JP2012109655A - Media receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a media receiving device capable of reducing time from receiving a transmission packet to video output of encoded video media information through extracting and decoding the information.SOLUTION: A media receiving device comprises: a transmission packet analysis separation unit 11 for analyzing a transmission packet 7 to output video time information 13 including decoding time information and display time information; an encoded video media analysis unit 17 for detecting the beginning of a video frame to notify the detection; an encoded video media decoding unit 20 for notifying decoding completion of the video frame; a reference time generating unit 8 for outputting reference time information of one's own device; and a video decoding time calculation unit 23 for calculating video output timing having the shortest elapsed time from the detection of the beginning of the video frame to video output by comparing a time of the detection of the beginning of the video frame with a time of the decoding completion and the display time information of the video frame.

Description

  The present invention relates to a media receiver that receives a transmission packet and decodes encoded video media information, and more particularly to a media receiver that shortens a processing delay time until a video signal is output.

DTS (Decoding Time-Stamp) indicating decoding time information in the PES header and display (output) time information in processing from TS packet compliant with MPEG-2 Systems standard to separation / decoding / display of encoded video media information Time information called PTS (Presentation Time-Stamp) is stored as required.
At this time, the time axis for the time information is indicated by time reproduction information called PCR (Program Clock Reference) indicating the reference time at the time of acquisition on the transmission device side stored in the adaptation area of the TS header. This time reproduction information is stored at a constant frequency, and the time axis reproduced on the receiving device side using this PCR is called STC (System Time Clock).

  That is, the receiving device side starts decoding the received encoded data sequence when the time indicated by the decoding time information DTS is reached with reference to the time axis STC reproduced from the time reproduction information PCR transmitted from the transmitting device side. In addition, the timing control is defined such that the decrypted media information is output when the time indicated by the display time information PTS is reached. At that time, the encoded media information to be decoded arrives by the DTS time, the decoding process is completed at the processing time 0 at the DTS instant, and the delay in consideration of the time required to change the order of the data sequence according to the encoding method It is defined by an ideal device model that is output at the PTS time having

Actually, if it is video media, it takes time to perform decoding processing according to the video encoding method, video correction processing to correct image quality degradation such as noise and distortion, and video pixel transfer time of the video signal itself. Become. In order to display a video on a video display device such as a monitor device, it is necessary to output at a constant cycle in accordance with a video signal format defined by SMPTE or the like.
Therefore, in order to make the video output interval to the video display device constant in the receiving device, the output timing to the video display device is set to a constant cycle by timing control independent of the decoding timing of the received encoded media information, and the output There are many mounting methods in which each process is controlled to match the timing and the final video pixel transfer timing is matched.
As a result, there is an asynchronous part between the reception of the TS packet and the final video display, a waiting time for timing adjustment occurs, and one frame is generated every time the video display delay time increases and the video display operation starts. There was a problem that caused blurring in time.

Therefore, in the prior art, a mechanism for controlling the interval at which a video signal is output using the display time information PTS, or an encoded video medium when the display time information PTS is given discretely instead of being given to all video frames. A mechanism for extracting a video frame interval from information and controlling a display interval is disclosed.
However, since the delay time differs depending on the video encoding method of the video media information and the processing configuration inside the receiving device, an offset that allows for a certain delay time is necessary, and the video signal is output after receiving the transmission packet. The problem that the delay time until becomes longer occurs.

For example, in Patent Document 1, when the time axis STC reproduced using the time reproduction information PCR in the TS packet matches the display time information PTS in the PES header, the counter circuit controls the video output timing for the video frame. It is disclosed that the video is output at the output timing according to the display time information notified from the transmitting device instead of the self-running timing in the receiving device by initializing the.
Further, in Patent Document 2, in the case of control for initializing video output timing with display time information PTS as in Patent Document 1, the output timing depends on the accuracy of the time notified as display time information PTS. It is disclosed that the correction is made within the range. In the case of a normal video display device, the interval at which video is displayed needs to be exactly constant, and large fluctuations are not allowed, so such measures are necessary.
Further, in Patent Document 3, even when the display time information PTS is not stored in all the video frames in the TS packet, the display time which is insufficient from the information regarding the video frame interval given as the parameter of the encoded video frame information. A mechanism for calculating information PTS and applying it to output timing control is disclosed.

  In transmission at a low rate such as one-segment broadcasting, it is desirable to allocate as much transmission bandwidth as possible to encoded video media information and to suppress control information to the minimum necessary to ensure good video quality. When a PES header is set for each video frame, a transmission band is consumed. Therefore, a method of adding a PES header only to a main video frame necessary for recovery from a transmission error or the like is employed. Also, when video frame signals are encoded on the transmission device side, not all video frame signals are encoded and transmitted as encoded video media information, and video frame signals are thinned out according to the processing status. There is also a case. In such a case, since the video display interval becomes unnatural if the video output timing is controlled at the self-running timing on the receiving side with respect to the video frame to which the display time information PTS is not given, such a device is necessary. Become.

JP 2004-128869 A JP 2004-128870 A JP 2007-251542 A

  The actual processing time from reception of a transmission packet, extraction and decoding of encoded media information to display output is the same as the output timing to the display device based on the display time information PTS notified from the transmission device. In addition, it depends on the device mounting method and coding method.

  Only when initializing the output timing with the display time information PTS or calculating the lack of display time information PTS from the encoded video media information as in the above-mentioned patent document, such ideal processing timing and actual However, there is a problem that the video display delay cannot be shortened even if there is a difference from the processing timing, and a buffer for holding the video frame signal for the processing time is required.

  The present invention has been made to solve the above-described problems, and provides a media receiver capable of shortening the time from reception of a transmission packet to extraction, decoding, and video output of encoded video media information. With the goal.

  The media receiver according to the present invention includes time reproduction information indicating a reference time of operation in a media transmitter that stores and outputs encoded video media information obtained by encoding a video signal in a transmission packet, and encoded video media information For receiving a transmission packet in which decoding time information indicating timing to start decoding and video time information including display time information indicating timing to output a video decoded video signal are added together with encoded video media information A receiving device that analyzes a received transmission packet to extract time reproduction information, encoded video media information, and video time information; and operation of the device at the time when the transmission packet is received The reference time information of the device and the time reproduction information extracted by the transmission packet analysis and separation means Reference time reproduction means for generating reference time control information so that the quasi-time information is synchronized with the time reproduction information, and the oscillation frequency of the reference signal serving as a reference for the reference time in the own device is adjusted based on the reference time control information The reference time generation means for controlling the advance of the reference time, the reference time information indicating the controlled reference time, and the reference frequency signal indicating the adjusted oscillation frequency are distributed within the apparatus, and the encoded video media information is analyzed. And detecting and notifying the head of the video frame and outputting the encoded video frame information as encoded video frame information; decoding the encoded video frame information to restore the video signal; and decoding the video frame Encoded video media decoding means for notifying completion of decoding when it is completed, and a video frame indicated by the reference time when the detection of the start of the video frame is notified The elapsed time from the detection of the start of the video frame to the output of the video is minimized by comparing the start detection time, the decoding completion time indicated by the reference time when the completion of decoding of the video frame is notified, and the display time information for the video frame. Video decoding time calculation means for calculating video output timing is provided.

  The media receiving device of the present invention is a video frame head detection time indicated by a reference time when a detection of the start of a video frame is notified, a decoding completion time indicated by a reference time when a video frame decoding completion is notified, And the video output timing that minimizes the elapsed time from video frame head detection to video output by comparing the display time information for the video frame and extracting the encoded video media information from the reception of the transmission packet, Time until decoding and video output can be shortened.

It is a block diagram which shows the media receiver by Embodiment 1 of this invention. It is a block diagram which shows an example of the relationship between the transmission packet handled by Embodiment 1 of this invention, and encoding video media information. It is explanatory drawing which shows an example of the packet structure which multiplexes encoding video media information in the transmission packet handled in Embodiment 1 of this invention. It is explanatory drawing which shows an example of the packet structure which multiplexes encoding video media information in the transmission packet handled in Embodiment 1 of this invention. It is a block diagram which shows the media receiver by Embodiment 2 of this invention. It is explanatory drawing which shows an example of the packet structure which multiplexes encoding video media information in the transmission packet handled in Embodiment 2 of this invention. It is explanatory drawing which shows an example of transition of the elapsed time from the video frame head detection time after a video frame to video decoding completion time in the media receiver by Embodiment 3 of this invention. It is explanatory drawing which shows an example of the transition of the screen coding system for every video frame in the media receiver by Embodiment 4 of this invention. It is explanatory drawing of the packet structure containing control information in the transmission packet handled in Embodiment 5 of this invention.

Embodiment 1 FIG.
1 is a block diagram showing a media receiving apparatus according to Embodiment 1 of the present invention.
In FIG. 1, a media transmitting apparatus 1 encodes media information such as video, audio and data into media packets, and further multiplexes a plurality of media packets into a transmission packet (TS packet) 2 with a predetermined configuration and transmits the media packets. And transmitting to the transmission line. The media reception device 3 receives the transmission packet 2 output from the media transmission device 1, separates encoded media information such as video, audio, and data from the transmission packet 2, decodes and outputs them, and outputs them to the video display device 4. A transmission packet reception unit 5, a reference time generation unit 8, a transmission packet analysis / separation unit 11, a reference time reproduction unit 15, an encoded video media analysis unit 17, an encoded video media decoding unit 20, and a video decoding time. A calculation unit 23, a video output timing generation unit 25, and a video signal post-processing unit 27 are provided. The video display device 4 is a display device that displays the video signal decoded by the media receiving device 3.
In addition, since the structure regarding media information other than video, such as an audio | voice and data, is known, these illustration and description are abbreviate | omitted.

  The transmission packet receiving unit 5 receives the transmission packet 2 output from the media transmission device 1 and outputs a transmission packet arrival notification 6 for notifying the reception timing to the reference time reproducing unit 15 and also transmits the transmission packet receiving unit 5. This is a functional unit that outputs the transmission packet 7 captured in step 1 to the transmission packet analysis / separation unit 11. The reference time generation unit 8 is a reference time generation unit that distributes the reference time information 9 and the reference time frequency signal 10 serving as a reference for operation to each functional unit in the media reception device 3. The transmission packet analysis / separation unit 11 analyzes the structure of the transmission packet 7 and outputs time reproduction information 12 indicating the reference time when the transmission packet is output in the media transmission device 1 to the reference time reproduction unit 15. Then, the decoding time information 13a indicating the decoding timing of the encoded video media information on the reference time and the display time information 13b indicating the output timing of the video signal are extracted, and these are extracted as the video time information 13 to the video decoding time calculation unit 23. The transmission packet analysis / separation means outputs the encoded video media information 14 stored in the transmission packet 7 and outputs the encoded video media information 14 to the encoded video media analysis unit 17. The video time information 13 is not shown, but when it is shown individually, it is set as the decoding time information 13a and the display time information 13b.

  The reference time reproduction unit 15 receives the transmission packet 2 arrival time obtained from the reference time information 9 output by the reference time generation unit 8 at the timing of the transmission packet arrival notification 6 notified by the transmission packet reception unit 5 and the transmission packet analysis and separation. The time reproduction information 12 extracted by the unit 11 is compared, the reference time control information 16 for controlling the operation of the reference time generation unit 8 is generated so that the values match, and this is output to the reference time generation unit 8 The reference time reproducing means. The encoded video media analysis unit 17 searches for an identifier indicating the breakpoint of the video frame in the encoded video media information 14 notified from the transmission packet analysis / separation unit 11, detects the start of the video frame, and uses this to detect the start of the video frame. It is an encoded video media analyzing means that outputs the detection notification 18 to the video decoding time calculation unit 23 and outputs the encoded video frame information 19 to the encoded video media decoding unit 20. The encoded video media decoding unit 20 decodes the encoded video frame information 19 to restore the video signal, outputs it as a video signal 22 to the video signal post-processing unit 27, and completes the decoding of the video frame. The encoded video media decoding means notifies the video decoding time calculation unit 23 as the video frame decoding completion notification 21.

  The video decoding time calculation unit 23 receives the video frame detection time obtained from the reference time information 9 at the timing when the video frame head detection notification 18 is notified and the reference time at the timing when the video frame decoding completion notification 21 for the video frame is notified. The elapsed time required for the decoding process of the video frame is calculated from the video frame decoding completion time obtained from the information 9, and from the relationship with the display time information 13b for the video frame, from the detection of the video frame head to the video output. This is a video decoding time calculation means for determining the video output timing with the shortest elapsed time, generating the video output control information 24, and outputting the video output control information 24 to the video output timing generation unit 25. The video output timing generation unit 25 controls the output interval at the reference time indicated by the reference time information 9 and the reference time frequency signal 10 based on the video output control information 24 according to the video frame interval, and outputs a video output timing notification 26. This is a functional unit that generates and outputs this to the video signal post-processing unit 27.

  The video signal post-processing unit 27 performs signal processing such as noise removal and distortion reduction and video frame order so that the restored video signal 22 is equivalent to the original video signal captured by the media transmission device 1. This is a functional unit that performs processing that accompanies the video encoding method such as switching, temporarily holds the video signal, and outputs the video signal based on the video output timing notification 26, and finally outputs the video signal. The video output signal 28 with the adjusted timing is output.

  FIG. 2 is an explanatory diagram showing an example of the relationship between the transmission packet 7 and the encoded video media information 14 handled by the media receiver 3 according to the first embodiment of the present invention. 3 and 4 are explanatory diagrams showing an example of a packet structure in which the encoded video media information 14 is multiplexed in the transmission packet 2. FIG.

Although the structure of the transmission packet is not directly related to the characteristic operation in the first embodiment, an example is given for convenience of explanation.
In FIG. 2, a transmission packet sequence 100 indicates a transmission packet 2 that is transmitted between the media transmission device 1 and the media reception device 3 via a transmission path such as a transmission network, and a transmission header 101 identifies the transmission packet. Additional information such as ID to be stored, and the media header 102 includes ID, display time information, and decoding that uniquely identify each media information when storing various media information such as video, audio, and data. This is a header in which additional information such as start information is stored. The encoded video media information 103 is data stored in the transmission packet sequence 100.

  Since the data sequence of the encoded video media information 103 is larger in size than the transmission packet, the encoded video media information 103 is divided into sizes that can be accommodated in each transmission packet in the transmission packet sequence 100 and sequentially stored. It will be. The example of FIG. 2 shows a case where the encoded video media information 103 is divided into three and stored in a transmission packet. Here, the transmission packet 104 is a transmission packet including the head portion of the encoded video media information 103, the transmission packet 105 is a transmission packet including an intermediate portion of the encoded video media information 103, and the transmission packet 106 is an encoded video media. A transmission packet including the final part of the information 103 is shown. The additional area 107 is an area for storing additional information such as time reproduction information for the purpose of stuffing when a data string stored in a transmission packet is insufficient and a free area is generated, or for a transmission packet. This additional area includes a multiplex standard that exists as a part of the transmission header 101 depending on the multiplex standard of the transmission format to be applied, and a multiplex standard that exists independently, but there is no essential difference in any storage method.

  In FIG. 2, the additional area 107 is stored only in the transmission packet 106 including the final part of the encoded frame information 103. However, the additional area 107 has an object of adding additional information to the transmission packet. It is possible to give to. The transmission header 101, the additional area 107, and the media header 102 are sequentially stored as necessary, and various data strings, for example, the encoded video media information 103, are divided into appropriate sizes and stored in the remaining area, and the transmission packet string 100 is stored. It becomes the operation which constitutes.

Next, the operation of the first embodiment will be described.
The media transmission device 1 encodes media information such as an input video media signal, audio media signal, and data signal by encoding video data, audio encoding, and data encoding according to an encoding method according to the characteristics of each media. Generate information. An example of a video encoding method is a data sequence encoded in accordance with video encoding standards such as MPEG-2 Video, MPEG-4 Video, MPEG-4 AVC / ITU-T H.264, and VC-1. And An example of an audio encoding method corresponds to a data string encoded in accordance with an audio encoding standard such as MPEG-1 Audio, MPEG-2 Audio, MPEG-2 / 4 AAC, Dolby AC-3, or the like.

  Then, in order to aggregate a plurality of types of encoded media information into one transmission data and easily output it to the transmission path, a data sequence for transmission is formed in a packet structure as shown in FIG. It is transmitted between the device 1 and the media receiving device 3. At this time, in order to identify what kind of media information is stored, additional information such as an encoded media type and a packet attribute is added to the transmission header 101 to form a packet, which is output to the transmission path.

  The case where video media information is transmitted will be further described. The video media information is divided in some unit, for example, a structure in which a significant unit such as a video frame structure in a progressive method or a video field structure in an interlace method is used. In many cases, the data sequence of the encoded video media information is divided in accordance with the breaks, stored in a transmission packet, and sent. This is because in the real-time transmission method, when receiving and decoding from an arbitrary timing, the processing can be started promptly from a meaningful place where the decoding can be executed. In applications such as digital broadcasting and Bluray Disc, the data sequence of encoded video media information that constitutes a video frame or video field is larger than the transmission packet, so it is sequentially divided and stored in the transmission packet. It will be.

  In the example shown in FIG. 2, the encoded video media information 103 is divided into three parts and stored in the transmission packet sequence 100, which means that the transmission packet 101 including the leading part has the leading part in the transmission header 101. In addition, the head presence / absence flag in the transmission header is set to “present”, and the head presence / absence flags in the other transmission packets 105 and 106 are set to “none”.

  Further, in the transmission packet 104 including the head portion, the media header 102 exists, and additional information related to the video media information is given. The media header 102 includes a video time including decoding time information 13a indicating the decoding timing of the video frame on the reference time on the media transmitting device 1 side given in the media transmitting device 1, and display time information 13b indicating the display timing. Information 13 is stored. When the decoding time information 13a and the display time information 13b have the same value, only one of them may be stored for improving transmission efficiency. In this case, the time information omitted as the same value is restored. In the transmission packet 106 including the final portion, the encoded video media information 103 is divided and sequentially stored. As a result, if the transmission packet 106 becomes too small with respect to the size of the transmission packet, a stuffing data string is inserted by the additional area 107. To compensate. In this additional area 107, additional information for storing various data strings can be added to the transmission packet, and time reproduction information 12 indicating the reference time on the media transmitting apparatus 1 side is stored. You can also.

For example, FIG. 3 shows an example in which parameters necessary for the description of the first embodiment are shown in bit arrangement in a TS packet structure defined by the MPEG-2 Systems standard as an example of a transmission packet.
In FIG. 3, the meaning of each parameter is out of the scope of the first embodiment, so detailed description is omitted. However, the TS packet is composed of a fixed length of 188 bytes, and in FIG. 188, the MSB (Most Significant Bit) in the byte is b7, the LSB (Least Significant Bit) is b0, and the bits between the MSB and the LSB are b6 to b1, respectively.

  In FIG. 3, byte position 1 to byte position 4 correspond to the transmission header 101, and byte position 5 to byte position M−1 correspond to the additional area 107. In the TS packet, when the presence of an additional area is specified by one of the flags at byte position 4 in adaptation_field_control, an additional area 107 exists, and among the flags at byte position 6, PCR_flag = 1, There is time information indicated by PCR_Base and PCR_Extension from position 7 to byte position 12. A set of both parameters is time information called PCR (Program_Clock_Reference), which corresponds to time reproduction information 12. The PCR_Base part is composed of a counter value with 90 KHz accuracy, and the PCR_Extension part is composed of a counter value with 27 MHz precision. Since a device conforming to the MPEG-2 Systems standard matches the operating frequency between transmission and reception, it is necessary to notify the PCR at a certain frequency. In the MPEG-2 Systems standard, parameters are set and notified at a transmission interval of 100 msec or less. It is supposed to be. By detecting the difference between the counter value transition of the PCR and the counter value transition in the own device on the media receiving device 3 side, the operating frequency difference between the transmission and reception and the reference time difference are calculated. By adjusting the reference time, the operating frequency and the reference time can be matched between transmission and reception.

Further, FIG. 4 shows an example of a PES header structure defined in the MPEG-2 Systems standard for an additional header related to media information existing when the head is specified in the TS header in a TS packet storing media information. Show.
Similar to the TS packet structure, this is an example in which parameters necessary for the description of the first embodiment are shown in bit arrangement. Since the meaning of each parameter is out of the range of the first embodiment, the detailed description is omitted, but the PES header corresponds to the media header 102. When one of the flags at byte position 8 in the PES header, PTS_DTS_flag is 10b or 11b (binary notation), time information called PTS (Presentation_Time_Stamp) from byte position 10 to byte position 14 exists and is displayed. It corresponds to the time information 13b. When PTS_DTS_flag is 11b (binary notation), there is time information called DTS (Decoding_Time_Stamp) from byte position 16 to byte position 19, which corresponds to decoding time information 13a. The time information is composed of a counter value with 90 KHz accuracy as in PCR_Base. On the time axis of the reference time information indicated by the separately notified PCR value, it indicates the time to start decoding the video frame and the time to start display.

  In accordance with such various encoding / transmission standards, a transmission packet sequence 100 provided with a plurality of types of media information and time information necessary for the restoration is assumed assuming an operation in a virtual device assuming an ideal operation model. Configured and transmitted. In an actual apparatus, the time information is corrected and applied in consideration of the time required for various operations.

In the media reception device 3, the transmission packet 2 transmitted from the media transmission device 1 via the transmission path is extracted as a transmission packet 7 by extracting a data string from a physical transmission signal in the transmission packet reception unit 5, and The reference time reproduction unit 15 is notified by the transmission packet arrival notification 6 that the transmission packet 2 has been received.
When the transmission packet analysis / separation unit 11 analyzes the packet structure of the transmission packet 7 and detects the time reproduction information described above, the transmission packet analysis / separation unit 11 notifies the reference time reproduction unit 15 of the contents as time reproduction information 12. Similarly, when decoding time information 13a or display time information 13b for a video frame is detected, it is notified to the video decoding time calculation unit 23 as video time information 13, and when encoded video media information is detected in the transmission packet 7. The encoded video media information 14 is extracted and notified to the encoded video media analysis unit 17.

  The reference time reproducing unit 15 takes in the reference time information 9 at that time at the timing of the transmission packet arrival notification 6 and holds the packet arrival time for the transmission packet 2. When the time reproduction information 12 is notified from the transmission packet analysis / separation unit 11, the time reproduction information 12 indicates the reference time in the media transmission device 1, the held packet arrival time indicates the reference time in the media reception device 3, and both references The reference time control information 16 for controlling the operating frequency and the reference time in the reference time generation unit 8 is calculated so as to coincide with each other, and is notified to the reference time generation unit 8. The reference time generation unit 8 distributes the reference time information 9 and the reference time frequency signal 10 to each functional unit while adjusting the operating frequency and the reference time absolute value related to the media receiver 3 based on the reference time control information 16. To do. Note that the method of matching the reference time between the media transmission device 1 and the media reception device 3 is the same as a known method, and therefore, only a brief description will be given here.

  According to a general method, the media receiving device 3 first initializes the reference time information in the reference time generation unit 8 with the value of the time reproduction information that arrives first after the reception operation starts and is extracted. Then, the time reproduction information transmitted from the media transmission device 1 with a certain frequency is compared with the reference time information of the own device, and if the time reproduction information is advanced, the operating frequency of the reference signal of the own device is the media transmission. It is determined that the operating frequency is lower than the operating frequency of the device 1, and conversely, if the reference time information of the own device is advanced, it is determined that the operating frequency of the reference signal of the own device is higher than the operating frequency of the media transmitting device 1. . At that time, based on the magnitude of the difference between the time reproduction information from the media transmission device 1 and the reference time information of the own device and the amount of change from when the previous time reproduction information was received, the media transmission device 1 and the own device. The difference between the reference operating frequency and the reference time information is calculated, and the reference time control information 16 is derived so that both the reference operating frequency and the reference time information match. Then, the reference time control information 16 is notified to the reference time generation unit 8, and the reference operating frequency in the reference time generation unit 8 is raised or lowered to match both the reference operating frequency and the reference time information of the media transmission device 1 and its own device. . As a result, it is possible to adjust the time until reception of the transmission packet, decoding of the encoded media information, and output in the ideal operation assumed when the media transmission device 1 generates the transmission packet 2.

  The encoded video media information 14 is converted into data based on the rules according to the video encoding scheme such as MPEG-2 Video, MPEG-4 Video, MPEG-4 AVC / ITU-T H.264 as described above. In order to improve coding efficiency, parameters commonly required for decoding processing are set sparsely at a certain frequency or set without any identifiers on the assumption that the parameters exist in a certain order Etc. have been devised. Therefore, there is a problem that normal video decoding processing cannot be performed even if video decoding processing is started in the middle of the encoded video media information 14. Therefore, in order to perform normal video signal output early in the initial stage of video decoding start or recovery from an abnormal state during video decoding, it is meaningful in video decoding processing such as the boundary of video frames constituting the video signal. There is a rule that a code that means a break is set at a certain point. By searching for this break, it is devised so that a start position where video decoding can be normally performed is detected, and video output can be restored early. For example, in the case of MPEG-2 Video, a data pattern in which “1” (binary notation) exists after 23 bits of “0” (binary notation) called “start_code” corresponds to the break. Even in MPEG-4 AVC / ITU-T H.264, the data differs depending on the encoding condition setting. Similarly, data with “1” (binary notation) after “0” (binary notation) continues for a predetermined number of bits. Patterns are separated and correspond to eyes. The type of encoded data can be identified by the identifier following the start_code.

  The encoded video media analysis unit 17 searches for such start_code while comparing the encoded video media information 14 with the bit pattern, and detects the break of the video frame by checking the identifier following the start_code. When a video frame break is detected, a video frame head detection notification 18 is notified. The video encoded media information is transmitted to the encoded video media decoding unit 20 as encoded video frame information 19 for video decoding along with the search for start_code. This is because the detection timing of the video frame break and the decoding timing of the video frame are processed in order so that they do not fluctuate depending on the processing order.

  The encoded video media decoding unit 20 performs video decoding processing on the encoded video frame information 19 in accordance with a predetermined rule defined by the video encoding method, restores the video signal 22 before video encoding, and performs video signal post-processing. To the unit 27. The details of the video decoding process are not directly related to the operation of the first embodiment, and thus will not be described in detail here. However, the video decoding process up to the end of the video frame in the process of decoding the encoded video frame information 19 is performed. Is completed, the video frame decoding completion notification 21 is notified.

  The video decoding time calculation unit 23 takes in the reference time information 9 at the timing when the video frame head detection notification 18 is received from the encoded video media analysis unit 17 and starts the head detection time for the video frame, that is, substantially starts the decoding process. Hold the decoding start time. Similarly, the reference time information 9 at the timing when the encoded video media decoding unit 20 is notified of the video frame decoding completion notification 21 is fetched, and the decoding completion time when the decoding process for the video frame is completed is held. Separately, the video time information 13 notified from the transmission packet analysis / separation unit 11 is also held. Thereby, the video decoding time calculation unit 23 can hold the decoding start time, the decoding completion time, the decoding time information defined by the media transmission device 1 and the display time information for the video frame. At this time, when notifying from each processing unit, a number such as a unique ID may be assigned to the video frame so that the time information can be associated. The video output timing is determined by comparing the time information.

When the video decoding time calculation unit 23 determines the display order of the video frames from the transition of the display time information and, if necessary, the parameters in the video encoded media information, and searches in the determined video frame order. The video output timing is calculated so as not to precede the decoding completion time of each video frame, and the video output control information 24 is notified to the video output timing generation unit 25.
The video output timing generation unit 25 outputs a video output timing notification 26 at a timing when the video output control information 24 and the reference time information 9 match. At that time, the video signal is output in accordance with a signal having a frequency unique to the video signal synchronized with the reference time frequency signal 10.
The video signal post-processing unit 27 outputs to the video display device 4 as a video output signal 28 in which the output time of the video signal 22 output from the encoded video media decoding unit 20 is adjusted in accordance with the timing when the video output timing notification 26 is notified. To do.
At this time, the video signal post-processing unit 27 may perform various signal processing such as edge enhancement, contrast adjustment, hue adjustment, and noise removal on the video signal 22 to output the video output signal 28 in order to improve the image quality. . In this case, the video output timing is fixedly delayed by the time required for the signal processing, but the time until video display described in the operation of the first embodiment is made constant and minimized. For this purpose, the calculation method of the video output timing that minimizes the elapsed time from the decoding completion time to the video output is not affected, and can be regarded as an output delay that is fixedly required in the video output.

  As described above, according to the media receiver of the first embodiment, time reproduction indicating the reference time of operation in the media transmitter that stores and outputs encoded video media information obtained by encoding a video signal in a transmission packet. Information and video time information including decoding time information indicating a timing at which decoding of encoded video media information should be started and display time information indicating timing at which video decoded video signals should be output are provided together with the encoded video media information A receiving device for receiving a transmission packet, a transmission packet analyzing / separating means for analyzing the received transmission packet and extracting time reproduction information, encoded video media information and video time information; The reference time information of the operation of the device at the time of the transmission and the time reproduction information extracted by the transmission packet analysis and separation means, In comparison, the reference time reproduction means for generating the reference time control information so that the reference time information in the own device is synchronized with the time reproduction information, and the reference time reference in the own device based on the reference time control information Reference time generating means for controlling the advance of the reference time by adjusting the oscillation frequency of the reference signal, and distributing the reference time information indicating the controlled reference time and the reference frequency signal indicating the adjusted oscillation frequency in the own device, Analyzing the encoded video media information, detecting and notifying the beginning of the video frame, and outputting the encoded video frame information by decoding the encoded video frame information, and restoring the video signal In addition, an encoded video media decoding means for notifying the completion of decoding when decoding of the video frame is completed, and a reference when the detection of the start of the video frame is notified The video frame start detection time indicated by the time, the decoding completion time indicated by the reference time when the completion of decoding of the video frame is notified, and the display time information for the video frame are compared, and the process from video frame start detection to video output Video decoding time calculation means for calculating the video output timing that minimizes the time, so the time from transmission packet reception to video decoding and video display is shortened to reduce the video display delay time, and the same characteristics It is possible to realize a media receiving apparatus that performs video display with the same video display timing with respect to reception of encoded video media information.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing a media receiver 3a according to Embodiment 2 of the present invention.
The difference between the media receiving device 3a of the second embodiment and the media receiving device 3 of the first embodiment is that the video decoding time accumulating unit 200 and the video display time determination are used instead of the video decoding time calculating unit 23 in the first embodiment. This is a point provided with a section 202. The video decoding time accumulation unit 200 holds the video time information 13 including the decoding time information 13a and the display time information 13b, receives the video frame head detection notification 18 or the video frame decoding completion notification 21, and the reference time information at that time 9, and outputs accumulated video time information 201 including each accumulated time information to the video display time determination unit 202. The video display time determination unit 202 is a functional unit that calculates video display timing from the received accumulated video time information 201 and outputs the video output control information 24. For other configurations, parts corresponding to those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 6 is an explanatory diagram showing the passage of time regarding the video decoding process and the video display process according to the second embodiment of the present invention.
In FIG. 6, the period from the detection of the start of the video frame to the completion of video decoding for the video frame is described as decoding processing [0], decoding processing [1], decoding processing [2]. Similarly, a period during which a video signal is output for the video frame is described as display processing [0], display processing [1], display processing [2]. At this time, the timing is different from the display time information extracted from the transmission packet, and details will be described later.

  Next, the operation of the second embodiment will be described. The basic operation in the media receiving device 3a is the same as that in the first embodiment, and the operation that is different is described. Decoding time information in the media header of the transmission packet 7 in the transmission packet analyzing / separating unit 11; When the display time information is extracted, an ID for identifying the video frame is assigned, and video time information 13 is generated and notified to the video decoding time storage unit 200. The transmission packet analysis / separation unit 11 also notifies the encoded video media analysis unit 17 including the video frame identification ID when the encoded video media information 14 is extracted from the transmission packet 7 and notified to the encoded video media analysis unit 17.

  The encoded video media analysis unit 17 searches the encoded video media information 14 for a video frame break, and when a video frame break is detected, the video frame head detection notification 18 is sent together with the video frame identification ID. 200, and the encoded video frame information 19 including the video frame identification ID is notified to the encoded video media decoding unit 20 in a format in which the video frame breaks are clearly indicated.

  The encoded video media decoding unit 20 performs video decoding processing on the encoded video frame information 19. When the video decoding of the video frame is completed, a video frame decoding completion notification 21 is notified to the video decoding time storage unit 200 together with the video frame identification ID. . The video decoding time accumulating unit 200 receives the video time information 13, the video frame head detection notification 18 and the video frame decoding completion notification 21 at the timing of the notification, and the video frame head detection time and the video frame decoding, respectively, incorporating the reference time information 9. The completion time is stored in association with the video frame identification ID. Each time information is collected and notified to the video display time determination unit 202 as accumulated video time information 201.

The video display time determination unit 202 generates video output control information 24 using the stored video time information 201. The generation method will be described in detail below.
First, the display order of video frames is determined based on the display time information 13b for each video frame and, if necessary, the parameters in the encoded video media information, and the video frame decoding completion time is referenced according to the display order. In the example shown in FIG. 6, for ease of explanation, the case where such rearrangement according to the display order does not occur is illustrated, but the relationship between the decoding completion time and the display start time even when rearrangement occurs. Does not change, and the correspondence indicated by the arrow lines intersects. Note that the display start time is not the display time information in the ideal model transmitted by the media transmission device 1, but means the time when the media reception device 3 described in the first embodiment actually starts outputting the video signal. .

In FIG. 6, when the decoding completion time of the nth video frame constituting the encoded media video information is td [n] and the display start time of the nth video frame is tp [n], decoding is performed from the decoding completion time. The time difference to the start time is
Δt [n] = tp [n] -td [n]
It is represented by

Here, since the display start time tp [n] for each video frame is a time that increases in increments of the video frame period, it can be described in a relative time from an arbitrary reference point, for example, the first video frame. When the video frame cycle time T and the offset time α are based on the decoding completion time td [0],
tp [n] = td [0] + nT + α
Can be expressed.

The video display start timing must be in increments of the video frame period, so it cannot be set to any timing, and if the video display start timing is earlier than the video decoding completion timing, there is no video frame to be displayed. Therefore, the correct video frame cannot be displayed. Therefore, it is necessary to perform control so that the video display start timing is generated so that the video display start timing is later than the video decoding completion timing for the video frame.
Therefore, in order to minimize the delay time from the video frame decoding completion time to the video frame display start time,
min [Δt [n]]> 0 Note that min [] means the minimum value of the set of Δt [n].
It is necessary to satisfy.

Since the encoded video frame is transmitted by changing the video encoding control in a fixed search period such as about 0.5 second period or 1 second period in general, it is determined by the time exceeding it. In the search period, when n = k is satisfied when the above condition is satisfied,
Δt [N] = tp [k] -td [k]
= (td [0] + kT + α) -td [k]
At this time, since the minimum delay time is ideally close to 0,
Δt [k] ≒ 0
Then, the offset time α is
(td [0] + kT + α) -td [k] = 0
α = (td [k] -td [0])-kT
And can be calculated.

Therefore, the display start time of each video frame is
tp [n] = td [0] + nT + α
= (td [0] + nT) + (td [k] -td [0])-kT
= (nk) × T + td [k]
Determined by
In the video output timing generation unit 25, after determining the video display start timing in this way, when the final video frame in the search period is m,
tp [m] = (mk) × T + td [k]
The video display is started at a timing coincident with the display start time calculated in step 1 and the current reference time distributed by the reference time information 9 in the media receiver 3a, and the video output is performed every video frame period T. A timing notification 26 is generated.

Since the video display start timing is determined depending on the video decoding completion timing, if the encoded video media information transmitted from the media transmission device 1 has the same characteristics, the video decoding process and the video display process are performed. The delay time control until is also the result of the same tendency. Therefore, the delay time from the video input to the video output between the media transmitting device 1 and the media receiving device 3 before and after the video decoding start timing is also about the power On / Off or the transmission cable. Stable operation can be realized without blurring for each operation such as insertion and removal.
At this time, even if the display time information 13b is directly applied as a value to be applied as the display time, there is only a relative time difference, and the elapsed time from the decoding completion time to the video output is minimized by the same calculation method. The video output display timing can be determined.

  As described above, according to the media receiver of the second embodiment, the video decoding time calculation means includes the display time indicated by the display time information for the video frame extracted by the transmission packet analysis and separation means, and the encoded video media decoding means. The video decoding time storage unit for storing the decoding completion time when the video frame decoding for the video frame is completed, and the difference time from the decoding completion time to the display time in the video frame are calculated. A video display time determination unit that determines the video output timing that minimizes the elapsed time from the completion of decoding to video output based on the difference time within a predetermined period based on the video frame, so that decoding is completed in a certain period Extraction and decoding of encoded video media information after receiving transmission packet by transition of difference value from time to display time And it is possible to determine the video output timing of constant and reduce such processing delay time until image output.

  In addition, according to the media receiver of the second embodiment, the encoded video media decoding means calculates the display start scheduled time for the video frame by extracting the video frame interval from the encoded video frame information, and the video decoding time. A calculating means for storing a display time indicated by display time information for the video frame extracted by the transmission packet analyzing and separating means and a decoding completion time for the video frame notified from the encoded video media decoding means; The difference time from the decoding completion time for the video frame to the scheduled display start time for the video frame is performed for a plurality of video frames for a predetermined period, and the elapsed time from the decoding completion to the video output is determined based on the difference time within the predetermined period. It has a video display time determination unit that determines the shortest video output timing. Video output timing for constant and reducing the processing delay time from the reception of the transmission packet by the transition of the difference value from the decoding completion time to the display start scheduled time in the video to the extraction, decoding and video output of the encoded video media information Can be determined.

Embodiment 3 FIG.
Since the configuration of the media receiving device 3a in the third embodiment in the drawing is the same as that in the second embodiment, it will be described with reference to FIG.
The video decoding time accumulation unit 200 according to the third embodiment accumulates the video frame head detection time notified from the encoded video media analysis unit 17 and the decoding completion time notified from the encoded video media decoding unit 20. In addition, the video display time determination unit 202 calculates a difference value between the decoding time information 13a extracted by the transmission packet analysis / separation unit 11 and the video frame head detection time, and searches for a peak where the difference value becomes maximum. The video output timing that minimizes the elapsed time from the decoding completion time to the video output is determined within a period determined based on the peak detection position and the number of detections. Other configurations are the same as those of the second embodiment.

FIG. 7 is a diagram showing an example of the transition of the elapsed time from the video frame head detection time after the video frame to the video decoding completion time in the media receiver 3a according to Embodiment 3 of the present invention. The operation of the third embodiment will be described.
The basic operation in the media receiving device 3a is the same as that in the second embodiment, and the operation in the video display time accumulating unit 200 as a difference will be described.
In the video encoding system as described above, in order to achieve both improvement in video encoding efficiency and early recovery from video decoding abnormality, a video frame encoded by the intra-screen encoding system at a certain period, that is, the video frame It is possible to restore the video frame by decoding the video only with the encoded video media information for the other video frames, and the other video frames have high similarity between the encoded video frames by the inter-screen coding method, that is, the adjacent video frames. Instead of encoding only the difference and reducing the amount of information, the video frame can be restored only after video decoding processing using a plurality of encoded video media information.

  As a result, encoded video frames based on the intra-picture encoding method have a relatively large amount of data and a long transmission time, and therefore, a tendency to require a long time from reception of a transmission packet of the video frame to completion of video decoding. There is. On the other hand, since the inter-picture encoding method requires a relatively small amount of data and the transmission time thereof is shortened, there is a tendency that less time is required from the transmission packet reception of the video frame to the completion of video decoding.

  Since the video encoding process is performed by combining such encoding methods having different characteristics at a constant period, the elapsed time from the detection of the start of the video frame to the completion of the decoding is fixed as shown in FIG. Roughness corresponding to the cycle occurs. Therefore, the transition of the difference value between the video frame head detection time and the decoding completion time for the encoded video frame is statistically processed to calculate an average range, and the transition value exceeds the average range and the difference value is A peak that becomes large is detected and determined by the number of detections. Since the periodicity needs to be more than one round, the detection accuracy at the video display time determination unit 202 is improved when the detection period is longer at least twice and the search period is longer. It is desirable to set the number of detections.

  The video decoding time storage unit 200 generates the stored video time information 201 for the search period determined in this way, and notifies the video display time determination unit 202 of it. The video display time determination unit 202 searches the time information in the notified video time information 201 for a delay time from the video frame decoding completion time to the video frame display start time, and controls to minimize the delay time The video output control information 24 is generated by determining the video output timing for performing the above. As a result, the search period for automatically generating the video output timing can be determined from the encoded media information extracted from the transmission packet 2.

  As described above, according to the media receiver of the third embodiment, the video decoding time storage unit is notified from the video frame head detection time notified from the encoded video media analyzing unit and from the encoded video media decoding unit. The video display time determination unit calculates the difference value between the decoding time information extracted by the transmission packet analysis and separation means and the video frame head detection time, and the peak value at which the difference value is maximized is stored. The video output timing that minimizes the elapsed time from the decoding completion time to the video output is determined within the period determined based on the peak detection position and the number of detections. The time until decoding and video display is shortened to reduce the video display delay time, and the video display timing is the same for reception of encoded video media information having the same characteristics. It is possible to realize a media receiving apparatus implementing the video display you.

Embodiment 4 FIG.
Since the configuration of the media receiver 3 (3a) in the fourth embodiment in the drawing is the same as that in the first or second embodiment, it will be described with reference to FIG. 5 of the second embodiment.
The encoded video media decoding unit 20 according to Embodiment 3 detects whether or not the encoded video frame is constructed by the intra-screen encoding method in the video decoding process. Further, in the video decoding time storage unit 200 and the video display time determination unit 202, when the encoded video media decoding unit 20 detects that the encoded video frame is constructed by the intra-screen encoding method, the detection position And the video output timing that minimizes the elapsed time from the decoding completion time to the video output within a period determined based on the number of times of detection. Other configurations are the same as those in the first or second embodiment.

FIG. 8 is a diagram showing an example of the transition of the screen encoding method for each video frame in the media receiver 3 according to Embodiment 4 of the present invention.
The operation of the fourth embodiment will be described. The basic operation in the media receiver 3 is the same as that in the first embodiment or the second embodiment, and the operation that is different will be described.
When video decoding processing of the encoded video frame information 19 is performed in the decoded video media decoding unit 20, whether the encoding method of the video frame is in accordance with the above-described intra-screen encoding method in the process or inter-frame code Identify whether the system is based on the conversion method, and perform processing according to each method. For example, as shown in FIG. 8, an intra-picture encoding method in which encoding processing is performed with only information of the video frame called I picture, and encoding processing is performed using difference information from a past video frame called P picture. Combining the inter-picture coding method based on unidirectional prediction, the inter-picture coding method based on bi-prediction in which coding processing is performed using difference information for both past video frames and future video frames called B pictures. A video encoding process is performed. While encoding the difference information can reduce the amount of data rather than directly encoding the information of the video frame, the video frame for which the difference is to be calculated is required and a decoding error such as a transmission error occurs. There is also a problem that the decoding process may not be normally performed at the time of occurrence. Therefore, encoding processing is performed so that I pictures exist at a fixed period. The video frame decoding completion notification 21 is notified including the coding method type, such as the intra-screen coding method or the inter-screen coding method.

  The video decoding time storage unit 200 holds various types of time information together with the encoding method type of the video frame, and determines the search time based on the number of detections of the encoded video frame by the intra-screen encoding method. Since the periodicity needs to be more than one round, the detection accuracy at the video display time determination unit 202 is improved when the detection period is longer at least twice and the search period is longer. It is desirable to set the number of detections.

  The video decoding time accumulating unit 200 generates accumulated video time information 201 for the search period determined as described above and notifies the video display time determining unit 202 of the accumulated video time information 201. The video display time determination unit 202 searches the time information in the notified video time information 201 for a delay time from the video frame decoding completion time to the video frame display start time, and controls to minimize the delay time The video output control information 24 is generated by determining the video output timing for performing the above. As a result, the search period for automatically generating the video output timing can be determined from the encoded media information extracted from the transmission packet 2.

  As described above, according to the media receiver of the fourth embodiment, when it is detected in the video decoding process by the encoded video media decoding means that the encoded video frame is constructed by the intra-screen encoding method. The video decoding time calculation means determines the video output timing that minimizes the elapsed time from the decoding completion time to the video output within the period determined based on the detection position and the number of detections. Media reception that shortens the time from reception to video decoding and video display to reduce video display delay time, and performs video display with the same video display timing for reception of encoded video media information with the same characteristics An apparatus can be realized.

Embodiment 5 FIG.
Since the configuration of the fifth embodiment on the drawing is the same as that of the first or second embodiment, a description will be given with reference to FIG. 1 of the first embodiment.
FIG. 9 is an explanatory diagram of a packet structure including control information in the transmission packet 2 handled in the fifth embodiment of the present invention.
FIG. 9 shows control related to media information such as video and audio in the TS packet structure defined by the MPEG-2 Systems standard as an example in the case of storing control information in a transmission packet 2 transmitted from the media transmission device 1 and transmitting it. The parameters necessary for the explanation of the fifth embodiment regarding the Program_Map_Table (PMT) which is information are shown in bit arrangement. Although the meaning of each parameter is not directly related to the feature points of the fifth embodiment, detailed description thereof will be omitted. In FIG. 9, the area surrounded by a thick frame line stores individual definitions for media information such as video and audio. This area is enumerated as many as the number of types of media information.

  The media type is specified by stream_type, the ID for identifying the transmission packet storing the media is specified by media_PID, and additional information for the media is stored in the ES_Info area. In the ES_info area, various information can be repeatedly embedded with a structure including an identifier called a descriptor format, an information length, and an information data string. A control information packet is generated by embedding the maximum elapsed time information of the encoded video media information stored in the transmission packet in this ES_info area.

  The transmission packet analysis / analysis unit 11 detects the PMT that is the control information when analyzing the transmission packet 7 and extracts video additional information for the encoded video media information from the ES_info area in the PMT. Then, when notifying the display time information 13b, it may be notified to the video decoding time calculation unit 23 including the encoded video media additional information, or may be separately notified when the video additional information is detected.

  In the video decoding time calculation unit 23, the encoded video frame corresponding to the timing at which the encoded video media additional information is notified is identified as the video frame corresponding to the notified maximum elapsed time, and based on the maximum elapsed time information. Thus, the video output control information 24 is generated by determining the video output timing that minimizes the elapsed time from the decoding completion time to the video output.

  As described above, according to the media receiving apparatus of the fifth embodiment, the transmission packet analyzing / separating means is applied to the control information packet of the transmission packet output from the media transmitting apparatus from the start of decoding of the video frame to the completion of decoding. If the maximum elapsed time information is included, the control information packet is analyzed to extract the maximum elapsed time information, and the video decoding time calculation means corresponds to the maximum elapsed time information based on the extraction timing in the transmission packet analysis and separation means The video output timing is determined based on the video frame head detection time indicated by the reference time when the encoded video media analysis means detects the video frame head and the maximum elapsed time information notified in the control information packet. As a result, the time from receiving the transmission packet to video decoding and video display is shortened. It is possible to reduce the display delay time, and to realize the media receiving apparatus implementing the video display in which the image display timing in the same for the reception of coded video media information of the same characteristics.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Media transmission device, 2 Transmission packet, 3, 3a Media reception device, 4 Video display device, 5 Transmission packet reception part, 6 Transmission packet arrival notification, 7 Transmission packet, 8 Reference time generation part, 9 Reference time information, 10 Reference Time frequency signal, 11 Transmission packet analysis / separation unit, 12 Time playback information, 13 Video time information, 14 Encoded video media information, 15 Reference time playback unit, 16 Reference time information, 17 Encoded video media analysis unit, 18 Video frame Start detection notification, 19 encoded video frame information, 20 encoded video media decoding unit, 21 video frame decoding completion notification, 22 video signal, 23 video decoding time calculation unit, 24 video output control information, 25 video output timing generation unit, 26 Video output timing notification, 27 Video signal post-processing unit, 28 Video output No., 200 video decoding time storage unit, 201 stored video time information, 202 a video display time determination unit.

Claims (6)

Time reproduction information indicating a reference time of operation in a media transmitting apparatus that stores and outputs encoded video media information obtained by encoding a video signal in a transmission packet, and indicates a timing to start decoding the encoded video media information Video time information including decoding time information and display time information indicating a timing at which a video signal after video decoding is to be output is a media reception device that receives a transmission packet attached together with the encoded video media information,
A transmission packet analyzing / separating means for analyzing the received transmission packet and extracting the time reproduction information, the encoded video media information, and the video time information;
The reference time information in the own device is synchronized with the time reproduction information by comparing the reference time information of the operation in the own device at the time when the transmission packet is received and the time reproduction information extracted by the transmission packet analyzing / separating means. Reference time reproduction means for generating reference time control information to
Based on the reference time control information, the oscillation frequency of the reference signal serving as the reference time in the device itself is adjusted to control the advance of the reference time, and the reference time information indicating the controlled reference time and the adjusted time are adjusted. A reference time generating means for distributing a reference frequency signal indicating an oscillation frequency within the apparatus;
Analyzing the encoded video media information, detecting and notifying the beginning of the video frame, and encoding video media analysis means for outputting as encoded video frame information;
Decoding the encoded video frame information to restore the video signal, and an encoded video media decoding means for notifying the completion of decoding when decoding of the video frame is completed;
Video frame head detection time indicated by the reference time when the detection of the start of the video frame is notified, decoding completion time indicated by the reference time when the completion of decoding of the video frame is notified, and the display for the video frame A media receiving apparatus comprising: a video decoding time calculating unit that compares time information and calculates a video output timing that minimizes an elapsed time from detection of a video frame head to video output. The video decoding time calculation means
A video decoding time storage unit for storing the display time indicated by the display time information for the video frame extracted by the transmission packet analyzing and separating unit and the decoding completion time when the video frame decoding for the video frame is completed by the encoded video media decoding unit; ,
A difference time from the decoding completion time to the display time in the video frame is calculated, the difference time is calculated for a plurality of video frames for a predetermined period, and based on the difference time within the predetermined period, the video from the decoding completion to the video time is calculated. The media receiving apparatus according to claim 1, further comprising: a video display time determination unit that determines a video output timing that minimizes an elapsed time until output. The encoded video media decoding means calculates the display start scheduled time for the video frame by extracting the video frame interval from the encoded video frame information,
The video decoding time calculation means
A video decoding time storage unit that stores a display time indicated by display time information for the video frame extracted by the transmission packet analysis and separation unit, and a decoding completion time for the video frame notified from the encoded video media decoding unit;
The difference time from the decoding completion time for the video frame to the scheduled display start time for the video frame is performed for a plurality of video frames for a predetermined period, and the elapsed time from the completion of decoding to video output based on the difference time within the predetermined period The media receiving apparatus according to claim 1, further comprising a video display time determination unit that determines a video output timing that minimizes time. The video decoding time storage unit stores the video frame head detection time notified from the encoded video media analyzing unit and the decoding completion time notified from the encoded video media decoding unit,
The video display time determination unit calculates a difference value between the decoding time information extracted by the transmission packet analysis and separation unit and the video frame head detection time, searches for a peak where the difference value is maximum, 4. The media reception according to claim 2, wherein a video output timing that minimizes an elapsed time from decoding completion time to video output is determined within a period determined based on the detection position and the number of detections. apparatus.   In the video decoding process in the encoded video media decoding means, when it is detected that the encoded video frame is constructed by the intra-screen encoding method, the video decoding time calculating means is based on the detection position and the number of detections. 5. The media receiving apparatus according to claim 1, wherein a video output timing that minimizes an elapsed time from decoding completion time to video output is determined within the determined period. 6. . The transmission packet analysis / separation means analyzes the control information packet when the control information packet of the transmission packet output from the media transmission device includes the maximum elapsed time information from the start of decoding of the video frame to the completion of decoding. To extract the maximum elapsed time information,
The video decoding time calculating means specifies a video frame corresponding to the maximum elapsed time information based on the extraction timing in the transmission packet analyzing and separating means, and a reference when the encoded video media analyzing means detects the head of the video frame. 6. The media reception according to claim 1, wherein the video output timing is determined based on the video frame head detection time indicated by the time and the maximum elapsed time information notified by the control information packet. apparatus.

Images