JP2012222511A - Moving image decorder and digital television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately send decoded image data to an image display to output a moving image speedily.SOLUTION: An image decoding unit 102 decodes coded image data 101 of a coded moving image to generate image data 108. An image output order determination unit 114 determines the order of each picture of the image data 108, the order being different from a temporal order as the moving image, as the image output order of the image data 108. Consequently, for example in zapping, that is user's checking broadcast contents by selecting one channel after another, the images can be displayed speedily.

Description

  The present invention relates to a moving picture decoding apparatus, and more particularly to a moving picture decoding apparatus in which the order of input encoded moving pictures is different from the order of outputting decoded video data.

  In recent years, with the spread of digital television broadcasts, the number of video decoding devices such as receivers that receive digital television broadcasts distributed in MPEG2 has increased.

  In the case of a moving picture encoded in MPEG2, the order of the encoded moving picture input to the decoding apparatus is different from the order in which the decoded video data is output, and the decoded video data is output immediately. I can't.

  For this reason, it is necessary to store the decoded video data once in the frame memory and rearrange them in the order in which the video should be output, and then send the video data to the video display device and display it on a display or the like. An example of a method for reducing the rearrangement calculation amount is described in Patent Document 1, for example.

  In such a situation, when viewing a digital television broadcast, a user often selects a channel one after another to check whether there is an interesting channel, and performs channel zapping to confirm the content of the broadcast.

  In this case, in order to confirm the broadcast contents quickly, it is necessary to display the video data as fast as possible after the channel selection instruction.

Japanese Patent Laid-Open No. 9-247666

  However, in the conventional technique, although the video data output from the decoder is once held in the frame memory, it cannot be sent to the video display device until it is rearranged in the correct output order, so that the moving image is quickly displayed. There was a problem that could not be drawn.

  The present invention solves the above-described problems, and an object of the present invention is to decode the encoded video data of the moving image in the moving image decoding apparatus to which the encoded video data of the encoded moving image is input. The object is to immediately send video data to a video display device so that a moving image can be displayed at high speed.

  In order to achieve the above object, a video decoding device according to claim 1 is a video decoding unit that decodes encoded video data of an encoded video and generates video data; and the video An image output order determining unit that determines an order different from a temporal order as a moving image for each picture of data as an output order of the video data.

  Therefore, in the present invention, the output order determining unit determines the order of the output of the video data, which is different from the temporal order as the moving image for each picture of the video data. The first decoded picture can be displayed. Therefore, when viewing a digital television broadcast, it is possible to display a moving image at a high speed when zapping a channel in which viewers select channels one after another and confirm the contents of the broadcast.

  As described above, according to the moving picture decoding apparatus of the present invention, the decoded video data can be sent immediately to the video display apparatus, so that a moving picture can be output at high speed.

It is a whole block diagram which shows the moving image decoding apparatus of the 1st Embodiment of this invention. It is a flowchart figure explaining operation | movement of the moving image decoding apparatus. It is a figure which shows the difference in the display timing of the picture between the case of the moving image decoding apparatus, and the conventional case. It is a whole block diagram which shows the moving image decoding apparatus of the 2nd Embodiment of this invention. It is a flowchart figure explaining operation | movement of the moving image decoding apparatus. FIG. It is a figure which shows the difference in the display timing of the picture between the case of the moving image decoding apparatus, and the conventional case. It is a whole block diagram which shows the moving image decoding apparatus of the 3rd Embodiment of this invention.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a moving picture decoding apparatus 100 according to Embodiment 1 of the present invention.

  In the figure, the moving picture decoding apparatus 100 includes a decoder 102, a frame memory 103, an output order management unit 105, an output timing management unit 106, and a time counter 107.

  The detailed configuration and operation of the moving picture decoding apparatus 100 will be described as follows.

  In FIG. 1, a decoder (video decoding unit) 102 obtains stream data 101 from a DTV broadcast wave or a data recording device such as an HDD, and decodes the stream data 101, thereby decoding video data 108 and its associated decoding. Information 110 is generated. The decode information 110 includes information for measuring the display timing of the picture (for example, information such as PTS (Presentation Time Stamp)) and information indicating whether the decoding is performed for the first time or the second time or later.

  The frame memory 103 is a data storage area for temporarily storing the video data 108 decoded by the decoder 102.

  The output order management unit 105 determines the output order based on the decode information 110 generated by the decoder 102. The output order management unit 105 basically determines the output order based on the information for measuring the display timing of the picture. In the case of the first decoding, the output order management unit 105 is concerned with the information for measuring the display timing of the picture. Make sure that the output order of the first decoded video data is first.

  The output timing management unit 106 acquires the output video information 113 from the output order management unit 105 in the order of output. The output video information 113 includes information for measuring the display timing of the picture, and the output video designation 111 is performed in synchronization with the time information 112 obtained from the time counter 107 based on the information. In addition, the output video information 113 includes a list of video data that can be output and information indicating whether the decoding is performed for the first time or for the second time or later. In the case of the first decoding, a time counter is included. The image output video designation 111 is immediately performed without synchronizing with the time information 112 of 107.

  The time counter 107 supplies the video output timing (System Time Clock, STC or audio playback timing) to the output timing management unit 106 as the time information 112.

  Video data 108 from the decoder 102 is temporarily stored in the frame memory 103 and is not output to the video display device 104 until the output video designation 111 is output from the output timing management unit 106, and the output order management unit The image output timing management unit 106 performs output image designation 111 in accordance with the image output order determined in 105, and an image is output. That is, the video data 109 to be displayed on the video display device 104 is switched according to the output video designation 111 of the output timing management unit 106. The video display device 104 includes a TV panel and a monitor.

  The output order management unit 105, the output timing management unit 106, and the time counter 107 determine an output order that is different from the temporal order as a moving image for each picture of video data as the output order of the video data. The image order determining unit 114 is configured.

  FIG. 2 is a flowchart showing the operation of the moving picture decoding apparatus 100 according to the first embodiment.

  In the figure, in step S 401, the decoder 102 decodes the encoded stream data 101, temporarily stores the video data 108 in the frame memory 103, and passes the decode information 110 to the image output order management unit 105.

  In step S402, the output order management unit 105 determines whether or not the decoding is the first decoding based on the information indicating whether or not the decoding is the first decoding included in the decoding information 110. If the decoding is the first decoding, the output video information 113 is displayed. Is output to the image output timing management unit 106, and the process of step S403 is performed. On the other hand, in the case of the second and subsequent decoding, the process of step S404 is performed.

  In step S 403, the output timing management unit 106 outputs an output video specification 111 that specifies video data to be displayed on the video display device 104, and the frame memory 103 outputs the output video according to the output video specification 111. The video data 109 indicated by the designation 111 is output to the video display device 104, and the moving image of the video data 109 is displayed on the video display device 104. The black screen is displayed until the first video data is displayed. Instead of the black screen, it is also possible to continue displaying the video data of the previously decoded stream.

  If the decoding is not the first decoding in step S402, that is, if the decoding is performed for the second time or later, in step S404, the image output order management unit 105 measures the display timing of the pictures included in the received decoding information 110. The information is rearranged so that the display timing is arranged from the past to the future, and a list of video data that can be output is created.

  After the rearrangement, in step S405, the image output order management unit 105 determines that display is possible if the picture at the top of the created list is not referred to at all thereafter, and in step S406, the head of the list is displayed. The image output video information 113 indicating that the current picture can be output is output to the image output timing management unit 112. On the other hand, if the first picture in the list is a picture to be referred to later, it is determined that display is impossible, and the process returns to step S401 to perform decoding processing.

  Subsequently, in step S407, the output timing management unit 106 compares the time information 112 from the time counter 107 with the display timing of the picture that can be output in the output video information 113, and compares the picture information of the picture. If the display timing has been reached, in step S403, an output video designation 111 for designating video data to be displayed on the video display device 104 is output, and the output video designation 111 is output from the frame memory 103 as described above. Is output to the video display device 104. On the other hand, if the display timing has not yet been reached, the process returns to step S401 and the next picture is decoded.

  FIG. 3 shows a difference in picture display timing between the case of this embodiment and the conventional case.

  In the figure, an input order 601 represents the order of pictures in the stream data 101 input to the decoder 102. A display timing 602 represents a display order when decoding and display are performed with a conventional configuration. A display timing 603 represents a display order when decoding and display are performed according to the first embodiment. Note that the input order 601, the conventional display timing 602, and the display timing 603 of the present embodiment are all represented in the form of picture type + conventional display order (for example, the display order is the first for an I picture. In some cases, it is written as “I1”).

  At the conventional display timing 602, video data cannot be displayed until decoding of the I3 picture and the B1 picture is completed at the fastest, and there is a black screen display period 604.

  On the other hand, at the display timing 603 of the present embodiment, the temporal display order as a moving image is B1, B2, I3 pictures..., But when the first picture I3 is decoded in the input order 601, this first picture I3. Is first displayed (this display is indicated by reference numeral 606), and the image data output order is determined. That is, the video data includes B1 and B2 pictures (first picture) and an I3 picture (second picture) positioned after the pictures B1 and B2 in the temporal display order as a moving picture. However, when it is determined that the decoding of the I3 picture is completed before the B1 and B2 pictures, the B1 and B2 pictures are not output, and the I3 picture is output first. The output order management unit 105 does not determine the output order of the pictures in the video data until it is determined to output the I3 picture for the first time. Thus, the black screen display period 605 can be further shortened. In order to completely set the black screen display period 605 to 0, the video data before stream switching may be continuously displayed. Note that after the first I3 picture is output, the B1 and B2 pictures are output as usual, but the subsequent I3 picture, which is the original output order, is output as shown by the broken line in the figure. It does not matter whether it is drawn or not.

  As described above, in the present embodiment, the video data obtained by decoding the first picture in the order of input of the pictures of the stream data 101 can be immediately sent to the video display device 104 and output. Therefore, when viewing a digital television channel, it is possible to realize high-speed image display during channel zapping operation for selecting channels one after another and confirming the broadcast content.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.

  The moving picture decoding apparatus according to the present embodiment has the same configuration as that shown in FIG. 1, but includes stream data 201, a decoder 202, an output order management unit 205, decode information 210, and unnecessary picture information 214 as shown in FIG. It has.

  The stream data 201 is stream data that may contain a display-unnecessary picture at the top in the input order. In addition to the decoder 102 shown in FIG. 1, the decoder 202 receives unnecessary picture information 214 from an image output order management unit 205 described later, and skips decoding of the picture indicated by the unnecessary picture information 214 or The unnecessary picture is ignored and the picture is decoded as usual (however, since it is not designated as an output image, it is not displayed), or the decoding of the slice layer of the unnecessary picture is skipped.

  The decoding information 210 generated by the decoder 202 includes GOP header and picture header information in addition to the decoding information 110 of FIG.

  In addition to the image output order management unit 102 in FIG. 1, the image output order management unit 205 generates unnecessary picture information 214 based on the information of the decode information 210 and the operation designation of the apparatus user.

  The unnecessary picture information 214 includes information indicating whether or not it is necessary to decode the slice layer of the input picture. An unnecessary picture is a picture that is determined to be undecodable by referring to the GOP header or picture information included in the decode information 210 (for example, the second and subsequent B pictures refer to past GOPs). It is. It is also possible to specify that the first B picture is unnecessary by the designation of the apparatus user, and designate a picture that can be decoded as an unnecessary picture.

  FIG. 5 is a flowchart showing the operation of the moving picture decoding apparatus 200 according to the second embodiment.

  In FIG. 5, steps S501 to S507 are the same as steps S401 to S407 shown in FIG. 2, but steps S508 and S509 are added.

  In step S509, it is determined whether or not there is an unnecessary picture in the second and subsequent pictures. If there is no unnecessary picture, the display order is rearranged in step S504 as usual, but there is an unnecessary picture. The unnecessary picture information 214 is passed to the decoder 202. In step S508, the decoder 202 only decodes the picture layer for the unnecessary picture designated by the received unnecessary picture information 214, and skips the decoding of the slice layer. Note that the unnecessary picture information 214 may be ignored and decoded.

  FIG. 6 shows the difference in the display timing of pictures according to the present embodiment and the prior art.

  In the figure, an input order 701 represents the order of pictures in the stream data 201 input to the decoder 202. A conventional display timing 702 represents a display order when decoding and display are performed with the conventional configuration. The display timing 703 of the present embodiment represents the display order when decoding and display are performed according to the configuration of FIG. Note that the input order 701, the conventional display timing 702, and the display timing 703 of the present embodiment are all the picture type + conventional display order (for example, “I1” when the display order is the first for an I picture). It is expressed in the format.

  In the conventional display timing 702, when it is determined that the B1 and B2 pictures decoded between the screens need to be decoded with reference to the past GOP and cannot be decoded, the decoding of the I3 picture ends at the fastest. Until this time, video data cannot be displayed, and there is a black screen display period 704.

  On the other hand, at the display timing 703 of the present embodiment, the first picture I3 in the input order is displayed first, and then the output of B1 and B2 pictures indicated by the unnecessary picture information 214 from the output order management unit 205 is skipped. Then, the head picture I3 is continuously displayed until the picture B4 that needs to be displayed thereafter (this display is indicated by reference numeral 706). Thereby, the black screen display period 705 is further shortened. In order to completely set the black screen display period 705 to 0, the video data before stream switching may be continuously displayed.

  Therefore, in this embodiment, some video data to be output at the beginning is not output, but the video data obtained by decoding the top picture in the input order is immediately displayed without contradicting the conventional display order. Can be sent to.

(Third embodiment)
Subsequently, a moving picture decoding apparatus according to a third embodiment of the present invention will be described with reference to FIG.

  This embodiment is the same as the configuration of FIG. 4, but further includes an STC 307, a tuner 350, a system decoder 351, an audio decoder 352, and an audio output device 353 as shown in FIG. In addition, 300 to 306 are equivalent to 100 to 101, 202, 103 to 104, 205 and 106 in FIG. 4, 308 to 311 are equivalent to 108 to 109, 210 and 111 in FIG. 4, and 313 to 314 are 113 in FIG. , 214.

  The STC 307 generates time information 312 that is synchronized with the television broadcast station that is the broadcast wave transmission source, and passes the time information 312 to the output timing management unit 306 and the audio decoder 352.

  The tuner 350 passes MPEG2 stream data 354 created by receiving and decoding broadcast waves to the system decoder 351.

  The system decoder 351 separates the MPEG2 stream data 354 into video stream data 301 including encoded moving images and audio stream data 355 including encoded audio. The video stream data 301 is passed to the video decoder 302, and the audio stream data 355 is passed to the audio decoder 352.

  When the audio decoder (audio decoding unit) 352 generates audio data 356 obtained by decoding the received audio stream data 355 and determines that it is time to output audio with reference to the time information 312, The audio data 356 is passed to the audio output device 353, and audio is output from the audio output device 353 such as a speaker.

  Note that the video stream data 301 in the digital television broadcast is a stream including pictures that do not need to be displayed, like the stream data 201 shown in FIG. 4 of the second embodiment. For this reason, the display timing is equivalent to the display timing 703 of the second embodiment.

  According to the present embodiment, when viewing a channel of a digital television, it is possible to speed up the process of confirming the content of a video when zapping is performed to continuously select a channel.

  As described above, the present invention can send decoded video data to a video display device immediately, so that it is possible to output a moving image at a high speed, which is useful as a moving image decoding device. .

102, 202, 302 Decoder (Video decoding unit)
103, 303 Frame memory 104, 304 Video display device 105, 205, 305 Output order manager 106, 306 Output timing manager 107 Time counter 114 Output order determiner 307 STC
350 Tuner 351 System Decoder 352 Audio Decoder (Audio Decoding Unit)
353 audio output device

Claims (9)

A video decoding unit that decodes encoded video data of the encoded moving image and generates video data;
A moving picture decoding apparatus comprising: an output order determining unit that determines an order different from a temporal order as a moving picture for each picture of the video data as an output order of the video data. The moving picture decoding apparatus according to claim 1, wherein
The image output order determining unit
A moving picture decoding apparatus, wherein decoding information for measuring a display timing of a picture is input from the video decoding unit, and an output order of the video data is determined based on the decoding information. The moving picture decoding apparatus according to claim 2, wherein
The video data includes a first picture and a second picture located after the first picture in the temporal order as a moving image,
The image output order determining unit
Determining that the second picture is to be output before the first picture when it is determined that the second picture has been decoded before the first picture based on the decoding information; A video decoding apparatus characterized by the above. The moving picture decoding apparatus according to claim 2, wherein
The video data includes a first picture and a second picture located after the first picture in the temporal order as a moving image,
The image output order determining unit
When it is determined that decoding of the second picture is completed before the first picture based on the decoding information, the second picture is output without displaying the first picture. A moving picture decoding apparatus characterized by determining. In the video decoding device according to any one of claims 1 to 4,
A frame memory for storing the video data;
The moving picture decoding apparatus, wherein the video data is output from the frame memory based on the determination of the output order of the output order determination unit. In the moving picture decoding apparatus according to claim 3 or 4,
The image output order determining unit
The moving picture decoding apparatus, wherein the output order of the pictures in the video data is not determined until it is determined to output the second picture. A video decoding unit that decodes encoded video data of the encoded moving image and generates video data;
An output order determining unit that outputs unnecessary picture information indicating that decoding of the first picture input to the video decoding unit is unnecessary to the video decoding unit;
The video decoding device, wherein the video decoding unit skips decoding of a picture corresponding to the unnecessary picture information. The moving picture decoding apparatus according to claim 7, wherein
The image output order determining unit
The moving picture decoding apparatus, wherein the unnecessary picture information is output for a picture that is an inter-coded picture and needs to be decoded with reference to a picture preceding the picture. The video decoding device according to any one of claims 1 to 8,
A tuner that receives digital television broadcast waves and generates encoded stream data;
A system decoder for separating encoded video data and encoded audio data from the encoded stream data;
An audio decoding unit for decoding the encoded audio data output from the system decoder;
An audio output device that outputs audio data obtained by decoding the encoded audio data;
The digital video receiving apparatus, wherein the moving picture decoding apparatus decodes the encoded video data output from the system decoder.

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