CN108307204A - A kind of ALP packaging methods based on multi-service TS streams - Google Patents

Abstract

The present invention provides an ALP encapsulation method based on multi-service TS streams. The method is applied to an ALP encapsulation device at the sending end. The method includes the following steps: when encapsulating ALP stream data packets, according to the PID value in the TS stream data packets , put the video data packets with the same PID value in the TS stream data packet into the same queue, and enqueue and encapsulate the video data packets respectively; the PID value is the value of the PID field in the TS stream data packet header; the queue’s The length is fixed and determined according to the MTU limit of the network where it is located. The ALP encapsulation method based on the multi-service TS stream provided by the invention improves the ALP encapsulation efficiency of the multi-service TS data stream on the basis of not changing the table message encapsulation header.

Description

A method of ALP encapsulation based on multi-service TS

technical field

The invention relates to the field of video program transmission, in particular to an ALP encapsulation method based on multi-service TS flows.

Background technique

With the rapid development of digital TV, the business handled by the front-end system is gradually increasing, and digital TV IP has become a trend. The American Advanced Television Service Advisory Committee (ATSC) has developed a new generation of standards, the ATSC3.0 standard. The ATSC Link-Layer Protocol in this standard defines a new data packet encapsulation format (hereinafter referred to as ALP encapsulation), which can support traditional TS data streams and general IP data stream video services. When encapsulating the TS data stream, the ALP protocol adopts three mechanisms of synchronous byte deletion, packet header deletion and empty packet deletion to reduce transmission overhead. Among them, packet header deletion is aimed at the situation that there are a large number of similar headers (except for CC bits, other fields are the same) in the TS packets loaded with video streams during video service transmission. The end uses the flag bit in the header of the ALP to restore these deleted headers. However, in a TS data stream containing multiple video services, the PID values of the TS packets loaded with different video service streams are different, and these packets with different PIDs are mixed together, making it almost impossible for the ALP encapsulator to use the ALP header when encapsulating The deletion mechanism causes the transmission resources to be wasted.

Do not find description or report similar to the present invention at present, also do not collect similar data both at home and abroad.

Contents of the invention

Aiming at the defects of header deletion mechanism in ALP encapsulation in the prior art, the purpose of the present invention is to provide an ALP encapsulation method based on multi-service TS streams when TS data streams contain multiple video services. The method is implemented as follows:

A kind of ALP encapsulation method based on multi-service TS flow, comprises the steps: according to the PID value in the TS flow data packet, the video data packet with the same PID value in the TS flow data packet is put into the same queue, and the video data packet Carry out separate queuing encapsulation.

Preferably, the PID value is the value of the PID field in the header of the TS stream data packet.

Preferably, it specifically includes the following sub-steps:

Step S100, obtain a TS stream data packet, and enter step S101;

Step S101, judging whether the PID value of the acquired TS stream data packet is 0; if yes, then enter step S102, if not, then enter step S103;

Step S102, read the content in the obtained TS stream data packet, compare the corresponding relationship between the program number in the TS stream data packet and the program mapping table (PMT) and the program number in the current program list (PLT) and the program mapping table Whether the corresponding relationship is the same, if yes, then return to step S100 for the next cycle, if not, then enter step S104;

Step S103, judging whether the PID value of the obtained TS stream data packet exists in the program list, if yes, then enter step S105, if not, then enter step S106;

Step S104, modifying the program list so that the program number in the program list is consistent with the program number in the obtained TS stream data packet, and then returns to step S100 for the next cycle;

Step S105, judging according to the program list whether the PID value of the obtained TS stream data packet belongs to the program mapping table or the video data packet, if it belongs to the program mapping table, then enters step S108, if it belongs to the video data packet, then enters step S107;

Step S106, ALP-encapsulates the obtained TS stream data packets separately, and then returns to step S100 to enter the next cycle;

Step S107, put the current video data packet into the corresponding queue for sorting, and then enter step S110;

Step S108, judging whether the corresponding video data in the current program mapping table is the same as that in the program list, if yes, then return to step S100, and enter the next cycle, if not, then enter step S109;

Step S109, revise the video data PID value corresponding to the current program number in the program list, and then return to step S100 to enter the next cycle;

Step S110, judge whether the current queue is full; if yes, then enter step S111, if not, then check whether the current queue time slice is exhausted, if exhausted, perform ALP encapsulation on video data, if not exhausted, then re-encapsulate Go back to step S100 and enter the next cycle;

Step S111, performing ALP encapsulation on the video data.

Preferably, in the step S102, the corresponding relationship between the program number in the TS stream data packet and the program mapping table and the corresponding relationship between the program number and the program mapping table in the current program list are: the TS stream data obtained from the program mapping table The PID value of the packet is stored in the program list, and stored in the program column as a state of one-to-one correspondence between the program number, the PID value of the program mapping table and the PID value of the video data packet.

Preferably, the lengths of the queues are all fixed and determined according to the MTU limit of the network where they are located.

The ALP encapsulation method based on the multi-service TS stream provided by the present invention is applied to an ALP encapsulation device. Among the video data packets in the received TS data stream, the data packets with the same PID value are put into the same queue, and the data packets with different PID values are put into different queues. The length of each queue is fixed, and the queue length is determined according to the MTU (Maximum Transmission Unit, Maximum Transmission Unit) limitation of the network where it is located. When a queue is full or the timing segment of a queue is exhausted, the queue is ALP-encapsulated. For TS stream data packets loaded with program specific information (PSI), program association table (PAT), conditional access table (CAT), program mapping table (PMT), etc., which are relatively less than video information, the The TS flow data packet is placed in the queue, but is separately encapsulated into an ALP data packet and sent.

Compared with the prior art, the present invention has the following beneficial effects:

1. The ALP encapsulation method based on multi-service TS streams provided by the present invention greatly improves the encapsulation efficiency when ALP encapsulates TS streams carrying multiple video services.

2. The ALP encapsulation method based on the multi-service TS stream provided by the present invention improves the ALP encapsulation efficiency without changing the header.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is a schematic diagram of a method for generating and updating a PLT table.

Fig. 2 is a schematic diagram of an ALP encapsulation method.

Fig. 3 is a flow chart of the ALP encapsulation method based on multi-service TS flows in the present invention.

Detailed ways

The following is a detailed description of the embodiments of the present invention: this embodiment is implemented on the premise of the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Example

This embodiment provides an ALP encapsulation method based on multi-service TS streams, the method includes the following steps: when encapsulating ALP data packets, using the difference in the PID field value in the TS stream data packets, the TS stream data packets have The video data packets with the same PID value are put into the same queue, and the video data streams are respectively queued and encapsulated.

Further, the PID field is the PID field in the header of the TS stream data packet.

As shown in Figure 3, this embodiment provides an ALP encapsulation method based on multi-service TS flows, specifically including the following sub-steps:

Step S100, obtain a TS stream data packet, and enter step S101;

Step S101, judging whether the PID value of the acquired TS stream data packet is 0; if yes, then enter step S102, if not, then enter step S103;

Step S102, read the content in the obtained TS stream data packet, compare whether the corresponding relationship between the program number and the PMT table in the TS stream data packet and the corresponding relationship between the program number and the PMT table in the current PLT table are the same, if yes, Then get back to step S100 again, carry out next cycle, if not, then enter step S104;

Step S103, judging whether the PID value of the obtained TS flow packet exists in the PLT table, if yes, then enter step S105, if not, then enter step S106;

Step S104, revise the PLT table so that the program number in the PLT table is consistent with the program number in the obtained TS stream data packet, and then return to step S100 for the next cycle;

Step S105, judge according to the PLT table whether the PID value of the obtained TS stream data packet belongs to the PMT table or belongs to the video data packet, if it belongs to the PMT table, then enters step S108, if it belongs to the video data packet, then enters step S107;

Step S106, ALP-encapsulates the obtained TS stream data packets separately, and then returns to step S100 to enter the next cycle;

Step S107, put the current video data packet into the corresponding queue for sorting, and then enter step S110;

Step S108, judge whether the corresponding video data in the current PMT table is identical with that in the PLT table, if yes, then get back to step S100 again, enter next cycle, if not, then enter step S109;

Step S109, modify the corresponding video data PID value of the current program number in the PLT table, then get back to step S100, and enter the next cycle;

Step S110, judge whether the current queue is full; if yes, then enter step S111, if not, then check whether the current queue time slice is exhausted, if exhausted, perform ALP encapsulation on video data, if not exhausted, then re-encapsulate Go back to step S100 and enter the next cycle;

Step S111, performing ALP encapsulation on the video data.

Further, the corresponding relationship in step S102 is: store the PID value of the TS stream data packet obtained from the program mapping table (PMT) in the program list (PLT), and store it in the program list (PLT) as The status of one-to-one correspondence between program number, PMT table PID value and video data packet PID value.

Further, the lengths of the queues are all fixed and determined according to the MTU limit of the network where they are located.

The scheme of this embodiment is described in detail below.

As shown in Figure 1, when the TS stream data packet is obtained in the ALP encapsulation device, the number of programs contained in the current TS stream data packet and the number of programs contained in the current TS stream data packet and the The PID value of the stream's PMT table. Find the corresponding TS stream data packet according to the obtained PID value of the required PMT table, read the content therein, find the PID value corresponding to the video information of the program, and record it in the program list (PLT).

After the PLT table is established, when the TS stream data packet is obtained, the video data packet can be distinguished from other types of data packets according to the PLT table. The PID values of the TS stream data packets carrying video data in the current transport stream should all be in the PLT table, and the PLT table is also updated in real time to deal with the PID value of the video data packets brought about when the program changes. Variety.

Please refer to Table 1 for a specific example of a PAT packet.

Read Table 1, you can get 3 programs in the current TS stream data packet, their sequence numbers are 01, 02, and 03 respectively, and the PMT tables of these three programs exist in the TS streams with PID values respectively 21, 22, and 23 in the packet. Refer to steps 101, 102, and 104 in Table 3 to generate a PLT table. And continue to get TS stream packets.

Table 1

program number PID value corresponding to PMT 01 20 02 twenty one 03 twenty two

Please refer to Tables 2, 3, and 4. These three tables give specific examples in the PMT tables with PID values of 20, 21, and 22. These three tables indicate that the PID values of the TS stream data packets in the three-channel program are 70, 73, and 76 respectively, and the PLT table shown in Table 5 can be generated from these information. It can be seen from Table 5 that it is sufficient to extract TS stream data packets with PID values of 20, 21, 22, 70, 73, and 76 each time. The extracted 20, 21, 22 can be used to update the PID value of the video data packet in the PLT table.

Table 2

table 3

Serve PIDs video 73 audio 74 PCR 75

Table 4

Serve PIDs video 76 audio 77 PCR 78

table 5

program number PID of the PMT table Video program PID 01 20 70 02 twenty one 73 03 twenty two 76

Please refer to Table 6, which shows an example of an incoming TS stream packet. Table 6 shows 10 TS data streams, and each TS data stream has multiple TS stream data packets with different PID values.

Table 6

According to step S103, the TS stream data packets with PID values of 20, 21, 22, 70, 73, and 76 can be filtered out, wherein the TS stream data packets with PID values of 20, 21, and 22 are used to update the PLT table, and the PID values are The TS stream data packets of 70, 73, and 76 are respectively loaded into three queues, and ALP encapsulation is performed when the queues are full. In the first TS flow packet, execute steps S100 and S101, read the PAT packet with a PID value of 00, read the PID value list in the PMT table as shown in Table 1, and program number and The corresponding PID values in the PMT table are respectively filled in the PLT table.

Execute step S103, step S105, step S108 and step S109 to read the PID values 70, 73 and 76 of the TS stream data packets in the program list (PLT).

Step S100 , step S101 , step S103 , step S105 to step S111 are executed cyclically, and the obtained TS stream data packets are respectively encapsulated into ALP data packets according to the PID values. The results of the encapsulated ALP packet are shown in Table 7.

Table 7

Whether to use header compression In-package PID 1st ALP packet no 00/20/21/22 2nd ALP packet no 71 3rd ALP packet no 72 4th ALP packet no 74/75/77/78 5th ALP packet Yes 70/70/70/70/70/70/70 6th ALP packet Yes 76/76/76/76/76/76/76 7th ALP packet Yes 70/70/70/70/70/70/70 8th ALP packet Yes 73/73/73/73/73/73/73 9th ALP packet Yes 76/76/76/76/76/76/76 10th ALP packet Yes 73/73/73/73/73/73/73 11th ALP packet Yes 76/76/76 12th ALP packet Yes 73/73/73/73 13th ALP Packet Yes 70/70/70

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. In the range.

The ALP encapsulation method based on the multi-service TS stream provided in this embodiment is applied to the ALP encapsulation device at the sending end. When encapsulating the ALP stream data packet, the PID value in the TS stream data packet is used to convert the video data of different TS stream data packets. The data are encapsulated separately; the PID value adopted in this embodiment is the value of the PID field in the TS header in the TS stream data packet. This embodiment improves the ALP encapsulation efficiency of the multi-service TS data stream without changing the encapsulation header of the table message.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (5)

1. a kind of ALP encapsulation method based on multi-service TS flow, it is characterized in that, comprises the steps: according to the PID value in the TS flow data packet, the video data packet with identical PID value in the TS flow data packet is put into same queue , and respectively enqueue and encapsulate the video data packets. 2. The ALP encapsulation method based on multi-service TS flows as claimed in claim 1, wherein the PID value is the value of the PID field in the TS flow packet header. 3. the ALP encapsulation method based on multi-service TS flow as claimed in claim 1, is characterized in that, specifically comprises the following sub-steps: Step S100, obtain a TS stream data packet, and enter step S101; Step S101, judging whether the PID value of the acquired TS stream data packet is 0; if yes, then enter step S102, if not, then enter step S103; Step S102, read the content in the obtained TS stream data packet, compare the corresponding relationship between the program number and the program mapping table in the TS stream data packet and whether the corresponding relationship between the program number and the program mapping table in the current program list is the same, if If yes, then return to step S100 for the next cycle, if not, then enter step S104; Step S103, judging whether the PID value of the obtained TS stream data packet exists in the program list, if yes, then enter step S105, if not, then enter step S106; Step S104, modifying the program list so that the program number in the program list is consistent with the program number in the obtained TS stream data packet, and then returns to step S100 for the next cycle; Step S105, judging according to the program list whether the PID value of the obtained TS stream data packet belongs to the program mapping table or the video data packet, if it belongs to the program mapping table, then enters step S108, if it belongs to the video data packet, then enters step S107; Step S106, ALP-encapsulates the obtained TS stream data packets separately, and then returns to step S100 to enter the next cycle; Step S107, put the current video data packet into the corresponding queue for sorting, and then enter step S110; Step S108, judging whether the corresponding video data in the current program mapping table is the same as that in the program list, if yes, then return to step S100, and enter the next cycle, if not, then enter step S109; Step S109, revise the video data PID value corresponding to the current program number in the program list, and then return to step S100 to enter the next cycle; Step S110, judge whether the current queue is full; if yes, then enter step S111, if not, then check whether the current queue time slice is exhausted, if exhausted, perform ALP encapsulation on video data, if not exhausted, then re-encapsulate Go back to step S100 and enter the next cycle; Step S111, performing ALP encapsulation on the video data. 4. The ALP encapsulation method based on multi-service TS flows as claimed in claim 3, characterized in that, in the step S102, the corresponding relationship between the program number and the program mapping table in the TS stream data packet and the program number in the current program list The corresponding relationship with the program mapping table is: store the PID value of the TS stream data packet obtained from the program mapping table in the program list, and store it in the program column as the program number, program mapping table PID value and video data packet PID A one-to-one mapping of values to the state. 5. The ALP encapsulation method based on multi-service TS flows according to claim 1 or 3, wherein the lengths of the queues are all fixed and determined according to the MTU limit of the network where they are located.