JP2011176703A - Media multiplexing apparatus, and media demultiplexing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a media multiplexing apparatus and a media demultiplexing apparatus capable of improving immunity of a media signal to an error to be applied to an identifier. <P>SOLUTION: A PID to be assigned for identifying a plurality of multiplexing elements, respectively, is assigned to the multiplexing elements so as to increase a code distance between PIDs. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a media multiplexer that multiplexes and transmits media signals such as video and audio of a plurality of programs, and a media separator that receives multiplexed signals and separates the media signals.

In transmission by MPEG (Moving Picture Experts Group) transport stream (hereinafter referred to as MPEG-TS), multiplexing is performed based on a packet identifier (Packet IDentification; hereinafter referred to as PID) having a different value for each medium. The media signals are separated (see, for example, Non-Patent Document 1). For this reason, the conventional media separating apparatus has a problem that it is vulnerable to errors added to the PID.
For example, when an error is added to the PID of a TS packet, a media signal corresponding to the PID before the error is lost for one TS packet. In addition, if an erroneously added PID coincides with another PID by chance, incorrect information is added to the media signal of the matched PID by one TS packet.
Further, in the conventional media multiplexing apparatus, it is not considered that an erroneous PID coincides with another PID by chance as described above due to an error added to the PID in the PID assignment.
This problem has a great influence on the reception quality and reproduction quality of media signals, particularly in the reception of digital broadcasts in a mobile body such as an automobile and in a wireless transmission environment with a high error rate.
As a conventional technique for solving such a problem, for example, in Patent Document 1, an error correction code is added to the PID of a media multiplexer, and the media separator corrects the multiplexed data with the error correction code. The invention which copes with the error added to PID by performing is disclosed.

JP 2000-32055 A

ITU-T Rec. H.222.0 (2000 E), p. 8-9, 18-19

In the invention disclosed in Patent Document 1, since it is necessary to perform processing according to a rule agreed in advance by both the media multiplexing device and the media separation device, when applying to an existing system, both the transmission and reception devices are There was an issue that had to be changed.
Further, in Patent Document 1, since assignment of a PID value is restricted by an error correction code, there is a problem that it cannot be applied when there is a PID fixed in advance by a standard or the like.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a media multiplexing device and a media separation device that can improve resistance to errors added to a PID (media signal identifier).

  The media multiplexing device according to the present invention is assigned to identify a plurality of inputted media signals in a media multiplexing device which inputs a plurality of media signals, multiplexes these media signals and outputs them as media multiplexed signals. An allocating unit that allocates identifiers to media signals so that the code distance between the identifiers is separated is provided.

  The media separation device according to the present invention is a media separation device which receives a media multiplexed signal obtained by multiplexing a plurality of media signals, separates the media signal from the media multiplexed signal, and outputs the multiplexed media signal. It is determined whether or not an identifier assigned to identify each of the converted media signals includes an error. If it is determined that an error is included, the identifier value before the error is added is determined in the media multiplexed signal. And an identifier selected from the identifier candidates that can appear in the above, and a correction unit that corrects an identifier determined to contain an error.

  According to the media multiplexing apparatus of the present invention, since the identifiers assigned for identifying the plurality of media signals are assigned to the media signals so that the code distances between the identifiers are separated from each other, the code distances between the identifiers are assigned apart from each other. Therefore, even when an error is added to the identifier, the probability of matching with another identifier can be lowered. Thereby, there is an effect that it is possible to improve resistance to errors added to the identifier of the media signal.

  According to the media separation device of the present invention, if it is determined that an error is included in the identifier of the media signal multiplexed in the media multiplex signal, it can appear in the media multiplex signal as the value of the identifier before the error is added. An identifier selected from the identifier candidates that is determined to contain an error is corrected. Thus, by correcting the error added to the identifier with the one selected from the identifier candidates that can appear in the media multiplexed signal, it is possible to improve the resistance to the error added to the identifier of the media signal. .

  Note that even if the above-described media multiplexing device and media separation device are applied independently, the above-described effects can be obtained, and application to an existing system is easy. As a result, there is an effect that it is possible to improve the reception / reproduction quality of the media in reception by a mobile unit or in a wireless transmission environment.

It is a block diagram which shows the structure of the media multiplexing apparatus by Embodiment 1 of this invention. It is a figure which shows an example of multiple control instruction information S121. It is a figure which shows an example of multiple | multiplex control setting information S122. It is a block diagram which shows the structure of the media separation apparatus by Embodiment 1 of this invention. It is a figure which shows an example of separation control information S421.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the configuration of a media multiplexing apparatus according to Embodiment 1 of the present invention. In FIG. 1, a media multiplexing apparatus B100 according to Embodiment 1 is an apparatus that receives multiplexing elements S101 to S110 and multiplexing control instruction information S121, and outputs a transmission transport stream (TS) S130 in which these elements are multiplexed. . In FIG. 1, the multiple elements S101 to S110 are the video S101, the audio S102, the reference time S103, the additional information S104, the video S105, the audio S106, and the reference time S107 that constitute the content of the program 2, respectively. These signals are additional information S108, additional information S109 and additional information S110, which are information common to programs 1 and 2 (common information).

The media multiplexing apparatus B100 includes a PID allocation unit (allocation unit) B101, a PAT generation unit B102, a PMT generation unit B103, and a multiplexing unit B104.
The PID allocation unit B101 is a component that generates and outputs multiple control setting information S122 based on the input multiple control instruction information S121.
The multiplex control instruction information S121 is a signal that modifies the multiplex elements S101 to S110, which are media signals such as video and audio of a plurality of different programs, and instructs a multiplexing method. Details of the multiple control instruction information S121 will be described later with reference to FIG.
The multiplex control setting information S122 is a signal in which items related to the multiplex element PAT and the multiplex element PMT are added to the multiplex control instruction information S121, and the PIDs of all the multiplex elements in the multiplex control instruction information S121 are set. Details of the multiple control setting information S122 will be described later with reference to FIG.

The PAT generation unit B102 is a configuration unit that generates a program association table (PAT) S111 based on the item content related to the multiple element PAT of the multiple control setting information S122 input from the PID allocation unit B101.
The PMT generation unit B103 is a configuration unit that generates program map tables (PMTs) for the number of programs based on the item content related to the multiple element PMT of the multiple control setting information S122 input from the PID allocation unit B101. FIG. 1 shows a case where the number of programs is two, and the number of PMTs generated by the PMT generation unit B103 increases or decreases according to the type of program number included in the multiplex control setting information S122. Here, PMT1 (S112) is generated as the PMT of program 1, and PMT2 (S113) is generated as the PMT of program 2.

  Multiplexer B104 receives multiplex elements S101 to S110, PAT (S111), PMT1 (S112), and PMT2 (S113), and based on multiplex control setting information S122, multiplex elements S101 to S110, PAT (S111), and PMT1 (S112) is a component that multiplexes PMT2 (S113) and outputs it as a transmission TS (S130).

  FIG. 2 is a diagram illustrating an example of the multiplex control instruction information S121. The multiplex control instruction information S121 shown in FIG. 2 includes, for each of the multiplex elements S101 to S110, the multiplex format of the multiplex format item C202, the PID of the PID item C203, the signal type of the signal type item C204, and the program of the program number item C205. It has a combination of number and bit rate of bit rate item C206.

The multi-element item C201 indicates which of the multi-elements S101 to S110 the combination described above relates to. That is, multiple elements S101 to S110 are set.
In the multiplex format item C202, a multiplex format for multiplexing the multiplex element signal shown in the multiplex element item C201 is set. Here, multiplexing is performed in one of the formats of PES (Packetized Elementary Stream), PCR (Program Clock Reference), and Section.

In the PID item C203, a PID assigned to a TS packet on which each multi-element signal set in the multi-element item C201 is placed is specified. Here, when there is no designation, it indicates that the media multiplexing apparatus B100 may arbitrarily assign the PID for the TS packet carrying the signal of the multiple element shown in the multiple element item C201.
In the signal type item C204, the type of each multi-element signal set in the multi-element item C201 is designated. Here, video, audio, reference time, and the like are designated as the signal type. There may be no designation.

In the program number item C205, a program number for specifying a program to which each multi-element signal set in the multi-element item C201 belongs is specified. 1 and 2 show a case where there are two programs, the program number of program 1 is “1”, and the program number of program 2 is “2”.
In the bit rate item C206, the bit rate of each multiplex element signal set in the multiplex element item C201 is designated. For example, the bit rate of the video S101 is 15 Mbps, and the audio S102 is 200 kbps.

  FIG. 3 is a diagram illustrating an example of the multiplex control setting information S122, which is generated based on the multiplex control instruction information S121 of FIG. As shown in FIG. 3, the multiplex control setting information S122 is an internal signal similar to the multiplex control instruction information S121, and for each of the multiplex elements S101 to S113, the multiplex format of the multiplex format item C302 and the PID item C303. It has a combination of PID, signal type of signal type item C304, program number of program number item C305, and bit rate of bit rate item C306. That is, the multiplex control setting information S122 is obtained by adding items related to the PAT and PMT to the multiplex control instruction information S121 and setting the PIDs of all the multiplex elements S101 to S113.

The multi-element item C301 indicates which of the multi-elements S101 to S113 the above-described combination relates to. That is, multiple elements S101 to S113 are set.
In the multiplex format item C302, a multiplex format for multiplexing each multiplex element signal set in the multiplex element item C301 is set. Here, multiplexing is performed in any one of PES, PCR, and Section formats.

In the PID item C303, a PID assigned to a TS packet on which each multi-element signal set in the multi-element item C301 is placed is specified.
In the signal type item C304, the type of each multi-element signal set in the multi-element item C301 is designated. Here, video, audio, reference time, PAT, PMT, and the like are designated as the signal type. Note that some of them may not be specified, but PAT and PMT are always specified.

In the program number item C305, a program number for specifying a program to which each multi-element signal set in the multi-element item C301 belongs is specified. The program number of program 1 is “1”, and the program number of program 2 is “2”. If there is no designation, it indicates that the multi-element signal does not belong to the program.
In the bit rate item C306, the bit rate of each multiplex element signal set in the multiplex element item C301 is designated. For example, the bit rate of the video S101 is 15 Mbps, and the PMT1 (S112) is 15 kbps.

  The number and configuration of the above-described multiple elements S101 to S110, and the contents of the corresponding multiple control instruction information S121 and multiple control setting information S122 are merely examples, and the present invention is not limited to the above contents. Absent.

Next, the operation will be described.
First, when the multiplex control instruction information S121 is input, the PID assigning unit B101 adds multiplex control information related to PAT and multiplex control information related to PMTs corresponding to the number of programs to the multiplex control instruction information S121. In the PID item C203 of the control instruction information S121, the PID is determined for all elements for which no PID is specified, and is output as the multiplex control setting information S122.
In the example of FIG. 3, the multiplex control information related to PAT is that the multiplex element item C301 is the multiplex element S111, the multiplex format item C302 is Section, the PID item C303 is “0x0000”, the signal type item C304 is PAT, and the program The number item C305 is not specified. In the multiplex control information regarding the PMT, the multiplex element item C301 is the multiplex element S112, the multiplex format item C302 is Section, the PID item C303 is “0x1100”, the signal type item C304 is PMT, and the program number item C305 is “1”. . The multi-element item C301 is the multi-element S113, the multi-format item C302 is Section, the PID item C303 is “0x1200”, the signal type item C304 is PMT, and the program number item C305 is “2”.

The determination of the PID by the PID allocation unit B101 described above is performed according to the following procedure.
(1) From all PIDs (0x0000 to 0x1FFF) that can be assigned in advance, the PID already specified in the PID item C203 of the multiple control instruction information S121 and the NULL PID (0x1FFF) are excluded. Things are obtained as PID candidates.
(2) For each PID in the PID candidate, the minimum code distance from all the PIDs specified in the PID item C203 is calculated. The calculation of the code distance between PIDs uses the Hamming distance, that is, the number of bits that do not match.
(3) Among the minimum code distances calculated for each PID, select one PID having the maximum minimum code distance.
(4) Among the multiplex elements for which no PID is specified in the PID item C203 of the multiplex control instruction information S121 (including the added multiplex control information), the one having the highest bit rate specified in the bit rate item C206 (C306) The PID selected in (3) is set in the PID item C203 (C303) of this multi-element.
(5) The operations of (1) to (4) are repeated until there is no multiple element of “No PID designation” in the PID item C203 (C303).

  In the above (4), when the bit rate is not specified, a method of using a predetermined approximate value prepared in advance for any one or a plurality of combinations of items C201 to C205, and bits for multiple elements S101 to S110 A method of measuring and using a rate, a method of using a value obtained by calculation from the bit rate of another multiple element specified in the bit rate item C306 of the multiple control setting information S122 for the multiple elements S111 to S113, etc. Execute.

Also, since some TS packets may be dropped during TS transmission, the bit rate of the TS packet transmitted on the transmission path in which an error is added to the TS may be set in the bit rate item C206. .
Further, by adding the PID and bit rate of the NULL packet as multiplexing elements to the multiplexing control instruction information S121 before executing the above-described PID determination, it is possible to cope with errors added to the NULL packet. .

  Next, when the PAT generation unit B102 receives the multiplex control setting information S122 from the PID allocation unit B101, among the signal type item C304 of the multiplex control setting information S122, the multiplex element whose signal type is PMT (S112, S113) The PID and program number of this multi-element are extracted, and a PAT defining the combination of the extracted PID and program number is generated. The PAT generated in this way is output as PAT (S111) from the PAT generation unit B102 to the multiplexing unit B104.

  Further, in the PMT generation unit B103, when the multiplex control setting information S122 is input from the PID allocation unit B101, a combination of PID and signal type is extracted from the multiplex control setting information S122 for each program number, and these combinations are defined. A PMT is generated and output for each program. The PMT generated in this way is output as PMT (S112 (corresponding to program 1) and S113 (corresponding to program 2)) from the PMT generating unit B103 to the multiplexing unit B104.

Multiplexer B104 includes multiple elements S101 to S104 related to program 1, multiple elements S105 to S108 related to program 2, additional information S109 and S110 that are information common to programs 1 and 2, PAT (S111) from PAT generator B102, and When the PMT (S112, S113) from the PMT generation unit B103 is input as a multiplex element and the multiplex control setting information S122 is input from the PID assignment unit B101, each multiplex element is referred to the multiplex format item C302 of the multiplex control setting information S122. The PID is specified with reference to the PID item C303. Thereafter, the multiplexing unit B104 generates a TS packet in which each of the multiplexing elements S101 to S113 is multiplexed in the specified multiplexing format and has the specified PID, and outputs it as a transmission TS (S130).
In addition, the multiplexing unit B104 adds a TEI (transport_error_indicator) indicating the presence of an error to the transmission TS (S130) in advance using an error correction code or the like.

As described above, according to the first embodiment, PIDs assigned for identifying a plurality of multiple elements are assigned to the multiple elements so that the code distance between the PIDs is the longest. Thereby, even if an error is added to the PID portion of the TS packet in transmission of the transmission TS (S130), the probability of matching with another PID can be lowered. Thereby, the tolerance with respect to the error added to PID of a multi-element can be improved.
Note that the PID determination procedure according to the first embodiment is a simple example, and any other method can be used as long as the method determines the PID so that the PIDs are separated from each other.

In the first embodiment, the PID determination may be performed according to the following procedure.
(1a) Among all PIDs (0x0000 to 0x1FFF) that can be assigned, PID candidates obtained by excluding the PID already specified in the PID item C203 of the multiple control instruction information S121 and the NULL PID (0x1FFF) Get as.
(2a) For each PID in the PID candidate, the maximum value of the bit rate / distance from all the PIDs specified in the PID item C203 is calculated as the evaluation value.
(3a) From each evaluation value calculated for each PID, one PID from which the minimum value is obtained is selected.
(4a) Among the multiplex elements for which no PID is specified in the PID item C203 of the multiplex control instruction information S121 (including the added multiplex control information), the one having the highest bit rate specified in the bit rate item C206 (C306) And the PID selected in (3a) is set in the PID item C203 (C303) of this multi-element.
(5a) The operations of (1a) to (4a) are repeated until there is no multiple element of “No PID designation” in the PID item C203 (C303).
By doing in this way, the distance of PID of multiple elements can be separated similarly to the procedures of (1) to (5), and more than the case where the PID is determined by the procedures of (1) to (5). It is possible to increase the distance between the PID of a multi-element having a high bit rate and the PID of another multi-element.

Note that the PID determination procedures (1a) to (5a) are simple examples. In other words, the method is not limited to the above procedures (1a) to (5a) as long as the PID can be determined such that the PID of the multi-element having a high bit rate is separated from the PID of another multi-element. .
For example, you may search for the combination of PID in which the sum of the bit rate / distance between each PID of all the multiplexing elements becomes the maximum.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a configuration of a media separating apparatus according to Embodiment 2 of the present invention. In FIG. 4, upon receiving the transmission TS from the media multiplexing apparatus B100 as the reception TS (S430), the media separation apparatus B400 of Embodiment 2 separates the media signal multiplexed on the reception TS (S430). This is an output device.
Note that the received TS (S430) is pre-added with TEI indicating the presence of an error from an error correction code or the like by the media multiplexing apparatus B100. Further, as in the first embodiment, the case where there are two programs is taken as an example.

  In the example of FIG. 4, the multiple elements S401 to S410 are the video S401, the audio S402, the reference time S403, the additional information S404, the PMT1 (S412) that constitute the content of the program 1, the video S405 that constitutes the content of the program 2, and the audio. S406, reference time S407, additional information S408, PMT2 (S413), additional information S409 that is information common to programs 1 and 2 (common information), additional information S410, and PAT (S411). As in the first embodiment, these signals are called multiple elements.

The media separation device B400 includes a TS correction unit (correction unit) B401, a separation unit B402, and a separation control information extraction unit B403.
The TS correction unit B401 is a component that corrects the PID of the received TS (S430) based on the separation control information S421 and outputs the corrected TS (S431).
The separation control information S421 is a signal that modifies the multiple elements S401 to S413, which are media signals such as video and audio of a plurality of different programs, and instructs a separation method. Details of the separation control information S421 will be described later with reference to FIG.
The content of the separation control information is multiplexed in the reception TS (S430) as PAT or PMT. However, the separation control information may be transmitted by another method without using PAT or PMT, and the media separation apparatus B400 may hold a predetermined value as separation control information in advance.

  The separation unit B402 is a component that separates and outputs the multiple elements S401 to S413 from the modified TS (S431). The separation control information extraction unit B403 is a component that inputs the PAT (S411), PMT1 (S412), and PMT2 (S413) separated by the separation unit B402 and extracts the separation control information S421 defined therein. The extracted separation control information S421 is output to the TS correction unit B401 and the separation unit B402.

  FIG. 5 is a diagram illustrating an example of the separation control information S421. The separation control information S421 shown in FIG. 5 includes, for each of the multiple elements S401 to S413, the multiplexing format of the multiplexing format item C502, the PID of the PID item C503, the signal type of the signal type item C504, and the program number of the program number item C505. Have a combination of

The multi-element item C501 indicates which of the multi-elements S401 to S413 the combination described above relates to. That is, multiple elements S401 to S413 are set.
In the multiplex format item C502, a multiplex format for multiplexing the multiplex element signal shown in the multiplex element item C501 is set. Here, it is multiplexed in one of the formats of PES, PCR, and Section.

In the PID item C503, a PID assigned to a TS packet on which each multi-element signal set in the multi-element item C501 is placed is specified.
In the signal type item C504, the type of each multi-element signal set in the multi-element item C501 is designated. Here, video, audio, reference time, and the like are designated as the signal type.
In the program number item C505, a program number for specifying a program to which each of the multiple element signals set in the multiple element item C501 belongs is specified. 4 and 5 show the case where there are two programs. The program number of program 1 is “1” and the program number of program 2 is “2”. If no program number is specified, the multiple element signal indicates that it does not belong to a program.

  The number and configuration of the multiple elements S401 to S413 described above and the content of the corresponding separation control information S421 are examples, and the present invention is not limited to the above content.

Next, the operation will be described.
In the separation control information S421, common information that does not belong to the PAT and the program in the initial state, and multiple elements that are known to appear are registered in advance. Hereinafter, the separation control information S421 illustrated in FIG. 5 will be described as an example. That is, in the PAT of the separation control information S421, the multi-element item C501 is the multi-element S411, the multi-format item C502 is Section, the PID item C503 is “0x0000”, the signal type item C504 is PAT, and the program number item C505 is “designated”. “None”.

  The TS correction unit B401 corrects the PID of the reception TS (S430) based on the separation control information S421, and generates a correction TS (S431). Since correction of PID is performed only for TS packets that are highly likely to have errors, the procedure for determining the following separation control information S421 is not greatly affected. Details of the PID correction procedure will be described later.

  For each multiplex element set in the separation control information S421, the separation unit B402 matches the PID of the multiplex element with the corresponding multi-element PID of the modified TS (S431) obtained by the TS modification unit B401. A TS packet to be specified is extracted, the multiplexing format specified in the multiplexing format item C502 of the multiplexing element is extracted from the TS packet, and the multiplexing element signal is specified in the multiplexing element item C501 via a buffer (not shown). To the output destination (video decoder or audio decoder). Further, the separation unit B402 outputs the PAT (S411), PMT1 (S412), and PMT2 (S413) separated from the modified TS (S431) to the separation control information extraction unit B403.

  In the separation control information extraction unit B403, the combination of the PMT program number and PID is extracted from the PAT (S411) separated from the modified TS (S431) by the separation unit B402. The information is selected and set in the multiplex format item C502, the PID item C503 is set with the PID that has been processed by the separator B402, and the signal type item C504 is set with PMT. Here, PMT1 with program number 1 is assigned to S412 and PMT2 with program number 2 is assigned to S413.

  Next, the separation control information extraction unit B403 receives the PMT1 (S412) of the program number 1, extracts the PID and the signal type from the program PMT1, and sets the multiplexing format corresponding to the signal type to PES, Section, PCR. Is selected in the multiple format item C502, the PID is set in the PID item C503, the signal type in the combination is set in the signal type C504, and the combination in the combination is set in the program number item C505. Information in which the program number (“1”) is set is added to the separation control information S421.

  On the other hand, upon receiving PMT2 (S413) of program number 2, the separation control information extraction unit B403 extracts the PID and signal type from the program PMT2, and sets the multiplexing format corresponding to this signal type to PES, Section, and PCR. One of them is selected and set in the multiple format item C502, the PID is set in the PID item C503, the signal type in the combination is set in the signal type C504, and the program in the combination is set in the program number item C505 Information in which the number (“2”) is set is added to the separation control information S421.

  Through the procedure described above, the content of the separation control information S421 is determined for each multiple element, and based on the separation control information S421 for which the content has been determined, the separation unit B402 converts the modified TS (S431) into the multiple elements S401 to S413. To separate.

Here, details of PID correction by the TS correction unit B401 will be described.
The TS correction unit B401 has a buffer (not shown) capable of storing a predetermined number N of TS packets. While erasing the TS packets in this buffer from the old TS (previously stored TS packets), The TS packets of the received TS (S430) are sequentially stored in the buffer.

Further, the TS correction unit B401 is a predetermined number M-th TS packet from the newest TS packet in the buffer (the TS packet accumulated Mth counting from the TS packet accumulated last). The PID is corrected according to the following procedure.
(1b) PID, TEI, and CC (continuity_counter) are acquired from the header of the TS packet.
(2b) When the TEI indicates no error (= 0), the PID correction of the TS packet is not performed.
(3b) If the TEI indicates that there is an error (= 1), it is determined that there is an error in the TS packet, and the processing from (4b) onward is executed.
(4b) The PID of the TS packet is set to PID1, the PID of a certain multi-element in the separation control information S421 is set to PID2, and PID2 having a code distance close to PID1 is specified in the separation control information S421.
(5b) Among TS packets existing before and after the TS packet, search for a TS packet that is closest to the TS packet, has the same PID as PID2, and has a continuous CC. When the searched TS packet is found both before and after the TS packet, it is determined that it is appropriate to replace the PID of the TS packet with PID2.
That is, PID1 determined to have an error and PID2 having the highest degree of bit match are selected as replacement targets.
(6b) When it is determined that the replacement is appropriate, the PID of the TS packet is replaced with PID2, and the processing of the TS packet is terminated.
(7b) If it is determined that the replacement is not appropriate, the PID correction of the TS packet is not performed, the next PID2 in the separation control information S421 is selected as the PID to be processed in (4b), and the above ( The processes from 4b) to (6b) are repeated.

  The TS correction unit B401 sequentially outputs TS packets whose PIDs have been corrected (replaced) by the above-described procedure as corrected TS (S431). For example, the predetermined number N can be determined so that the TS packets stored in the buffer are about 1 second. Further, the predetermined number M can be set in the vicinity of N / 2nd.

  As described above, according to the second embodiment, when it is determined that an error is included in the PID of the multiplexed element multiplexed in the reception TS (S430), the value of the PID before the error is added is included in the reception TS. The PID selected from the PID candidates that can appear in the list is corrected. In this way, by correcting the error added to the PID with the one selected from the PID candidates that can appear in the received TS, the influence of the error added to the PID of the multi-element can be reduced, and the tolerance to the error is improved. Can do.

  In the second embodiment, the media separation device B400 is shown. However, instead of outputting the multiple elements S401 to S413, a TS correction device that outputs the correction TS (S431) may be configured.

In the second embodiment, the TS correction unit B401 may have the following configuration.
First, the TS correction unit B401 determines the bit rate of each multiplex element, and newly adds a bit rate item (for example, C506) for each multiplex element to the separation control information S421, and each multiplex element obtained by the determination. Add a bitrate corresponding to.
The bit rate determination method includes a method of using a predetermined approximate value prepared in advance for any one or a plurality of combinations of items C501 to C505 of the separation control information S421, a packet appearance rate in the reception TS (S430), There is a method of measuring for each multiple element in the separation control information S421.

Further, in the second embodiment, the PID may be corrected by the following procedure.
(1c) Obtain PID, TEI, and CC from the header of the TS packet.
(2c) When the TEI indicates no error (= 0), the PID correction of the TS packet is not performed.
(3c) When the TEI indicates that there is an error (= 1), it is determined that there is an error in the TS packet, and the processing from (4b) onward is executed.
(4c) The PID of the TS packet is PID1, the PID of a certain multi-element in the separation control information S421 is PID2, the bit rate corresponding to PID2 is acquired for each PID2, and the bit rate / (PID1 and PID2 code) (Distance) is calculated as an evaluation value, and the following determination (5c) is made in order from PID2 having the largest evaluation value.
(5c) Among TS packets existing before and after the TS packet, search for a TS packet that is closest to the TS packet, has the same PID as PID2, and has a continuous CC. When the searched TS packet is found both before and after the TS packet, it is determined that it is appropriate to replace the PID of the TS packet with PID2.
In other words, PID2 that has the highest bit coincidence with the PID1 determined to have an error and the highest bit rate is selected as a replacement target.
(6c) When it is determined that the replacement is appropriate, the PID of the TS packet is replaced with PID2, and the processing of the TS packet is terminated.
(7c) When it is determined that the replacement is not appropriate, the PID correction of the TS packet is not performed, and the next PID2 in the separation control information S421 is selected as the PID to be processed in (4c), and the above ( The processes from 4c) to (6c) are repeated.
By doing in this way, the influence of the error added to PID of a multiplex element can be reduced, and error tolerance can be improved. In particular, when a high bit rate multiplex element affects other multiplex elements, the effect of improving error tolerance can be exhibited.

Furthermore, in the PID correction procedures (1b) to (7b) and (1c) to (7c) shown in the second embodiment, the received TS (S430) is a TS corrected by the error correction code, and each TS If the added error correction code remains in the packet, the TS correction unit B401 may perform correction using the error correction code again before outputting the corrected TS (S431), and then output the corrected TS (S431). .
By doing so, the TS packet that cannot be corrected by the correction by the error correction code performed before the input of the reception TS (S430) is corrected by the correction of the PID part by the TS correction unit B401. When entering the possible range, errors contained in the TS packet can be eliminated.

  B100 Media multiplexer, B101 PID allocation unit (allocation unit), B102 PAT generation unit, B103 PMT generation unit, B104 multiplexing unit, B400 media separation device, B401 TS correction unit (correction unit), B402 separation unit, B403 separation control information Extraction unit.

Claims (9)

In a media multiplexer that inputs a plurality of media signals, multiplexes these media signals and outputs them as media multiplexed signals,
A media multiplexing apparatus, comprising: an assigning unit that assigns identifiers assigned to identify each of the plurality of input media signals to the media signals such that a code distance between the identifiers is separated.   The assigning unit is configured so that an identifier assigned to a media signal having the highest transmission rate among the plurality of media signals is separated from the identifier assigned to another media signal by a code distance. The media multiplexer according to claim 1, wherein the identifier is assigned.   3. The media multiplexing apparatus according to claim 1, wherein the assigning unit sets a value designated from the outside to at least one of the identifiers assigned to the media signals. The media multiplexed signal is a transport stream,
4. The media multiplexing apparatus according to claim 1, wherein the identifier is a PID (Packet IDentification) that identifies a media signal packetized in the transport stream. In a media separation device for inputting a media multiplexed signal in which a plurality of media signals are multiplexed, and separating and outputting the media signal from the media multiplexed signal,
It is determined whether or not an identifier assigned to identify each of the media signals multiplexed in the input media multiplexed signal includes an error. When it is determined that an error is included, before the error is added, An apparatus for separating media, comprising: an identifier selected from candidate identifiers that can appear in the media multiplexed signal as an identifier value, and correcting an identifier determined to contain the error.   The correction unit selects an identifier having the highest degree of bit coincidence with an identifier determined to include the error from among identifier candidates that can appear in the media multiplexed signal as a value of the identifier before the error is added. The media separating apparatus according to claim 5, wherein:   The correction unit has the highest bit coincidence with the identifier determined to include the error among the identifier candidates that may appear in the media multiplexed signal as the identifier value before the error is added, and is transmitted. 6. The media separating apparatus according to claim 5, wherein an identifier of a media signal having the highest rate is selected.   6. The correction unit according to claim 5, wherein when the input media multiplexed signal is corrected in advance by an error correction code, the correction unit performs correction by the error correction code after correcting the identifier. The media separating apparatus according to claim 1. The media multiplexed signal is a transport stream,
9. The media separating apparatus according to claim 5, wherein the identifier is a PID that identifies a media signal packetized in the transport stream.

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