CN100359950C

CN100359950C - Remultiplexing method for MPEG-2 transmission stream

Info

Publication number: CN100359950C
Application number: CNB021124027A
Authority: CN
Inventors: 李斌; 李晖; 刘衍
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2002-07-02
Filing date: 2002-07-02
Publication date: 2008-01-02
Anticipated expiration: 2022-07-02
Also published as: CN1466386A

Abstract

The present invention relates to a multiplexing method of moving picture expert group-2 transport streams, particularly to a multiplexing technique of MPEG-2 transport streams. The method comprises the steps that a lookup table is established; the lookup table, corresponding to MPEG-2 transport streams received by each path, has 8192 table items; the table items x (0</=x</=8191), corresponding to carried PID received from the transport stream of the path, are data packets of x; each table item contains information A, B, C; PID fields of packet heads of received data packets are extracted one by one; the corresponding table items in the lookup table are read according to the PID fields of the data packets; the data packets are respectively processed according to the information of the table items. The present invention has the advantages that the processing capacity of multiplexing devices can be enhanced, and a plurality of output transport streams can be realized.

Description

Remultiplexing method for MPEG-2 transmission stream

Technical field

The invention belongs to motion image expert group 2 (MPEG-2) code stream transmission field, be specifically related to the MPEG-2 transmission and flow multiplex technique again.

Background technology

Be to realize that MPEG-2 transmits the transmission of stream on network, using MEPG-2 to transmit that transmission stream packets that the stream re-multiplexer transmits the part or all of program in the stream with multichannel MPEG-2 reconfigures usually is that a new MPEG-2 transmits stream in transmission over networks.

According to the program specific information (PSI) in the MPEG-2 transmission stream of each reception, MPEG-2 transmits the stream re-multiplexer can know wherein include which program.The user can select part or all of program to be reassembled into new transmission stream output then.According to PSI information, multiplexer can determine that these selecteed programs are made up of the transport stream packet packet (TS bag) that carries which grouping label (PID), thereby multiplexer can further determine need be from flow during the transmission that is inserted into output of the extraction packet that carries which PID flows by the transmission that receives.

When from the transmission stream packets that receives, extracting packet, normally from the transmission stream packets that receives, extract the PID field, compare one by one with the pid value of above-mentioned definite permission output, as mate, then this packet is extracted and exports, otherwise abandons.The method of this extraction packet need compare the PID field of each packet of receiving with each selected pid value, mate or all do not match up to taking place, and relatively expends cpu resource, influences the disposal ability of multiplexer.

Above-mentioned MPEG-2 transmits the stream re-multiplexer and has following two defectives: 1, bag extracting method efficient is low.2, have only the MPEG-2 of an output to transmit stream.

U.S. Pat 5835493 " MPEG transport stream remultiplexer " discloses the technical scheme that a kind of MPEG-2 transmits the stream re-multiplexer.According to this scheme, can receive multichannel MPEG-2 and transmit stream, therefrom extract multi-channel program and carry out again multiplexingly, reconfiguring is that a new MPEG-2 transmits stream output.

The MPEG-2 that this invention is described transmits in the stream re-multiplexer and is described to: " according to the PID field of packet, extract packet from the transmission stream that receives, and the packet that is extracted is inserted in the transmission stream of output." but this invention does not provide concrete bag extracting method, and described multiplexer also has only the MPEG-2 of an output to transmit stream.

Summary of the invention

Technical problem to be solved by this invention overcomes the existing in prior technology shortcoming, propose a kind of efficiently, the MPEG-2 of multichannel output transmits the stream remultiplexing method.

The present invention proposes MPEG-2 transmission stream remultiplexing method and may further comprise the steps:

The first step, set up a look-up table;

It is as follows that this searches structure: the MPEG-2 that the corresponding every road of this look-up table receives transmits stream all 8192 list items; The corresponding packet that PID is x that carries that transmits the stream reception from this road of list item x (0≤x≤8191); Wherein, the information that each list item comprised has:

Information A: to show which output port is this packets need output to and whether this packet needs to store in the system storage;

Information B: this information has been stored a pid value for each output transmits stream, shows that this packet is inserted into the PID field value after each output transmits in the stream;

Information C: if this packets need stores in the system storage, this information shows the memory address of this packet;

Second goes on foot, extracts one by one the PID field that receives packet packet header;

The 3rd step, according to the PID field of this packet, read corresponding look-up table list item; Divide following processing according to the information of list item to this packet again:

1. judge according to information A which output is this packets need be inserted into and transmit in the stream;

2. insert the respectively output transmission stream of this packet for needs, the PID field with this packet one by one is revised as the pid value of preserving for correspondence output transmission stream among the information B, during the output that then this packet is inserted into correspondence transmits and flows;

3. judge according to information A whether needs store in the system storage this packet,, forwarded for second step to if do not need storage;

4. if this packets need is stored, this packet is stored into the address of information C appointment; Forwarded for second step to.

It is fairly simple that the MPEG-2 based on look-up table that the present invention proposes transmits the stream remultiplexing method, is easy to realize.Can judge fast that a MPEG-2 transport stream packet need output in the MPEG-2 transmission stream of which output, thereby save cpu resource, improve the disposal ability of multiplexer, can realize the transmission stream of a plurality of outputs.

Description of drawings

Fig. 1 is the flow chart of the method for the invention.

Fig. 2 is the structure chart of the look-up table of the above-mentioned embodiment of the present invention;

Fig. 3 is the structure chart of a list item of look-up table among Fig. 2;

Fig. 4 is a flow chart of handling a transmission stream packets that receives.

Embodiment

Below in conjunction with drawings and Examples technical scheme of the present invention is described in further detail:

Referring to Fig. 1, going into the 8 transmission stream re-multiplexers that go out with one 16 is example, and multiplexing method of the present invention is done specific descriptions:

The first step is set up a look-up table.

The structure of look-up table is as shown in Figure 2: this look-up table is that each receives each the possible PID that transmits stream and distributes a look-up table list item.In MPEG-2 TS bag, the PID field length is 13 bits, and 8192 kinds of possible values can be arranged, and system has 16 to receive when transmitting stream, and look-up table list item number is 8192*16, i.e. list item (0)-list item (8192*16-1).

If the base address T_ADR_BASE of look-up table, look-up table list item length is T_ELE_LEN.From receive transmitting PID that stream (x) receives be like this for the address that the MPEG-2 TS of (y) wraps corresponding look-up table list item:

T_ADR_BASE+(8192*x+y)*T_ELE_LEN；(0≤x≤15，0≤y≤8191)。

Referring to Fig. 3, each list item of look-up table comprises 10 fields.Each field implication is as follows:

Field 0 has 9 significant bits, and each bit of this field and other 8 field implications are as follows:

Bit I (0≤I≤7) is 1, shows need be inserted among the transmission stream I of output to transmission stream packets that should list item, i.e. and information A, field (I+1) shows that this packet is inserted into the PID value that output transmits the back heart in the stream, i.e. information B; If bit I (0≤I≤7) is 0, show that corresponding packet does not need to be inserted into output and transmits among the stream I, field (I+1) content is meaningless.

Bit 8 is 1 to show and need store specified memory into to transmission stream packets that should list item that field 9 shows the memory address of this packet, i.e. information C.If bit 8 is 0 to show transmission stream packets that should list item is not needed to store in the memory block that field 9 contents are meaningless.

In second step, extract the PID field that receives in the packet packet header one by one.

The 3rd step, read the corresponding list item of searching according to PID, according to the information in the look-up table list item this packet is handled.Returned for second step.

This step is divided into 5 steps again, with reference to figure 4, specifically implements as follows:

1, reads look-up table list item field 0.

2,, returned for second step if field 0 is 0.

3, if field 0 the 1st (0≤I≤7) bit is 1, the PID field of replacing this packet with the pid value in the look-up table list item field (I+1), and this packet is inserted into output transmits and flow among the I.

4,, returned for second step if field 0 the 8th bit is 0

5 otherwise, store this packet into look-up table list item field 8 specified memory.Returned for second step.

Claims

1, remultiplexing method for MPEG-2 transmission stream may further comprise the steps:

The first step, set up a look-up table;

This look-up table configuration is as follows: the MPEG-2 that the corresponding every road of this look-up table receives transmits stream all 8192 list items; List item x (0≤x≤8191) is corresponding transmit from this road that stream receives to carry the grouping label be the packet of x; Wherein, the information that each list item comprised has:

Information B: this information has been stored a grouping index value for each output transmits stream, shows that this packet is inserted into the grouping label field value after each output transmits in the stream;

Second goes on foot, extracts one by one the grouping label field that receives packet packet header;

The 3rd step, according to the grouping label field of this packet, read corresponding look-up table list item; Divide following processing according to the information of list item to this packet again:

2. insert the respectively output transmission stream of this packet for needs, the grouping label field with this packet one by one is revised as the grouping index value of preserving for correspondence output transmission stream among the information B, during the output that then this packet is inserted into correspondence transmits and flows;