JP2012249086A - Video receiver - Google Patents

Abstract

Compared to recording MPEG2-TTS in a recording unit, the amount of recorded data can be reduced, and a transport stream before deletion from a transport stream after deleting null packets is restored by simple processing. A video receiving apparatus capable of performing the above is obtained.
A video receiver 4 receives a transport stream S1 including a plurality of transport packets, and deletes null packets from the plurality of transport packets included in the transport stream S1. A deletion processing unit 12 that generates a transport stream S2 and records it in the recording unit 13 by adding deletion number information regarding the number of deleted null packets to the deletion portion of the null packet.
[Selection] Figure 2

Description

  The present invention relates to a video receiving apparatus.

  In a communication protocol using MPEG (Moving Picture Experts Group) 2-TS (Transport Stream), the video transmission apparatus adds a PCR (Program Clock Reference) for each transport packet at a predetermined interval. The video reception device detects the PCR included in the transport packet and regenerates the clock of the video transmission device based on the detected PCR. In MPEG2-TS, meaningless transport packets (null packets) are included in the transport stream in order to adjust the communication speed. The video transmitting apparatus adds PCR to the transport stream including a null packet.

  The following Patent Documents 1 and 2 disclose a technique for converting MPEG2-TS into MPEG2-TTS (Time-stamped Transport Stream) by adding a 4-byte time stamp to each MPEG2-TS transport packet. It is disclosed.

JP 2008-35197 A JP 2008-35198 A

  When the transport stream received by the video receiver is recorded in a recording unit such as a hard disk, it is desirable to record the transport stream after deleting the null packet in order to reduce the amount of recording data. In this case, the position of the transport packet including the PCR differs before and after the null packet is deleted. Therefore, also in the transport stream input to the decoder, the position of the transport packet including the PCR is different from the original position (position in the transport stream before the null packet is deleted). Therefore, the decoder cannot accurately reproduce the clock of the video transmission device only by the detected PCR. Therefore, by using MPEG2-TTS with a time stamp added, even if a null packet is deleted at the time of recording, the decoder determines the original position of the transport packet including the PCR based on the time stamp. Can be restored. Therefore, the decoder can reproduce the clock of the video transmission apparatus based on the PCR included in the transport packet restored to the original position.

  However, when MPEG2-TTS is recorded in the recording unit, a 4-byte time stamp is added to all the transport packets included in the transport stream after the null packet is deleted. Therefore, the recording data amount increases by the data amount corresponding to “the number of transport packets” × “4 bytes”.

  If the decoder does not support MPEG2-TTS, it is necessary to restore MPEG2-TS from MPEG2-TTS by inserting a null packet into MPEG2-TTS read from the recording unit. The number of null packets to be inserted can be calculated using the time stamp interval. However, when a real-time clock or the like is used at the time of adding a time stamp, the number of null packets to be inserted may not accurately match the time stamp interval due to a clock error or the like. In this case, it is necessary to determine the number of null packets to be inserted based on an error tendency or the like, but this determination process is complicated, and if the number is incorrectly determined, the complete MPEG2-TS is determined. Can not be restored.

  The present invention has been made in view of such circumstances, and can reduce the amount of recorded data as compared with the case of recording MPEG2-TTS in a recording unit, and can be deleted from a transport stream after deleting null packets. It is an object of the present invention to obtain a video receiving apparatus capable of restoring the transport stream before the processing by simple processing.

  The video reception apparatus according to the first aspect of the present invention includes a receiving unit that receives a first transport stream including a plurality of transport packets, and a plurality of transports included in the first transport stream. Deleting a null packet from the packet and adding a piece of information about the number of deleted null packets to the deleted portion of the null packet, thereby generating a second transport stream and recording it in the recording unit; It is characterized by providing.

  According to the video reception device according to the first aspect, the deletion processing unit deletes null packets from the plurality of transport packets included in the first transport stream, and information on the number of deleted null packets. Is added to the deleted portion of the null packet to generate a second transport stream and record it in the recording unit. Therefore, the information is added to the deleted portion of the null packet and not to all the transport packets. Therefore, the amount of recorded data can be reduced as compared with the case where MPEG2-TTS is recorded in the recording unit. Is possible. Further, since the information is information on the number of deleted null packets, when restoring the transport stream before deleting from the transport stream after deleting the null packets, the number described in the information It is enough to insert a null packet. As a result, complicated calculations and processing are not required, and it is possible to easily restore the transport stream before deleting the null packet.

  The video reception device according to the second aspect of the present invention is the video reception device according to the first aspect, in particular, a decoder that decodes a transport stream, reads the second transport stream from the recording unit, and A restoration processing unit for deleting the information and inserting the number of null packets according to the information to restore the first transport stream and input to the decoder. To do.

  According to the video reception device according to the second aspect, the restoration processing unit reads the second transport stream from the recording unit, deletes the information, and inserts the number of null packets according to the information. The first transport stream is restored. As described above, the first transport stream can be restored from the second transport stream by a simple process. As a result, even when the decoder does not support MPEG2-TTS, video can be reproduced. It becomes possible.

  The video reception device according to the third aspect of the present invention is the video reception device according to the first aspect, in particular, a decoder that decodes a transport stream, reads the second transport stream from the recording unit, and An adjustment processing unit that deletes information and adjusts the timing of inputting a plurality of transport packets included in the second transport stream to the decoder based on the information. It is a feature.

  According to the video reception device of the third aspect, the adjustment processing unit reads the second transport stream from the recording unit, deletes the information, and includes a plurality of transformers included in the second transport stream. The timing for inputting the port packet to the decoder is adjusted based on the information. As described above, the timing at which a plurality of transport packets included in the second transport stream are input to the decoder can be adjusted by simple processing. As a result, the decoder does not support MPEG2-TTS. However, the video can be reproduced.

  The video receiving apparatus according to the fourth aspect of the present invention is characterized in that, in the video receiving apparatus according to any one of the first to third aspects, a plurality of pieces of information having different data lengths are used as the information. To do.

  According to the video receiving apparatus according to the fourth aspect, a plurality of pieces of information having different data lengths are used. Therefore, in principle, the amount of recorded data can be reduced by using information with a short data length. In addition, if the data length is short with the information with a short data length to represent the number of null packets to be deleted, it is possible to cope with such an exceptional situation by using the information with the long data length. It becomes possible.

  According to the present invention, compared to the case of recording MPEG2-TTS in a recording unit, the amount of recording data can be reduced, and a transport stream before deletion from a transport stream after deleting null packets can be simplified. It can be restored by processing.

It is a figure which shows the whole structure of the video delivery system which concerns on embodiment of this invention. It is a block diagram which simplifies and shows the structure of the video receiver which concerns on the 1st Embodiment of this invention. It is a figure which shows a transport stream. It is a figure which shows the 1st example of deletion number information. It is a figure which shows the 2nd example of deletion number information. It is a block diagram which simplifies and shows the structure of the video receiver which concerns on the 2nd Embodiment of this invention. It is a figure which shows a transport stream.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the element which attached | subjected the same code | symbol in different drawing shall show the same or corresponding element.

  FIG. 1 is a diagram showing the overall configuration of the video distribution system 1. As shown in FIG. 1, the video distribution system 1 includes a video transmission device 2, a communication network 3 such as an IP (Internet Protocol) network, a video reception device 4, and a television 5 such as a liquid crystal display device. ing. The video transmission device 2 is, for example, a transmission server installed in a transmission station for IP retransmission service. The video receiver 4 is, for example, an STB (Set Top Box) installed in the user's home. Note that the function of the video reception device 4 may be built in the television 5, and in this case, the television 5 functions as the video reception device.

  The video transmission device 2 transmits an MPEG2-TS transport stream S1 toward the communication network 3. The transport stream S1 includes a plurality of transport packets having a data length of 188 bytes. In addition to the transport packet including the video signal, the plurality of transport packets include a transport packet (null packet) including a meaningless signal such as all zero for adjusting the communication speed. Note that, in the MPEG2-TS transport stream S1, unlike the MPEG2-TTS, a 4-byte time stamp is not added to each transport packet. The video reception device 4 receives the transport stream S1 from the communication network 3. Then, processing such as decoding is performed, and the transport stream after the processing is transmitted to the television 5, thereby reproducing the video on the television 5.

<First Embodiment>
FIG. 2 is a block diagram showing a simplified configuration of the video reception device 4A according to the first embodiment of the present invention. As shown in FIG. 2, the video reception device 4 </ b> A includes a reception unit 11, a deletion processing unit 12, a recording unit 13 such as a built-in hard disk, a restoration processing unit 14, a decoder 15, and a transmission unit 16. The recording unit 13 may be an external hard disk or the like externally connected to the video receiving device 4A.

  The receiving unit 11 receives the transport stream S1 from the communication network 3, and inputs the transport stream S1 to the deletion processing unit 12. The deletion processing unit 12 generates a transport stream S2 based on the transport stream S1, and inputs the transport stream S2 to the recording unit 13. The recording unit 13 records the transport stream S2. The restoration processing unit 14 reads the transport stream S2 from the recording unit 13, generates a transport stream S3 based on the transport stream S2, and inputs the transport stream S3 to the decoder 15. The decoder 15 generates a video signal S4 by decoding the transport stream S3, and inputs the video signal S4 to the transmission unit 16. The transmission unit 16 transmits the video signal S4 toward the television 5. Thereby, an image is reproduced on the television 5.

  FIG. 3 is a diagram illustrating transport streams S1 to S3. Transport streams S1, S2, and S3 are shown in FIGS. 3A, 3B, and 3C, respectively. For simplification of explanation, FIG. 3 shows only some of the transport packets included in the transport streams S1 to S3. In FIG. 3, the transport packets P1 to P8 including the video signal in the payload portion are sanded, and the null packets N1 to N4 are not hatched. Further, the hatched hatching is added to the transport packet including the PCR in the header part.

  With reference to FIGS. 2 and 3, the transport stream S <b> 1 is input from the reception unit 11 to the deletion processing unit 12. In the example shown in FIG. 3A, three null packets N1 to N3 are inserted between the transport packet P1 and the transport packet P2, and the transport packet P5 and the transport packet P6. 1 null packet N4 is inserted in between.

  The deletion processing unit 12 deletes the null packets N1 to N4 from the plurality of transport packets included in the transport stream S1. Further, the deletion processing unit 12 adds information on the number of deleted null packets (hereinafter referred to as “deleted number information”) to the deleted portion of the null packet. In the example shown in FIG. 3B, the deletion processing unit 12 deletes the three pieces of null packets N1 to N3, and deletes the deletion number information G1 indicating “3” as one null packet N1. It is added to the previous transport packet P1 (or the transport packet P2 immediately after the null packet N3). Further, the deletion processing unit 12 deletes the deletion number information G2 indicating “1” with the deletion of one null packet N4, and the transport packet P5 (or null packet N4) immediately before the null packet N4. To the next transport packet P6). The deletion processing unit 12 records the generated transport stream S2 in the recording unit 13.

  FIG. 4 is a diagram illustrating a first example of the deletion number information G1. 4A shows a mode in which the deletion number information G1 is added to the transport packet P1, and FIG. 4B shows the bit contents of the deletion number information G1. As shown in FIG. 4A, the deletion number information G1 follows the transport packet P1. The deletion number information G1 has a data length of 1 byte from bit B0 which is the least significant bit to bit B7 which is the most significant bit. Seven bits of bits B0 to B6 indicate the maximum number of deleted null packets from “1” to “127”. Bit B7 is an extension bit for indicating the presence / absence of extension data. When the value of bit B7 is “1”, it indicates that deletion number information of 1 byte continues after deletion number information G1. When the value of bit B7 is “0”, it indicates that the deletion number information of 1 byte does not follow the deletion number information G1. In the example shown in FIG. 4B, the value of bit B7 is “0”.

  FIG. 5 is a diagram illustrating a second example of the deletion number information G1. FIG. 5A shows a mode in which the deletion number information G1, G1A is added to the transport packet P1, and FIG. 5B shows the bit contents of the deletion number information G1, G1A. ing. As shown in FIG. 5A, the deletion number information G1 follows the transport packet P1, and the deletion number information G1A follows the deletion number information G1. The deletion number information G1 has a data length of 1 byte of bits B0 to B7, and the deletion number information G1A has a data length of 1 byte of bits B8 to B15. Bits B7 and B15 are extension bits. When each value is “1”, this indicates that 1-byte deletion number information continues after itself, and each value is “0”. In some cases, it is indicated that 1-byte deletion number information does not follow itself. In the example shown in FIG. 5B, the value of bit B7 is “1”, and the value of bit B15 is “0”. In this case, 14 bits of bits B0 to B6 and B8 to B14 indicate the maximum number of deleted 16384 null packets from “1” to “16384”. By setting the value of bit B15 to “1”, the deletion number information can be further continued after the deletion number information G1A.

  When the number of continuously deleted null packets is 1 or more and 127 or less, the deletion processing unit 12 uses the deletion number information G1 shown in FIG. Is 128 or more and 16384 or less, the deletion number information G1 and G1A shown in FIG. 5 is used.

  4 and 5 show the deletion number information G1 and G1A of 1 byte length, the data length of the deletion number information is not limited to this example. 4 and 5 show examples of the deletion number information G1 and G1A, but the same applies to other deletion number information G2 and the like.

  Referring again to FIGS. 2 and 3, the transport stream S <b> 2 is input from the recording unit 13 to the restoration processing unit 14. The restoration processing unit 14 deletes the deletion number information included in the transport stream S2. In addition, the restoration processing unit 14 inserts the number of null packets corresponding to the deleted number information into the deleted portion of the deleted number information. In the example shown in FIG. 3C, the restoration processing unit 14 deletes the deletion number information G1, and three null packets N1 according to the number information “3” indicated by the deletion number information G1. ... N3 are inserted into the deletion location of the deletion number information G1. Further, the restoration processing unit 14 deletes the deleted number information G2, and inserts one null packet N4 into the deleted position of the deleted number information G2 in accordance with the number information “1” indicated by the deleted number information G2. To do. As a result, the transport stream S1 shown in FIG. The restoration processing unit 14 inputs the generated transport stream S3 to the decoder 15.

  By the above processing by the restoration processing unit 14, the position of the PCR is reproduced in the transport stream S3 to the original position (that is, the position in the transport stream S1 before the null packet is deleted by the deletion processing unit 12). Yes. Therefore, the decoder 15 can decode the transport stream S3 based on the clock of the video transmission device 2 reproduced based on the PCR.

  As described above, according to the video reception device 4A according to the present embodiment, the deletion processing unit 12 deletes null packets from a plurality of transport packets included in the transport stream S1, and also deletes the deleted null packets. By adding deletion number information regarding the number to the deletion portion of the null packet, a transport stream S2 is generated and recorded in the recording unit 13. Therefore, since the deletion number information is added only to the deleted portion of the null packet and not to all the transport packets, the amount of recorded data is smaller than when the MPEG2-TTS is recorded in the recording unit 13. Can be reduced. Since the deleted number information is information related to the number of deleted null packets, when the transport stream S1 is restored from the transport stream S2, the number of null packets described in the deleted number information is inserted. All you need is enough. As a result, complicated calculation and processing are not required, and it is possible to easily restore the transport stream S1 before deleting the null packet. The same applies to a second embodiment described later.

  In addition, according to the video reception device 4A according to the present embodiment, the restoration processing unit 14 reads the transport stream S2 from the recording unit 13, deletes the deleted number information, and the number corresponding to the deleted number information. The transport stream S1 is restored by inserting a null packet. In this way, the transport stream S1 can be restored from the transport stream S2 by simple processing, and as a result, even when the decoder 15 does not support MPEG2-TTS, it is possible to reproduce the video. .

  In addition, according to the video reception device 4A according to the present embodiment, as shown in FIGS. 4 and 5, a plurality of data lengths with different data lengths are obtained by making the data length of the deletion number information variable by setting the extension bits. The deleted number information is used. Therefore, in principle, it is possible to reduce the amount of recording data in the recording unit 13 by using deletion number information having a short data length (for example, 1 byte). In addition, when the deletion length information with a short data length indicates the number of null packets to be deleted and the data length is insufficient, the deletion number information with a long data length (for example, 2 bytes) is used. It is possible to deal with exceptional situations. The same applies to a second embodiment described later.

<Second Embodiment>
FIG. 6 is a block diagram showing a simplified configuration of the video reception device 4B according to the second embodiment of the present invention. As illustrated in FIG. 6, the video reception device 4 </ b> B includes a reception unit 11, a deletion processing unit 12, a recording unit 13, an adjustment processing unit 20, a decoder 15, and a transmission unit 16.

  The adjustment processing unit 20 reads the transport stream S2 from the recording unit 13, generates the transport stream S5 based on the transport stream S2, and inputs the transport stream S5 to the decoder 15.

  FIG. 7 is a diagram showing transport streams S1, S2, and S5. (A), (B), and (C) of FIG. 7 show the transport streams S1, S2, and S5, respectively.

  Referring to FIGS. 2 and 7, transport stream S <b> 2 is input from recording unit 13 to adjustment processing unit 20. The adjustment processing unit 20 deletes the deletion number information included in the transport stream S2. In addition, the adjustment processing unit 20 adjusts the timing at which the transport packet included in the transport stream S2 is input to the decoder 15 based on the deletion number information. In the example shown in FIG. 7C, the adjustment processing unit 20 deletes the deleted number information G1, and 3 (pieces) × 188 according to the number information “3” indicated by the deleted number information G1. The waiting time T1 is calculated by a calculation of (byte) × 8 (bit) ÷ bit rate. Then, after the input of the transport packet P1 to the decoder 15 is completed, the input of the next transport packet P2 to the decoder 15 is started at the timing when the waiting time T1 has elapsed. Similarly, the adjustment processing unit 20 deletes the deletion number information G2, and according to the number information “1” indicated by the deletion number information G2, 1 (pieces) × 188 (bytes) × 8 (bits) ÷ The waiting time T2 is calculated by a calculation called a bit rate. Then, after the input of the transport packet P5 to the decoder 15 is completed, the input of the next transport packet P6 to the decoder 15 is started at the timing when the waiting time T2 has elapsed.

  Through the above processing by the adjustment processing unit 20, the position of the PCR is reproduced in the original position in the transport stream S5 input from the adjustment processing unit 20 to the decoder 15. Therefore, the decoder 15 can decode the transport stream S5 based on the clock of the video transmission device 2 reproduced based on the PCR.

  As described above, according to the video reception device 4B according to the present embodiment, the adjustment processing unit 20 reads the transport stream S2 from the recording unit 13, deletes the deletion number information, and is included in the transport stream S2. The timing for inputting the plurality of transport packets to the decoder 15 is adjusted based on the deletion number information. As described above, the timing at which a plurality of transport packets included in the transport stream S2 are input to the decoder 15 can be adjusted by simple processing. As a result, the decoder 15 does not support MPEG2-TTS. However, the video can be reproduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

4 video receiving device 11 receiving unit 12 deletion processing unit 13 recording unit 14 restoration processing unit 15 decoder 20 adjustment processing unit

Claims (4)

A receiving unit for receiving a first transport stream including a plurality of transport packets;
By deleting null packets from a plurality of transport packets included in the first transport stream, and adding information on the number of deleted null packets to the deletion position of the null packets, the second transport A deletion processing unit that generates a stream and records it in a recording unit;
A video receiving device. A decoder that decodes the transport stream;
The second transport stream is read from the recording unit, the information is deleted, and the number of null packets corresponding to the information is inserted to restore the first transport stream to the decoder. Input the restoration processing unit,
The video receiving device according to claim 1, further comprising: A decoder that decodes the transport stream;
Read the second transport stream from the recording unit, delete the information, and input the plurality of transport packets included in the second transport stream to the decoder. An adjustment processing unit that adjusts based on;
The video receiving device according to claim 1, further comprising:   The video reception device according to claim 1, wherein a plurality of pieces of information having different data lengths are used as the information.

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