JP2007189587A - Stream conversion device, information recorder and stream converting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stream conversion device and method capable of converting even a TS (transport stream) that is not a TS with an arranged data format into a PS (program stream) and simplifying a device configuration, and an information recorder. <P>SOLUTION: The stream conversion device has a detecting and dividing part (step S10 and S11) for analyzing a TS header included in an inputted TS and detecting and dividing a TS packet including video data and sound data from the inputted TS, a buffer, a PS converting part (step S13) for generating a PES (packetized elementary stream) packet of a TS from a TS payload of the TS packet divided by the detecting and dividing part to write the PES packet in the buffer, reading the PES payload included in the PES packet of the TS from the buffer when an amount of data stored in the buffer becomes a prescribed value or more, adding a header to the read PES payload to generate a PS pack, and an SCR (system clock reference) setting part (step S14) for rewriting the value of the header of the PS. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stream conversion device that converts a transport stream (TS) that is digital video / audio information into a program stream (PS) that is digital video / audio information, an information recording device including the stream conversion device, and a stream conversion method. Is.

  In recent years, digital broadcasting has started in many countries, and digital broadcasting programs are transmitted by TS. Along with this, devices that can record and play back digital broadcast programs as they are TS are being developed. On the other hand, in the current DVD logic standard (DVD-Video standard, DVD-Audio standard, DVD Video Recording standard, DVD Stream Recording standard), it is defined that a program is stored in PS. Therefore, in order to save a digital broadcast program on a DVD in a format conforming to the DVD logical standard, it is necessary to convert TS to PS.

  Also, TS is standardized assuming use in an environment where transmission errors occur, and has a higher degree of redundancy than PS standardized for storage. For this reason, when a digital broadcast program is recorded in the TS format, there is a problem that a large number of recording areas are used. From the above, an information recording apparatus that converts TS into PS and records it is necessary (see, for example, Patent Documents 1 and 2).

JP 2005-513936 A (summary) Japanese Patent Laying-Open No. 2004-312441 (paragraphs 0039-0048, FIGS. 1 and 2)

  However, the information recording apparatus described in Patent Document 1 generates and records a TS that has a format that facilitates conversion from TS to PS. The conversion from TS to PS is intended only for the TS generated by this information recording apparatus. For this reason, in this information recording apparatus, conversion from TS to PS can be performed only after a process of adjusting the data format of TS.

  The information recording apparatus described in Patent Document 2 uses a 27 MHz clock generator to set a parameter called a PS system clock reference (SCR). Therefore, this information recording apparatus cannot perform conversion from TS to PS without a clock generator.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to perform the conversion from TS to PS without processing the data format, and the apparatus. Is to provide a stream conversion apparatus, an information recording apparatus equipped with the stream conversion apparatus, and a stream conversion method.

  The stream converter of the present invention is a stream converter that converts a TS that is a video / audio digital data stream into a PS that is a video / audio digital data stream, and analyzes a TS header included in the input TS, Detection and separation unit for detecting and separating TS packets including video data and audio data from the input TS, buffer means, and generating TS PES packet from TS payload of TS packets separated by the detection and separation unit When the amount of data stored in the buffer means becomes equal to or greater than a predetermined value, the PES payload contained in the PES packet of the TS is read from the buffer means, and the read PS conversion unit that generates a PS pack by adding a header to the PES payload It is characterized in Rukoto.

  The information recording apparatus of the present invention includes the stream converter, a recording unit that stores a PS file output from the stream converter, and an operation for storing the PS file output from the stream converter in the recording unit. And a control unit for controlling.

  According to the stream conversion device, the information recording device, and the stream conversion method of the present invention, conversion from TS to PS can be performed on data that has not undergone the process of adjusting the data format, and the configuration of the device is simplified. The effect that it can be done can be obtained.

  Hereinafter, a stream conversion apparatus, an information recording apparatus equipped with the stream conversion apparatus, and a stream conversion method according to an embodiment of the present invention will be described with reference to the drawings.

  First, it was standardized by MPEG2 specification from MPEG transport stream (Transport Stream: TS) which is digital video / audio information standardized by MPEG2 specification (ITU-T recommendation H.222.0 | ISO / IEC13818-1). A conversion process to an MPEG program stream (Program Stream: PS) which is digital video / audio information will be described.

  FIG. 1 is a diagram illustrating a data structure of a TS. As shown in FIG. 1, a TS is composed of a TS packet (TS packet) having a fixed length of 188 bytes. Each TS packet is composed of a TS header (TS header) and a TS payload (TS payload). Video data and audio data are included in the TS payload.

  FIG. 2 is a diagram illustrating a data structure of the PS. As shown in FIG. 2, the PS is configured by a PS pack (PS pack). The PS pack has a variable length, but is usually 2048 bytes in order to match the sector length in a DVD (digital versatile disc) or the like. Each PS pack is composed of a pack header, a system header, and a PES packet (Packetized Elementary Stream packet). The system header is essential in the first PS pack of the PS, but may or may not be present in PS packs after the first PS pack. Video data and audio data are included in the PES packet.

  Details of the data structure of TS and PS are described in ITU-T Recommendation H.264. 222.0 | ISO / IEC13818-1.

  The TS includes video data and audio data for one program or more, and information for separating a plurality of programs. On the other hand, video data and audio data for only one program can be included in the PS. Therefore, in the conversion from TS to PS, one or more PSs are generated from one TS.

  FIG. 3 is a diagram showing the flow of data processing in the conversion from TS to PS. As shown in FIG. 3, in the conversion process from TS to PS, first, TS packets constituting the TS are classified according to video, audio, or other types. In FIG. 3, the TS packet of the video of the program 1, the TS packet of the audio of the program 1, the TS packet of the video of the program N (N is an integer of 2 or more), the TS packet of the audio of the program N, and other than video / audio TS packets are shown. Next, TS header information and the like are removed from the video TS packet and audio TS packet, and video data and audio data are extracted. In FIG. 3, video data of program 1, audio data of program 1, video data of program N, and audio data of program N are extracted, and TS packets other than video TS packets and audio TS packets are extracted. Is shown to have been destroyed. Next, a PS is generated based on the extracted video data and audio data. FIG. 3 shows that a PS for program 1 and a PS for program N are generated.

  FIG. 4 is a block diagram schematically showing the configuration of the information recording apparatus according to the embodiment of the present invention. As shown in FIG. 4, the information recording apparatus according to the embodiment controls the operation of the stream conversion apparatus 1 that performs conversion processing from TS to PS, the recording unit 2 that records information, and the entire information recording apparatus. And a control unit 3 for performing the above. The recording unit 2 includes a hard disk drive for writing and reading information on a magnetic disk, an optical disk device for writing and reading information on an optical disk such as a DVD, or a semiconductor memory device for writing and reading information on a semiconductor memory. Is done.

  FIG. 5 is a block diagram schematically showing the configuration of the stream conversion apparatus 1 shown in FIG. As shown in FIG. 5, the stream conversion apparatus 1 according to the embodiment of the present invention includes a detection / separation unit 11 that detects and separates various types of information from a TS, and a PS conversion unit that performs a process of converting a TS into a PS. 12, an SCR setting unit 13 for setting a PS system clock reference (SCR), and a conversion control unit 14 for controlling the operation of the entire stream conversion apparatus. The detection / separation unit 11 includes a buffer 11a, and mainly performs processing of steps S10 to S12 shown in FIG. The PS conversion unit 12 includes a buffer 12a, and mainly performs the process of step S13 shown in FIG. The SCR setting unit 13 performs a process of step S14 shown in FIG. Each of the buffers 11a and 12a may be divided into a plurality of storage areas, and may include a plurality of different buffer memories.

  FIG. 6 is a flowchart showing an overall flow of TS-to-PS conversion processing executed in the stream conversion apparatus 1. As shown in FIG. 6, in the conversion process from TS to PS, first, acquisition of a program association table (Program Association Table: PAT) from TS (Step S10), and program map table (Program Map Table: PMT) Is acquired (step S11). The PAT and PMT information will be required later when separating video packets and audio packets from the TS. After obtaining the PAT and PMT, the TS read file pointer is once returned to the head (step S12). Then, video data and audio data are extracted from the TS, and the process of generating a PS (step S13) is entered. However, at this time, a correct value is not set in the SCR of the PS. The data processing in FIG. 3 corresponds to the processing in step S13 in FIG. Finally, the SCR of PS is rewritten to a correct value (step S14). As a SCR rewriting method, a PS SCR is rewritten on the buffer in the SCR setting unit 13 and then the PS is recorded in the recording unit 2, and a PS SCR recorded in the recording unit 2 by the SCR setting unit 13 There is a method to rewrite.

  Next, the PAT acquisition process shown in step S10 of FIG. 6 will be described. FIG. 7 is a diagram illustrating a relationship between a TS packet and a PAT. As shown in FIG. 7, the PAT is included in the TS payload of a TS packet whose packet identifier (PID) is 0. The PAT may be larger than the TS packet. In this case, the PAT is separated into a plurality of TS packets. In the TS packet including the head of the PAT, the payload unit start indicator (payload_unit_start_indicator) in the TS header is 1, the 1st byte of the TS payload is a pointer field (pointer field), and the PAT data from the 2nd byte of the TS payload. Begins. In a TS packet that does not include the beginning of the PAT, payload_unit_start_indicator in the TS header is 0, and PAT data starts from the beginning (1st byte) of the TS payload. When acquiring the PAT, a packet having a PID of 0 and a payload_unit_start_indicator of 1 in the TS header is first acquired. Thereafter, the entire PAT can be acquired by acquiring packets whose PID is 0. The total length of the PAT is a value obtained by adding 3 bytes to the section length (section_length) of the PAT, that is, (section_length + 3) bytes. Note that section_length is shown in FIG. 10, which will be described later, showing the data structure of PAT.

  FIG. 8 is a flowchart showing the PAT acquisition process shown in step S10 of FIG. 9 is a diagram showing a data structure in the TS header shown in FIG. 7, and FIG. 10 is a diagram showing a data structure of the PAT shown in FIG.

  As shown in FIG. 8, in the PAT acquisition process, first, the TS header is read from the TS (step S100), and payload_unit_start_indicator and PID are acquired from the read TS header. After reading, the TS reading file pointer is moved to the head of the TS payload. The length of the TS header can be determined from the adaptation field control (adaptation_field_control) and the adaptation field length (adaptation_field_length) in the TS header shown in FIG. When adaptation_field_control is 1, there is no adaptation field (adaptation_field), and the TS header is 4 bytes. When adaptation_field_control is 2, there is no TS payload and the TS header is 188 bytes. When adaptation_field_control is 3, the length of the TS header is (4 + adaptation_field_length) bytes.

  As shown in FIG. 8, after reading the TS header, the PAT is acquired from the TS packet whose PID is 0 (step S101). When the payload_unit_start_indicator in the TS header is 1 (step S102), the section_length in the PAT is acquired (step S103), and the PAT data in the TS payload is read into the buffer (step S105). When payload_unit_start_indicator in the TS header is 0 (step S102), reading into the buffer (step S105) is performed only when the head of the PAT has already been acquired (step S104). When the data amount in the buffer reaches (section_length + 3) bytes, the reading is terminated (step S106). The buffer used here is included in the buffer 11a shown in the block diagram of FIG.

  After reading the entire PAT into the buffer, the PMT PID is obtained from the PAT (step S107). The PID of the PMT exists in a repetitive portion in the data structure of the PAT shown in FIG. However, the PID of a set of PMTs whose program number (program_number) in the PAT is 0 is ignored. There may be a plurality of PMT PIDs. After PAT acquisition, the PMT acquisition process is entered.

  Next, the PMT acquisition process shown in step S11 of FIG. 6 will be described. FIG. 11 is a flowchart showing in detail the PAT acquisition process shown in step S11 of FIG. FIG. 12 shows the data structure of the PMT.

  Like the PAT, the PMT may be divided into a plurality of TS packets and included in the TS packet. The flowchart of FIG. 11 shows the process when the PMT has one PID for easy understanding. When there are a plurality of PMT PIDs, the same processing is performed in parallel.

  As shown in FIG. 11, in the PMT acquisition process, first, the TS header is read from the TS (step S110). The process of reading the TS header is the same as the process in the case of PAT acquisition shown in step S100 of FIG. After reading the TS header, the PMT packet is identified from the PID value. When payload_unit_start_indicator in the TS header is 1, after obtaining section_length from the PMT (steps S112 and S113), the PMT data of the TS payload is read out to the buffer (steps S114 and S115). When payload_unit_start_indicator in the TS header is 0, reading to the buffer is performed only when the head of the PMT has already been acquired (steps S112, S114, and S115). When the data amount in the buffer reaches (section_length + 3) bytes, the reading is terminated (step S116). As shown in FIG. 12, the total length of the PMT is a value obtained by adding 3 bytes to the section length (section_length), that is, (section_length + 3) bytes. The buffer used here is included in the buffer 11a shown in the block diagram of FIG.

  After reading the entire PMT into the buffer, the video PID and audio PID are acquired from the PMT (step S117). The elementary PID (elementary_PID) when the stream identifier (stream_id) of the repeated portion in the data structure of the PMT shown in FIG. 12 is “0x2” is the video PID, and the stream_id is “0x3” or “0xf”. The elementary_PID is the voice PID. Note that '0x' means hexadecimal notation, and '0x ·' means that '·' is a hexadecimal number.

  Next, the conversion process from TS to PS shown in step S13 of FIG. 6 will be described. FIG. 13 is a flowchart showing the process of generating the PS by extracting the video and audio TS packets in step S13 of FIG. FIG. 13 shows a case where there is one program (that is, a case where there is one each of video and audio) in order to make the explanation easy to understand. If there are a plurality of programs, the same processing is performed in parallel. FIG. 14 is a diagram illustrating the data structure of the PS pack header, FIG. 15 is a diagram illustrating the data structure of the PS system header, and FIG. 16 is a diagram of the PES packet (padding stream: padding stream). It is a figure which shows a data structure.

  As shown in FIG. 13, in the process of step S13 of FIG. 6, first, the first PS pack of PS is generated (step S120). Here, the total length of the PS pack is 2048 bytes. The PS pack is composed of a pack header having the data structure shown in FIG. 14, a system header having the data structure shown in FIG. 15, and a PES packet (padding_stream) having the data structure shown in FIG.

  As shown in FIG. 14, the PS pack header has a total length of 14 bytes by setting the pack stuffing byte (pack_stuffing_byte) to 0 bytes. As shown in FIG. 15, the PS system header has a total length of 18 bytes by setting the repeated portion twice. As shown in FIG. 16, the PES packet (padding stream) of PS is set to 2016 bytes by filling the PES payload part with “0xFF” of 2010 bytes. Further, the pack header parameter shown in FIG. 14 is set to the value shown in FIG. 17, the system header parameter shown in FIG. 15 is set to the value shown in FIG. 18, and the PES header ( The parameter of (padding stream) is set to the value shown in FIG.

  As shown in FIG. 13, after the first PS pack is generated, a packet that is a video packet and includes the head of the frame is searched (step S122). The retrieved video packet and the packet before the packet including the head of the frame are discarded. Whether or not the head of the frame is included is determined by checking whether or not payload_unit_start_indicator is 1 in the TS header.

  As shown in FIG. 13, after finding a packet that is a video frame and includes the head of the frame, the type of TS packet is classified. When a video packet has arrived, the process proceeds to video packet processing (step S125). When an audio packet has arrived, the process proceeds to audio packet processing (step S126), and any other packet has arrived. Discards the packet.

  Next, details of processing (steps S125 and S126) when a video TS packet or an audio TS packet comes will be described. Video data and audio data are stored in a PES packet format. FIG. 20 is a diagram illustrating a data structure of a PES packet. Video data and audio data are included in the PES payload in the PES packet. FIG. 21 is a diagram showing the relationship between TS packets constituting the TS and the PES packet generated from the TS, and FIG. 22 is a diagram showing the relationship between the PES packet generated from the TS and the PS. It is.

  As shown in FIG. 21, since the PES packet is generally larger than the TS packet, the data of the PES packet is divided into a plurality of TS packets and included. In addition, the video PES packet in the TS includes data for one frame. On the other hand, as shown in FIG. 22, one PS pack contains one PES packet in one PS pack. Therefore, at the time of conversion from TS to PS, as shown in FIG. 22, it is necessary to divide the PES payload of the TS PES packet according to the size of the PS PS pack.

  FIG. 23 is a flowchart showing in detail the processing of the video TS packet shown in step S125 of FIG. As shown in FIG. 23, in the processing of the video packet in FIG. 13, first, it is checked whether or not the payload_unit_start_indicator is 1 in the TS header to determine whether or not the TS packet includes the PES header. Determination is made (step S1000). As shown in FIG. 23 and FIG. 21, when payload_unit_start_indicator is 1 in the TS header, the PES header data is read after reading the PES header (step S1001) and incrementing the frame number counter (step S1002). Are read out to the video buffer (step S1003). The frame number counter is used when the SCR is set to a correct value later. As shown in FIGS. 23 and 21, when the payload_unit_start_indicator in the TS header is 0, only the PES payload is read (step S1003).

  As shown in FIGS. 23 and 22, after the PES payload reading (step S1003), if the buffer data amount exceeds 2048 bytes, the PS PS pack is output to the PS file (step S1005). The PS pack to be output is composed of a pack header and a PES packet (or composed of a pack header, a system header and a PES packet), and the length of the PES payload is adjusted so that the pack length is 2048 bytes.

  As shown in FIG. 23, after the PS pack is output, the presentation time stamp (PTS) data and the decoding time stamp (DTS) data are removed from the data of the PES header (step S1006).

  FIG. 24 is a flowchart showing in detail the processing of the audio TS packet shown in step S126 of FIG. As shown in FIG. 24, the audio packet processing shown in FIG. 13 is different from the video packet processing (FIG. 23) in that there is no frame number counter processing (step S1003 in FIG. 23). Except for this point, the process shown in FIG. 24 is the same as the process shown in FIG.

FIG. 25 is a flowchart showing in detail the process of rewriting the SCR of the PS shown in step S14 of FIG. As shown in FIG. 25, in the SCR rewriting (step S132), the SCR value SCR _p represents the estimated arrival time of the last byte of the SCR base (SCR_base). SCR_base is shown in FIG. 14 regarding the data structure of the PS pack header. When the PS file playback time is T, the number of PS file bytes is L, and R is a positive integer, the estimated arrival time t of the R-byte data of the stream can be obtained by the following equation.

The reproduction time T of the PS file can be obtained from the number of frames F of the PS file. Since the frame rate of NTSC video is 30000/1001 (≈29.97) Hz, the playback time T of the stream can be expressed by the following equation using the number of frames F.

The last byte of the SCR_base of the p-th pack header in the total number P of MPEG2 packs is the (2048 × p + 9) byte. Thus, estimated arrival time _{t p} of SCR_base the p-th pack header can be obtained by the following equation.

Since the SCR value 27000000 corresponds to 1 second, the SCR value SCR _p of the p-th pack header can be obtained by the following equation.

In the present embodiment, the SCR value SCR _p is rewritten by the above equation.

  As described above, according to the present embodiment, even if it is not a TS whose format is arranged so that conversion to PS is easy, it can be converted into PS. Even without a clock generator, the SCR value can be set appropriately.

It is a figure which shows the data structure of TS. It is a figure which shows the data structure of PS. It is a figure which shows the flow of the data processing in conversion from TS to PS. 1 is a block diagram schematically showing a configuration of an information recording apparatus according to an embodiment of the present invention. FIG. 5 is a block diagram schematically showing the configuration of the stream conversion apparatus shown in FIG. 4. It is a flowchart which shows the whole flow of the conversion process from TS to PS performed in the stream converter which concerns on embodiment of this invention. It is a figure which shows the relationship between TS packet and PAT. It is a flowchart which shows the PAT acquisition process shown by step S10 of FIG. 6 in detail. It is a figure which shows the data structure of TS header. It is a figure which shows the data structure of PAT. It is a flowchart which shows in detail the PMT acquisition process shown by step S11 of FIG. It is a figure which shows the data structure of PMT. It is a flowchart which shows in detail the process which extracts TS packet shown by step S13 of FIG. 6, and produces | generates PS. It is a figure which shows the data structure of the pack header of PS. It is a figure which shows the data structure of the system header of PS. It is a figure which shows the data structure of a PES packet. It is a figure which shows the value of the parameter of a pack header in the first PS pack of PS. It is a figure which shows the value of the parameter of a system header in the first PS pack of PS. It is a figure which shows the value of the parameter of the PES header (padding stream) in the first PS pack of PS. It is a figure which shows the data structure of a PES packet. It is a figure which shows the relationship between a TS packet and a PES packet. It is a figure which shows the relationship between the PES packet produced | generated from TS and PS. 14 is a flowchart showing in detail processing of a video TS packet shown in step S125 of FIG. 14 is a flowchart showing in detail the processing of the audio TS packet shown in step S126 of FIG. It is a flowchart which shows in detail the process which rewrites SCR of PS shown by FIG.6 S14.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stream converter, 2 Recording part, 3 Control part, 11 Detection separation part, 11a buffer, 12 PS conversion part, 12a buffer, 13 SCR setting part

Claims (12)

A stream converter for converting a TS which is a video / audio digital data stream into a PS which is a video / audio digital data stream,
A detection separation unit that analyzes a TS header included in the input TS and detects and separates TS packets including video data and audio data from the input TS; and
Buffer means;
A TS PES packet is generated from the TS payload of the TS packet separated by the detection separation unit, written to the buffer means, and when the amount of data stored in the buffer means exceeds a predetermined value, A stream conversion apparatus comprising: a PS conversion unit that reads a PES payload included in a PES packet from the buffer unit and adds a header to the read PES payload to generate a PS pack.   A system clock reference value is calculated based on the size of a PS file composed of PS packs generated by the PS conversion unit and the number of frames of video data included in the PS file, and the system clock reference of the PS file is calculated. The stream conversion apparatus according to claim 1, further comprising: an SCR setting unit that sets the value to the value acquired by the calculation. The SCR setting unit sets the system clock reference value of the pack header of the p-th PS file (p is a positive integer) as SCR _p , F as the number of frames in the PS file, and L as the number of bytes in the PS file. Then, the following formula SCR _P = {900900F × (2048 × p + 9)} / L
The stream conversion apparatus according to claim 2, wherein the system clock reference is calculated based on the stream conversion time.   4. The stream conversion apparatus according to claim 1, wherein the buffer means is a part of the PS conversion unit. The buffer means has a plurality of storage areas,
The writing to the buffer unit by the PS conversion unit is a process of writing a PES header and a PES payload included in a TS payload of the TS to each of the different storage areas of the buffer unit. The stream converter according to any one of 1 to 4.   The stream according to any one of claims 1 to 5, wherein the PS conversion unit generates a PES header that does not include a presentation time stamp and a decoding time stamp when there is no PES header in the TS packet. Conversion device.   The PS conversion unit copies the PES header of the TS packet including the PES header, and removes the presentation time stamp and the decoding time stamp from the copied PES header, thereby not including the presentation time stamp and the decoding time stamp. The stream conversion apparatus according to claim 1, wherein the stream conversion apparatus generates a stream.   The stream according to any one of claims 1 to 7, wherein the PS conversion unit makes a total amount of data of the header and the PES payload added to the PES payload be a constant amount. Conversion device.   9. The stream conversion according to claim 1, wherein the PS pack generated by the PS conversion unit outputs the PS pack of video PS and the PS pack of audio PS to the same PS file. apparatus. The buffer means has a plurality of storage areas,
The stream conversion apparatus according to claim 1, wherein the PS conversion unit uses a number of the storage areas corresponding to the number of programs included in the TS. A stream converter according to any one of claims 1 to 10,
A recording unit for storing a PS file output from the stream converter;
An information recording apparatus comprising: a control unit that controls an operation of storing the PS file output from the stream conversion apparatus in the recording unit. A stream conversion method for converting a TS which is a video / audio digital data stream into a PS which is a video / audio digital data stream,
Analyzing the TS header included in the input TS, detecting and separating TS packets including video data and audio data from the input TS,
A TS PES packet is generated from the TS payload of the separated TS packet and written to the buffer means,
When the amount of data stored in the buffer means exceeds a predetermined value, the PES payload included in the PES packet of the TS is read from the buffer means,
A stream conversion method, wherein a PS pack is generated by adding a header to the read PES payload.

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