JP3882295B2 - Digital broadcast receiving apparatus and video signal muting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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.
[0002]
[Prior art]
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. This class of video 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.
[0003]
[Problems to be solved by the invention]
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.
[0004]
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).
[0005]
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.
[0006]
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.
[0007]
In the reverse case, that is, when switching from HDTV to SDTV, the memory 311 is used for SDTV decoding 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.
[0008]
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. It is an object of the present invention to provide a digital broadcast receiving apparatus and a video signal mute method that do not output a distorted video until the decoding process is completed.
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, an information extraction means for extracting information on the resolution of a program video included in a digital broadcast signal received by a digital broadcast receiver, and a video signal included in the received digital broadcast signal Decoding means for decoding; output means for outputting the program video decoded by the decoding means; and discrimination means for discriminating switching of the resolution of the program video using information extracted by the information extraction means. The discriminating means receives the one channel when the information about the resolution of the program video extracted by the information extracting means is different from the information about the resolution of the program video received before. When switching is determined, and when the determining means determines the resolution switching, the output means Wherein the output of the program video is configured to be stopped.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
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.
[0011]
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 a 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 comparison processing means 6 is led to the resolution data 12 detected at present and the resolution data 12d detected before that. 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 decoding 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.
[0012]
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 HDTV , and outputs a decoding completion signal 13 to the mute processing means 7 when the first decoded video has been 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.
[0013]
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 the mute processing on / off control on 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 a microcomputer, for example, 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, it 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 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, a mute process is performed when the channel is changed, so that 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.
[0014]
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.
[0015]
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.
[0016]
【The invention's effect】
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.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of mottled broadcasting.
FIG. 3 is a diagram illustrating the concept of image disturbance at the time when the resolution changes.
FIG. 4 is a diagram illustrating the structure of an MPEG-2 video stream.
FIG. 5 is a diagram showing another embodiment of the present invention.
FIG. 6 is a diagram showing another embodiment of the present 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)

A digital broadcast receiving apparatus that receives a digital broadcast signal including program video having different resolution and information related to the resolution of the program video,
Information extracting means for extracting information about the resolution of the program video included in the received digital broadcast signal;
Decoding means for decoding a video signal included in the received digital broadcast signal;
Output means for outputting the program video decoded by the decoding means ;
And a discriminating means for discriminating a cutting conversion despite resolution of the program video by using the information extracted in the information extracting means,
The discriminating means switches the resolution when the information related to the resolution of the program video extracted by the information extracting means is different from the information related to the resolution of the previously received program video during reception of one channel. Determine
Wherein when the determining means has determined the switching of the resolution, the digital broadcast receiving apparatus characterized by output program video from the output device is stopped. The digital broadcast signal has information related to decoding of a video signal included in the digital broadcast signal,
The digital broadcast receiving apparatus according to claim 1, wherein the decoding unit decodes the video signal based on information related to the decoding.   2. The digital broadcast reception according to claim 1, wherein when the digital broadcast signal after the resolution is switched is decoded by the decoding means, the output means cancels the stop of the output of the video program. apparatus. A digital broadcast receiver for receiving an SDTV video stream and an HDTV video stream,
Information extracting means for extracting information about resolution included in the video stream;
Decoding means for decoding the received video stream;
Output means for outputting the video decoded by the decoding means;
Discriminating means for discriminating switching between the SDTV and the HDTV using the information extracted by the information extracting means,
The determination unit compares the information about the resolution of the video stream extracted by the information extraction unit with the information about the resolution of the video stream received before, while receiving one channel, and the result of the comparison , If the two are different, determine the switching between the HDTV and SDTV,
The digital broadcast receiving apparatus according to claim 1, wherein when the determining means determines the switching, the video from the output means is subjected to a video mute process. The video stream has information regarding the video stream decoding,
5. The digital broadcast receiving apparatus according to claim 4, wherein the decoding means decodes the video stream based on information related to the decoding.   5. The digital broadcast reception according to claim 4, wherein when the video stream is decoded after the resolution of the video stream is switched in the decoding unit, the output unit cancels the video mute processing. apparatus. A method for muting a video signal,
A video signal and a receiving step for receiving information relating to the resolution of the video signal;
An extraction step of extracting information relating to the resolution of the video signal;
A determination step of determining that the resolution of the video signal has been switched when the information regarding the resolution of the extracted program video is different from the resolution of the previously received program video during reception of one channel;
When it is determined that the resolution of the video signal has been switched, an output step of performing video mute processing on the video signal to be output and outputting,
A method for muting a video signal comprising: A digital broadcast receiver for receiving a digital broadcast signal including a first program video having a first resolution and its resolution data, a second program video having a second resolution and its second resolution data,
Information extracting means for extracting the resolution data contained in the received digital broadcast signal;
Decoding means for outputting the first or second program video included in the received digital broadcast signal for decoding;
Discriminating means for discriminating switching between the first program video and the second program video using the information extracted by the information extracting means;
In the receiving channel, when the first program video is switched to the second program video in the reception channel, the determination means determines that the resolution data of the second program video extracted by the information extraction means is the resolution data of the first program video. Determine the switching of the program video at different times,
The digital broadcast receiving apparatus according to claim 1, wherein when the determining means determines the switching of the program video, the video output from the decoder is subjected to video mute processing.   The digital broadcast receiver according to claim 1, wherein the determining means determines the switching of the program video by comparing the resolution data of the first program video and the resolution data of the second program video.

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