CN104702977A - Achievement method for searching TS stream synchronization head of digital TV - Google Patents

Abstract

The invention relates to an achievement method for searching a TS stream synchronization head of a digital TV. The method is that a synchronizing state is achieved after detecting A successive synchronizing bits; a synchronizing losing state is achieved when B successive synchronizing bits are not detected under the synchronizing state. Compared with the prior art, the method has the advantages of quickly searching the TS stream synchronizing head, and being high in efficiency, high in precision, and low in cost.

Description

A kind of implementation method of digital TV TS stream synchronous head search

Technical field

The present invention relates to a kind of TS and flow synchronous head searching method, especially relate to the implementation method of a kind of digital TV TS stream synchronous head search.

Background technology

Digital Television is the new technology just grown up recent years, develops very fast.Code stream form in Digital Television is TS stream mainly, and carrying out analyzing and processing to Digital Television must realize for TS stream.TS stream has the code stream form of regulation, in order to analyzing and processing TS stream, must find the complete packet form of TS, and first must find the packet header that TS wraps, i.e. the synchronous head of TS stream.The problems such as the synchronous head ubiquity search efficiency searching TS stream in prior art is low, the time of searching is long.

Summary of the invention

Object of the present invention be exactly in order to overcome above-mentioned prior art exist defect and the implementation method that a kind of digital TV TS stream synchronous head is searched for is provided.

Object of the present invention can be achieved through the following technical solutions:

An implementation method for digital TV TS stream synchronous head search, is characterized in that, think enter synchronous regime when continuous A sync byte being detected, does not detect that B sync byte thinks synch lost state continuously under synchronous regime.

Preferably, described A is 4-6, and B is 2-4.

Preferably, described A is 5, and B is 3.

Preferably, described TS stream format is: 4 byte TS heads and 184 byte TS data, wherein TS head is: 1 byte of sync position is 0x47,1 error of transmission instruction, 1 load start instruction, 1 transmission priority, 13 PID, 2 bit encryptions control, and 2 adjustment fields control, and 4 identical PID TS wrap counting.

Preferably, the method specifically comprises the following steps:

1) arranging synchronous regime during initialization is asynchronous N_SYNC, counting CNT=0;

2) receive when cushioning full 188 byte data and start process;

3) whether if synchronous regime is asynchronous N_SYNC, then comparing current data is 0x47:

If a) current data is not 0x47, then counts CNT clear 0, abandon 1 byte data, return step 2;

If b) current data is 0x47, then counts CNT and add 1, and perform step c);

C) judge whether counting CNT reaches 5, if not to 5, then abandons 188 byte datas, returns step 2;

If d) count CNT to reach 5, then thought synchronously, arranging synchronous regime is synchronous SYNC, and counting CNT=0, processes this TS bag data, return step 2;

4) whether if synchronous regime is synchronous SYNC, then comparing current data is 0x47:

A) if current data is 0x47, then count CNT clear 0, process this TS bag data, return step 2;

B) if current data is not 0x47, then count CNT and add 1, and perform step C);

C) count CNT and whether reach 3, if not to 3, then process this TS bag data, return step 2;

D) if counting CNT reaches 3, then think and lose synchronously, putting synchronous regime is asynchronous N_SYNC, and counting CNT clear 0, abandons 1 byte data, return step 2.

Compared with prior art, the present invention has TS and flows that synchronous head retrieval rate is fast, efficiency is high, precision is accurate, realize low cost and other advantages.

Accompanying drawing explanation

Fig. 1 is concrete flow chart of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

Embodiment

The bag that TS flows employing 188 byte length is that unit transmits, current flux is generally about 40Mbps, Digital Television adopts mpeg2 coding, often overlap SD joint target flow and be generally 4-5Mbps, therefore each frequency of Digital Television and each TS flow reusable 8 programs, actual multiplexing 6 programs many.

TS stream format is: TS head (4 byte) and TS data (184 byte).TS head is: synchronous (1 byte) is 0x47, error of transmission instruction (1), load start instruction (1), transmission priority (1), PID (13), control extension (2), adjustment field controls (2), identical PID TS wraps counting (4), totally 4 bytes.First must find synchronous head when therefore analyzing conversion TS, then carry out different process according to different PID for each TS bag.

The algorithm of search synchronous head as shown in Figure 1.First need to carry out the synchronous search of TS when analyzing TS bag in Fig. 1, be divided into two states, be i.e. synchronous and synchronization loss.Think when continuous 5 sync bytes being detected and enter synchronous regime, under synchronous regime, do not detect continuously that 3 sync bytes think synchronization loss, under carrying out must being in synchronous regime when TS bag is analyzed.Process the analysis and processing module that 188 byte block are TS bag in figure, carry out different process depending on different application.

1. arranging synchronous regime during initialization is asynchronous (N_SYNC), counting CNT=0.

2. receive when cushioning full 188 byte data and start process.

Whether if 3. synchronous regime is asynchronous (N_SYNC), then comparing current data is 0x47:

If a) current data is not 0x47, then counts CNT clear 0, abandon 1 byte data, return step 2.

If b) current data is 0x47, then counts CNT and add 1;

C) count CNT and whether reach 5, if not to 5, then abandon 188 byte datas, return step 2.

If d) count CNT to reach 5, then think synchronously, synchronous regime has been set for synchronous (SYNC), counting CNT=0; Process this TS bag data (188 byte), return step 2.

4. whether if synchronous regime is synchronous (SYNC), then comparing current data is 0x47:

If a) current data is 0x47, then counts CNT clear 0, process this TS bag data (188 byte), return step 2.

If b) current data is not 0x47, then counts CNT and add 1;

C) count CNT and whether reach 3, if not to 3, then process this TS bag data (188 byte), return step 2.

If d) count CNT to reach 3, then think and lose synchronously, putting synchronous regime is asynchronous (N_SYNC), and counting CNT clear 0, abandons 1 byte data, return step 2.

Claims (5)

1. an implementation method for digital TV TS stream synchronous head search, is characterized in that, think enter synchronous regime when continuous A sync byte being detected, does not detect that B sync byte thinks synch lost state continuously under synchronous regime.

2. the implementation method of a kind of digital TV TS stream synchronous head search according to claim 1, it is characterized in that, described A is 4-6, and B is 2-4.

3. the implementation method of a kind of digital TV TS stream synchronous head search according to claim 2, it is characterized in that, described A is 5, and B is 3.

4. the implementation method of a kind of digital TV TS stream synchronous head search according to claim 3, it is characterized in that, described TS stream format is: 4 byte TS heads and 184 byte TS data, and wherein TS head is: 1 byte of sync position is 0x47,1 error of transmission instruction, 1 load start instruction, 1 transmission priority, 13 PID, 2 bit encryptions control, 2 adjustment fields control, and 4 identical PID TS wrap counting.

5. the implementation method of a kind of digital TV TS stream synchronous head search according to claim 4, it is characterized in that, the method specifically comprises the following steps:

1) arranging synchronous regime during initialization is asynchronous N_SYNC, counting CNT=0;

2) receive when cushioning full 188 byte data and start process;

3) whether if synchronous regime is asynchronous N_SYNC, then comparing current data is 0x47:

If a) current data is not 0x47, then counts CNT clear 0, abandon 1 byte data, return step 2;

If b) current data is 0x47, then counts CNT and add 1, and perform step c);

C) judge whether counting CNT reaches 5, if not to 5, then abandons 188 byte datas, returns step 2;

If d) count CNT to reach 5, then thought synchronously, arranging synchronous regime is synchronous SYNC, and counting CNT=0, processes this TS bag data, return step 2;

4) whether if synchronous regime is synchronous SYNC, then comparing current data is 0x47:

A) if current data is 0x47, then count CNT clear 0, process this TS bag data, return step 2;

B) if current data is not 0x47, then count CNT and add 1, and perform step C);

C) count CNT and whether reach 3, if not to 3, then process this TS bag data, return step 2;

D) if counting CNT reaches 3, then think and lose synchronously, putting synchronous regime is asynchronous N_SYNC, and counting CNT clear 0, abandons 1 byte data, return step 2.