JP2007074228A - Video program receiver for performing low-delay digital encoded video switching, and transmitting/receiving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video program receiver and a transmitting/receiving system, in which delay in video display which may be generated at the time of switching video programs can be reduced in the distribution service of a plurality of video programs based on digital video encoding. <P>SOLUTION: When a user executes zapping, a control part 150 in the video program receiver 100 changes a switch 140 at the timing of the zapping, and while using a video image of a changed channel up-converted in a service program as a reference frame, outputs a selected program image of the changed channel. Consequently images can be continuously displayed in a fixed small delay which is the processing time of a segmenting device 120 and an up converter 130 during zapping. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology in which a receiving device that receives a plurality of video programs provides a viewing service by switching the programs, and more particularly, to a technology for reducing a delay in video display that occurs when switching video programs.

  In general, an encoding technique used for a digital video program distribution service achieves high compression by using temporal correlation of video signals. In this case, the receiving apparatus stores the decoded video of a plurality of frames in a storage unit such as a memory in the receiving apparatus, and refers to the decoded video of the stored frame, thereby decoding the video of other frames. Process. Therefore, the receiving apparatus cannot normally decode the video of the subsequent frame in a state where the decoded video is not stored in the storage unit.

  On the other hand, in the recent coding technology, it is possible to normally decode the video of the frame independently without referring to other frames at an appropriate time interval. It is designed to realize such encoding. A frame encoded by this encoding method is referred to as an intra encoded frame. When the internal memory is reset when the internal memory is started up, the receiving apparatus can normally perform the decoding process from the time when the intra-encoded frame is received thereafter (see Non-Patent Document 1).

  However, in an encoding technique using an intra-encoded frame, a receiving device that receives a plurality of video programs by a distribution service changes from the start of the switching operation when switching from the program of the video program being received to another program. The video cannot be displayed until the intra-coded frame of the program is received. For this reason, a certain time lag occurs between the start of the switching operation and the video display.

  In addition, in the OFDM modulation method used in terrestrial digital broadcasting, modulation / demodulation is based on FFT or the like, so that a processing delay that cannot be ignored during demodulation occurs. For example, in current digital broadcasting, an intra-encoded frame is sent once every 0.5 seconds at the longest, so that there is a case where a video is not displayed for a maximum of 0.5 seconds when switching programs. In the case of digital terrestrial broadcasting, a delay in the demodulation described above is further added, so that there is a time lag of several seconds from the start of the program switching operation to the video display. That is, there is a delay of several seconds from the program switching until the service is normally reproduced. Due to such a delay, the user cannot easily perform a zapping action (an action of quickly changing channels) that is possible in analog broadcasting, and the usability is deteriorated.

  In order to improve such a usability problem regarding zapping, the receiving device may receive all the video programs that are the target of the distribution service and continue to update all the intra-encoded frames that are reference frames. Conceivable. However, this method requires a tuner for each channel of the video program, and also requires a storage unit for storing the reference frames of all video programs. For this reason, the cost of the receiving apparatus is increased and the circuit scale is increased, which is difficult to realize (for example, see Patent Document 1).

Kameyama, 1 other, "IDG Information Communication Series MPEG-1 / MPEG-2 / MPEG-4 Digital Broadcasting Textbook (above)", IDG Japan, February 1, 2003 JP 2000-101467 A

  Accordingly, the present invention has been made in view of the background art described above, and an object of the present invention is to reduce a video display delay caused when switching video programs in a distribution service for a plurality of video programs performed by digital video encoding. It is an object of the present invention to provide a video program receiving apparatus and a transmission / reception system that can be used.

  A video program receiving apparatus according to the present invention receives encoded video signals of a plurality of programs and a reduced video signal of a zapping program, selects one of the plurality of programs, and selects the selected A video program receiving apparatus for generating an output signal by decoding a video signal and generating an output signal using the video signal of the zapping program at the time of zapping, wherein one of the received programs A first tuner that outputs a video signal of the selected program and outputs identification information of the selected program; a second tuner that outputs a video signal of the received zapping program; Of the video signal of the zapping program output by the second tuner, the identification information of the program And a switching signal for switching to the second tuner side when it is determined that the program switching has occurred based on the identification information of the program output by the first tuner And a switch for generating the output signal using the video signal enlarged by the enlargement unit in response to a switching signal output from the control unit to the second tuner side. It is characterized by.

  The video program receiving apparatus according to the present invention further includes a storage unit for storing a reference frame of the video, performs a motion compensation prediction process using the reference frame stored in the storage unit, and generates the output signal. In this case, when the control unit determines that the program switching has occurred based on the program identification information output by the first tuner, it outputs a switching signal for switching to the second tuner side. When the reference frame after switching is recognized for the video signal of the program output by the first tuner, a switching signal for switching to the first tuner is output, and the switch is switched by the control unit. When the signal is a switching signal to the second tuner side, the switched video signal enlarged by the enlargement unit Stored in the storage unit, when a switching signal to the first tuner side is characterized by storing a reference frame in the video signal of the program that is output by the first tuner in the storage unit.

  In the video program receiving apparatus according to the present invention, when the control unit determines that the program switching has occurred based on the identification information of the program output by the first tuner, When the switching signal is output and the reference frame after switching is recognized for the video signal of the program output by the first tuner, the switching signal is output to the first tuner, and the switch controls When the switching signal output by the unit is a switching signal to the second tuner side, the video signal after switching enlarged by the enlargement unit is used as the output signal, and the switching signal to the first tuner side is In some cases, the output signal is a signal obtained by decoding the video signal of the program output by the first tuner. And wherein the door.

  The video program receiving apparatus according to the present invention is characterized in that the video signal of the zapping program is a video signal of an uncompressed video distribution program having a different angle of view.

  The video program transmission / reception system according to the present invention is a video program receiving apparatus, a video program distributing apparatus for distributing a video signal obtained by encoding the plurality of programs and a video signal of a reduced zapping program to the video program receiving apparatus. It is characterized by comprising.

  According to the present invention, when a plurality of video programs are distributed by digital video encoding, the video signal of the zapping program on the second tuner side is used when switching the video program. It is possible to reduce the delay. That is, zapping can be easily realized. Further, the video program receiving apparatus does not need to be provided with a tuner for each program, and it is not necessary to provide a storage unit for storing a reference frame for each program, so that the cost and the circuit scale can be reduced. It becomes possible.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment of the present invention is an example using the MPEG-2 encoding method. FIG. 1 is a diagram showing a configuration of a video program distribution apparatus according to an embodiment of the present invention. The video program distribution device 1 includes delay units 2-1 to 6, encoders 3-1 to 6, a multi-screen generation device 4, an encoder 5, and a multiplexer 6. The delay units 2-1 to 6 have a delay memory for generating a delay time corresponding to the processing time of the multi-screen generating apparatus 4, and each of the programs 1 to 6 is input and a delay is generated by the delay memory. . As a result, the multiplexer 6 can achieve video synchronization between the programs 1 to 6 and the multi-screen service program. The encoders 3-1 to -6 receive the programs 1 to 6 delayed by the delay units 2-1 to -6, respectively, perform encoding processing, generate an ES (Elementary Stream), and the multiplexer 6 A TS (Transport Stream) for multiplexing is output.

  The multi-screen generating device 4 inputs the programs 1 to 6 and generates a service program that divides each of the programs 1 to 6 into one image. The encoder 5 receives the service program generated by the multi-screen generating device 4 and performs an encoding process. The multiplexer 6 inputs the programs encoded by the encoders 3-1 to 6, respectively, receives the service program encoded by the encoder 5, performs multiplexing processing, and multiplexes TS is generated. The video program distribution device 1 sends the multiplexed TS generated in this way to a network from a transmitting station or the like where the video program distribution device 1 is provided. Thereby, the video program distribution apparatus 1 can always transmit the above-mentioned service program in real time using the service channel. For example, CATV realizes a service for introducing a program distributed by the company by a method similar to the above-described service program.

  In FIG. 1, the video program distribution apparatus 1 includes six delay units 2-1 to 6 and encoders 3-1 to 6 corresponding to six programs 1 to 6, respectively. The number is not fixed, and it is assumed that the delay unit 2 and the encoder 3 corresponding to the number of programs targeted for the program distribution service are provided.

  FIG. 2 is a diagram illustrating a configuration of the multi-screen generation device 4 illustrated in FIG. For convenience of explanation, the configuration of the multi-screen generation device 4 corresponding to the four programs 1 to 4 is shown. The multi-screen generation device 4 includes down converters 7-1 to -4 and a screen synthesis unit 8. The down converters 7-1 to -4 input the programs 1 to 4, respectively, and down-convert (reduce) the programs 1 to 4. The screen synthesis unit 8 inputs the programs reduced by the down converter 7 and arranges the screens of the programs on one screen. That is, a service program is generated by dividing each input program into one image.

  Hereinafter, the configuration and operation of the video program receiving device in a system constituted by the video program distributing device and the video program receiving device described later will be described separately in the first, second, and third embodiments. In the first to third embodiments, the video program receiving apparatus reduces the delay in video display when switching a program (channel switching) with a first tuner for selecting one of a plurality of programs. And a second tuner.

  In the first embodiment, at the time of program switching, the video on the service program side (second tuner side) is stored as a reference frame in a video memory, motion compensation prediction is performed using the reference frame, and the video is output as a zapping video. . In the second embodiment, the video on the service program side is output as the video at the time of zapping when the program is switched. In the third embodiment, at the time of program switching, the video on the uncompressed video distribution program side (second tuner side) is output as the video at the time of zapping. Hereinafter, Examples 1 to 3 will be described in detail.

  First, Example 1 will be described. FIG. 3 is a diagram showing the configuration of the video program receiving apparatus according to the first embodiment of the present invention. This video program receiving apparatus 100 includes a delay unit 11, a tuner 12, a variable length decoding unit 13, an inverse quantization unit 14, an inverse orthogonal transform unit 15, an adder 16, a motion compensation prediction unit 17, a video memory 18, and a format conversion unit. 19, tuner 112, variable length decoding unit 113, inverse quantization unit 114, inverse orthogonal transform unit 115, adder 116, motion compensation prediction unit 117, video memory 118, clipping device 120, upconverter 130, switch 140, and control Part 150 is provided. In FIG. 3, the delay unit 11 to the format conversion unit 19 shown in the upper part of the drawing have a function of selecting one of a plurality of programs and decoding the video of the program. On the other hand, from the tuner 112 to the up-converter 130 shown in the lower part of the drawing, the video of one program out of the video of the service program is cut out and up-converted (enlarged), and the video is used as a reference frame. Has a function to use the video generated by zapping at the time of zapping, that is, a low delay switching function. The switch 140 and the control unit 150 are used to realize a low delay switching function.

  When the video program receiving device 100 receives the multiplexed TS sent from the video program distribution device 1, the delay unit 11 inputs the multiplexed TS, and delay processing corresponding to the processing of the clipping device 120 and the up-converter 130. I do. When receiving the multiplexed TS delayed by the delay unit 11, the tuner 12 separates the multiplexed programs and outputs a stream of programs (selected programs) corresponding to one selected channel. Further, the tuner 12 outputs the program identifier corresponding to the selected channel to the control unit 150 as selected program information. The variable length decoding unit 13 receives a stream of the selection program from the tuner 12 and performs a variable length decoding process. Further, the variable length decoding unit 13 outputs the prediction mode and the motion vector to the motion compensated prediction unit 17, and outputs the angle of view information, the picture type, and the reference frame reception information to the control unit 150. The inverse quantization unit 14 receives the decoding result from the variable length decoding unit 13 and performs inverse quantization. The inverse orthogonal transform unit 15 receives the inverse quantization result from the inverse quantization unit 14, performs inverse orthogonal transform, and outputs a video of the selection program.

  The video memory 18 stores video reference frames, that is, I-picture frames and P-picture frames in the case of MPEG-2. The motion compensation prediction unit 17 reads a reference frame from the video memory 18, inputs a prediction mode and a motion vector from the variable length decoding unit 13, and performs motion compensation prediction. The adder 16 adds the video output by the inverse orthogonal transform unit 15 and the video predicted by motion compensation by the motion compensation prediction unit 17. The format converter 19 receives the video from the adder 16 and performs format conversion.

  The control unit 150 controls the synchronization between the video of the selection program and the video of the service program, the control of the cutout position of the area where the video is cut out by the cutout device 120, and the switch for selecting the reference frame stored in the video memory 18 140 switch control is performed. Specifically, the control unit 150 receives the selected program information from the tuner 12 and the view angle information, the picture type, and the reference frame reception information of the selected program from the variable length decoding unit 13, respectively, and the identifier of the selected channel Is output to the clipping device 120. In addition, the control unit 150 outputs a pixel size for up-conversion obtained from the angle-of-view information and the picture type to the up-converter 130 and outputs a reference frame switching signal to the switch 140. The reference frame switching signal is information for selecting a reference frame stored in the video memory 18. The video memory 18 stores either the reference frame of the video of the selected program selected by the tuner 12 or the video of the cut program cut out from the service program.

  The tuner 112 receives the multiplexed TS, separates the multiplexed program, and outputs a service program stream. The variable length decoding unit 113, the inverse quantization unit 114, the inverse orthogonal transform unit 115, the adder 116, the motion compensation prediction unit 117, and the video memory 118 are the variable length decoding unit 13, the inverse quantization unit 14, and the inverse orthogonal transform unit. 15, the adder 16, the motion compensation prediction unit 17, and the video memory 18.

  The cutout device 120 receives the multi-screen video of the service program from the adder 116 and also receives selection program information from the control unit 150 to cut out the area indicated by the selection program information. As shown in FIG. 4, when a multi-screen video of a service program including four videos is input, the cutout device 120 cuts out an area in which the program selected by the tuner 12 is displayed according to the selection program information.

  The up-converter 130 receives the video clipped by the clipping device 120 and the pixel size from the control unit 150, up-converts the input video to the pixel size, and generates a broadcast-sized video. This pixel size is the pixel size of the video of the program selected by the tuner 12. As illustrated in FIG. 4, the up-converter 130 receives the video clipped from the clipping device 120 and generates a video having the same normal broadcast size as the video of the selection program according to the pixel size.

  The switch 140 receives the video of the selection program from the adder 16, the video cut and up-converted in the service program from the up converter 130, and the switching signal from the control unit 150. Then, the switch is switched according to the switching signal.

  Here, it is assumed that program 2 is selected in tuner 12 and the channel is changed from program 1 to program 2. The control unit 150 monitors whether or not the selected program information input from the tuner 12 has changed, and determines that there has been a change from the program 1 to the program 2. And a switching signal is output so that it may switch to the service program side. When the switch 140 receives a switching signal on the service program side from the control unit 150, the video of the program 2 cut out by the cutout device 120 and upconverted by the upconverter 130 is stored only once as a reference frame in the video memory 18. Is done. At this time, the reference frame of the previous program 1 is discarded. In this case, the video on the service program side stored in the video memory 18 is substantially the same as the reference frame on the selection program side that should be originally stored. Since the tuner 12 side and the tuner 112 side are synchronized, the video program receiving apparatus 100 performs motion compensation prediction using the reference frame stored in the video memory 18 and adds the adder 16. The motion compensation prediction unit 17 and the format conversion unit 19 output the video of the program 2. That is, the video program receiving apparatus 100 performs a decoding process using the video of the clipping program 2 on the service program side as a reference frame at the timing of the start of the program switching operation (start of zapping), and outputs the video of the program 2. Note that this video uses the up-converted video as a reference frame, and motion compensation prediction is performed using the reference frame. Therefore, the resolution is partially reduced as compared with a normal video.

  Then, when receiving the reference frame reception information of channel 2 (I channel or P channel frame reception information) from the variable length decoding unit 13, the control unit 150 outputs a switching signal so as to switch to the selection program side. At this point, the decoding / playback process on the selected program side is stable. When the switch 140 receives a selection program side switching signal from the control unit 150, the video memory 18 stores the reference frame of the video of the channel 2 selection program. Thereafter, the video program receiving apparatus 100 outputs a video that has been motion compensation predicted using the reference frame of the program 2 on the selected program side, that is, a normal video.

  As described above, according to the first embodiment, when the user performs zapping (channel change operation), the video program receiving apparatus 100 causes the control unit 150 to switch the switch 140 at that timing, and the service program is up-converted. The changed channel selection program video is output using the video of the later channel as a reference frame. As a result, at the time of zapping, the video can be displayed without interruption with a certain small delay, which is the processing time of the clipping device 120 and the up-converter 130. In this case, the video program receiving apparatus 100 switches the switch 140 at the timing when the control unit 150 recognizes the changed channel reference frame, and selects the changed channel as usual using the reference frame of the selection program. Outputs the program video. Therefore, although the resolution of the video immediately after zapping is partially reduced, it is possible to reduce the delay in video display when switching programs.

  According to the first embodiment, when the service program is not changed by a single ID or channel, the tuner 112 is used as a dedicated tuner for low delay switching. As a result, the video program receiving apparatus 100 as a whole can be reduced in cost and circuit scale, and a multiple program distribution service can be realized more easily. Further, the tuner 112 dedicated to low-delay switching operates in a state in which the service program is constantly received, so even when a transmission method that requires time for demodulation processing, such as terrestrial digital broadcasting, is used. The delay at the time of program switching can be reduced.

  Next, Example 2 will be described. FIG. 5 is a diagram showing a configuration of a video program receiving apparatus according to Embodiment 2 of the present invention. The video program receiving apparatus 200 includes a delay unit 11, a tuner 12, a variable length decoding unit 13, an inverse quantization unit 14, an inverse orthogonal transform unit 15, an adder 16, a motion compensation prediction unit 17, a video memory 18, and a format conversion unit. 19, tuner 112, variable length decoding unit 113, inverse quantization unit 114, inverse orthogonal transform unit 115, adder 116, motion compensation prediction unit 117, video memory 118, format conversion unit 219, clipping device 220, upconverter 230, A switch 240 and a control unit 250 are provided. In FIG. 5, the delay unit 11 to the format conversion unit 19 shown in the upper part of the drawing have a function of selecting one of a plurality of programs and decoding the video of the program. On the other hand, the tuner 112 to the up-converter 230 shown in the lower part of the drawing cut out and up-convert the video of one of the service program videos, and use the video for zapping, that is, low-latency switching. It has a function. The switch 240 and the control unit 250 are used to realize a low delay switching function. In FIG. 5, the same reference numerals as those in FIG.

  As in the first embodiment, the control unit 250 performs synchronization control, cutout position control, and switch control of the switch 240 for selecting any one of the video of the selection program or the video of the service program. Specifically, the control unit 250 inputs the selected program information from the tuner 12 and the angle-of-view information, the picture type, and the reference frame reception information of the selected program from the variable length decoding unit 13, respectively. The selected program information indicating the identifier of the current channel is output to the clipping device 220. Further, the control unit 150 outputs a pixel size for up-conversion to the up-converter 230 and outputs a video switching signal to the switch 240.

  The format conversion unit 219 has the same function as the format conversion unit 19. The clipping device 220 inputs the multi-screen video of the service program converted by the format conversion unit 219 and inputs selection program information from the control unit 250 to cut out an area indicated by the selection program information. The up-converter 230 receives the video clipped by the clipping device 220 and also receives a pixel size from the control unit 150, up-converts the input video to the pixel size, and generates a normal broadcast size video.

  The switch 240 receives the video of the selected program from the format conversion unit 19, the video cut and up-converted in the service program from the up-converter 230, and the switching signal from the control unit 250. Then, the switch is switched according to the switching signal.

  Here, it is assumed that program 2 is selected in tuner 12 and the channel is changed from program 1 to program 2. The control unit 250 monitors whether or not the selected program information input from the tuner 12 has changed, and determines that there has been a change from the program 1 to the program 2. And a switching signal is output so that it may switch to the service program side. When the switch 240 receives a switching signal on the service program side from the control unit 250, the video of the program 2 up-converted by the up-converter 230 is output via the switch 240. Since this video is an up-converted video, the overall resolution is lower than that of a normal video.

  Then, when the reference frame reception information of the program 2 is input from the variable length decoding unit 13, the control unit 250 outputs a switching signal so as to switch to the selected program side. When the switch 240 receives the selection program side switching signal from the control unit 250, the video of the program 2 on the selection program side is output via the switch 240.

  As described above, according to the second embodiment, when the user performs zapping (channel change operation), the video program receiving apparatus 200 causes the control unit 250 to switch the switch 240 at that timing, and the service program is up-converted video. Is output. The video program receiving apparatus 200 switches the switch 240 at the timing when the control unit 250 recognizes the changed channel reference frame, and outputs the video of the changed channel selection program as usual. Therefore, although the resolution of the video immediately after zapping is lowered, the video display delay at the time of program switching can be reduced.

  Next, Example 3 will be described. FIG. 6 is a diagram showing the configuration of the video program receiving apparatus according to the third embodiment of the present invention. In the video program distribution apparatus (not shown) in the third embodiment, a multiplexed TS obtained by multiplexing a plurality of programs targeted for a video distribution service, and a video of the multiplexed TS having different (reduced) angle of view. And an uncompressed video distribution program consisting of the video of the program. In FIG. 6, this video program receiving apparatus 300 includes a delay unit 11, a tuner 12, a variable length decoding unit 13, an inverse quantization unit 14, an inverse orthogonal transform unit 15, an adder 16, a motion compensation prediction unit 17, and a video memory 18. , A format conversion unit 19, a tuner 310, a reproduction processing unit 320, an up-converter 330, a switch 340, and a control unit 350. In FIG. 6, the delay unit 11 to the format conversion unit 19 shown in the upper part of the drawing have a function of selecting one of a plurality of programs and decoding the video of the program. On the other hand, the tuner 310, the reproduction processing unit 320, and the up-converter 330 shown in the lower part of the drawing reproduce and upconvert one of the videos of the uncompressed video distribution program, and use the video for zapping. It has a function, that is, a low delay switching function. Further, the switch 340 and the control unit 350 are used to realize a low delay switching function. In FIG. 6, the same reference numerals as those in FIG. 3 or FIG.

  The control unit 350 performs synchronization control and switch control of the switch 340 for selecting one of the video of the selection program or the video of the uncompressed video distribution program. Specifically, the control unit 350 inputs the selected program information from the tuner 12 and the angle-of-view information, the picture type, and the reference frame reception information of the selected program from the variable length decoding unit 13, respectively, and upconverts the selected program information. The pixel size is output to the up-converter 330 and a video switching signal is output to the switch 340.

  The tuner 310 inputs the uncompressed video distribution program sent from the video program distribution device, inputs selection program information from the tuner 12, selects a program from the uncompressed video distribution program according to the selection program information, Outputs the program stream. The playback processing unit 320 inputs the stream of the uncompressed video distribution program selected from the tuner 310 and performs playback processing. The up-converter 330 inputs the video of the program reproduced by the reproduction processing unit 320, inputs the pixel size from the control unit 350, up-converts the input video to the pixel size, and outputs a normal broadcast size video. Is generated.

  The switch 340 receives the video of the selection program from the format conversion unit 19, the video obtained by up-converting the uncompressed video distribution program from the up-converter 330, and the switching signal from the control unit 350. Then, the switch is switched according to the switching signal.

  Here, it is assumed that program 2 is selected in tuner 12 and the channel is changed from program 1 to program 2. The control unit 350 monitors whether the selected program information input from the tuner 12 has changed, and determines that there has been a change from the program 1 to the program 2. Then, a switching signal is output so as to switch to the uncompressed video distribution program side. When the switch 340 receives a switching signal on the uncompressed video distribution program side from the control unit 350, the video of the program 2 up-converted by the up-converter 330 is output via the switch 340. Since this video uses an up-converted video, the overall resolution is lower than that of a normal video.

  Then, when the reference frame reception information of channel 2 is input from the variable length decoding unit 13, the control unit 350 outputs a switching signal so as to switch to the selection program side. When the switch 340 receives the selection program side switching signal from the control unit 350, the video of the program 2 is output via the switch 340.

  As described above, according to the third embodiment, the tuner 310 is operated in conjunction with the uncompressed video distribution program corresponding to the selected program information output by the tuner 12, and the video program receiving apparatus 300 is connected to the tuner 12. The video on the tuner 310 side is output until decoding / reproduction according to the above becomes possible. Specifically, when the user performs zapping (channel change operation), the video program receiving apparatus 300 changes the upconverted video of the uncompressed video distribution program by the control unit 350 switching the switch 340 at that timing. Output as video corresponding to the later channel. Then, the video program receiving apparatus 300 switches the switch 340 at the timing when the control unit 350 recognizes the reference frame of the changed channel, that is, the timing at which decoding and reproduction is possible, and the changed channel selection program as usual. Output video. Therefore, although the resolution of the video immediately after zapping is reduced, the delay in video display at the time of program switching can be reduced.

  The present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the technical idea thereof. For example, in the first embodiment, the tuner 12 is used for program selection and the tuner 112 is configured for low delay switching. However, the tuner 112 is not used as a dedicated tuner for realizing the low delay switching function. In addition to the low delay switching function, it may be used as a tuner that realizes a function of simultaneously receiving a plurality of programs and selecting a program. In this case, the function of the tuner 112 is switched by the user's selection, and a format conversion unit is provided at the subsequent stage of the clipping device 120 so that the format conversion unit outputs the format-converted video to the display device or the recording device. Configure. As a result, the tuners 12 and 112 can realize a double tuner function during normal times, and the tuner 112 can realize a low delay switching function during zapping.

  In the second embodiment, a video output of the format conversion unit 219 may be output to the outside by using a switch (not shown) without using the clipping device 220 and the up-converter 230. Accordingly, the video program receiving apparatus 200 can output videos of a plurality of different programs using the two tuners 12 and the tuner 112.

  In the second embodiment, when the control unit 250 receives macroblock information from the variable length decoding unit 13 and the information is an intra-coded block, a switch signal for switching to the selected program side is set to the switch 240. If it is a block other than that, a switching signal for switching to the service program side may be output to the switch 240. Thereby, since the switch 240 is switched in units of macroblocks, high-quality switching, that is, output of high-resolution video can be realized.

  In the third embodiment, in the case of simultaneous broadcasting that simultaneously realizes digital broadcasting and analog broadcasting, zapping of digital broadcasting can be realized by using the tuner 310 as a tuner for receiving analog broadcasting.

  In addition, the first to third embodiments have been described by using the example using the MPEG-2 encoding method, but the present invention is not limited to this, and the decoding is performed by storing the reference frame of the video in the video memory 18. The present invention can also be applied to the encoding method. For example, in the first and second embodiments, the multi-screen generation device 4 of the video program distribution device 1 generates one multi-image from a plurality of screens, and the clipping devices 120 and 220 of the video program reception devices 100 and 200 provide services. Upconvert one video of the multi-images of the program. For this reason, the up-converted video image is likely to deteriorate in image quality due to high compression, and the resolution is lower than that of a normal video image. Therefore, the image quality of the service program image needs to be high quality. Therefore, the program uses the MPEG-2 encoding method, and the service program uses a higher quality encoding method in a high compression environment, such as H.264. The H.264 encoding method may be used.

  Further, the tuners 112 and 310 side are different from the encoding method on the tuner 12 side, for example, H.264. The H.264 encoding method may be used, and the clipping devices 120 and 220, the up-converter 130, and the up-converters 230 and 330 may be configured to be able to perform decoding processing. Thereby, in the future, when the encoding method of program distribution on the tuner 12 side is changed to the encoding method on the tuners 112 and 310 side, the tuners 112 and 310 side can be used as the selected program side. Therefore, it is possible to cope with future changes in the encoding method.

It is a figure which shows the structure of the video program delivery apparatus by embodiment of this invention. It is a figure which shows the structure of the multi-screen production | generation apparatus of FIG. It is a figure which shows the structure of the video program receiver by embodiment (Example 1) of this invention. It is a figure which shows the process of the clipping device 120 and the up converter 130 of FIG. It is a figure which shows the structure of the video program receiver by embodiment (Example 2) of this invention. It is a figure which shows the structure of the video program receiver by embodiment (Example 3) of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video program delivery apparatus 2 Delay part 3, 5 Encoder 4 Multi screen production | generation apparatus 6 Multiplexer 7 Down converter 8 Screen synthetic | combination part 11 Delay unit 12, 112, 310 Tuner 13, 113 Variable length decoding part 14, 114 Reverse Quantization units 15 and 115 Inverse orthogonal transformation units 16 and 116 Adders 17 and 117 Motion compensation prediction units 18 and 118 Video memory 19 and 219 Format conversion units 100 and 200 and 300 Video program reception devices 120 and 220 Clipping devices 130 and 230 , 330 Upconverter 140, 240, 340 Switch 150, 250, 350 Control unit 320 Reproduction processing unit

Claims (5)

Receiving the encoded video signals of the plurality of programs and the reduced video signal of the zapping program, selecting one of the plurality of programs, decoding the selected video signal, and outputting the output signal When generating and zapping, a video program receiving device that generates an output signal using the video signal of the zapping program,
A first tuner that selects one of the plurality of received programs, outputs a video signal of the selected program, and outputs identification information of the selected program;
A second tuner for outputting a video signal of the received zapping program;
An enlargement unit for enlarging a video signal corresponding to the identification information of the program among the video signals of the zapping program output by the second tuner;
A control unit that outputs a switching signal for switching to the second tuner when it is determined that switching of the program has occurred based on the identification information of the program output by the first tuner;
A video program reception comprising: a switch for generating the output signal using the video signal enlarged by the enlargement unit in response to a switching signal output from the control unit to the second tuner side apparatus. The video program receiving device according to claim 1,
Further, the image processing apparatus includes a storage unit that stores a reference frame of video, performs a motion compensation prediction process using the reference frame stored in the storage unit, and generates the output signal.
If the control unit determines that the program switching has occurred based on the program identification information output by the first tuner, the control unit outputs a switching signal for switching to the second tuner side, When the reference frame after switching is recognized for the video signal of the program output by the tuner, a switching signal for switching to the first tuner side is output,
When the switching signal output by the control unit is a switching signal to the second tuner side, the switch stores the video signal after switching expanded by the expansion unit in the storage unit, In the case of a switching signal to the tuner side, the reference frame in the video signal of the program output by the first tuner is stored in the storage unit. The video program receiving device according to claim 1,
If the control unit determines that the program switching has occurred based on the program identification information output by the first tuner, the control unit outputs a switching signal for switching to the second tuner side, When the reference frame after switching is recognized for the video signal of the program output by the tuner, a switching signal for switching to the first tuner side is output,
When the switching signal output by the control unit is a switching signal to the second tuner side, the switch uses the video signal after switching expanded by the expansion unit as the output signal, and the first tuner side In the case of the switching signal, a video program receiving apparatus characterized in that a signal obtained by decoding the video signal of the program output by the first tuner is used as the output signal. The video program receiving device according to claim 3.
A video program receiving apparatus, wherein the video signal of the zapping program is a video signal of an uncompressed video distribution program having a different angle of view.   5. The video program receiving device according to claim 1, a video signal obtained by encoding each of the plurality of programs, and a video signal of a reduced zapping program are distributed to the video program receiving device. A video program transmission / reception system, comprising:

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