial delivery bit rate of 4 Mbps, the normal delivery method shown in FIG. 9 accumulates the base layer data that takes 1 second until the start of playback as shown in FIG. Complete in 0.25 seconds. The buffering amount for each layer is notified from the buffer amount detection means 206 to the decoding means 204 at a fixed period.

  When determining that the buffering amount of the base layer has reached the target buffering amount based on the notification from the buffer amount detecting unit 206 (step ST7009), the decoding unit 204 starts decoding of the base layer (step ST7010). As a result, video reproduction with an image quality corresponding to the base layer is started.

  On the other hand, the delivery speed determination means 106 of the video delivery device 100 confirms that the transmission of 1 Mbit base layer data corresponding to the base layer data for 1 second has been completed based on the detection result of the delivery data amount detection means 107. Then (step ST7011), it recognizes that the initial distribution state has ended, and determines the distribution bit rate of each layer in the normal distribution state (step ST7012). As described above, in the normal distribution state, the distribution bit rate of the base layer is set to the same value as the encoding bit rate, so the distribution bit rate of the base layer is determined to be 1 Mbps. In addition, each enhancement layer is prioritized from lower enhancement layers within a range in which the sum of the distribution bit rates of each enhancement layer does not exceed the remaining bandwidth (the bandwidth obtained by subtracting the bandwidth allocated to the base layer from the available network bandwidth). In addition, since the encoding bit rate of the enhancement layer is assigned as the delivery bit rate, the delivery bit rates of the first and second enhancement layers are determined to be 1 Mbps and 2 Mbps, respectively. In this example, since the available network bandwidth is 4 Mbps, the distribution bit rate of each layer is determined as described above. However, if the available network bandwidth is 3 Mbps, the second extension layer is set. If the same value as the encoding bit rate (2 Mbps) is assigned as the delivery bit rate, the sum of the delivery bit rates of the extension layer is 3 Mbps, which exceeds the remaining bandwidth of 2 Mbps. Therefore, the basic layer = 1 Mbps, the first extension layer = It is determined that 1 Mbps and the second enhancement layer = 0 Mbps.

  Thereafter, the delivery speed determining means 106 sets the delivery bit rate (basic layer = 1 Mbps, first enhancement layer = 1 Mbps, second enhancement layer = 2 Mbps) of each layer determined in step ST7012 in the content reading means 102 (step ST7013).

  Thereby, the content reading means 102 reads the base layer data, the first enhancement layer data, and the second enhancement layer data from the content file 411 at 1 Mbps, 1 Mbps, and 2 Mbps, respectively. Data of each layer read by the content reading means 102 is packetized by the packetizing means 103, and then transmitted from the sending means 104 to the video receiving device 200 (step ST7014). At this point, since the basic layer data for one second from the top of the content file 411 has already been read, the first and second extension layer data are stored for one second from the top of the content file 411. Reading is started from the position where data is skipped.

  In the video receiving device 200, the receiving unit 201 receives the packet sent from the video distribution device 100, and the depacketizing unit 202 extracts the base layer data, the first enhancement layer data, and the second enhancement layer data from the packet. The data is stored in the buffering means 203 (step ST7015). As described above, the buffer amount detection unit 206 detects the buffering amount for each layer at a constant period, and notifies the decoding unit 204 of the detection result.

  When the decoding unit 204 determines that the buffering amount of the first and second enhancement layer data has reached the target buffering amount based on the notification from the buffer amount detection unit 206, the decoding unit 204 of the first and second enhancement layer data Decoding is started (steps ST7016 and ST7017). As a result of decoding the first and second enhancement layer data, bitmap data with improved image quality is output, and video display of the second enhancement layer quality is started. Since the first and second enhancement layer data are distributed at distribution bit rates of 1 Mbps and 2 Mbps, respectively, the data for 1 second, which is the target buffering amount, arrives in 1.25 seconds from the start of reproduction.

  With the above operation, the video playback waiting time, which normally takes 1 second from the playback start request, can be reduced to 0.25 seconds, and the image quality can be improved in the middle of playback without performing any special operation from the video receiving device 200 side. I showed that.

[Effect of the first embodiment]
According to the present embodiment, it is possible to reduce the waiting time until video is played when video content distribution starts without the video receiving device 200 notifying the video distribution device 100 of the buffer usage status. it can. The reason is that the distribution data amount detection means 107 for detecting the distribution amount of the basic layer data is provided in the video distribution device 100, and the distribution data of the basic layer data detected by the distribution data amount detection means 107 from the start of the distribution of the video content. This is because the distribution bit rate of the base layer data is set to a value larger than the encoding bit rate until the amount reaches the target amount.

  In addition, according to the present embodiment, the video reception device 200 does not notify the video distribution device 100 of the buffer usage status, and at the timing when the base layer data is sufficiently buffered in the video reception device, The enhancement layer data can be transmitted from the distribution apparatus 100 to the video reception apparatus 200, and the image quality can be improved. The reason is that, after the distribution data amount of the basic layer data detected by the distribution data amount detection means 107 reaches the target amount, the base layer data and the extension layer data are displayed at the distribution bit rate corresponding to the encoded bits. This is because transmission from the distribution apparatus 100 to the video reception apparatus 200 is performed.

  Furthermore, according to the present embodiment, it is possible to distribute data for displaying as high-quality video as possible using the available network bandwidth. The reason is that a value corresponding to the encoding bit rate of the layer is preferentially assigned from the lower layer as a distribution bit rate signal of the layer within a range in which the sum of the distribution bit rates of each layer does not exceed the available network bandwidth. It is because it is doing.

[Other Embodiments of the Invention]
In the first embodiment, as shown in the graph of FIG. 8, the distribution state is described as two distribution states of an initial distribution state and a normal distribution state, but it is not necessary to specify two states. . As shown in the graph of FIG. 10, it may be separated into three states. In this case, after the buffering of the base layer is completed in 0.25 seconds from the start of distribution, the buffering of the first enhancement layer is started. Since buffering of the first enhancement layer is usually performed at 1 Mbps (the same rate as the encoding bit rate) at 3 Mbps, buffering is completed in 0.33 seconds. As a result, the image quality corresponding to the first enhancement layer is improved in 0.58 seconds from the start of reproduction. Further, although not performed in the first embodiment, the switching of each distribution rate may be changed smoothly.

  In the first embodiment, an example is described in which the base layer is distributed at 4 Mbps in the initial distribution state, but may be performed at an arbitrary bit rate as long as the available network bandwidth is not exceeded. In addition to the basic layer, the distribution of the first enhancement layer may be added. Also, the distribution rate at that time may be other than 1 Mbps which is the encoding bit rate of the first enhancement layer.

  In the first embodiment, the target buffering amount is described as a method for setting the target buffering amount on the video distribution device 200 side. However, a method for notifying the target value when requested from the video reception device side, Alternatively, the rate change timing may be notified by notifying the start of decoding of the base layer.

  Furthermore, in the first embodiment, the measurement result of the network bandwidth that can be used for the distribution of the video content via the available bandwidth specifying means 108 is used for setting the available network bandwidth. For example, the value of a network bandwidth securing request by SIP may be specified. A set value set by the user may be used.

[Effects of other embodiments]
According to the present embodiment, it is possible to shorten the period during which video is displayed with basic layer quality with poor image quality. The reason is that after the base layer data is transmitted by a target amount, the first enhancement layer data is transmitted at a delivery bit rate faster than the encoded bit rate.

  The present invention can be applied to uses such as a video distribution device such as a VOD server.

It is a block diagram which shows the whole structure of the video delivery system concerning the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the video delivery apparatus 100 of the 1st Embodiment of this invention. It is a block diagram which shows the structural example of the video receiver 200 of the 1st Embodiment of this invention. It is a figure which shows an example of the content information of the 1st Embodiment of this invention. It is a figure for demonstrating the determination method of the decoding object layer, and is the figure which showed an example of the buffering state. It is a figure for demonstrating the determination method of the decoding object layer, and is the figure which showed another example of the buffering state. It is a sequence diagram for demonstrating the operation | movement of the 1st Embodiment of this invention. It is a graph which shows the change of the delivery bit rate in the 1st Embodiment of this invention. It is a graph which shows the change of the delivery bit rate in a normal video delivery system. It is a graph which shows the change of the delivery bit rate in other embodiment of this invention.

Explanation of symbols

10… Video distribution system
100 ... Video distribution device
101 ... Scalable content storage means
102 ... Content reading means
103 ... Packetizing means
104 ... Transmission means
105 ... Content information management means
106 ... Delivery speed determination means
107: Distribution data amount detection means
108 ... Available bandwidth designation means
200 ... Video receiver
201 ... Receiving means
202 ... Depacketizing means
203 ... Buffering means
204 ... decoding means
205 ... Display means
206 ... Buffer amount acquisition means
300 ... Network
400 ... Content information

Claims (33)

A video distribution device that distributes video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers, and a video reception device that receives the video content distributed from the video distribution device;
The video distribution device includes:
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
Distribution speed determination means for determining a distribution bit rate of each of the basic signal and the extension signal of each layer, wherein the distribution data of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content Distribution speed determining means for determining a distribution bit rate of the basic signal to a value larger than an encoding bit rate of the basic signal until the amount reaches a first target amount;
A distribution unit that distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit;
The video receiver is
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
Decoding means for decoding the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount. A featured video distribution system. The video distribution system according to claim 1, wherein
The distribution speed determination unit of the video distribution apparatus is configured to determine whether the basic signal and each of the hierarchies after the distribution data amount of the basic signal detected by the distribution data amount detection unit has reached the first target amount. Determine the distribution bit rate of the extended signal to a value corresponding to the encoding bit rate of the signal,
The buffer amount detection means of the video reception device detects the accumulated amount of the extension signal of each layer buffered in the buffering means,
The decoding means of the video reception device is an extension signal in which the accumulation amount detected by the buffer amount detection means is equal to or greater than a target amount determined for the extension signal among the extension signals of each layer. An extension signal in which the accumulated amount detected by the buffer amount detection means of the extension signal of the lower layer lower than the extension signal is equal to or more than a target amount determined for each of the extension signals of the lower layer, A video distribution system characterized by decoding together with a signal. The video distribution system according to claim 1 or 2,
The video distribution device includes an available bandwidth designating unit for designating an upper limit value of a bandwidth that can be used for the distribution of the video content, and
The distribution speed determination means of the video distribution apparatus is from the start of distribution of the video content until the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount. On the condition that the upper limit value is larger than the encoding bit rate of the basic signal, the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal within a range not exceeding the upper limit value. In addition, after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount, the sum of the distribution bit rates of the signals does not exceed the upper limit value. A video distribution system characterized by preferentially determining a distribution bit rate signal of a lower layer signal to a value corresponding to the encoding bit rate The video distribution system according to claim 3, wherein
The delivery data amount detection means of the video delivery device detects the delivery data amount of the lowest extension signal located in the lowest hierarchy of the extension signals,
The delivery speed determination means of the video delivery device is detected by the delivery data amount detection means after the delivery data amount of the basic signal detected by the delivery data amount detection means reaches the first target amount. The upper limit value is larger than the sum of the encoding bit rate of the basic signal and the encoding bit rate of the lowest extension signal until the distribution data amount of the lowest extension signal reaches the second target amount. On the condition that the sum of the delivery bit rate of the basic signal and the delivery bit rate of the least significant extension signal does not exceed the upper limit value, the delivery bit rate of the least significant extension signal is set to the least significant extension signal. And a distribution data amount of the least significant extension signal detected by the distribution data amount detection means reaches the second target amount. After that, within a range in which the sum of the delivery bit rates of the respective signals does not exceed the upper limit value, the delivery bit rate of the signals is preferentially set to a value corresponding to the encoding bit rate of the signal from the lower layer signal. A video distribution system characterized by deciding. The video distribution system according to any one of claims 1 to 4,
The video distribution system according to claim 1, wherein the first target amount is a data amount of the basic signal that needs to be buffered in order to enable stable reproduction in the video reception device. The video distribution system according to claim 4, wherein
The video distribution system characterized in that the second target amount is a data amount of the least significant extension signal that needs to be buffered in order to enable stable reproduction in the video reception device. . The video distribution system according to any one of claims 1 to 6,
The video distribution device includes a content storage unit in which the video content is stored, and
The distribution unit of the video distribution device includes:
Content reading means for reading the signals of each layer stored in the content storage unit at the distribution bit rate of the corresponding hierarchy determined by the distribution speed determining means;
Packetizing means for packetizing the signals of each layer read by the content reading means;
A video distribution system comprising: transmission means for transmitting each signal packetized by the packetizing means to a network. The video distribution system according to claim 7, wherein
The receiving unit of the video receiving device is
Receiving means for receiving the packet distributed from the video distribution device;
Video distribution comprising: depacketizing means for extracting the basic signal and the extended signal from the packet received by the receiving means, and storing the extracted basic signal and the extended signal in the buffering means system. The video distribution system according to any one of claims 1 to 8,
The basic signal is a basic layer of a video scalable codec,
The video distribution system, wherein the extension signal is an extension layer of a video scalable codec. The video distribution system according to claim 9, wherein
The video scalable codec is ITU-T H.264 Scalable Video Coding. A video distribution device that distributes video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers,
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
Distribution speed determination means for determining a distribution bit rate of each of the basic signal and the extension signal of each layer, wherein the distribution data of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content Distribution speed determining means for determining a distribution bit rate of the basic signal to a value larger than an encoding bit rate of the basic signal until the amount reaches a first target amount;
And a distribution unit that distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit. apparatus. The video distribution device according to claim 11, wherein
The distribution speed determining means, after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount, the distribution bit of the basic signal and the extension signal of each layer A video distribution apparatus characterized in that the rate is determined to a value corresponding to the encoding bit rate of the signal. The video distribution device according to claim 11 or 12,
An available bandwidth designating unit for designating an upper limit value of a bandwidth that can be used for distribution of the video content,
The delivery speed determination means is configured to determine whether the upper limit value is between the start of delivery of the video content and the delivery data amount of the basic signal detected by the delivery data amount detection means reaches the first target amount. On the condition that it is larger than the encoding bit rate of the basic signal, the distribution bit rate of the basic signal is determined to be a value larger than the encoding bit rate of the basic signal within a range not exceeding the upper limit value, and the amount of distribution data After the distribution data amount of the basic signal detected by the detecting means reaches the first target amount, the signal from the lower layer is within a range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value. A video distribution apparatus that preferentially determines the distribution bit rate of the signal to a value corresponding to the encoding bit rate of the signal. The video distribution device according to claim 13.
The delivery data amount detection means detects the delivery data amount of the lowest extension signal located in the lowest hierarchy among the extension signals,
The distribution speed determination means is configured to detect the least significant extension signal detected by the distribution data amount detection means after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount. Until the distribution data amount reaches the second target amount, on the condition that the upper limit value is larger than the sum of the encoding bit rate of the basic signal and the encoding bit rate of the least significant extension signal, In the range where the sum of the delivery bit rate of the basic signal and the delivery bit rate of the least significant extension signal does not exceed the upper limit value, the delivery bit rate of the least significant extension signal is greater than the encoding bit rate of the least significant extension signal. After the distribution data amount of the least significant extension signal detected by the distribution data amount detection means reaches the second target amount, In the range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value, the distribution bit rate of the signals is determined to be a value corresponding to the encoding bit rate of the signals preferentially from the lower layer signal. Distribution device. The video delivery device according to any one of claims 11 to 14,
The first target amount is a data amount of the basic signal that needs to be buffered in order to enable stable reproduction in a video reception device that receives and reproduces the video content. A featured video distribution device. The video distribution device according to claim 14, wherein
The video distribution device, wherein the second target amount is a data amount of the least significant extension signal that needs to be buffered in order to enable stable reproduction in the video reception device . The video distribution apparatus according to any one of claims 11 to 16,
A content storage unit in which the video content is stored;
The delivery unit
Content reading means for reading the signals of each layer stored in the content storage unit at the distribution bit rate of the corresponding hierarchy determined by the distribution speed determining means;
Packetizing means for packetizing the signals of each layer read by the content reading means;
A video distribution apparatus comprising: transmission means for transmitting each signal packetized by the packetizing means to a network. The video delivery device according to any one of claims 11 to 17,
The basic signal is a basic layer of a video scalable codec,
The video distribution apparatus, wherein the extension signal is an extension layer of a video scalable codec. The video distribution apparatus according to claim 18, wherein
The video distribution apparatus, wherein the video scalable codec is ITU-T H.264 Scalable Video Coding. (A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. A video receiving apparatus for receiving the video content,
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
Decoding means for decoding the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount. A featured video receiver. The video receiver according to claim 20, wherein
The distribution speed determination unit of the video distribution apparatus is configured to determine whether the basic signal and each of the hierarchies after the distribution data amount of the basic signal detected by the distribution data amount detection unit has reached the first target amount. Determine the distribution bit rate of the extended signal to a value corresponding to the encoding bit rate of the signal,
The buffer amount detection means detects the accumulated amount of the extension signal of each layer buffered in the buffering means,
The decoding means is an extension signal in which the accumulation amount detected by the buffer amount detection means is equal to or greater than a target amount determined for the extension signal, among the extension signals of each layer, and the extension signal An extension signal in which the accumulated amount detected by the buffer amount detection means of the extension signal in the lower layer is equal to or more than the target amount defined for each extension signal in the lower layer is decoded together with the basic signal. A video receiver characterized by: A video distribution method for distributing video content that is hierarchically encoded into a basic signal and an extension signal of one or more layers,
Distribution data amount detection means detects the distribution data amount of the basic signal,
The distribution rate determining means for determining the distribution bit rate of each of the basic signal and the extended signal of each layer is the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content. Until the first target amount is reached, the delivery bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal;
A video distribution method, wherein the distribution unit distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit . The video distribution method according to claim 22, wherein
After the delivery speed determining means has reached the first target quantity, the delivery bit of the basic signal and the extension signal of each layer after the delivery data quantity of the basic signal detected by the delivery data quantity detection means has reached the first target quantity. A video distribution method, wherein the rate is determined to a value corresponding to the encoding bit rate of the signal. 24. The video distribution method according to claim 22 or 23.
An available bandwidth designation means designates an upper limit value of a bandwidth that can be used for the distribution of the video content, and
The upper limit value is set until the delivery speed determining means has reached the first target amount until the delivery data amount of the basic signal detected by the delivery data amount detection means from the start of delivery of the video content. On the condition that it is larger than the encoding bit rate of the basic signal, the distribution bit rate of the basic signal is determined to be a value larger than the encoding bit rate of the basic signal within a range not exceeding the upper limit value, and the amount of distribution data After the distribution data amount of the basic signal detected by the detecting means reaches the first target amount, the signal from the lower layer is within a range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value. A video distribution method characterized by preferentially determining the distribution bit rate of the signal to a value corresponding to the encoding bit rate of the signal. The video distribution method according to claim 24, wherein
The distribution data amount detection means detects the distribution data amount of the lowest extension signal located in the lowest hierarchy of the extension signals;
The least significant extension signal detected by the distribution data amount detection means after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount by the distribution speed determination means Until the distribution data amount reaches the second target amount, on the condition that the upper limit value is larger than the sum of the encoding bit rate of the basic signal and the encoding bit rate of the least significant extension signal, In the range where the sum of the delivery bit rate of the basic signal and the delivery bit rate of the least significant extension signal does not exceed the upper limit value, the delivery bit rate of the least significant extension signal is greater than the encoding bit rate of the least significant extension signal. After the distribution data amount of the least significant extension signal detected by the distribution data amount detection means reaches the second target amount, In the range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value, the distribution bit rate of the signals is determined to be a value corresponding to the encoding bit rate of the signals preferentially from the lower layer signal. Delivery method. (A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. A video receiving method for receiving the video content,
The receiving unit receives the basic signal distributed from the video distribution device and the extended signal of each layer,
Buffering means buffers the basic signal received by the receiving unit and the extension signal of each layer,
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
The decoding means decodes the basic signal buffered in the buffering means after the accumulated amount of the basic signal detected by the buffer quantity detecting means reaches the first target amount. Video receiving method. The video receiving method according to claim 26, wherein
The distribution speed determining means, after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount, the distribution bit of the basic signal and the extension signal of each layer Determine the rate according to the encoding bit rate of each signal,
The buffer amount detection means detects the accumulated amount of the extension signal of each layer buffered in the buffering means,
The decoding means is an extension signal in which the accumulation amount detected by the buffer amount detection means is equal to or greater than a target amount determined for the extension signal, among the extension signals of each layer, and the extension signal An extension signal in which the accumulated amount detected by the buffer amount detection means of the extension signal in the lower layer is equal to or more than the target amount defined for each extension signal in the lower layer is decoded together with the basic signal. And a video receiving method. A program for causing a computer to function as a video distribution device that distributes video content hierarchically encoded into a basic signal and an extension signal of one or more layers,
The computer,
Distribution data amount detection means for detecting the distribution data amount of the basic signal;
Distribution speed determination means for determining a distribution bit rate of each of the basic signal and the extension signal of each layer, wherein the distribution data of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content A delivery speed determining means for determining a delivery bit rate of the basic signal to a value larger than an encoding bit rate of the basic signal until the amount reaches a first target amount;
A program for functioning as a distribution unit that distributes the basic signal and the extended signal of each layer according to the distribution bit rate of each of the basic signal and the extended signal of each layer determined by the distribution speed determining unit. The program according to claim 28,
The distribution speed determining means, after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount, the distribution bit of the basic signal and the extension signal of each layer A program for determining a rate according to an encoding bit rate of each signal. The program according to claim 28 or 29,
Causing the computer to function as an available bandwidth designating unit for designating an upper limit value of a bandwidth that can be used for distributing the video content; and
The delivery speed determination means is configured to determine whether the upper limit value is between the start of delivery of the video content and the delivery data amount of the basic signal detected by the delivery data amount detection means reaches the first target amount. On the condition that it is larger than the encoding bit rate of the basic signal, the distribution bit rate of the basic signal is determined to be a value larger than the encoding bit rate of the basic signal within a range not exceeding the upper limit value, and the amount of distribution data After the distribution data amount of the basic signal detected by the detecting means reaches the first target amount, the signal from the lower layer is within a range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value. A program characterized by preferentially determining the distribution bit rate of the signal to a value corresponding to the encoding bit rate of the signal. The program according to claim 30, wherein
The delivery data amount detection means detects the delivery data amount of the lowest extension signal located in the lowest hierarchy among the extension signals,
The distribution speed determination means is configured to detect the least significant extension signal detected by the distribution data amount detection means after the distribution data amount of the basic signal detected by the distribution data amount detection means reaches the first target amount. Until the distribution data amount reaches the second target amount, on the condition that the upper limit value is larger than the sum of the encoding bit rate of the basic signal and the encoding bit rate of the least significant extension signal, In the range where the sum of the delivery bit rate of the basic signal and the delivery bit rate of the least significant extension signal does not exceed the upper limit value, the delivery bit rate of the least significant extension signal is greater than the encoding bit rate of the least significant extension signal. After the distribution data amount of the least significant extension signal detected by the distribution data amount detection means reaches the second target amount, The distribution bit rate of the signal is preferentially determined from the lower layer signal within a range in which the sum of the distribution bit rates of the signals does not exceed the upper limit value, and a value corresponding to the encoding bit rate of the signal is determined. . (A) distribution data amount detection means for detecting a distribution data amount of the basic signal in video content hierarchically encoded into a basic signal and an extension signal of one or more layers; (B) the basic signal and each layer Distribution speed determination means for determining the distribution bit rate of each extension signal, wherein the distribution data amount of the basic signal detected by the distribution data amount detection means from the start of distribution of the video content reaches a first target amount. Until the distribution bit rate of the basic signal is determined to be larger than the encoding bit rate of the basic signal, and (C) the basic signal determined by the distribution rate determination unit and each layer Distributed from a video distribution device including a distribution unit that distributes the basic signal and the extended signal of each layer according to a distribution bit rate of each extended signal. The video receiving apparatus for receiving the video content to a program for realizing a computer,
The computer,
A receiving unit that receives the basic signal distributed from the video distribution device and the extended signal of each layer;
Buffering means for buffering the basic signal and the extension signal of each layer received by the receiving unit;
A buffer amount detecting means for detecting an accumulation amount of the basic signal buffered in the buffering means;
After the accumulated amount of the basic signal detected by the buffer amount detecting means reaches the first target amount, the buffering means functions as a decoding means for decoding the basic signal buffered. program. The program according to claim 32,
The distribution speed determination unit of the video distribution apparatus is configured to determine whether the basic signal and each of the hierarchies after the distribution data amount of the basic signal detected by the distribution data amount detection unit has reached the first target amount. Determine the distribution bit rate of the extended signal to a value corresponding to the encoding bit rate of the signal,
The buffer amount detection means detects the accumulated amount of the extension signal of each layer buffered in the buffering means,
The decoding means is an extension signal in which the accumulation amount detected by the buffer amount detection means is equal to or greater than a target amount determined for the extension signal, among the extension signals of each layer, and the extension signal An extension signal in which the accumulated amount detected by the buffer amount detection means of the extension signal in the lower layer is equal to or more than the target amount defined for each extension signal in the lower layer is decoded together with the basic signal. The program characterized by doing.

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