JP2006148969A - Muting method for video signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent outputting a distorted image from a switching of a resolution to the completion of a decoding process for a resolution setting, after the switching in a device for receiving, decoding and reproducing a program, when receiving a mottled broadcasting in which the programs of video signal with different resolution are broadcasted, in turn with respect to time. <P>SOLUTION: A storage processing means 6 records a detected resolution. A comparison processing means 5 compares the detected resolution with a previously detected resolution which is stored in the storage processing means 6, and muting processing means 7 performs muting. When decoding is completed with the resolution after the switching, an MPEG decoder 3 outputs a decode completion signal to the muting processing means 7 and releases muting. Thereby, when switching the resolution of an image, the output of the distorted image is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for receiving and playing back a digital broadcast. When a program having a different resolution is broadcast at the same service at different times, the received / reproduced video distorted at the place of the program whose resolution changes is displayed. The present invention relates to a method for muting a video signal for preventing the occurrence of the above.

  As a digital broadcast, PerfecTV using the encoding / multiplexing system defined in MPEG2 (Moving Picture Experts Group 2)! CS (Communication Satellite) satellite digital broadcasting is known. MPEG2 classifies several classes according to video resolution, etc., and the current NTSC system television signal, etc., corresponds to the MP @ ML (Main Profile at Main Level) class, which is PerfecTV! This MP @ ML is also used in the broadcasting. An image of this class has a resolution of, for example, horizontal 720 dots × vertical 480 dots. In this MPEG2 system, it is essential to be able to process a lower profile and a lower level. For example, even when a video having a resolution of 360 horizontal dots × 240 vertical dots is received, it can be decoded and reproduced. PerfecTV! In the CS satellite digital broadcasting, the resolution differs depending on the channel, and the receiving and reproducing apparatus that receives and reproduces the channel determines the resolution of the video every time the channel is switched. In this channel switching, since a received signal is interrupted, processing is performed so as not to display a distorted image.

  In conventional digital broadcasting, the resolution may be different for each channel, but during reception and playback of one channel, broadcasting is performed at the same resolution used for that channel, so the resolution for decoding must be changed. There is no.

  Following CS satellite digital broadcasting, BS (Broadcasting Satellite) satellite digital broadcasting is about to be performed. In this broadcasting, digital high-definition broadcasting using MPEG @ MP @HL (Main Profile at High Level) is scheduled in succession to the high-definition broadcasting service based on MUSE (Multiple Sub Nyquist Sampling Encoding).

  Since this digital high-definition broadcast is also compressed by the MPEG2 system, multi-channel broadcast is scheduled. For this reason, a shortage of content is expected. In this case, for example, high-definition documentary programs and entertainment programs are broadcast during high-definition during golden time, and news programs are broadcast digitally at the conventional resolution. Broadcasting is being considered. This is shown in FIG. 201 is an example of program organization, 202 is a time axis, 211 is an SDTV (Standard Definition Television) program that is a program corresponding to the current NTSC broadcast, 212 is also an SDTV program, and 221 is an HDTV (High Definition Television) that is equivalent to high-definition television. It is a program. FIG. 2 shows an example of mottled broadcasting in which news reports are broadcast on SDTV from 19:00, for example, on the same channel, and dramas from 20:00 are broadcast on HDTV.

  In the case of this example, the resolution of the video is switched while receiving and reproducing a certain channel. At this time, the current reception / playback apparatus displays a distorted video where the resolution is switched. This conceptual diagram is shown in FIG. In MPEG decoding, a memory is used, and then video data is decoded. At this time, the memory capacity to be used varies depending on the video resolution. Reference numeral 311 denotes a memory necessary for decoding SDTV video, and 301 denotes a memory necessary for decoding HDTV. As shown in FIG. 2, when switching from SDTV to HDTV at 20:00, the MPEG decoder that has been decoded using the memory area 311 switches the memory area from 311 to 301 in order to decode the HDTV video. At the same time, the horizontal / vertical synchronizing signal for displaying the video is also switched for HDTV. Therefore, there is a problem that the SDTV video is displayed on the screen as shown in FIG. 3 until the HDTV video is completely decoded. FIG. 3 is a diagram for explaining the concept of disordered video. Actually, the memory is not always used two-dimensionally as shown in the figure. Although it is displayed side by side on the right side, the problem is not changed.

  In the opposite case, that is, when switching from HDTV to SDTV, the memory 311 is used to decode SDTV instead of the memory 301 used for HDTV decoding, and the horizontal / vertical synchronization signal is used. Switch to SDTV. For this reason, there is a problem that a video in which a part of the HDTV video is enlarged is displayed until the SDTV video is completely decoded.

  The present invention relates to an apparatus for receiving and decoding and playing back a mottled broadcast in which programs of video signals having different resolutions are broadcast over time. An object of the present invention is to provide a method for muting a video signal so as not to output a distorted video until the decoding process is completed.

  In order to solve the above-mentioned problem, a digital broadcast receiving / reproducing apparatus includes an information extracting unit that extracts resolution data in a signal defined by MPEG2, a storage processing unit that stores the extracted resolution data, and an extracted resolution data Comparison processing means for comparing the resolution data stored therein, and mute processing means for performing video mute on the reproduced video signal output when a difference is detected in the comparison processing means, and the comparison processing means When it is determined that the resolution of the detected video is different from the stored resolution, the mute processing unit performs the video mute and cancels the video meet when the video is correctly decoded and output. Is achieved.

  As described above, according to the present invention, when a digital broadcast signal is received and reproduced such that a program of video signals with different video resolutions is broadcast continuously in one channel, such as switching between SDTV and HDTV. In addition, the video signal to be output is detected and muted when the resolution of the video signal is switched, and when the video signal is decoded after the resolution is switched, the muting process is canceled and the video signal is output. Since it can be output, a distorted video signal is not output at the time of switching the resolution.

  An embodiment of the present invention is shown in FIG. In FIG. 1, reference numeral 1 is an input terminal for a video signal compressed and encoded by the MPEG2 system, 2 is information extraction means for extracting desired information data from header information indicating a certain delimiter of the encoded signal, and 3 is encoded. MPEG decoder 4 for decoding the received signal, 4 for decoding memory used by the MPEG decoder 3 for decoding processing, 5 for storage processing means for storing the resolution extracted by the information extracting means 2, and 6 for resolution extracted by the information extracting means 2 And comparison processing means for outputting a signal when the resolutions stored in the storage processing means 5 are different from each other, 7 is a mute processing means for muting the video signal decoded by the MPEG decoder 3, and 8 is An output terminal for outputting a video signal output from the mute processing means 7, 11 is an M extracted by the information extracting means 2 Decoding control data necessary for EG decoding, 12 is the resolution data of the video extracted by the information extracting means 2, 12d is the resolution data of the previous detection stored in the storage processing means 5, and 13 is the video data in the MPEG decoder 3. Decoding completion signal indicating that decoding is complete and correct video can be output, 14 is a decoded video signal, and 15 is a signal when the comparison unit determines that the video resolution is different.

The operation of this embodiment will be described next. When receiving a digital broadcast, decoding it and outputting it, the information extraction means 2 analyzes the information of the header part of the packetized signal, leads the decoding control data 11 necessary for decoding to the MPEG decoder 3, and further The video resolution data 12 is sent to the storage processing means 5 and the comparison processing means 6. The MPEG decoder 3 decodes the encoded signal derived from the input terminal 1 by using the decoding memory 4 and guides it to the mute processing means 7 as the original video signal 14 decoded. The mute processing means 7 normally outputs the video signal through the output terminal 8 without performing mute. Each time the resolution data 12 is detected, the storage processing means 5 guides the stored resolution data 12 d to the comparison processing means 6 and re-stores the detected resolution data 12. As a result, the resolution data 12 detected at present and the resolution data 12d detected before that are guided to the comparison processing means 6. The comparison processing means 6 compares the derived resolution data 12 and 12d, and if they are different, makes a mute processing request to the mute processing means 7. Further, the MPEG decoder 3 guides to the mute processing means a decode completion signal 13 indicating that the decoding of the first video for canceling the mute is completed when the decoding of the video after the resolution is switched is completed. . The mute processing means 7 performs a mute process on the video output in response to the mute request from the comparison processing means 6, cancels the mute process by the decode completion signal 13 from the MPEG decoder 3, and outputs a video signal.

  As shown in FIG. 4, the signal encoded by the MPEG2 system is composed of a series of data streams having a header called a sequence header, and the data following the header is, for example, a GOP (Group Of Picture). It is video data with a structure called. Reference numeral 401 denotes a video data stream, which switches between 410 SDTV video data and 420 HDTV video data stream. 411 is a sequence header constituting the SDTV video stream 410, 412 is video data (GOP) following the sequence header 411, 421 is a sequence header constituting HDTV video stream 420, and 422 is video data (GOP) following the sequence header. It is. Here, the resolution data of the video is in the sequence header. The information extraction means 2 extracts resolution data from this sequence header. When the HDTV video data 420 is input from the input terminal 1 and the information extraction means 2 detects the video resolution 12 from the sequence header, the HDTV resolution 12 and the SDTV resolution 12d are led to the comparison processing means 6. Therefore, a mute processing request is issued to the mute processing means 7 because the resolutions do not match. As a result, the mute processing means 7 mutes the video, so that the distorted video as shown in FIG. 3 is not displayed. The MPEG decoder 3 starts decoding the video data after switching to HTDV, and outputs a decoding completion signal 13 to the mute processing means 7 when the first decoded video is completely decoded. The mute processing means 7 receives this decoding completion signal 13, cancels the mute processing, and outputs a decoded video signal. As the timing at which the decoding completion signal 13 is output, for example, the time when the decoding of the first I picture after the video resolution is switched in the sequence header can be used. An I picture is an intra-frame encoded image defined by the MPEG system, and is encoded only with data in the frame. Therefore, the original video signal is obtained by decoding only with the data. Can do. As described above, according to the present embodiment, since the mute process can be performed during the period in which the distorted video is output immediately after switching from SDTV to HDTV, the distorted video is not output. In the description of the operation of this embodiment, the operation at the time of switching from SDTV to HDTV has been described. Needless to say, this is the same at the time of switching from HDTV to SDTV. When different programs are broadcast as mottled broadcasts, even when only HDTV is used and when a program with different video resolutions is broadcasted, a distorted video is not output by performing the same processing. In this embodiment, digital broadcasting using MPEG2 encoding / decoding has been described as an example. However, if the video stream is an encoding / decoding scheme having resolution information of the video, the present invention can be applied. Can do.

  Another embodiment of the present invention is shown in FIG. This embodiment is different from the embodiment of FIG. 1 in that the control means 9 is used instead of the comparison processing means 6 and the storage processing means 5 and the resolution data 12 extracted by the information extraction means 2 and the MPEG decoder 3 output. The other points are the same as those of the embodiment of FIG. 1 in that the decoding completion signal 13 is guided to the control means 9 and the control means 9 performs on / off control of the mute processing to the mute processing means 7. Hereinafter, the operation of the difference from the embodiment of FIG. 1 will be described. The control means 9 is, for example, a microcomputer, and performs comparison with the derived new resolution data 12 while holding the resolution data 12 detected by the information extraction means 2. The control means 9 instructs the mute processing means 7 to perform mute when it is determined that the resolution is different from the comparison. When the control means 9 receives the decoding completion signal 13 from the MPEG decoder 3, the control means 9 instructs the mute processing means 7 to cancel the mute processing. As described above, in this embodiment as well, as in the embodiment of FIG. 1, video muting is performed when the video stream is switched from SDTV to HDTV, and muting is canceled when the HDTV video signal is completely decoded. Therefore, a distorted video is not output at the time of switching the resolution. Further, in the present embodiment, only the operation relating to the present invention has been described for the control means 9, but this can be incorporated into the function of the control means for controlling the reception / playback apparatus. Therefore, the configuration can be simplified. In the control of the reception / playback apparatus, since the mute process is performed when the channel is changed, the mute control can also be used. In addition, as described in the embodiment of FIG. 1, it is needless to say that when the programs having different resolutions are linked regardless of the SDTV / HDTV, the present invention can prevent the distorted video from being output. Similarly, the broadcast encoding / decoding system is not limited to the MPEG2 system.

  Another embodiment of the present invention is shown in FIG. This embodiment is different from the other embodiments in that the mute processing request is sent from the MPEG processing unit 7 to the mute processing unit 7 instead of the comparison processing unit 6 or the control unit 9 issuing a mute processing request to the mute processing unit 7. The other points are the same as in the other embodiments in that execution / cancellation of the mute process is instructed. Hereinafter, the operation of points different from the other embodiments will be described. Information 11 necessary for decoding is derived from the information extracting means 2 to the MPEG decoder 3. The decoding data 11 also includes resolution data. When the resolution is changed, the usage mode of the decoding memory is changed as shown in FIG. 3, for example. In this case, the MPEG decoder 3 outputs an instruction signal 16 for performing mute processing to the mute processing means 7. When the decoding of the first video data after the resolution is switched is completed, the MPEG decoder 3 outputs a signal 16 that instructs the mute processing means 7 to cancel the mute processing. As described above, in this embodiment as well, as in the other embodiments, video muting is performed when the resolution of the video stream is switched, and muting is performed when the video signal of the resolution after switching is completed. Can be canceled, so that a distorted video is not output at the time of switching the resolution. Furthermore, according to the present embodiment, the MPEG decoder itself can set the decoding memory for the decoding process and switch the horizontal / vertical synchronization signal at the same time as the resolution is switched, so that the mute process can be requested at the same time. Therefore, it is not necessary to add a new means for monitoring the switching of resolution, and the configuration can be simplified. Further, as in the other embodiments, the broadcast encoding / decoding method is not limited to the MPEG2 method, and the encoded data has decoding control data for decoding it, thereby changing the decoding state. I just need it.

  As other embodiments of the present invention, although not shown in the drawings, in each of the embodiments shown in FIGS. 1, 5, and 6, the timing at which the mute processing means 7 cancels the mute processing is used. Instead, there is a method of releasing after a certain time. For example, since the video data of the MPEG2 system is a television signal, it has a frame structure. Therefore, after the resolution is switched, a correct video having been decoded can be output after a period of 1.2 frames. Therefore, the timing for releasing the mute is, for example, two frames after the mute process is performed. Thus, the mute is released after a normal video is output. As described above, in this embodiment, as in the other embodiments, the video mute can be performed when the resolution of the video stream is switched, and the mute can be released when the correct video signal can be output. No distorted video is output when the resolution is switched. Furthermore, in this embodiment, the mute release timing is managed by time, so that it is only necessary to count the vertical synchronization signal and the like, thereby simplifying the processing.

It is a figure which shows one Example of this invention. It is a figure which shows the example of a mottled broadcast. It is a figure which shows the concept of the video disturbance at the time of the resolution changing. It is a figure which shows the structure of the video stream of an MPEG2 system. It is a figure which shows another one Example of this invention. It is a figure which shows another one Example of this invention.

Explanation of symbols

1 ... Input terminal,
2 Information extraction means,
3 ... MPEG decoder,
4 ... Decoding memory,
5 ... Memory processing means,
6: Comparison processing means,
7: Mute processing means,
8: Output terminal,
9: Control means,
11: Decode control data,
12 ... Resolution data of video,
12d: Resolution data of the video once stored,
13: Decoding completion signal,
14: Decoded video signal,
15 ... Mute control signal,
16: Mute control signal,
201: Stream example of video signals with different resolutions,
202 ... time axis,
301 ... Example of memory use when decoding HDTV,
311... Example of memory use when SDTV is decoded.

Claims (9)

An apparatus for receiving and playing back a digital broadcast, the information extracting means for extracting information data necessary for resolution and decoding of a video signal, the decoding means for performing decoding using the decoding data extracted by the information extracting means, Mute processing means for performing a mute process on the video signal decoded by the decoding means or outputting the signal as it is, a storage processing means for storing the resolution data of the video extracted by the information extraction means, and an extraction by the information extraction means Comparison processing means for comparing the resolution data of the recorded video and the resolution data of the video stored in the storage processing means,
The video signal is muted by the mute processing means when the comparison result of the comparison processing means is different from the stored video resolution and the extracted video resolution, and the decoding of the video signal is completed by the decoding means A method for muting a video signal, wherein the mute processing in the mute processing means is canceled by a signal indicating   2. The video signal mute method according to claim 1, wherein the decoding is completed when the first intra-frame encoded image after the switching of the video resolution is decoded.   2. The video signal mute method according to claim 1, wherein the mute processing means releases the mute at a predetermined time after the mute processing. An apparatus for receiving and playing back a digital broadcast, the information extracting means for extracting information data necessary for resolution and decoding of a video signal, the decoding means for performing decoding using the decoding data extracted by the information extracting means, Mute processing means for performing a mute process on the video signal decoded by the decoding means or outputting the signal as it is, and a control means for controlling each of these means,
The control means instructs the mute processing means to perform a mute process on the video signal when the resolution of the video extracted by the information extraction means is different from the resolution so far. A method for muting a video signal, wherein when the signal indicating that the decoding of the video signal is completed is received by the decoding means, the mute processing means is instructed to cancel the mute processing.   5. The video signal muting method according to claim 4, wherein the decoding is completed when the first intra-frame encoded image after the switching of the video resolution is decoded.   5. The video signal mute method according to claim 4, wherein the mute processing means releases the mute at a predetermined time after the mute processing. An apparatus for receiving and playing back a digital broadcast, the information extracting means for extracting information data necessary for resolution and decoding of a video signal, the decoding means for performing decoding using the decoding data extracted by the information extracting means, Mute processing means for performing a mute process on the video signal decoded by the decoding means or outputting the signal as it is,
The decoding means instructs the mute processing means to perform a mute process on the video signal when the resolution of the video to be decoded is different from the resolution so far according to the decoding control data extracted by the information extraction means. And then instructing the mute processing means to cancel the mute processing when the decoding of the video signal after the resolution is switched is completed.   8. The video signal mute method according to claim 7, wherein the decoding is completed when the first intra-frame encoded image after the switching of the video resolution is decoded. 8. The video signal mute method according to claim 7, wherein the mute processing means releases the mute at a predetermined time after the mute processing.

Images