JP5049086B2 - Digital broadcast receiver - Google Patents

Description

  The present invention relates to a digital broadcast receiving apparatus, and more particularly, to a digital broadcast receiving apparatus suitable for use in receiving broadcasts that have been hierarchically transmitted and switching between the respective layers for viewing.

  In Japanese terrestrial digital broadcasting, hierarchical transmission in which a plurality of programs are transmitted within one channel can be used. In hierarchical transmission, it is possible to transmit up to three layers composed of one or more segments at the same time, and in order of increasing required CN ratio (Carrier to Noise Ratio) due to differences in transmission path coding methods. It is called a hierarchy / middle hierarchy / weak hierarchy. The weak layer can transmit high-quality video and audio compared to the strong layer, but the reception stability is low. In contrast, the strong layer cannot transmit high-quality video and audio, but the reception stability is low. There is a characteristic that it is high. In digital broadcast receivers that receive broadcasts that have been transmitted hierarchically, when the reception level of the broadcast signal decreases, the video signal and sound are switched from the weaker layer to the stronger layer, such as when the broadcast signal is received. It is possible to switch and output the video / audio of the hierarchy.

  By using this function and transmitting programs with the same content in the weak and strong layers, in areas where the broadcast signal reception level is high, high-quality video and audio in the weak layer are received, and the broadcast signal reception level In regions with low, it is possible to receive video and audio of a strong hierarchy with high reception stability.

  Such an apparatus for switching and outputting a hierarchy is described in, for example, the following Patent Document 1.

JP 2003-274302 A

  The video / audio transmitted in the weak layer and the strong layer has a difference in broadcasting time of about several seconds at the maximum due to the difference in encoding processing at the time of broadcasting signal transmission. For this reason, when the video and audio of the weak layer and the strong layer are switched and output as they are on the receiver side, the video and audio shifted by a few seconds compared to before switching is output, which gives the user watching the program a sense of incongruity. There is a problem that it ends up.

  The present invention has been made to solve the above problems, and its purpose is to obtain the delay time of video / audio of each layer and adjust the output timing thereof so that the user can switch the layer. An object of the present invention is to provide a digital broadcast receiving apparatus that can be viewed without interruption of video and audio when viewing.

  In order to solve the above problems, a digital broadcast receiving apparatus according to a first aspect of the present invention receives a real-time clock that provides real-time time and a signal that is multiplexed and modulated with a plurality of video and audio signals and transmitted hierarchically. A demodulating receiver, a packet separating unit for separating a necessary signal from a signal demodulated by the receiving unit, and a buffer unit for each layer for temporarily storing signals of each layer separated by the packet separating unit A hierarchical decoding unit for each layer that decodes a signal temporarily stored in the buffer unit for each layer, and among the video and audio of each layer decoded by the hierarchical decoding unit for each layer, An output selection unit that selects video / audio of any one layer, and the video / audio of each layer decoded by the layer decoding unit for each layer, monitors the timing of scene change in each layer, and each layer Scene change A hierarchical scene detection unit that detects increase / decrease information of the signal value of the video / audio signal before and after the timing, and an output control unit that switches the selection of the output selection unit, the output control unit from the hierarchical scene detection unit Based on the output scene detection signal of each layer, the scene change direction indicating the signal value increase / decrease information before and after the scene detection, and the time information at the time of scene detection obtained from the real-time clock, The delay time of the video / audio output timing with respect to another layer is calculated, and the buffer unit corresponding to the calculated delay time is set to be increased with respect to the buffer unit of the layer that is not delayed. .

  According to a second aspect of the present invention, in the digital broadcast receiver of the first aspect, the output control unit is configured to detect a scene detection time of the scene detection signal output from the hierarchical scene detection unit, and a video / audio signal before and after the scene detection. A scene change direction indicating signal value increase / decrease information is set as one set, and is stored for each layer, and a shift time of the scene detection time is obtained, and the scene detection time is set to the shift time for a certain layer. Pattern matching comparison is performed with the combination of the scene detection time and the scene change direction shifted by a minute, and the combination of the scene detection time and the scene change direction of another layer, and from the number of matching combinations, It is characterized in that the delay time of the video / audio output timing of a certain layer and another layer is obtained.

  A third invention relates to the digital broadcast receiving apparatus according to the second invention, wherein the scene detection time and the scene obtained by shifting the scene detection time by the shift time with respect to a hierarchy for a plurality of the shift times. Pattern matching comparison is performed between the combination of the change direction and the combination of the scene detection time and the scene change direction of another layer, and the shift time that maximizes the number of matching combinations is It is characterized by a delay time of the output timing of the video / audio of the hierarchy.

  According to a fourth aspect of the present invention, there is provided a digital broadcast receiving apparatus comprising: a real-time clock that provides a real-time time; a receiving unit that receives and demodulates a signal that has been multiplexed and modulated with a plurality of video and audio signals; A packet separation unit that separates a necessary signal from a signal demodulated by the reception unit; a buffer unit for each layer that temporarily stores a signal of each layer separated by the packet separation unit; Video of any one of the hierarchical decoding unit for each layer that decodes the signal temporarily stored in the buffer unit and the video / audio of each layer decoded by the hierarchical decoding unit for each layer The output selection unit for selecting audio and the video / audio of each layer decoded by the hierarchical decoding unit for each layer are monitored, and either the signal value of the video / audio signal of each layer is increased or decreased Changed direction A hierarchy scene detection unit that detects the timing of a scene change only when the output selection unit switches the selection of the output selection unit, and the output control unit includes a scene of each hierarchy output from the hierarchy scene detection unit. Based on the detection signal and the time information at the time of scene detection acquired from the real-time clock, the delay time for the other layers of the video / audio output timing of each layer is calculated, and for the buffer unit of the layer not delayed The setting is made to increase the buffer amount corresponding to the calculated delay time.

  According to a fifth aspect of the present invention, in the digital broadcast receiving apparatus according to the fourth aspect, the output control unit holds a scene detection time of a scene detection signal output from the hierarchical scene detection unit for each layer, and the scene detection Time matching time is obtained by performing pattern matching comparison between the scene detection time obtained by shifting the scene detection time by the shift time and the scene detection time of another layer for a certain layer. The delay time of the output timing of the video / audio of a certain layer and the other layer is obtained from the number of.

  A sixth invention relates to the digital broadcast receiving apparatus according to the fifth invention, wherein, for a plurality of shift times, a time obtained by shifting the scene detection time by the shift time with respect to a certain layer, and another layer Pattern matching comparison is performed with the scene detection time, and the shift time that maximizes the number of matching times is set as the delay time of the video / audio output timing of one layer and another layer .

  The seventh invention relates to the digital broadcast receiving apparatus according to the second and fifth inventions, wherein pattern matching comparison is performed for all of the time intervals of one scene detection time of a certain layer and the time intervals of scene detection times of another layer. And the time interval with the matched pattern is used as the shift time of the scene detection time.

  The eighth invention relates to the digital broadcast receiving apparatus of the second, third, fifth, sixth and seventh inventions, and performs pattern matching comparison between the scene detection time and a time obtained by shifting the scene detection time by the shift time. When performing, or when performing pattern matching comparison between the time intervals of the scene detection times, the values match if they are within a predetermined threshold. Is.

  According to a ninth aspect of the present invention, in the digital broadcast receiver of the first or fourth aspect, the output control unit calculates a delay time for the other layers of the video / audio output timing of each layer a plurality of times, and is calculated. Further, the average value of the plurality of delay times is used as the delay time of the output timing of video / audio from other layers of each layer.

  According to a tenth aspect of the present invention, in the digital broadcast receiving apparatus according to the first or fourth aspect, the output control unit calculates a delay time of the video / audio output timing of each layer with respect to another layer a plurality of times. Among the plurality of delay times, the largest delay time is set as the delay time of the video / audio output timing from the other layers of each layer.

  According to the digital broadcast receiving apparatus of the present invention, the video / audio is interrupted when the user switches the hierarchy and views by adjusting the output timing by obtaining the delay time of the video / audio of each hierarchy. It is possible to provide a digital broadcast receiving apparatus that can be viewed smoothly and smoothly.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a digital broadcast receiving apparatus according to the present embodiment. As shown in FIG. 1, the digital broadcast receiving apparatus 100 according to the present embodiment includes an input terminal 101, a receiving unit 102, a packet separating unit 103, a strong layer buffer unit 104, a strong layer decoding unit 105, a weak layer buffer unit 106, a weak layer buffer, From hierarchy decoding section 107, strong hierarchy scene detection section 108, weak hierarchy scene detection section 109, video output selection section 110, video output terminal 111, audio output selection section 112, audio output terminal 113, output control section 114, and real time clock 115 Become.

  From the input terminal 101, a signal in which a plurality of video / audio / data is multiplexed and modulated and transmitted hierarchically is input. The receiving unit 102 performs demodulation processing and error correction processing on a signal input from the input terminal 101. The packet separation unit 103 selectively extracts desired video / audio / data from the multiplexed signal. The strong layer buffer unit 104 is a part for buffering the strong layer signal, and the strong layer decoding unit 105 decodes the strong layer signal. The weak layer buffer unit 106 is a part that buffers a weak layer signal, and the weak layer decoding unit 107 decodes the weak layer signal.

  The strong hierarchy scene detection unit 108 detects a scene change from the video signal decoded by the strong hierarchy decoding unit 105, while the weak hierarchy scene detection unit 109 detects from the video signal decoded by the weak hierarchy decoding unit 107. Detect scene changes.

  The video output selection unit 110 selects one of the video signals decoded by the strong layer decoding unit 105 and the weak layer decoding unit 107. The video output terminal 111 is a terminal that outputs the video signal selected by the video output selection unit 110.

  The audio output selection unit 112 selects one of the audio signals decoded by the strong layer decoding unit 105 and the weak layer decoding unit 107. The audio output terminal 113 is a terminal that outputs the audio signal selected by the audio output selection unit 112.

  The output control unit 114 adjusts the buffer amounts of the strong layer buffer unit 104 and the weak layer buffer unit 106 based on the signal indicating the scene change supplied from the strong layer scene detection unit 108 and the weak layer scene detection unit 109. The selection of the video output selection unit 110 and the audio output selection unit 112 is controlled.

  The real-time clock 115 provides real-time information that can be used by the receiver.

  Next, an operation example of matching the output timing of the video and audio of the strong hierarchy and the weak hierarchy will be described with reference to FIG.

  FIG. 2 is a diagram for explaining how the buffer amount of the weak layer is adjusted when the signal of the strong layer has a delay compared to the weak layer.

  A signal in which a plurality of video / audio / data is multiplexed and modulated and hierarchically transmitted is input to the input terminal 101, and the receiving unit 102 performs demodulation processing and error correction processing. Then, the packet separation unit 103 extracts the strong layer signal and supplies it to the strong layer buffer unit 104, while extracting the weak layer signal and supplies the weak layer signal to the weak layer buffer unit 106. The strong layer buffer unit 104 supplies the strong layer signal to the strong layer decoding unit 105 when the buffer becomes full. The strong hierarchy decoding unit 105 decodes the supplied strong hierarchy signal and outputs the strong hierarchy video and audio. Similarly, the weak layer buffer unit 106 supplies a weak layer signal to the weak layer decoding unit 107 when the buffer becomes full. The weak hierarchy decoding unit 107 decodes the supplied weak hierarchy signal and outputs video / audio of the weak hierarchy.

  Here, in order to eliminate the time lag between the video and audio output timings of the strong hierarchy and the weak hierarchy, for example, the output control unit 114 delays the video and audio of the weak hierarchy from the video and audio of the strong hierarchy. In such a case, the buffer amount of the strong layer buffer unit 104 is inserted by a delay time larger than the buffer amount of the buffer unit 106 of the weak layer. On the other hand, when the video / audio of the strong layer is delayed than the video / audio of the weak layer, the buffer amount of the weak layer buffer unit 106 is larger than the buffer amount of the strong layer buffer unit 104 by the delay time. insert.

For example, as shown in FIG. 2, when signals broadcast from a broadcasting station as scenes S ₀ , scenes S ₁ , scenes S ₂ ,... Are received, at the beginning of the scene S ₀ , FIG. It is assumed that the signal in the strong layer is delayed by 5 seconds compared with the signal in the weak layer in FIG. If the buffer amount of the weak layer buffer unit 106 is large enough to store data for 3 seconds, the buffer amount of the weak layer buffer unit 106 is 8 seconds by adding the size of 5 seconds for the delay. Adjust to have a minute size. As a result, the output of the weak layer signal is delayed from the weak layer buffer unit 106, and the difference in output timing between the strong layer signal and the weak layer signal is adjusted.

  The video output selection unit 110 selects one of the video signals decoded by the strong layer decoding unit 105 and the weak layer decoding unit 107 and outputs the selected video signal to the video output terminal 111. The audio output selection unit 112 selects one of the audio signals decoded by the strong layer decoding unit 105 and the weak layer decoding unit 107 and outputs the selected audio signal to the audio output terminal 113. Whether the video output selection unit 110 or the audio output selection unit 112 selects a strong hierarchy or a weak hierarchy is controlled by the output control unit 114 based on a user setting or a radio wave reception status.

  In this way, by adjusting the buffer amount of the strong hierarchy buffer unit 104 or the weak hierarchy buffer unit 106, the video / audio output timings of the strong hierarchy and the weak hierarchy can be matched. As a result, it is possible to smoothly switch the video and audio of the strong hierarchy and the weak hierarchy without a sense of incongruity.

  The output control unit 114 always monitors the signal indicating the scene change supplied from the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109 in the output control unit 114 for the time difference between the video and audio output timings of the strong hierarchy and the weak hierarchy. Based on the timing information when the signal indicating the scene change is received, the time difference between the output timings of the strong hierarchy and the weak hierarchy is obtained.

  It is assumed that the amount of output timing deviation between layers will vary depending on the broadcasting station and program contents, and there is also a means to know how much the output timing difference between layers occurs. Since it is not included in the broadcast signal, there is a problem that it is difficult to know on the conventional receiver side.

  In the present embodiment, scene detection is performed by the scene detection unit in each layer, and the difference in video / audio output timing between layers is obtained by comparing each layer.

  Then, by setting the buffer amount corresponding to the time lag in the strong hierarchy buffer unit 104 or the weak hierarchy buffer unit 106, it is possible to automatically match the video / audio output timings of the strong hierarchy and weak hierarchy.

  Next, a process for detecting a time lag between the video and audio output timings of the strong hierarchy and the weak hierarchy and adjusting the buffer amount of each buffer unit will be described with reference to FIGS.

  FIG. 3 is a diagram illustrating a data configuration stored in the display memory 200.

  Although not shown in FIG. 1, the digital broadcast receiving apparatus 100 includes a display memory 200 that stores the video signal decoded by the strong layer decoding unit 105 and the weak layer decoding unit 107.

  As shown in FIG. 3, the display memory 200 stores pixel information 201 corresponding to the number of pixels in the vertical direction and the horizontal direction. The pixel information 201 holds color information for the corresponding pixel on the display screen. In this embodiment, the color information is luminance signal information Y and color difference signal information Cb and Cr, and the color information of each pixel is output to the video output terminal 111.

  FIG. 4 is an explanatory diagram of the luminance value table 302 held by the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109 for detecting scene changes, and FIG. FIG. 4B shows the configuration of the luminance value table 302. The strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109 divide the area on the screen represented by the display memory 200 into 4 × 4 block areas 301 as shown in FIG. The average value of the luminance signal information Y of the pixels included in the block area 301 is obtained and stored in the corresponding position of the luminance value table 302 shown in FIG.

  In the present embodiment, an example is shown in which the area on the screen represented by the display memory 200 is divided into 4 × 4 block areas. However, the number of divisions of the area is appropriately changed depending on the balance between processing load and detection accuracy. It can be done. In general, the detection accuracy of a scene change can be increased by increasing the number of divisions of the area, but the required memory resources and the processing load increase accordingly. This may be done by determining an appropriate division number as a mounting problem related to the performance and cost of the digital broadcast receiving apparatus.

  Further, in this embodiment, an example in which the average value of the luminance signal information Y of the pixels included in each block region 301 is stored in the corresponding position of the luminance value table 302 is shown, but the information stored in the luminance value table 302 is The present invention is not limited to this, and color difference signal information Cb and Cr of pixels included in each block region 301 may be used.

  In order to detect a scene change, the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109, as shown in the flowchart of FIG. 5, convert the luminance value table 302 into the strong hierarchy decoding unit 105, the weak hierarchy decoding. Each frame of the video signal output from each of the units 107 is sequentially obtained (401a).

  Next, the value of each storage position in the obtained luminance value table 302 is compared with the value of the corresponding position in the luminance value table 302 one frame before, and a block area whose difference value exceeds the threshold defined by the system is determined. Check and obtain the number (402a).

  For each block area exceeding the threshold, it is checked whether the difference value obtained in step 402a is positive or negative, and the larger total number (positive or negative) is stored (403a). . When the total number is more positive, the luminance value of the image changes in the direction before and after the scene change occurs, and when the total number is more negative, the scene change occurs. This means that the brightness value of the image has changed in the direction of darkening before and after.

  Next, it is checked whether the number of block areas exceeding the threshold obtained in step 402a is larger or smaller than the number determined by the system (404a). If the number of block areas exceeding the threshold is greater than the number determined by the system, it is determined that the video scene has changed, and the scene change detection signal and before and after the scene change are output to the output control unit 114. Information indicating the brightness change direction (positive or negative) of the luminance value is notified (405a). On the other hand, if the number of block areas exceeding the threshold is smaller than the number determined by the system, it is determined that the scene has not changed, and the process ends without doing anything.

  By performing the above steps 401a to 405a for each frame of the video, the output control unit 114 determines the timing at which a scene change has occurred and the brightness change direction of the luminance value due to the scene change for each of the strong hierarchy and the weak hierarchy. You can know sequentially.

  Here, using FIGS. 6A and 6B, the scene change detection signal supplied from the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109 to the output control unit 114, and the brightness change direction of the luminance value. The notification method will be described.

  FIG. 6A is a diagram illustrating a case where the scene change detection signal and the brightness change direction of the luminance value are notified by dedicated signal lines. When the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109 (shown only in the strong hierarchy scene detection unit 108 in FIGS. 6A and 6B) detects the occurrence of a scene change, the scene change detection signal Sk, A pulse signal Sp indicating the direction of change in brightness value is simultaneously transmitted to each dedicated signal line.

  As for the pulse signal Sp indicating the brightness change direction of the luminance value, the pulse signal Sp is transmitted when it is positive (change in the brighter direction), and the pulse signal Sp is transmitted when negative (change in the darker direction). do not do.

  First, the output control unit 114 receives a scene change detection signal from a signal line that notifies the scene change detection signal Sk, and detects that a scene change has occurred. Next, when the scene change detection signal is received, the state of the signal line for notifying the pulse signal Sp indicating the brightness change direction of the luminance value is read. If the pulse signal Sp is generated, the brightness change direction is positive (brighter). If the pulse signal is not generated, it is detected that the light / dark change direction is negative (change in the dark direction).

  FIG. 6B is a diagram when the scene change detection signal and the brightness change direction of the luminance value are notified by the same signal line. When detecting a scene change, the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109 first transmits a scene change detection signal Sk, and then transmits a pulse signal Sp indicating the brightness change direction of the luminance value. However, similarly to the description in FIG. 6A, with respect to the brightness change direction of the luminance value, a pulse signal is transmitted when the brightness value is positive (change to a brighter direction), and negative (change to a darker direction). If not, do not send a pulse signal.

  Thereby, the output control unit 114 first receives the scene change detection signal Sk and detects that a scene change has occurred. After that, if the pulse signal Sp is received continuously after the scene change detection signal Sk, the light / dark change direction is positive (change to a brighter direction), and if the pulse signal Sp is not received continuously, the light / dark change direction is negative. It is detected that (change to the direction of darkening).

  6 (a) and 6 (b), regarding the pulse signal Sp indicating the brightness change direction of the luminance value, a pulse is generated when it is positive, and a pulse is not generated when it is negative. In addition, a pulse may not be generated when positive, and a pulse may be generated when negative.

Next, the processing of the output control unit 114 that has received the scene change detection signal Sk and the pulse signal Sp indicating the brightness change direction of the luminance value will be specifically described.
FIG. 7 shows the scene detection table 600a held by the output control unit 114 for each of the strong hierarchy and the weak hierarchy. For each of the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109, when the scene change detection signal Sk is received, the time is acquired from the real-time clock 115 and stored in # 1 of the scene detection time 601a. . At the same time, the information of the positive / negative pulse signal Sp indicating the brightness change direction of the brightness value is stored in # 1 of the brightness change state 602a. Further, a time difference from the scene detection time # 2 when the previous scene change detection signal Sk is received is obtained and stored in # 1 of the scene interval time 603a.

  In the example of FIG. 7, # 2 of the scene detection time 601a is “00:25”, and # 1 of the scene detection time 601a is “00:10”. Therefore, # 1 of the scene interval time 603a is “15” is stored.

  These values are stored in a FIFO (First In First Out) method. When a new scene change detection signal Sk is received and stored in # 1, the previous value is moved to the next index and is stored in the table. The oldest #Nth value is discarded.

  Here, the scene detection time 601a located at the same index in the scene detection table 600a and the luminance light / dark change direction 602a are set as one set and set as combination data 604a.

  FIG. 8 is a diagram illustrating a processing flow of the output control unit 114. When the output control unit 114 receives the scene change detection signal Sk and the positive / negative pulse signal Sp indicating the brightness change direction of the luminance value from the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109, the output control unit 114 is shown in FIG. Process 700a is executed.

  The output control unit 114 first acquires the time when the scene change detection signal Sk is received from the real-time clock 115 (701a).

  Next, it is determined whether the received scene change detection signal Sk is a strong hierarchy scene change detection signal or a weak hierarchy scene change detection signal (702a).

  When the received scene change detection signal Sk is a strong hierarchy scene change detection signal, the previous scene detection time is referred to from the strong hierarchy scene detection table 600a, and the difference time from the current scene detection time is obtained. (703a) As described with reference to FIG. 7, the scene detection time 601a, the luminance light / dark change direction 602a, and the scene interval time 603a are stored in # 1 of the scene detection table 600a in the strong hierarchy by the FIFO method. The Nth value is discarded (704a).

  When the received scene change detection signal Sk is a weak-layer scene change detection signal, the previous scene detection time is referred to from the weak-layer scene detection table 600a, and the difference time from the current scene detection time is referred to. (705a), as described with reference to FIG. 6, the scene detection time 601a, the luminance light / dark change direction 602a, and the scene interval time 603a are stored in # 1 of the scene detection table 600a in the weak hierarchy, as described in FIG. The old #Nth value is discarded (706a).

  After that, based on the updated scene detection table 600a, when the received scene change detection signal Sk is a strong hierarchy scene change detection signal, the strong hierarchy synchronization processing 800a is performed, and the received scene change detection signal is a weak hierarchy scene. In the case of a change detection signal, weak hierarchy synchronization processing 800a ′ is performed.

  Next, specific processing of the strong hierarchy synchronization processing 800a will be described with reference to the flowchart of FIG. For the weak hierarchy synchronization process 800a ', the "strong hierarchy" that appears in the description of the strong hierarchy synchronization process 800a may be read as "weak hierarchy".

  First, pattern matching comparison is performed for all entries of the scene interval time 603a # 1 in the strong layer scene detection table 600a and the scene interval time 603a of the weak layer scene detection table 600a (801a).

  If there is no matching weak hierarchy scene interval time 603a, it is determined that the delay time cannot be detected, and the process ends without doing anything (802a).

  On the other hand, if there is a matching weak-scene scene interval time 603a, a corresponding scene detection time 601a (belonging to the same # number) of the weak-scene scene interval time 603a is acquired, and a strong-hierarchy scene detection time 603a is obtained. The time difference between # 1 of 601a and # 1 is obtained and set as the base value of the delay time (803a).

  Next, the base value of the delay time obtained in step 803a is added to the scene detection time 601a of the strong hierarchy (804a). Then, a pattern matching comparison is performed between the combination data 604a of the strong hierarchy scene detection table 600a and the combination data 604a of the weak hierarchy scene detection table 600a to obtain the number of matching combination data 604a. (805a).

  In the procedure 801a, when there is another matching weak-scene scene interval time 603a (806a), the procedures 803a to 806a are repeatedly executed, and the number of each combination data 604a that matches is stored in the temporary memory. Keep it. After that, when there is no other weak hierarchical scene interval time 603a that matches, in step 805a, the base value of the delay time that maximizes the value of M is set as the detected delay time (807a).

  Since the value of the scene detection time 601a includes an error, when performing the pattern matching comparison of the steps 801a and 805a, a threshold value that allows for the error is set by the system, and when the value is compared, the value error is If the values are within the threshold value, the values may be regarded as matching.

  Subsequently, it is determined whether the difference between the delay time obtained in the procedure 807a and the delay time obtained in the past strong hierarchy synchronization process 800a or weak hierarchy synchronization process 800a ′ is larger or smaller than a threshold defined by the system ( 808a). If the difference is smaller than the threshold value, it is determined that there is no change from the delay time obtained in the past, and the process ends without doing anything. If the difference is larger than the threshold, it is determined that there has been a change from the delay time obtained in the past, and the video / audio output timings of the strong hierarchy and the weak hierarchy are corrected.

  Specifically, first, the decoding process of the decoding unit of the hierarchy not delayed is temporarily stopped (809a). Then, in accordance with the positive and negative base values of the delay time, the buffer capacity corresponding to the time corresponding to the delay is set to increase toward the buffer portion of the hierarchy that is not delayed (810a). Then, the decoding process of the decoding unit stopped in step 809a is resumed (811a).

  By executing the above processing, it is possible to always match the video / audio output timings of the strong hierarchy and the weak hierarchy.

  Hereinafter, a second embodiment will be described. In this example, the overall configuration is the same as the configuration of the first embodiment shown in FIG. 1, and is the same operation except for the operation of the output control unit 114. Therefore, in the present embodiment, the output control unit 114 that has received the scene change detection signal Sk output from the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109 and the pulse signal Sp indicating the brightness change direction of the luminance value. The process will be described. The output control unit 114 also holds the scene detection table 600a shown in FIG. 7 for each of the strong hierarchy and the weak hierarchy, and the operation is the same as the flow shown in FIG. However, since the operations of the strong hierarchy synchronization process 800a and the weak hierarchy synchronization process 800a ′ in FIG. 8 are different from those in the first embodiment, the strong hierarchy synchronization process 800a is set to 800b, and the weak hierarchy synchronization process 800a ′ is set to 800b ′. Only the processing of this part will be described.

  The specific processing of the strong hierarchy synchronization processing 800b will be described with reference to the flowchart of FIG. As for the weak hierarchy synchronization process 800b ', the "strong hierarchy" that appears in the description of the strong hierarchy synchronization process 800b may be read as "weak hierarchy".

  First, pattern matching comparison is performed on the continuous M pieces of combination data from # 1 to #M of the combination data 604a in the strong layer scene detection table 600a and the combination data 604a of the weak layer scene detection table 600a. (801b). If there is no matching weak hierarchy combination data 604a, it is determined that the delay time cannot be detected, and the process ends without doing anything (802b).

  If there is matching weak hierarchy combination data 604a, the latest scene detection time 601a closest to the current time is acquired from the detected M combination data 604a of the weak hierarchy, and strong hierarchy scene detection is performed. A time difference from # 1 at time 601a is calculated, and this is set as a delay time (803b).

  Note that since the value of the scene detection time 601a includes an error, when performing pattern matching comparison in the procedure 801b, a threshold value that allows for an error is set by the system, and when comparing values, the value error is within the threshold value. It may be considered that the values match with each other.

  Subsequently, it is determined whether the difference between the delay time obtained in step 803b and the delay time obtained in the past strong hierarchy synchronization process 800b or weak hierarchy synchronization process 800b 'is larger or smaller than a threshold (804b).

  If the difference is smaller than the threshold value, it is determined that there is no change from the delay time obtained in the past, and the process ends without doing anything. If the difference is larger than the threshold, it is determined that there has been a change from the delay time obtained in the past, and the video / audio output timings of the strong hierarchy and the weak hierarchy are corrected.

Specifically, first, the decoding process of the decoding unit of the hierarchy not delayed is temporarily stopped (805b). Then, in accordance with the positive and negative base values of the delay time, the buffer capacity corresponding to the delay time is set to increase toward the buffer portion of the hierarchy that is not delayed (806b). Then, the decoding process of the decoding unit stopped in step 805b is resumed (807b).
By executing the above processing, it is possible to always match the video / audio output timings of the strong hierarchy and the weak hierarchy.

  The third embodiment will be described below. In this example, the overall configuration is the same as that of the first embodiment shown in FIG. 1, and the operation is the same as that of the strong hierarchy scene detection unit 108, the weak hierarchy scene detection unit 109, and the output control unit 114. All are the same except. In addition, since the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109 perform the same process up to the generation of the luminance value table 302 shown in FIG. Processing will be described.

  In order to detect a scene change, the strong hierarchy scene detection unit 108 and the weak hierarchy scene detection unit 109, as shown in the flowchart of FIG. 11, store the luminance value table 302, the strong hierarchy decoding unit 105, and the weak hierarchy decoding. Each frame of the video signal output from each of the units 107 is sequentially obtained (401b).

  Next, the calculated value of each storage position in the brightness value table 302 is compared with the value of the corresponding position in the brightness value table 302 one frame before, the difference value is positive, and the absolute value of the difference value is a threshold value. The exceeding block area is checked and its number is obtained (402b).

  It is checked whether the number of block areas obtained in step 402b is larger or smaller than the number determined by the system (403b).

  If the number of block areas exceeding the threshold is greater than the number determined by the system, it is determined that the video scene has changed and that the luminance value of the video has changed in the direction of increasing brightness before and after the scene change. A scene change detection signal is supplied to the control unit 114 (404b).

  By performing the processing of steps 401b to 404b for each frame of the video, the output control unit 114 can change the scene only when a scene change occurs in the direction in which the luminance value becomes brighter for each of the strong layer and the weak layer. The timing when the change occurs can be known sequentially.

  In the present embodiment, the example in which the number of block areas in which the difference value is positive and the absolute value of the difference value exceeds the threshold defined by the system is obtained in the step 402b. However, the difference value is negative. In addition, the number of block areas in which the absolute value of the difference value exceeds a threshold defined by the system may be obtained. In this case, the output control unit 114 can sequentially know the timing at which a scene change has occurred for each of the strong hierarchy and the weak hierarchy only when a scene change occurs in a direction in which the luminance value of the screen becomes darker.

Next, the processing of the output control unit 114 that has received the scene change detection signal Sk will be specifically described.
FIG. 12 shows a scene detection table 600b held by the output control unit 114. Each of the strong hierarchy and the weak hierarchy has this scene detection table 600b. When the scene change detection signal Sk is received for each, the time is acquired from the real-time clock 115 and stored in # 1 of the scene detection time 601b. . Further, a time difference from the scene detection time # 2 when the previous scene change detection signal Sk is received is obtained and stored in # 1 of the scene interval time 603b.

  These values are stored in a FIFO manner, and when a new scene change detection signal Sk is received and stored in # 1, the previous value is moved to the next index and the oldest #Nth in the table. The value is discarded.

  FIG. 13 is a diagram illustrating a processing flow of the output control unit 114. When the output control unit 114 receives the scene change detection signal Sk from the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109, the process 700b shown in FIG. 13 below is executed.

  The output control unit 114 first acquires the time when the scene change detection signal Sk is received from the real-time clock 115 (701b).

Next, it is determined whether the received scene change detection signal Sk is a strong hierarchy scene change detection signal or a weak hierarchy scene change detection signal (702b).
When the received scene change detection signal Sk is a strong hierarchy scene change detection signal, the previous scene detection time is referred to from the strong hierarchy scene detection table 600b, and the difference time from the current scene detection time is obtained. (703b), as described with reference to FIG. 12, the scene detection time 601b and the scene interval time 603b are stored in # 1 of the scene detection table 600b in the strong hierarchy by the FIFO method, and the oldest # N-th value is discarded. (704b).

  In addition, when the received scene change detection signal Sk is a weak hierarchy scene change detection signal, the previous scene detection time is referred to from the weak hierarchy scene detection table 600b, and the difference time from the current scene detection time is referred to. (705b), and as described with reference to FIG. 12, the scene detection time 601b and the scene interval time 603b are stored in # 1 of the weak hierarchy scene detection table 600b by the FIFO method, and the oldest #Nth value is stored. Is discarded (706b).

  Thereafter, based on the updated scene detection table 600b, when the received scene change detection signal Sk is a strong hierarchy scene change detection signal, the strong hierarchy synchronization processing 800c is performed, and the received scene change detection signal is a weak hierarchy scene change. In the case of a detection signal, weak hierarchy synchronization processing 800c ′ is performed.

  Next, specific processing of the strong hierarchy synchronization processing 800c will be described with reference to the flowchart of FIG. For the weak hierarchy synchronization process 800c ', the "strong hierarchy" that appears in the description of the strong hierarchy synchronization process 800c may be read as "weak hierarchy".

First, pattern matching comparison is performed for all entries of the scene interval time 603b # 1 in the strong hierarchy scene detection table 600b and the scene interval time 603b of the weak hierarchy scene detection table 600b (801c).
If there is no matching weak hierarchy scene interval time 603b, it is determined that the delay time cannot be detected, and the process ends without doing anything (802c).

  On the other hand, if there is a matching weak layer scene interval time 603b, the corresponding scene detection time 601b (belonging to the same # number) of the detected weak layer scene interval time 603b is acquired, and the strong layer scene detection time 603b is obtained. The time difference between # 1 of 601b and # 1 is obtained and used as the base value of the delay time (803c).

Next, the base value of the delay time is added to the scene detection time 601b of the strong hierarchy (804c). Then, pattern matching comparison is performed between the scene detection time 601b of the strong hierarchy and the scene detection time 601b of the weak hierarchy, the number of matching patterns is obtained, and this is set as M (805c).
If there is another matching weak scene interval time 603b in the step 801c (806c), the steps 803c to 806c are repeatedly executed, and the number of the respective combination data 604a that matches each other is stored in the temporary memory. Keep it. After that, when there is no other weak hierarchical scene interval time 603b that matches, in step 805c, the base value of the delay time that maximizes the value of M is set as the detected delay time (807c).

  Since the value of the scene detection time 601b includes an error, when performing pattern matching comparison in steps 801c and 805c, a threshold value that allows for error is set by the system, and when comparing values, the value error If the values are within the threshold value, the values may be regarded as matching.

  Subsequently, it is determined whether the difference between the delay time obtained in the procedure 807c and the delay time obtained in the past strong hierarchy synchronization processing 800c or weak hierarchy synchronization processing 800c ′ is larger or smaller than a threshold defined by the system ( 808c). If the difference is smaller than the threshold value, it is determined that there is no change from the delay time obtained in the past, and the process ends without doing anything. If the difference is larger than the threshold, it is determined that there has been a change from the delay time obtained in the past, and the video / audio output timings of the strong hierarchy and the weak hierarchy are corrected.

  Specifically, first, the decoding process of the decoding unit of the hierarchy not delayed is temporarily stopped (809c). Then, in accordance with the positive and negative base values of the delay time, the buffer capacity corresponding to the time corresponding to the delay is set to increase toward the buffer portion of the hierarchy that is not delayed (810c). Then, the decoding process of the decoding unit stopped in step 809c is resumed (811c).

  By executing the above processing, it is possible to always match the video / audio output timings of the strong hierarchy and the weak hierarchy.

  Hereinafter, a fourth embodiment will be described. In this example, the overall configuration is the same as that of the third embodiment, and the same operation is performed except for the operation of the output control unit 114. Therefore, here, the processing of the output control unit 114 that receives the scene change detection signal Sk output from the strong hierarchy scene detection unit 108 or the weak hierarchy scene detection unit 109 will be described. In the present embodiment, the output control unit 11 also holds the scene detection table 600b shown in FIG. 12 for each of the strong hierarchy and the weak hierarchy, and has the same operation as the flow shown in FIG. Since operations other than the strong hierarchy synchronization process 800c and the weak hierarchy synchronization process 800c ′ in FIG. 13 are the same, the strong hierarchy synchronization process 800c is set to 800d, and the weak hierarchy synchronization process 800c ′ is set to 800d ′. To do.

  A specific process of the strong hierarchy synchronization process 800d will be described with reference to the flowchart of FIG. For the weak hierarchy synchronization process 800d ', the "strong hierarchy" that appears in the description of the strong hierarchy synchronization process 800d may be read as "weak hierarchy".

  First, pattern matching comparison is performed for the M consecutive scene detection times 601b from # 1 to #M in the scene detection table 600b in the strong hierarchy and the scene detection times 601b in the scene detection table 600b in the weak hierarchy (801d). If the matching scene detection time 601b of the weak hierarchy does not exist, it is determined that the delay time cannot be detected, and the process ends without doing anything (802d).

  When the matching scene detection time 601b of the weak hierarchy exists, the scene detection time 601b of the latest time closest to the current time is acquired from the detected M scene detection times 601b of the weak hierarchy, and the scene detection of the strong hierarchy is performed. A time difference from # 1 at time 601a is calculated and set as a delay time (803d).

  Since the value of the scene detection time 601b includes an error, when performing the pattern matching comparison in the procedure 801d, a threshold value that allows for the error is set by the system, and when the value comparison is performed, the value error is within the threshold value. It may be considered that the values match with each other.

  Subsequently, it is determined whether the difference between the delay time obtained in the procedure 803d and the delay time obtained in the past strong hierarchy synchronization process 800d or weak hierarchy synchronization process 800d ′ is larger or smaller than a threshold defined by the system ( 804d). If the difference is smaller than the threshold value, it is determined that there is no change from the delay time obtained in the past, and the process ends without doing anything. If the difference is larger than the threshold, it is determined that there has been a change from the delay time obtained in the past, and the video / audio output timings of the strong hierarchy and the weak hierarchy are corrected.

  Specifically, first, the decoding process of the decoding unit of the hierarchy not delayed is temporarily stopped (805d). Then, in accordance with the positive and negative base values of the delay time, the buffer capacity corresponding to the time corresponding to the delay is set to increase toward the buffer portion of the hierarchy that is not delayed (806d). Then, the decoding process of the decoding unit stopped in step 805d is resumed (807d).

  By executing the above processing, it is possible to always match the video / audio output timings of the strong hierarchy and the weak hierarchy.

  In the first to fourth embodiments, in order to detect delay time with higher accuracy, for example, first, the delay time obtained by the output control unit 114 is held in a memory, The process ends without correcting the output timing of the video / audio of the weak hierarchy. This is repeated every time a scene change detection signal is received, and a plurality of delay time values are collected. Of the collected delay times, the delay time with the largest number of the same delay times may be used as the final delay time. Alternatively, an average value of a plurality of collected delay times may be used as the final delay time.

  The user cannot temporarily view the television program until the decoding process of the strong hierarchy or the weak hierarchy is temporarily stopped, the buffer memory is set, and the decoding process is restarted. In order to avoid this, for example, when correcting the delay time of the strong hierarchy, this time is forcibly switched to the weak hierarchy and received. Conversely, when correcting the delay time of the weak layer, this time can be forcibly switched to the strong layer and received, thereby avoiding a situation in which the user cannot temporarily view the television program.

  Operations of the video output selection unit 110 and the audio output selection unit 112 immediately after channel selection in this case will be described. For example, if the strong layer is delayed from the weak layer, increasing the video / audio buffer amount of the weak layer will take time until the buffer becomes full.・ There is a problem that it takes time to start outputting audio. Therefore, immediately after channel selection, the video and audio of the strong hierarchy are forcibly output, and when the video and audio of the weak hierarchy can be output, the video and audio are switched to the video and audio of the weak hierarchy for the first time.

  First, immediately after channel selection, the output control unit 114 controls the video output selection unit 110 and the audio output selection unit 112 so as to output video / audio of a higher hierarchy. Thereafter, when the output control unit 114 detects that the buffer of the weak layer buffer unit 106 is full, the output control unit 114 causes the video output selection unit 110 and the audio output selection unit 112 to output the video / audio of the weak layer. Control. In this way, the video and audio of the strong hierarchy are output immediately after the channel selection, and the output can be switched to the video and audio of the weak hierarchy when the output timing of the weak hierarchy matches the strong hierarchy.

  In this way, by adjusting the video and audio buffer amounts of the weak and strong layers, the output timing of the weak and strong layers can be adjusted, and when switching between the weak and strong layers, video and audio are output. Can be switched smoothly. In addition, immediately after the channel selection, by outputting the video and audio of the strong hierarchy, the video / audio output start can be presented without delay.

  That is, a viewer who wants to watch a video with a low-level signal with good quality, instead of temporarily viewing the video with a high-level signal with poor video quality, Video can be provided.

  In the first to fourth embodiments, the output timing is synchronized between the two layers, the weak layer and the strong layer. By providing the scene detection unit in the output timing, the output timing can be synchronized.

  Furthermore, in the first to fourth embodiments, description has been given by taking as an example the reception of a broadcast in which a program having the same content is transmitted by the concept of calling video / audio a hierarchy, but even if it does not fall under the concept of a hierarchy, In the case where programs having the same contents are transmitted in a plurality of channels in parallel, an embodiment in which output timing is synchronized between the plurality of channels is also conceivable.

  In the first to fourth embodiments, an example in which a time lag between the output timings of the video and audio of the strong hierarchy and the weak hierarchy is detected for each frame of the video signal has been shown. When configured, this time lag detection process may be performed for each field.

Furthermore, in the first to fourth embodiments, the output control unit 114 indicates the processing procedure depending on whether the scene change detection signal is a strong hierarchy or a weak hierarchy, but is sent from a broadcasting station in advance. If it is known which of the output timings of the strong hierarchy and the weak hierarchy is delayed, only one processing procedure needs to be executed. For example, when it is known that the weak hierarchy is delayed compared to the strong hierarchy, if the scene change detection signal is the weak hierarchy, the output control unit 114 executes the processing of the above embodiment, If the scene change detection signal is a strong hierarchy, the process ends without doing anything.
Conversely, if it is known that the strong hierarchy is delayed compared to the weak hierarchy, and the scene change detection signal is the strong hierarchy, the output control unit 114 performs the processing of the above embodiment. If the scene change detection signal is in a weak hierarchy, the process ends without doing anything.

  The present invention can be applied to a receiver having a function of switching and receiving broadcasts in which a plurality of videos / audios having the same contents are transmitted in parallel.

It is a block diagram of the digital broadcast receiver in the 1st to 4th embodiment concerning the present invention. It is a figure explaining a mode that the buffer amount of a weak hierarchy is adjusted when the signal of a strong hierarchy has a delay compared with a weak hierarchy. It is the figure which showed the data structure stored in the display memory 200 in the 1st to 4th embodiment which concerns on this invention. It is a figure explaining the relationship between the contents stored in the display memory 200 and the luminance value table in the first to fourth embodiments according to the present invention. It is a figure which shows the process in which the strong hierarchy scene detection part and the weak hierarchy scene detection part 109 in the 1st and 2nd embodiment which concern on this invention supply a scene change detection signal and the brightness change direction of a luminance value. In the 1st and 2nd embodiment which concerns on this invention, it is a figure which shows the method to notify the output control part 114 of the scene change detection signal and the brightness change direction of a luminance value. It is a figure explaining the scene detection table 600a in the 1st and 2nd embodiment which concerns on this invention. It is a figure which shows the process of the output control part 114 in 1st and 2nd embodiment which concerns on this invention. It is a figure which shows the detail of the strong hierarchy synchronous process 800a in 1st Embodiment based on this invention. It is a figure which shows the detail of the hierarchy synchronous process 800b in 2nd Embodiment which concerns on this invention. It is a figure which shows the process in which the strong hierarchy scene detection part and the weak hierarchy scene detection part 109 in the 3rd and 4th embodiment which concern on this invention supply a scene change detection signal. It is a figure explaining the scene detection table 600b in the 3rd and 4th embodiment which concerns on this invention. It is a figure which shows the process of the output control part 114 in the 3rd and 4th embodiment which concerns on this invention. It is a figure which shows the detail of the strong hierarchy synchronous process 800c in 3rd Embodiment which concerns on this invention. It is a figure which shows the detail of the strong hierarchy synchronous process 800d in 4th Embodiment based on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Digital broadcast receiver 101 ... Input part 102 ... Receiving part 103 ... Packet separation part 104 ... Strong hierarchy buffer part 105 ... Strong hierarchy decoding part 106 ... Weak hierarchy buffer part 107 ... Weak hierarchy decoding part , 108 ... Strong hierarchy scene detection unit, 109 ... Weak hierarchy scene detection unit, 110 ... Video output selection unit, 111 ... Video output terminal, 112 ... Audio output selection unit, 113 ... Audio output terminal, 114 ... Output control unit, 115 ... real time clock, 200 ... display memory, 201 ... pixel information, 301 ... block area, 302 ... luminance value table, 400a, 400b ... scene detection processing, 600a, 600b ... scene detection table, 601a, 601b ... scene detection time, 602a ... Brightness / darkness change direction, 603a, 603b ... Scene interval time, 700a, 700b ... Output control Parts processing, 800a~800d ... strong hierarchical synchronization processing, 800a'~800d '... weak hierarchical synchronization process.

Claims (6)

A receiving unit that receives and demodulates a signal that has been multiplexed and modulated with a plurality of video and audio signals and transmitted hierarchically;
A packet separator that separates a necessary signal from the signal demodulated by the receiver;
A buffer unit for each layer that temporarily stores signals of each layer separated by the packet separation unit;
A layer decoding unit for each layer that decodes a signal temporarily stored in the buffer unit for each layer;
An output selection unit that selects video / audio of any one layer from the video / audio of each layer decoded by the layer decoding unit for each layer;
The video / audio of each hierarchy decoded by the hierarchy decoding unit for each hierarchy is monitored, and the information on the increase / decrease of the signal value of the video / audio signal before and after the scene change timing of each hierarchy And a hierarchical scene detection unit that outputs a scene detection signal and increase / decrease information ,
An output control unit that switches the selection of the output selection unit,
The output control unit sets a scene detection time of a scene detection signal output from the hierarchy scene detection unit and a scene change direction indicating the increase / decrease information, and holds this for each hierarchy,
Obtaining the shift time of the scene detection time,
A combination of the scene detection time obtained by shifting the scene detection time by the shift time with respect to a certain hierarchy and the scene change direction, and a combination of a scene detection time and a scene change direction of another hierarchy. Perform pattern matching comparison,
From the number of matched combinations, the delay time of the video / audio output timing of one layer and the other layer is obtained, and the buffer amount corresponding to the obtained delay time is determined for the buffer portion of the layer that is not delayed. A digital broadcast receiver characterized by being set to increase. For a plurality of shift times, a combination of the scene detection time obtained by shifting the scene detection time by the shift time with respect to a certain hierarchy and the scene change direction, and a scene detection time and a scene change in another hierarchy Pattern matching comparison is performed by combination with direction, and the shift time that maximizes the number of matched combinations is set as the delay time of video / audio output timing of one layer and another layer The digital broadcast receiver according to claim 1 . A receiving unit that receives and demodulates a signal that has been multiplexed and modulated with a plurality of video and audio signals and transmitted hierarchically;
A packet separator that separates a necessary signal from the signal demodulated by the receiver;
A buffer unit for each layer that temporarily stores signals of each layer separated by the packet separation unit;
A layer decoding unit for each layer that decodes a signal temporarily stored in the buffer unit for each layer;
An output selection unit that selects video / audio of any one layer from the video / audio of each layer decoded by the layer decoding unit for each layer;
The video / audio of each layer is monitored by the hierarchical decoding unit for each layer, and the scene changes only when the signal value of the video / audio signal of each layer changes in either the increasing or decreasing direction. A hierarchical scene detection unit that detects the timing of and outputs as a scene detection signal;
An output control unit that switches the selection of the output selection unit,
The output control unit holds the scene detection time of the scene detection signal output from the hierarchy scene detection unit for each hierarchy,
Obtaining the shift time of the scene detection time,
A pattern matching comparison is performed between the scene detection time obtained by shifting the scene detection time by the shift time and a scene detection time of another hierarchy with respect to a certain hierarchy. A digital broadcast characterized in that a delay time of a video / audio output timing of a hierarchy is obtained and a buffer amount corresponding to the obtained delay time is set to be increased with respect to a buffer section of a hierarchy that is not delayed Receiver device. For a plurality of shift times, for a certain layer, perform a pattern matching comparison between the time when the scene detection time is shifted by the shift time and the scene detection time of another layer,
4. The digital broadcast receiving apparatus according to claim 3 , wherein the shift time for maximizing the number of coincident times is set as a delay time of video / audio output timing of a certain hierarchy and another hierarchy . Pattern matching comparison is performed for all the time intervals of one scene detection time of a certain layer and the time intervals of scene detection time of another layer,
4. The digital broadcast receiving apparatus according to claim 1 , wherein a time interval with the matched pattern is set as a shift time of the scene detection time . When performing pattern matching comparison between the scene detection time and the time when the scene detection time is shifted by the shift time, or when performing pattern matching comparison between the time intervals of the scene detection time,
6. The digital broadcast receiving apparatus according to claim 1 , wherein when the values to be compared with each other are within a predetermined threshold, the values are matched .

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