JP2000261393A - Device and method for multiplexing, and computer- readable storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To multiplex plural transport streams with a small quantity of hardware. SOLUTION: Plural data strings as the plural transport streams are inputted, stored in plural buffers 103 together with a pseudo PCR value generated from a pseudo PCR generator 105 and then read by a controller 104. A PCR extractor 106 extracts a PCR from a read data string; a difference arithmetic unit 107 calculates a difference value between a generated PCR value and the read pseudo PCR value; an adder 108 adds the difference value and the read data string. A switching switch 109 switches and outputs the read data string and the added value so as to multiplex the added value to the multiplexing position of the extracted PCR.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexing system suitable for use in correcting a PCR value when multiplexing a transport stream in a data transmission system using a transport stream which is a data transmission format. The present invention relates to an apparatus, a method, and a computer-readable storage medium used in the apparatus and the method.

[0002]

2. Description of the Related Art Recently, MPEG (Moving Pic)
cure Experts Group) 2 standard [IS
O / IEC (International Organ)
Ization for Stadizatio
n / International Electrote
[Technical Commission: International Organization for Standardization / International Electrotechnical Commission] 13818-1-3], a digital processing system is becoming a standard for video transmission systems.

In a digital video transmission system using a multiplexing device conforming to the MPEG2 system defined by ISO / IEC1381-1, a program clock reference (PCR: Program) representing a reference time defining a reception time on a decoding side. Clock Refer
By transmitting the “reverse”, synchronization between the transmitting side and the receiving side is matched.

FIG. 2 is a diagram showing ISO / IEC1318-1 to 3
1 is a block diagram showing a configuration of a transmission side in a general digital video transmission system according to FIG. In FIG. 2, 2
Reference numeral 01 denotes an encoder of a digital transmission system conforming to ISO / IEC1318-1 to 3-3, reference numeral 202 denotes a video encoder for compressing digital video data according to ISO / IEC1318-2, and reference numeral 203 denotes an ISO / IEC13.
A program clock reference (PCR) generator 204 specified in 18-1 is an ISO / IEC 131
This is a transport stream generator that generates a transport stream TS according to 8-1.

Next, the transmission operation of the digital transmission device configured as described above will be described. The encoder 202 converts the input digital video data into ISO / IEC13
According to 18-2, information having high spatial and temporal correlation is examined, and the amount of information is compressed by converting the information into data having low redundancy. In this compressed data sequence,
A unit that can be independently decompressed is referred to as an access unit (AU), and is referred to as a video elementary stream.

A video elementary stream is generally a unit based on an access unit, and has a variable length along with a stream ID indicating the attribute of the elementary stream, time stamp information indicating decoding time and display time on the decoding side, and the like. It is converted into a packetized elementary stream. Transport stream generator 20
4 converts the variable-length video packetized elementary stream into a fixed-length transport stream packet according to the transmission path. In addition, the outputs of the PCR generator 203 are simultaneously multiplexed and output.

FIG. 3 shows an apparatus for multiplexing a plurality of transport streams generated by a plurality of digital transmission apparatuses configured as described above. In FIG. 3, 30
1 is a buffer for storing a transport stream, 30
A transport stream multiplexer 2 generates a plurality of transport streams into one transport stream TS according to a transmission path.

Next, the operation of the multiplexing apparatus configured as described above will be described. The two transport streams generated by the encoder 201 of FIG.
Are stored in the buffer 301. The transport stream multiplexer 302 multiplexes the transport streams stored in each buffer 301 in a time-division manner as one transport stream according to the transmission path and outputs the multiplexed one.

[0009]

In the data multiplexing method using the conventional multiplexing apparatus as described above, the time variation in multiplexing appears as jitter at the time of PCR reproduction in the decoder, and the PCR reproducing device of the decoder has Depending on performance,
The upper limit of the time fluctuation value in the multiplexing by the transport stream multiplexer is restricted.

As a solution to this problem, a multiplexer shown in FIG. 4 has been proposed. In FIG. 4, reference numeral 401 denotes a buffer for storing a transport stream, and 402 denotes a P for extracting and reproducing a PCR from the transport stream.
The CR reproducer 403 multiplexes the transport stream stored in each buffer 401 as one transport stream in a time-division manner according to the transmission path, and also generates a new PCR from the system clock from the PCR reproducer 402. Is a transport stream multiplexer that generates, multiplexes, and outputs.

In the multiplexing apparatus shown in FIG. 4, there is no upper limit of the PCR jitter at the decoder and the upper limit of the time fluctuation value in the multiplexing. However, the case where the number of transport streams to be multiplexed is increased cannot be dealt with, and the multiplexing is limited to the number of PCR reproducers 402 configured in advance. Therefore, when multiplexing a plurality of transport streams, a PCR reproducer for the transport streams to be multiplexed and a new PC
An R generator is required, and there is a problem that the amount of hardware is considerably increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to enable multiplexing of a plurality of transport streams with a small amount of hardware.

[0013]

In order to achieve the above object, a multiplexing apparatus according to the present invention receives a plurality of data strings each coded and multiplexed with reference time information, and multiplexes each data string. In a multiplexing apparatus that multiplexes and outputs in a time-division manner, a generating unit that generates time information, a plurality of buffer units that store the plurality of data strings and the generated time information, and a plurality of buffer units. Control means for controlling reading, extracting means for extracting the position of the reference time information from the read data string, and calculating a difference value between the read time information and the generated time information Calculating means, adding means for adding the read data string and the difference value, output of the adding means and the read data in accordance with the position of the extracted reference time information. It is provided switching means for switching and outputting a column.

Further, according to the multiplexing method of the present invention, a multiplexing method of receiving a plurality of data strings each coded and multiplexed with reference time information, multiplexing each data string in a time-division manner, and outputting the multiplexed data string is provided. A generation procedure for generating time information; an accumulation procedure for storing the plurality of data strings and the generated time information in a plurality of buffer means; a control means for controlling reading of the plurality of buffer means; An extraction procedure for extracting the position of the reference time information from the output data sequence, and an operation procedure for calculating a difference value between the read time information and the generated time information,
An addition procedure for adding the read data string and the difference value, and a switching procedure for switching and outputting the added output and the read data string according to the position of the extracted reference time information Are provided.

Further, in the storage medium according to the present invention,
A process of generating time information, a process of storing a plurality of data strings each of which is encoded and multiplexed with reference time information and the generated time information in a plurality of buffer units, and controlling reading of the plurality of buffer units. Processing, a process of extracting the position of the reference time information from the read data string, a process of calculating a difference value between the read time information and the generated time information, A process of adding the output data sequence and the difference value and a process of switching and outputting the added output and the read data sequence according to the position of the extracted reference time information are executed. For storing programs.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is based on ITU-T (Int
electronic Telecommunications
ion Union-Telecommunicanicati
on Standardization Secte
r: International Telecommunication Union-Telecommunication Standardization Division)
222.0: Video data encoded according to ISO / IEC13818-2 is stipulated in ITU-T Recommendation H.22. 222.0: I
A case where cis 17 encoding is performed by SO 3 / IEC 13818-1 will be described as an example.

FIG. 1 is a block diagram showing an embodiment of a multiplexing device according to the present invention. In FIG. 1, reference numeral 101 denotes ITU-T Recommendation H-222.0: IS0 / IEC138.
A plurality of input terminals to which a plurality of transport stream packets encoded according to 18-1 to 18-1 are input;
02 is an auxiliary information input terminal for multiplexing control; 103 is a plurality of input buffers for storing input transport stream packets; 104 is a plurality of transport stream packets read from each input buffer 103; A controller for controlling the conversion into a transport stream packet; 105, a pseudo PCR generator for generating time information; 106, a PCR extractor for extracting a PCR value from the transport stream packet; 107, a pseudo PCR difference calculator; A PCR adder, 109 is a stream switcher, and 110 is an output terminal of the multiplexed transport stream packet.

Next, the operation of the multiplexer configured as described above will be described. A plurality of transport stream packets are input to the input terminal 101, and the input buffer 10
3 respectively. Simultaneous pseudo PCR generator 10
5 is stored in the input buffer 103. The controller 104 controls each input buffer 10
3 is monitored, and the transport stream packets stored in one input buffer 103 corresponding to the transmission path are read. At the same time, its input buffer 1
Also, the pseudo PCR value stored in 03 is read.

The read transport stream packet is supplied to a PCR extractor 106, a PCR adder 108 and a stream switch 109. Further, the read pseudo-PCR value is supplied to the pseudo-PCR difference calculator 107. The pseudo PCR difference calculator 107 calculates the difference between the pseudo PCR value supplied from the controller 104 and the output value of the pseudo PCR generator 105. The difference operation value is the delay amount of the corresponding transport stream packet in the input buffer 103.

The calculated pseudo PCR difference value is obtained by PCR
The signal is supplied to the adder 108. The PCR adder 108 adds the transport stream packet supplied from the controller 104 and the pseudo PCR difference value supplied from the pseudo PCR difference calculator 107, and supplies the result to the stream switch 109. The PCR extractor 106 selects a packet in which a PCR as reference time information is multiplexed from the transport stream packets supplied from the controller 104, and switches the position information of the transport stream packet in which the PCR value is multiplexed. To the container 109.

The stream switcher 109 is controlled by the output of the PCR extractor 106, outputs the position information of the transport stream packet in which the PCR value is multiplexed, and outputs the signal from the PCR adder 108 at the time of reception. In this case, the transport stream supplied from the controller 104 is output. The output selected by the stream switch 109 is output to the output terminal 110 as a multiplexed transport stream packet.

The controller 104 controls the multiplexing of the transport stream packet input from each input terminal 101 according to the information from the auxiliary information input terminal 102. For example, a transport stream packet in which a plurality of programs are multiplexed is input to the input terminal 10.
When it is input to 1, any program among them can be designated from the attached information input terminal 102 and multiplexed.

As described above, the present embodiment receives a plurality of encoded and PCR-multiplexed data strings, generates time information, and compares the plurality of data strings with the generated time information. Each of them is stored in a plurality of buffers, controls reading from the plurality of buffers, extracts PCR as reference time information from the read data string, and calculates a difference between the generated time information and the read time information. Then, the difference and the read data string are added, and the PCR extracted from the read data string is added.
The readout data sequence and the added value are switched and output so that the added value is multiplexed at the multiplexed position.

Next, a storage medium according to the present invention will be described. The system including the blocks in FIG. 1 can be configured by a computer system including a CPU and a memory. In that case, the memory constitutes a storage medium according to the present invention. In this embodiment, the storage medium includes:
A program for executing a processing procedure for controlling the above-described operation is stored.

As the storage medium, ROM, R
Semiconductor memory such as AM, optical disk, magneto-optical disk,
A magnetic medium or the like may be used, and these may be configured and used in a CD-ROM, a floppy disk, a magnetic tape, a magnetic card, a nonvolatile memory card, or the like.

Therefore, by using this storage medium in a system or apparatus other than the system or apparatus shown in FIG. 1, the system or computer reads out and executes the program code stored in this storage medium. A function equivalent to the above embodiment can be realized,
The same effect can be obtained, and the object of the present invention can be achieved.

An OS running on a computer
Perform part or all of the processing, or after the program code read from the storage medium is written into the memory provided in the extended function board inserted into the computer or the extended function unit connected to the computer. ,
Even when the CPU or the like provided in the extended function board or the extended function unit performs a part or all of the processing based on the instruction of the program code, the same functions as those of the above embodiment can be realized and the same effects can be obtained. You can get
The object of the present invention can be achieved.

[0028]

As described above, according to the present invention,
The time variation in the multiplexing of the transport stream to be multiplexed is monitored, and a new PCR value is corrected at the time of multiplexing, so that a plurality of transport streams can be multiplexed with a small amount of hardware. Further, the effect increases as the number of programs to be multiplexed increases.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a multiplexing device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a transmission side of a general digital video transmission system according to ISO / IEC13818-1 to 3;

FIG. 3 is a block diagram showing a configuration of a conventional multiplexer.

FIG. 4 is a block diagram showing a configuration of another conventional multiplexer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Input terminal 102 Control information input terminal 103 Input buffer 104 Controller 105 Pseudo PCR generator 106 PCR extractor 107 Difference calculator 108 PCR adder 109 Stream switcher 110 Output terminal

Claims (13)

[Claims] 1. A multiplexing apparatus that receives a plurality of data strings each coded and multiplexed with reference time information, multiplexes each data string in a time-division manner, and outputs the multiplexed time-sequence information. A plurality of buffer means for storing the plurality of data strings and the generated time information; a control means for controlling reading of the plurality of buffer means; and a position of the reference time information from the read data string. Extracting means for extracting the difference between the read time information and the generated time information; and adding means for adding the read data sequence and the difference value. Switching means for switching between the output of the adding means and the read data string according to the position of the extracted reference time information and outputting the data string. . 2. The data sequence described in ITU-T Recommendation H.2. 22
2.0: The multiplexing apparatus according to claim 1, wherein the multiplexing apparatus is a transport stream represented by ISO / IEC13818-1 to ISO13818-1. 3. The reference time information described in ITU-T Recommendation 2
22-0: The multiplexing apparatus according to claim 1, wherein the multiplexing apparatus is a PCR represented by ISO / IEC13818-1 to 3818-3. 4. The extraction means extracts a PCR multiplexed in a transport stream which is the data string, and the switching means outputs the PCR when the PCR is multiplexed when outputting the transport stream. 4. The multiplexing apparatus according to claim 3, wherein an output of said adding means is multiplexed at a position where the multiplexing means is located. 5. The control unit according to claim 1, wherein the control unit reads out the data string stored in the plurality of buffer units according to an accumulation amount of the plurality of buffer units.
The multiplexing device of claim 6. The multiplexing apparatus according to claim 5, wherein said control means has a receiving means for receiving control information to be multiplexed, and controls multiplexing according to said control information. . 7. A multiplexing method for receiving a plurality of data strings each coded and multiplexed with reference time information, multiplexing each data string in a time-division manner, and outputting the multiplexed time-sequence information. An accumulation procedure for storing the plurality of data strings and the generated time information in a plurality of buffer means; a control means for controlling reading of the plurality of buffer means; and a reference time from the read data string. An extraction procedure for extracting the position of information; an arithmetic procedure for calculating a difference value between the read time information and the generated time information; and adding the read data sequence and the difference value Multiplexing, comprising: an addition procedure; and a switching procedure of switching and outputting the added output and the read data string according to the position of the extracted reference time information. Method. 8. The data string described in ITU-T Recommendation H.8. 22
2.0: The multiplexing method according to claim 7, wherein the multiplexing method is a transport stream represented by ISO / IEC13818-1 to ISO13818-1. 9. The reference time information according to ITU-T Recommendation 2
22-0: The multiplexing method according to claim 7, wherein the PCR is a PCR shown in ISO / IEC13818-1-3. 10. The extracting step extracts a PCR multiplexed in a transport stream that is the data stream, and the switching step includes the step of extracting the PCR when outputting the transport stream. 10. The multiplexing method according to claim 9, wherein the output of the adding procedure is multiplexed at a position where the multiplexing is performed. 11. The multiplexing method according to claim 7, wherein said control procedure reads out said data sequence stored in said plurality of buffer means according to the storage amount of said plurality of buffer means. 12. The multiplexing method according to claim 11, wherein the control procedure includes a receiving procedure for receiving control information to be multiplexed, and performs multiplexing control according to the control information. 13. A process for generating time information; a process for storing a plurality of data strings each coded and multiplexed with reference time information and the generated time information in a plurality of buffer means; Means for controlling reading of the means; processing for extracting the position of the reference time information from the read data string; and calculating a difference value between the read time information and the generated time information. Processing, adding the read data string and the difference value, and switching and outputting the added output and the read data string according to the position of the extracted reference time information. And a computer-readable storage medium storing a program for executing the processing.