JP2011066587A - Video decoding method, device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously reproduce video by making a time stamp continuous regardless of a selection event when selecting and decoding video from multiple video data. <P>SOLUTION: A time stamp acquisition unit 107 obtains time stamp information at a preset stream reading position about each stream stored in N pieces of stream buffers. A decoding stream setter 108 sets a stream to be decoded and a time stamp to start decoding. A stream transferring unit 105 reads streams from a reading position corresponding to the set time stamp to the next reading position from stream buffers 101 to 104 and transfers the streams to a decoder buffer 106, and a stream decoding unit 109 decodes the streams to generate image information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a video decoding method, a video decoding apparatus, and a video decoding program for decoding a plurality of encoded video data in synchronization.

  A plurality of video contents can be recorded on a storage medium such as a DVD. In digital broadcasting, a plurality of video channels can be broadcast. Thus, in recent video storage media and broadcasts, a plurality of video data can be distributed simultaneously.

  Such video contents and video channels are independent video contents, and the viewer can select and play back desired content. In practice, the video stream is first stored in the buffer. When playing back the video, the head position of the specific video data or the position where playback can be started is searched for the stream stored in the buffer, and the video data is decoded and displayed from the searched position. To do.

  For example, when viewing while switching channels in digital broadcasting, when the channel is switched, the playback start position is searched from the video data of the channel stored in the buffer, and the video data is searched from the searched position. Decodes and displays the decoded video. During this search process, since there is no image data to be reproduced, the video of the channel before switching is displayed in a stopped state.

  In addition, two video contents among a plurality of video contents may be decoded and displayed at the same time. In this case, the two decoders independently decode and display the respective encoded data to be decoded.

  On the other hand, multi-view video coding (MVC) is an international standard coding method as an encoding method for compressing a plurality of camera images together. It is standardized as H.264 Annex H. In MVC, a plurality of encoded video data is compressed and encoded in a multiplexed form. Encoded data of frames having the same time stamp are continuously multiplexed. That is, the encoded data is a stream obtained by multiplexing a plurality of video data. Since frames with the same time stamp are continuously multiplexed, the decoder can decode and output MVC encoded data, so that multiple camera videos with the same time stamp can be decoded and output continuously. .

  The standards and features of this multi-view video coding (MVC) are described in Non-Patent Document 1 and the like.

Supervised by Satoshi Okubo, Junya Tsuno, Yoshihiro Kikuchi, Teruhiko Suzuki, “Revised Third Edition H.264 / AVC Textbook”, Impress R & D, Chapter 13, 2009.

  A process of reading a plurality of encoded video data or a multiplexed stream such as MVC from a buffer, decoding one or more videos, and selecting and decoding one or more other videos. Suppose. At this time, it is assumed that the time stamp of the video before selection and the time stamp of the video after selection are decoded continuously. Further, when two or more videos are decoded, a process of synthesizing one image from images of the same time stamp is assumed. For example, while two videos are being reproduced from four or more video data, another two videos are selected and decoded. Here, it is assumed that one horizontally long image is synthesized by horizontally connecting two images having the same time stamp.

  In the conventional decoding process, when another video is selected while decoding video data, the playback start position is searched for the stream stored in the buffer, and the video data is read from the searched position and decoded. . At this time, since there is no image information to be reproduced until another video is decoded, the video of the channel before selection is displayed in a stopped state. Therefore, when the video is selected and switched, there is a problem that the video is stopped between the video before the switching and the video after the switching, and the quality of the reproduced video is deteriorated.

  The present invention solves the above-described problems, and reproduces video with continuous time stamps without degrading the quality of the video at the time of switching when selecting and decoding the video from a plurality of video data. The purpose is to be able to continue.

  The present invention uses the following means in order to solve the above problems.

  A first invention is a video decoding device that obtains image information by decoding encoded data of video information composed of a plurality of (N) streams, and includes N stream buffers in which each stream is stored; , For each stream stored in the stream buffer, a time stamp acquisition unit that obtains time stamp information at a preset stream read position, a stream decoding unit that decodes the stream to create image information, and a stream decoding unit A decoder buffer for reading a stream, a decoding stream setting unit for setting a decoding stream and a decoding start time stamp, and from the reading position corresponding to the time stamp set by the decoding stream setting unit to the next reading position from the stream buffer Stream of Characterized in that it comprises a stream transfer unit for transferring the file.

  According to the present invention, by providing two types of buffers, a stream buffer and a decoder buffer, a plurality of video data is temporarily stored in each stream buffer, and when a selection event occurs, the data is selected from the stream buffer. The obtained stream is taken out and the stream is transferred to the decoder buffer. Regardless of the selection event, the decoder continues to decode the decoder buffer stream. Thereby, it is possible to continuously reproduce the video with the time stamps continuously.

A second invention is a video decoding apparatus that obtains image information by decoding encoded data of video information composed of a plurality of (N) streams, and includes N stream buffers in which each stream is stored; , For each stream stored in the stream buffer, a time stamp acquisition unit that obtains time stamp information at a preset stream reading position, and M pieces (2 ≦ M ≦ N) for generating image information by decoding the stream A stream decoding unit of
The M decoder buffer from which the stream decoding unit reads the stream, the decoding stream setting unit that sets the decoding stream and the decoding start time stamp, and the reading corresponding to the time stamp set by the decoding stream setting unit from the stream buffer A stream transfer unit that reads a stream from the position to the next read position and transfers the stream to a decoder buffer.

  According to the present invention, by providing two or more stream decoding units, two or more video data can be transferred from the data stored in the stream buffer to the decoder buffer and decoded in parallel.

  A third invention is the video decoding device according to the first or second invention, wherein the time stamp acquisition unit searches for a specific bit arrangement in the stream for each stream stored in the stream buffer. The stream read position is specified, and time stamp information preset at the stream read position is obtained.

  According to the present invention, a stream reading position having a specific bit arrangement is set in advance in the video stream, and time stamp information is set at that position. For such a video stream, the time stamp acquisition unit searches the specific bit arrangement in the stream in the stream buffer to identify the stream read position, and the time stamp information set in advance at the stream read position. obtain. Thereby, the time stamp information acquisition process can be performed in parallel with the decoding process of the encoded data, and the decoding process can be performed continuously.

  The fourth invention is the video decoding device according to the first or second invention, wherein the time stamp acquisition unit sets a stream set in advance in the encoded data for each stream stored in the stream buffer. The time stamp information at the stream read position is obtained by decoding the read position information and the time stamp information.

  According to the present invention, time stamp information at each stream reading position is set in advance in the video stream separately from the encoded video data. For such a video stream, the time stamp acquisition unit identifies the stream reading position, and obtains time stamp information preset at the stream reading position. Thereby, the time stamp information acquisition process can be performed in parallel with the decoding process of the encoded data, and the decoding process can be performed continuously.

  The fifth invention is the video decoding apparatus according to the first or second invention, wherein the time stamp acquisition unit is preset in a stream created in advance separately from each stream stored in the stream buffer. The time stamp information at the stream reading position is obtained by decoding the time stamp information at the stream reading position.

  According to the present invention, the time stamp information at each stream reading position is set in advance in a stream (time stamp stream) different from the video stream. For such a video stream and time stamp stream, the time stamp acquisition unit decodes the time stamp stream to obtain time stamp information at the stream reading position. Thereby, the time stamp information acquisition process can be performed in parallel with the decoding process of the encoded data, and the decoding process can be performed continuously.

  In the sixth aspect of the invention, video decoding is performed to decode video data encoded data composed of a stream (multiplexed stream) obtained by multiplexing a plurality (N) of streams to which stream identifiers are assigned, to obtain image information. A stream buffer for storing a multiplexed stream, and a time stamp acquisition unit for obtaining a stream identifier and time stamp information at each preset stream reading position for the multiplexed stream stored in the stream buffer; A stream decoding unit that decodes the stream to generate image information, a decoder buffer from which the stream decoding unit reads the stream, a decoding stream setting unit that sets a decoding stream and a timestamp to start decoding, and a stream buffer, Set in the decoding stream setting section And from the reading position corresponding to the time stamp to the next reading position, reading a stream corresponding to the stream identifier, characterized in that it comprises a stream transfer unit for transferring to the decoder buffer.

  According to the present invention, by providing two types of buffers, a stream buffer and a decoder buffer, a multiplexed stream obtained by multiplexing a plurality of video encoded data is temporarily stored in the stream buffer, and a selection event occurs. Sometimes, the selected stream is taken out of the stream buffer and the stream is transferred to the decoder buffer. Regardless of the selection event, the decoder continues to decode the decoder buffer stream. Thereby, it is possible to continuously reproduce the video with the time stamps continuously.

  A seventh aspect of the present invention is a video decoding method for obtaining image information by decoding encoded data of video information composed of a stream (multiplexed stream) obtained by multiplexing a plurality of (N) streams assigned stream identifiers. A stream buffer for storing a multiplexed stream, and a time stamp acquisition unit for obtaining a stream identifier and time stamp information at each preset stream reading position for the multiplexed stream stored in the stream buffer; , M (2 ≦ M ≦ N) stream decoding units that decode the stream to generate image information, M decoder buffers from which the stream decoding unit reads the stream, a stream to be decoded, and a timestamp to start decoding From the decoding stream setting section that sets the From the reading position corresponding to the time stamp set in the stream setting unit to the next read position to read the stream corresponding to the stream identifier, characterized in that it comprises a stream transfer unit for transferring to the decoder buffer.

  According to the present invention, by providing two or more stream decoding units, two or more video data can be transferred from the data stored in the stream buffer to the decoder buffer and decoded in parallel.

  An eighth invention is the video decoding device according to the sixth or seventh invention, wherein the time stamp acquisition unit searches for a specific bit arrangement in the stream for the multiplexed stream stored in the stream buffer. Thus, a stream reading position is specified, and a stream identifier and time stamp information preset at the stream reading position are obtained.

  According to the present invention, a stream reading position having a specific bit arrangement is set in advance in the multiplexed stream, and a stream identifier and time stamp information are set at the position. For such a multiplexed stream, the time stamp acquisition unit searches a specific bit arrangement in the stream in the stream buffer to identify the stream read position, and a stream identifier set in advance at the stream read position and Get timestamp information. Thereby, the process of acquiring the stream identifier and the time stamp information can be performed in parallel with the process of decoding the encoded data, and the decoding process can be performed continuously.

  A ninth invention is the video decoding device according to the sixth or seventh invention, wherein the time stamp acquisition unit presets the multiplexed stream stored in the stream buffer in the encoded data. Decoding the stream read position information, the stream identifier, and the time stamp information obtains the stream identifier and the time stamp information at the stream read position.

  According to the present invention, a stream identifier and time stamp information at each stream reading position are set in advance in the multiplexed stream separately from the video encoded data. For such a multiplexed stream, the time stamp acquisition unit specifies a stream reading position, and obtains a stream identifier and time stamp information preset at the stream reading position. Thereby, the process of acquiring the stream identifier and the time stamp information can be performed in parallel with the process of decoding the encoded data, and the decoding process can be performed continuously.

  The tenth invention is the video decoding apparatus according to the sixth or seventh invention, wherein the time stamp acquisition unit is preset in a stream created in advance separately from each stream stored in the stream buffer. The stream identifier and the time stamp information at the stream reading position are obtained by decoding the stream identifier and the time stamp information at the stream reading position.

  According to the present invention, the stream identifier and the time stamp information at each stream reading position are set in advance in a stream (time stamp stream) different from the multiplexed stream. For such a video stream and time stamp stream, the time stamp acquisition unit decodes the time stamp stream to obtain a stream identifier and time stamp information at the stream reading position. Thereby, the process of acquiring the stream identifier and the time stamp information can be performed in parallel with the process of decoding the encoded data, and the decoding process can be performed continuously.

  According to the present invention, when a video is selected from a plurality of video data and decoded, the decoder continues to decode the decoder buffer stream regardless of the selection event. Thereby, it is possible to continuously reproduce the video with the time stamps continuously.

It is a figure which shows the structural example 1 of the video decoding apparatus in a 1st example. It is a figure which shows the video decoding process flow. It is a figure which shows the image | video decoding process flow. It is a figure which shows the image | video decoding process flow. It is a figure which shows the structural example 2 of the video decoding apparatus in a 1st example. It is a figure which shows the example of a stream structure. It is a figure which shows the structural example 1 of the video decoding apparatus in a 2nd example. It is a figure which shows the structural example 2 of the video decoding apparatus in a 2nd example. It is a figure which shows the structural example 1 of the video decoding apparatus in a 3rd example. It is a figure which shows the structural example 2 of the video decoding apparatus in a 3rd example. It is a figure which shows the example of a stream structure. It is a figure which shows the structural example 1 of the video decoding apparatus in a 4th example. It is a figure which shows the structural example 2 of the video decoding apparatus in a 4th example. It is a figure which shows an example of a system configuration in the case of implement | achieving a video decoding apparatus by a software program.

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

[First example]
In the first example, a video decoding apparatus that obtains image information by decoding one stream out of encoded data (stream) of video information composed of four (A, B, C, D) streams. An example is shown. It is assumed that the read position and the time stamp of each stream are set in advance and are created one by one as a stream (time stamp stream) separate from the encoded video data.

  FIG. 1 shows a configuration example 1 of the video decoding apparatus of the first example. Stream buffer 101 for storing stream A, stream buffer 102 for storing stream B, stream buffer 103 for storing stream C, stream buffer 104 for storing stream D, and time stamp stream for each stream (A, B, C, D), a time stamp acquisition unit 107 that obtains time stamp information at the stream reading position of each stream, a stream decoding unit 109 that decodes the stream to create image information, and a stream decoding unit 109 From the decoder buffer 106 for reading the stream, the decoding stream setting unit 108 for setting the decoding stream and the time stamp for starting decoding, and the stream buffers (A, B, C, D) 101 to 104, From the reading position corresponding to the time stamp set in tough 108 reads the stream to the next reading position, and a stream transfer unit 105 for transferring to the decoder buffer 106. It is assumed that streams are sequentially accumulated in the stream buffers (A, B, C, D) 101 to 104, and a sufficient amount of streams is always accumulated in the buffer.

Based on the above assumptions, it is assumed that one of the images A, B, C, and D is read and decoded in the following order. That is, the selection event is as follows.
(1) Time T1 to T2: Video A
(2) Time T2 to T3: Video B
(3) Time T3 to T4: Video C
(4) Time T4 to T5: Video D
First, processing from the stream buffer 101 to 104 to transfer to the decoder buffer 106 is shown. FIG. 2 shows a flowchart. The time stamp acquisition unit 107 decodes the time stamp stream (A, B, C, D), and obtains the read position and time stamp information of each video stream in advance (steps S101 and S102).

  The decoded stream setting unit 108 sets the stream transfer unit 105 to read the stream corresponding to the time stamp from time T1 to time T2 for the stream A (step S103). The stream transfer unit 105 reads out the stream A corresponding to the time stamp from the time T1 to the time T2 from the stream buffer 101 using the read position information obtained by the time stamp acquisition unit 107, and transfers it to the decoder buffer 106. (Step S104).

  Next, the decoded stream setting unit 108 sets the stream transfer unit 105 so as to read the stream corresponding to the time stamp from time T2 to time T3 for the stream B. The stream transfer unit 105 reads out the stream B corresponding to the time stamp from the time T2 to the time T3 from the stream buffer 102 using the read position information obtained by the time stamp acquisition unit 107, and transfers it to the decoder buffer 106. .

  The same processing is performed for the video C and the video D. For the video C, the streams at the times T3 to T4 and for the video D at the times T4 to T5 are read from the respective stream buffers 103 and 104 and transferred to the decoder buffer 106. .

  Processing from this stream buffer to transfer to the decoder buffer 106 may follow the flowchart shown in FIG. The decoded stream setting unit 108 sets the stream transfer unit 105 to read the stream corresponding to the time stamp from time T1 to time T2 for the stream A (step S201). The time stamp acquisition unit 107 performs decoding of the time stamp stream A until a stream reading position corresponding to the time stamp from time T1 to time T2 is obtained, and acquires a time stamp (step S202). The stream transfer unit 105 reads out the stream corresponding to the time stamp from time T1 to time T2 from the stream buffer 101 using the information on the read position obtained by the time stamp acquisition unit 107 and transfers it to the decoder buffer 106 ( Step S203).

  The above operation is performed in the same manner for video B, video C, and video D.

  Subsequently, according to the flowchart shown in FIG. 4, the stream decoding unit 109 reads and decodes the stream accumulated in the decoder buffer 106 (steps S301 and S302).

  Through the above processing, the time stamps can be continuously decoded from video A to video D, and the video can be continuously decoded and reproduced.

  The read position and time stamp information of each stream may be created as one stream (multiplexed time stamp stream) for four video streams. In this case, the time stamp acquisition unit 107 reads the multiplexed time stamp stream instead of the four time stamp streams, and obtains time stamp information at the stream reading position.

  The time stamp acquisition unit 107 decodes the time stamp stream to obtain the time stamp and the reading position. However, the time stamp information may be previously used in the video stream.

  The configuration of the video decoding apparatus in this case is shown as configuration example 2 in FIG. In the configuration example 2, the time stamp acquisition unit 207 is different from the configuration example 1 described above, and the other parts are the same as those in the configuration example 1.

  In the configuration of the video stream in the configuration example 2, two types of patterns are assumed. The first stream configuration is shown as a stream configuration example 1 in FIG. In stream configuration example 1, a start code of a specific bit pattern is set at the read position, and time stamp information is set near the start code. In this case, for each stream stored in the stream buffer, the time stamp acquisition unit 207 searches for the start code in the stream to identify the stream reading position, and the time stamp set in advance at the stream reading position. get information.

  A second stream configuration is shown as a stream configuration example 2 in FIG. In the stream configuration example 2, time stamp information and read position information are set near a predetermined specific position X. Depending on how X is set, it can be set near the beginning of the stream or near the end of the stream. In addition, each time stamp information may be set at different positions. In this case, the time stamp acquisition unit 207 decodes the time stamp information and the read position information set in advance in the encoded data for each stream stored in the stream buffer, so that the time stamp at the stream read position is obtained. get information. Furthermore, the value of X can be included in a specific position of the video stream. In this case, after the value of X is first decoded, the time stamp information and the read position information are decoded.

  The processes other than the time stamp acquisition unit 207 are the same, and operate according to the flowcharts of FIGS.

[Second example]
In the second example, the video decoding apparatus obtains image information by decoding two streams out of encoded data (stream) of video information composed of four (A, B, C, D) streams. An example is shown. It is assumed that the read position and time stamp of each stream are set in advance and are created one by one as a stream (time stamp stream) separate from the encoded video data.

  FIG. 7 shows a configuration example 1 of the video decoding device of the second example. Stream buffer 301 for storing stream A, stream buffer 302 for storing stream B, stream buffer 303 for storing stream C, stream buffer 304 for storing stream D, and time stamp stream for each stream (A, B, C, D), a time stamp acquisition unit 307 that obtains time stamp information at the stream reading position of each stream, and a stream decoding unit (P, Q) 311 that decodes the stream to create image information 313, decoder buffers (P, Q) 311 and 312 from which the stream decoding units (P, Q) 311 and 313 respectively read streams, a decoding stream setting unit 308 for setting a stream to be decoded and a time stamp for starting decoding ,story A stream from the reading position corresponding to the time stamp set by the decoding stream setting unit 308 to the next reading position is read from the buffers (A, B, C, D) 301 to 304 and transferred to the decoder buffers 310 and 312. And a stream transfer unit 305. It is assumed that streams are sequentially accumulated in the stream buffers (A, B, C, D) 301 to 304, and a sufficient amount of streams is always accumulated in the buffer.

Based on the above assumptions, it is assumed that two videos out of the videos A, B, C, and D are read and decoded in the following order.
(1) Time T1 to T2: Video A and Video B
(2) Time T2 to T3: Video C and Video D
First, processing from the stream buffer 301 to 304 to transfer to the decoder buffers 310 and 312 will be described. The flowchart is the same as in FIG. The time stamp acquisition unit 307 decodes the time stamp stream (A, B, C, D), and obtains the read position and time stamp information of each video stream in advance (steps S101 and S102).

  The decoded stream setting unit 308 performs stream transfer so that the stream corresponding to the time stamp from time T1 to time T2 is read for stream A, and then the stream corresponding to the time stamp from time T1 to time T2 is read for stream B. The unit 305 is set (step S103). The stream transfer unit 305 reads the stream A corresponding to the time stamp from time T1 to time T2 from the stream buffer 301 using the information on the read position obtained by the time stamp acquisition unit 307, and transfers it to the decoder buffer 310. The stream B corresponding to the time stamp from time T1 to time T2 is read from the stream buffer 302 and transferred to the decoder buffer 312 (step S104).

  Next, the decoded stream setting unit 308 reads the stream corresponding to the time stamp from time T2 to time T3 for stream C, and reads the stream corresponding to the time stamp from time T2 to time T3 for stream D. The transfer unit 305 is set. The stream transfer unit 305 reads out the stream C corresponding to the time stamp from time T2 to time T3 from the stream buffer 303 using the information on the read position obtained by the time stamp acquisition unit 307, and transfers it to the decoder buffer 310. The stream D corresponding to the time stamp from time T2 to time T3 is read from the stream buffer 304 and transferred to the decoder buffer 312.

  The processing from the transfer of the stream buffers 301 to 304 to the decoder buffers 310 and 312 may follow the flowchart shown in FIG. The decoded stream setting unit 308 sets the stream transfer unit 305 to read out the stream corresponding to the time stamp from time T1 to time T2 for the stream A, and sets the time stamp from time T1 to time T2 for the stream B. The stream transfer unit 305 is set to read the corresponding stream (step S201).

  The time stamp acquisition unit 307 performs decoding of the time stamp stream A until a stream read position corresponding to the time stamp from time T1 to time T2 is obtained, and a stream read position corresponding to the time stamp from time T1 to time T2. Until the time stamp stream B is decoded (step S202).

  The stream transfer unit 305 reads the stream A corresponding to the time stamp from time T1 to time T2 from the stream buffer 301 using the information on the read position obtained by the time stamp acquisition unit 307, and transfers it to the decoder buffer 310. The stream B corresponding to the time stamp from time T1 to time T2 is read from the stream buffer 302 and transferred to the decoder buffer 312 (step S203).

  The above operation is performed in the same manner for video C and video D. The stream transfer unit 305 transfers the stream to the decoder buffer (P) 310 or the decoder buffer (Q) 312, but may transfer to either decoder buffer.

  Subsequently, according to the flowchart shown in FIG. 4, the stream decoding unit (P) 311 reads and decodes the stream accumulated in the decoder buffer 310 (steps S301 and S302). Similarly, the stream decoding unit (Q) 313 reads and decodes the stream stored in the decoder buffer 312. The stream decoding unit 311 and the stream decoding unit 313 execute processing independently.

  Through the above processing, the time stamps can be continuously decoded from video A to video D, and the video can be continuously decoded and reproduced.

  As in the first example, the read position and time stamp information of each stream may be created as one stream (multiplexed time stamp stream) for four video streams. In this case, the time stamp acquisition unit 307 reads the multiplexed time stamp stream instead of the four time stamp streams, and obtains time stamp information at the stream reading position.

  Similarly to the first example, the time stamp acquisition unit 307 decodes the time stamp stream to obtain the time stamp and the reading position. However, the time stamp information is put in the video stream in advance and used. You may do it.

  The configuration of the video decoding apparatus in this case is shown as configuration example 2 in FIG. The configuration of the video stream is the configuration shown in FIG. 6A or 6B, as in the first example. Processes other than the time stamp acquisition unit 407 shown in FIG. 8 are the same as those in the configuration example 1 shown in FIG. 7, and operate according to the flowcharts of FIGS.

[Third example]
In the third example, an example of a video decoding device that obtains image information by decoding one video stream from a multiplexed stream in which four (A, B, C, D) video streams are multiplexed in advance. Show. Each video stream in the multiplexed stream is distinguished by a stream identifier. It is assumed that the read position of the multiplexed stream, the stream identifier, and the time stamp are set in advance, and are created as a stream (multiplexed time stamp stream) different from the multiplexed stream.

  FIG. 9 shows a configuration example 1 of the video decoding apparatus of the third example. A stream buffer 501 that stores the multiplexed stream, a time stamp acquisition unit 507 that obtains a stream identifier and time stamp information at the stream reading position from the multiplexed time stamp stream, and stream decoding that decodes the stream to create image information Set by the decoding stream setting unit 508 from the decoding unit 509, the decoder buffer 506 from which the stream decoding unit 509 reads the stream, the decoding stream setting unit 508 that sets the decoding stream and the time stamp to start decoding The stream transfer unit 505 reads a stream from the read position corresponding to the stream identifier and the time stamp to the next read position and transfers it to the decoder buffer 506. It is assumed that sequentially multiplexed streams are accumulated in the stream buffer 501, and a sufficient amount of streams are always accumulated in the buffer.

Based on the above assumption, it is assumed that one video is read out and decoded in the following order among the videos A, B, C, and D, as in the first example.
(1) Time T1 to T2: Video A
(2) Time T2 to T3: Video B
(3) Time T3 to T4: Video C
(4) Time T4 to T5: Video D
First, processing from the stream buffer 501 to the transfer to the decoder buffer 506 is shown. The flowchart is the same as in FIG. The time stamp acquisition unit 507 decodes the multiplexed time stamp stream to obtain in advance the read position, stream identifier, and time stamp information of each video stream (A, B, C, D) (steps S101 and S102). .

  The decoded stream setting unit 508 sets the stream transfer unit 505 to read the stream corresponding to the time stamp from time T1 to time T2 for the stream A (step S103). The stream transfer unit 505 reads the stream A corresponding to the time stamp from the time T1 to the time T2 from the stream buffer 501 using the information on the read position obtained by the time stamp acquisition unit 507, and transfers it to the decoder buffer 506. (Step S104).

  Next, the decoded stream setting unit 508 sets the stream transfer unit 505 so as to read the stream corresponding to the time stamp from time T2 to time T3 for the stream B. The stream transfer unit 505 reads the stream B corresponding to the time stamp from the time T2 to the time T3 from the stream buffer 501 using the information on the read position obtained by the time stamp acquisition unit 507, and transfers it to the decoder buffer 506. .

  The same processing is performed for the video C and the video D. The stream at the times T3 to T4 for the video C and the times T4 to T5 for the video D is read from the stream buffer 501 and transferred to the decoder buffer 506.

  Processing from the stream buffer 501 to the decoder buffer 506 may be performed according to the flowchart shown in FIG. The decoded stream setting unit 508 sets the stream transfer unit 505 to read the stream corresponding to the time stamp from time T1 to time T2 for the stream A (step S201). The time stamp acquisition unit 507 performs decoding of the multiplexed time stamp stream until a stream read position corresponding to the time stamp from time T1 to time T2 of the stream A is obtained (step S202). The stream transfer unit 505 reads the stream A corresponding to the time stamp from the time T1 to the time T2 from the stream buffer 501 using the information on the read position obtained by the time stamp acquisition unit 507, and transfers it to the decoder buffer 506. (Step S203).

  The above operation is performed in the same manner for video B, video C, and video D.

  Subsequently, according to the flowchart shown in FIG. 4, the stream decoding unit 509 reads and decodes the stream stored in the decoder buffer 506 (steps S301 and S302).

  Through the above processing, the time stamps can be continuously decoded from video A to video D, and the video can be continuously decoded and reproduced.

  The time stamp acquisition unit 507 decodes the multiplexed time stamp stream to obtain the stream identifier, the time stamp, and the reading position. The stream identifier and the time stamp information are put in the multiplexed stream in advance and are used. May be.

  The configuration of the video decoding apparatus in this case is shown as configuration example 2 in FIG. In this case, two types of patterns are assumed for the configuration of the video stream. The first stream configuration is shown as a stream configuration example 3 in FIG. In the configuration example 3, a start code of a specific bit pattern is set at a reading position, and a stream identifier and time stamp information are set near the start code. In this case, the time stamp acquisition unit 607 searches the start code in the stream for the multiplexed stream stored in the stream buffer 601, identifies the stream reading position, and is preset to the stream reading position. Get stream identifier and timestamp information.

  A second stream configuration is shown as a stream configuration example 4 in FIG. In Configuration Example 4, a stream identifier, time stamp information, and readout position information are set near a predetermined specific position X. Depending on how X is set, it can be set near the beginning of the stream or near the end of the stream. In addition, each time stamp information may be set at different positions. In this case, the time stamp acquisition unit 607 decodes the stream read position information, the stream identifier, and the time stamp information that are set in advance in the encoded data for the multiplexed stream stored in the stream buffer 601. The stream identifier and time stamp information at the stream reading position are obtained. Furthermore, the value of X can be included in a specific position of the video stream. In this case, first, after decoding the value of X, the stream identifier and the time stamp information are decoded.

  Processes other than the time stamp acquisition unit 607 are the same as those in the configuration example 1 shown in FIG. 9 described above, and operate according to the flowcharts of FIGS.

[Fourth example]
In the fourth example, an example of a video decoding apparatus that obtains image information by decoding two video streams from a multiplexed stream in which four (A, B, C, D) video streams are multiplexed in advance. Show. Each video stream in the multiplexed stream is distinguished by a stream identifier. It is assumed that the read position of the multiplexed stream, the stream identifier, and the time stamp are set in advance, and are created as a stream (multiplexed time stamp stream) different from the multiplexed stream.

  FIG. 12 shows a configuration example 1 of the video decoding apparatus of the fourth example. A stream buffer 701 for storing the multiplexed stream, a time stamp acquisition unit 707 for obtaining a stream identifier and time stamp information at the stream reading position of each stream from the multiplexed time stamp stream, and creating image information by decoding the stream Stream decoders (P, Q) 711, 713, decoder buffers (P, Q) 710, 712 from which the stream decoders (P, Q) 711, 713 respectively read streams, and the streams to be decoded and decoding are started A stream from the read position corresponding to the stream identifier and time stamp set by the decoded stream setting unit 708 to the next read position is read from the decoded stream setting unit 708 for setting the time stamp and the stream buffer 701, and the decoding is performed. Composed of stream transfer unit 705. transferring to Dabaffa. It is assumed that streams are sequentially accumulated in the stream buffer 701 and a sufficient amount of streams is always accumulated in the buffer.

Based on the above assumptions, it is assumed that two videos out of the videos A, B, C, and D are read and decoded in the following order.
(1) Time T1 to T2: Video A and Video B
(2) Time T2 to T3: Video C and Video D
First, processing from the stream buffer 701 to transfer to the decoder buffers 710 and 712 will be described. The flowchart is the same as in FIG. The time stamp acquisition unit 707 decodes the multiplexed time stamp stream to obtain in advance the read position, stream identifier, and time stamp information of each video stream (steps S101 and S102).

  The decoded stream setting unit 708 reads the stream corresponding to the time stamp from time T1 to time T2 for stream A, and then performs stream transfer so as to read the stream corresponding to the time stamp from time T1 to time T2 for stream B. The unit 705 is set (step S103). The stream transfer unit 705 reads the stream A corresponding to the time stamp from the time T1 to the time T2 from the stream buffer 701 using the information on the read position obtained by the time stamp acquisition unit 707, and the decoder buffer (P) 710 The stream B corresponding to the time stamp from time T1 to time T2 is read from the stream buffer 701 and transferred to the decoder buffer (Q) 712 (step S104).

  Next, the decoded stream setting unit 708 reads the stream corresponding to the time stamp from time T2 to time T3 for stream C, and reads the stream corresponding to the time stamp from time T2 to time T3 for stream D. The transfer unit 705 is set. The stream transfer unit 705 reads out the stream C corresponding to the time stamp from the time T2 to the time T3 from the stream buffer 701 using the information on the read position obtained by the time stamp acquisition unit 707, and the decoder buffer (P) 710 The stream D corresponding to the time stamp from time T2 to time T3 is read from the stream buffer 701 and transferred to the decoder buffer (Q) 712.

  The processing from the transfer of the stream buffer 701 to the decoder buffers 710 and 712 may follow the flowchart shown in FIG. The decoded stream setting unit 708 sets the stream transfer unit 705 to read out the stream corresponding to the time stamp from time T1 to time T2 for stream A, and sets the time stamp from time T1 to time T2 for stream B. The stream transfer unit 705 is set to read the corresponding stream (step S201). The time stamp acquisition unit 707 performs decoding of the multiplexed time stamp stream until the stream reading position corresponding to the time stamp from time T1 to time T2 of the stream A is obtained, and the time from time T1 to time T2 of the stream B The time stamp stream is decoded until the stream reading position corresponding to the stamp is obtained (step S202). The stream transfer unit 705 reads the stream A corresponding to the time stamp from the time T1 to the time T2 from the stream buffer 701 using the information on the read position obtained by the time stamp acquisition unit 707, and the decoder buffer (P) 710 The stream B corresponding to the time stamp from time T1 to time T2 is read from the stream buffer 701 and transferred to the decoder buffer (Q) 712 (step S203).

  The above operation is performed in the same manner for video C and video D. The stream transfer unit 705 transfers the stream to the decoder buffer (P) 710 or the decoder buffer (Q) 712, and may transfer to either decoder buffer.

  Subsequently, according to the flowchart shown in FIG. 4, the stream decoding unit (P) 711 reads and decodes the stream stored in the decoder buffer (P) 710 (steps S301 and S302). Similarly, the stream decoding unit (Q) 713 reads and decodes the stream stored in the decoder buffer (Q) 712. The stream decoding unit (P) 711 and the stream decoding unit (Q) 713 execute processing independently.

  Through the above processing, the time stamps can be continuously decoded from video A to video D, and the video can be continuously decoded and reproduced.

  Similarly to the third example, the time stamp acquisition unit 707 decodes the time stamp stream to obtain a time stamp and a reading position. However, a stream identifier and time stamp information are put in the video stream in advance, You may use it.

  The configuration of the video decoding apparatus in this case is shown as configuration example 2 in FIG. The configuration of the video stream is the configuration of FIG. 11A or FIG. 11B, as in the third example. The processes other than the time stamp acquisition unit 807 are the same as those in the configuration example 1 described with reference to FIG. 12, and operate according to the flowcharts of FIGS.

  The video decoding process described above can be realized by a computer and a software program, and the program can be recorded on a computer-readable recording medium or provided through a network.

  FIG. 14 is a diagram illustrating an example of a system configuration when the video decoding apparatus described above is realized by a software program.

  The CPU 10 is a processing device that fetches and executes instructions of the video decoding program. A video stream input device 11, a program storage device 12, a memory 14, a display control device 15, and an input device 17 are connected to the CPU 10 via a system bus.

  The video stream input device 11 inputs the encoded video stream by network communication or broadcast reception. The program storage device 12 is an external storage device of the hard disk device, and stores a video decoding program 13 for causing the CPU 10 to perform video decoding processing.

  The video decoding program 13 is loaded into the memory 14 when the system is started up, and is read and executed by the CPU 10 when the video stream is decoded. Further, the memory 14 is provided with a stream buffer for storing the video stream input by the video stream input device 11 and a decoder buffer for storing a stream to be decoded.

  The decoded video is displayed on the display device 16 via the display control device 15. The input device 17 is an input device such as a keyboard, a remote controller, or the like, and is used for inputting a selection event for selecting an image.

101 to 104, 201 to 204, 301 to 304, 401 to 404, 501, 601, 701, 801 Stream buffer 105, 205, 305, 405, 505, 605, 705, 805 Stream transfer unit 106, 206, 310, 312 , 410, 412, 506, 606, 710, 712, 810, 812 Decoder buffer 107, 207, 307, 407, 607, 707, 807 Time stamp acquisition unit 108, 208, 308, 408, 508, 608, 708, 808 Decoded stream setting unit 109, 209, 311, 313, 411, 413, 509, 609, 711, 713, 811, 813 Stream decoding unit

Claims (15)

A video decoding method executed by a video decoding device that obtains image information by decoding encoded data of video information composed of N (N ≧ 2) streams,
The video decoding device has N stream buffers for storing the N streams, and one decoder buffer for storing a stream to be decoded.
For each stream stored in the stream buffer, execute a time stamp obtaining step for obtaining time stamp information at a preset stream reading position;
A decoding stream setting step for setting a stream to be decoded and a time stamp for starting decoding;
A stream transfer step of reading a stream from a reading position corresponding to the time stamp set in the decoding stream setting step to the next reading position from one of the N stream buffers and transferring the stream to the decoder buffer; And
A video decoding method, comprising: performing a stream decoding step of decoding the stream accumulated in the decoder buffer to create image information. A video decoding method executed by a video decoding device that obtains image information by decoding encoded data of video information composed of N (N ≧ 2) streams,
The video decoding device includes N stream buffers for storing the N streams, and M (2 ≦ M ≦ N) decoder buffers for storing streams to be decoded,
For each stream stored in the stream buffer, execute a time stamp obtaining step for obtaining time stamp information at a preset stream reading position;
A decoding stream setting step for setting M decoding streams and a time stamp for starting decoding;
A stream from the reading position corresponding to the time stamp set in the decoding stream setting step to the next reading position is read from one of the N stream buffers and transferred to one of the M decoder buffers. A stream transfer step for performing processing on each of the M decoder buffers;
A video decoding method, comprising: performing a stream decoding step of decoding each stream stored in the M decoder buffers to create image information. A video decoding method according to claim 1 or claim 2, wherein
In the time stamp acquisition step,
For each stream stored in the N stream buffers, a stream reading position is identified by searching for a specific bit arrangement in the stream, and time stamp information set in advance at the stream reading position is obtained. A video decoding method characterized by the above. A video decoding method according to claim 1 or claim 2, wherein
In the time stamp acquisition step,
For each stream stored in the N stream buffers, decoding the stream reading position information and time stamp information set in advance in the encoded data to obtain the time stamp information at the stream reading position. A video decoding method. A video decoding method according to claim 1 or claim 2, wherein
In the time stamp acquisition step,
The time stamp information at the stream reading position is obtained by decoding the time stamp information at the stream reading position, which is set in advance in a stream created separately from each stream stored in the N stream buffers. And a video decoding method. Video decoding method executed by a video decoding apparatus that obtains image information by decoding encoded data of video information composed of multiplexed streams obtained by multiplexing N (N ≧ 2) streams assigned stream identifiers Because
The video decoding device has one stream buffer for storing the multiplexed stream and one decoder buffer for storing a stream to be decoded,
For the multiplexed stream stored in the stream buffer, a time stamp obtaining step for obtaining a stream identifier and time stamp information at each stream reading position set in advance is executed,
A decoding stream setting step for setting a stream to be decoded and a time stamp for starting decoding;
A stream transfer step of reading the stream corresponding to the stream identifier from the reading position corresponding to the time stamp set in the decoding stream setting step to the next reading position from the stream buffer and transferring the stream to the decoder buffer And
A video decoding method, comprising: performing a stream decoding step of decoding the stream accumulated in the decoder buffer to create image information. Video decoding method executed by a video decoding apparatus that obtains image information by decoding encoded data of video information composed of multiplexed streams obtained by multiplexing N (N ≧ 2) streams assigned stream identifiers Because
The video decoding device includes one stream buffer in which the multiplexed stream is stored, and M (2 ≦ M ≦ N) decoder buffers that store streams to be decoded,
For a multiplexed stream stored in the stream buffer, execute a time stamp acquisition step for obtaining a stream identifier and time stamp information at each stream read position set in advance,
A decoding stream setting step for setting M decoding streams and a time stamp for starting decoding;
A process of reading a stream corresponding to a stream identifier from the reading position corresponding to the time stamp set in the decoding stream setting step to the next reading position from the stream buffer and transferring it to one of the M decoder buffers Performing a stream transfer step for each of the M decoder buffers,
A video decoding method, comprising: performing a stream decoding step of decoding each stream stored in the M decoder buffers to create image information. The video decoding method according to claim 6 or 7, wherein
In the time stamp acquisition step,
For the multiplexed stream stored in the stream buffer, the stream reading position is specified by searching for a specific bit arrangement in the stream, and the stream identifier and time stamp information set in advance at the stream reading position are obtained. And a video decoding method. The video decoding method according to claim 6 or 7, wherein
In the time stamp acquisition step,
For the multiplexed stream stored in the stream buffer, the stream identifier and the time stamp information at the stream read position are decoded by decoding the stream read position information, the stream identifier, and the time stamp information set in advance in the encoded data. The video decoding method characterized by obtaining. The video decoding method according to claim 6 or 7, wherein
In the time stamp acquisition step,
The stream identifier and the time stamp at the stream reading position are decoded by decoding the stream identifier and the time stamp information at the stream reading position, which are set in advance in a stream created separately from each stream stored in the stream buffer. A video decoding method characterized by obtaining information. A video decoding apparatus that obtains image information by decoding encoded data of video information composed of N (N ≧ 2) streams,
N stream buffers each storing the N streams;
One decoder buffer for storing the stream to be decoded;
For each stream stored in the stream buffer, a time stamp acquisition unit that obtains time stamp information at a preset stream reading position;
A decoding stream setting unit for setting a stream to be decoded and a time stamp for starting decoding;
A stream transfer unit that reads a stream from a read position corresponding to the time stamp set in the decoded stream setting unit to the next read position from one of the N stream buffers and transfers the stream to the decoder buffer;
A video decoding apparatus, comprising: a stream decoding unit that decodes a stream stored in the decoder buffer to create image information. A video decoding apparatus that obtains image information by decoding encoded data of video information composed of N (N ≧ 2) streams,
N stream buffers each storing the N streams;
M (2 ≦ M ≦ N) decoder buffers for storing streams to be decoded;
For each stream stored in the stream buffer, a time stamp acquisition unit that obtains time stamp information at a preset stream reading position;
A decoding stream setting unit for setting M decoding streams and a time stamp for starting decoding;
A stream from the reading position corresponding to the time stamp set by the decoding stream setting unit to the next reading position is read from one of the N stream buffers and transferred to one of the M decoder buffers. A stream transfer unit for performing processing on each of the M decoder buffers;
A video decoding apparatus comprising: M stream decoding units that respectively decode the streams stored in the M decoder buffers to generate image information. A video decoding device that decodes encoded data of video information composed of a multiplexed stream in which N (N ≧ 2) streams assigned stream identifiers are multiplexed to obtain image information,
One stream buffer in which the multiplexed stream is stored;
One decoder buffer for storing the stream to be decoded;
A time stamp obtaining unit for obtaining a stream identifier and time stamp information at each preset stream read position for the multiplexed stream stored in the stream buffer;
A decoding stream setting unit for setting a stream to be decoded and a time stamp for starting decoding;
A stream transfer unit that reads a stream corresponding to a stream identifier from a read position corresponding to a time stamp set in the decoded stream setting unit to a next read position from the stream buffer and transfers the stream to the decoder buffer;
A video decoding apparatus, comprising: a stream decoding unit that decodes a stream stored in the decoder buffer to create image information. A video decoding device that decodes encoded data of video information composed of a multiplexed stream in which N (N ≧ 2) streams assigned stream identifiers are multiplexed to obtain image information,
One stream buffer in which the multiplexed stream is stored;
M (2 ≦ M ≦ N) decoder buffers for storing streams to be decoded;
A time stamp obtaining unit for obtaining a stream identifier and time stamp information at each preset stream read position for the multiplexed stream stored in the stream buffer;
A decoding stream setting unit for setting M decoding streams and a time stamp for starting decoding;
Processing for reading a stream corresponding to a stream identifier from a reading position corresponding to a time stamp set by the decoding stream setting unit to a next reading position from the stream buffer and transferring it to one of the M decoder buffers A stream transfer unit for each of the M decoder buffers;
A video decoding apparatus comprising: M stream decoding units that respectively decode the streams stored in the M decoder buffers to generate image information.   A video decoding program for causing a computer to execute the video decoding method according to any one of claims 1 to 10.

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