WO2020011205A1

WO2020011205A1 - Broadcast system-based transport protocol conversion method and system

Info

Publication number: WO2020011205A1
Application number: PCT/CN2019/095450
Authority: WO
Inventors: 徐异凌; 张文军; 张渴; 柳宁; 管云峰
Original assignee: 上海交通大学
Priority date: 2018-07-11
Filing date: 2019-07-10
Publication date: 2020-01-16

Abstract

The present invention provides a broadcast system-based transport protocol conversion method and system. The method comprises: encapsulating a media resource into a first protocol packet according to a first protocol; and performing packet conversion on the first protocol packet to obtain a TS packet for network transport. According to the present invention, when new network protocols, such as MMT, are implemented on a broadcast network, an existing infrastructure can be utilized, thereby providing more plentiful and diverse media services with low costs.

Description

Transmission protocol conversion method and system based on broadcasting system

This application is based on a Chinese invention patent with an application date of July 11, 2018 and application number CN201810758261.8 as the basis for claiming priority.

Technical field

The present invention relates to the field of multimedia transmission, and in particular, to a transmission protocol conversion method and system based on a broadcast system.

Background technique

From the analog television era to the digital television era, the traditional broadcast television business has won the favor of the masses of users with its rich content, high-definition picture, and high-fluidity of presentation, thus having a huge media market. In contrast, the Internet, especially the mobile Internet digital media business, has rapidly developed and popularized with its advantages of sharing, openness, and interaction. In recent years, new media businesses represented by digital media, especially online video and mobile video, are becoming a major growth point for information consumption. The development of the Internet and mobile Internet has brought severe challenges to the traditional radio and television industry, and at the same time has brought good development opportunities.

The development of media network technology has made the broadcasting industry more open and richer in entertainment resources. How to integrate and present shared information and personalized content has become a hot topic of research today. With the widespread application of home digital media systems, traditional single-device, single-content consumption, such as televisions and computers, has been unable to meet people's home entertainment consumption needs. Specifically, at the media consumption level, current mass media content provides users with more consumption options, but due to the loose association and organizational relationship between content, there is a serious information gap when users consume. For video media content, the lack of an effective content description mechanism due to the dynamic and time-varying nature of video content makes this problem particularly serious. In terms of content delivery technology, how to combine with broadcast content to drive the consumption of diverse content is Providing users with more personalized, intelligent, and socialized consumer experiences is another challenging issue for broadcasting to adapt to future media applications. In terms of terminal applications of content, the trend of socialization and intelligence under network conditions is obvious, but the terminal The contradictions between functions and limitations are prominent, and users urgently need the synchronous coupling technology of multi-terminal media content in order to achieve a more complete consumer experience.

New media transmission technologies featuring intelligent processing of media content, intelligent distribution of media networks, terminal coupling, and resonance consumption have become research hotspots in academia, standards, and industry in recent years. Internationally, the MPEG (Moving Pictures Experts Group) standards organization has formulated the MMT (MPEG Media Transport) protocol. In China, the Digital Audio and Video Codec Technical Standards Working Group has also formulated the corresponding standard, namely the Smart Media Transport (SMT) protocol. Both the first protocol and the SMT protocol are packet-oriented application-layer transmission protocols, and both support multi-network convergence and multi-screen interaction technologies. They provide a good solution to the above problems, and also expand the service area of traditional TV. These protocols can provide intelligent, diversified, and personalized media services, thereby forming a new generation of media content services.

At the level of media content distribution, broadcasting is still an important content delivery method. Transport stream (TS) in MPEG-2 provides sufficient flexibility for the multiplexing technology, and the TS stream uses a fixed-length packet structure. When transmission errors destroy the synchronization information of a packet, The receiver can detect the synchronization information of subsequent packets at a fixed position, thereby restoring synchronization. MPEG-2TS has a wide range of applications in the broadcast field due to its good anti-jamming, channel environment adaptability, and low receiver cost, so a lot of existing infrastructure is based on TS streams. As mentioned above, pure TS stream based broadcast services cannot meet consumer demand. At the present stage, when new media transmission technologies represented by the first protocol are implemented, how to use existing broadcasting equipment becomes a problem that must be solved.

Summary of the invention

In view of the defects in the prior art, an object of the present invention is to provide a transmission protocol conversion method and system based on a broadcast system.

A transmission system conversion method based on a broadcast system provided according to the present invention includes:

Initial encapsulation step: encapsulating media resources into a first protocol package according to the first protocol;

Packet conversion step: perform packet conversion on the first protocol packet to obtain a TS packet for network transmission.

Preferably, the packet conversion step includes:

ULE encapsulation sub-step: ULE encapsulation of the first protocol packet to obtain a ULE packet;

TS encapsulation sub-step: TS encapsulation of the ULE packet to obtain a TS packet.

Preferably, the packet structure of the ULE packet includes: an HDR segment, a first protocol data segment, and a CRC segment;

The first protocol data segment is a ULE packet payload, that is, a first protocol packet;

The CRC segment is a cyclic redundancy check code, 32 bits;

The HDR segment includes:

length: 16 bits, indicating the byte length of the first protocol packet encapsulated in the ULE;

type: 16 bits, indicating the type of the first protocol packet.

Preferably, the TS packet includes: a header and a payload segment;

The header includes:

Sync byte: 8 bits;

Error code: 1 bit, set to "1" when there is an uncorrectable bit error in the TS packet;

Unit start indication: 1 bit, set to "1" when the payload segment is the first data segment after ULE packet segmentation;

Priority: 1 bit, in packets with the same PID, set to "1" when the priority is higher;

PID: 13 bits, corresponding to the first protocol packet;

Scrambling control: 2 bits, indicating the scrambling mode of the load;

AF control: 2 bits, indicating whether the header adaptive field is included after the header;

Continuous counter: 4 bits, incremented with packets with the same PID.

Preferably, it also includes:

Decapsulation step: The received TS packet is converted into a packet that is inverse to the packet conversion step to obtain a first protocol packet.

A transmission protocol conversion system based on a broadcast system provided according to the present invention includes:

Preliminary encapsulation module: encapsulating media resources into a first protocol package according to the first protocol;

Packet conversion module: perform packet conversion on the first protocol packet to obtain a TS packet for network transmission.

Preferably, the packet conversion module includes:

ULE encapsulation submodule: ULE encapsulation of the first protocol packet to obtain a ULE packet;

TS encapsulation submodule: TS encapsulation of the ULE packet to obtain a TS packet.

The CRC segment is a cyclic redundancy check code, 32 bits;

The HDR segment includes:

type: 16 bits, indicating the type of the first protocol packet.

Preferably, the TS packet includes: a header and a payload segment;

The header includes:

Sync byte: 8 bits;

PID: 13 bits, corresponding to the first protocol packet;

Scrambling control: 2 bits, indicating the scrambling mode of the load;

Continuous counter: 4 bits, incremented with packets with the same PID.

Preferably, it also includes:

Decapsulation module: The received TS packet is converted into a packet that is inverse to the packet conversion module to obtain a first protocol packet.

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

The invention enables new network protocols such as MMT to be implemented on a broadcast network, and can utilize existing infrastructure, thereby providing a richer and more diversified media service at a lower cost.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 is a system frame diagram of an embodiment of the present invention;

FIG. 2 is a schematic diagram of converting a MMTP packet to a TS packet according to an embodiment of the present invention; FIG.

FIG. 3 is a schematic diagram of a ULE packet structure;

FIG. 4 is a schematic diagram of a TS packet structure.

detailed description

The present invention is described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In this embodiment, the MMT protocol is used as an example for description, but the present invention is not limited thereto.

As shown in FIG. 1 and FIG. 2, a method for converting a transmission system based on a broadcast system according to the present invention includes:

The media resources in the server are encapsulated into MMTP packets according to the MMT protocol. After the packet conversion, the TS packets that can adapt to the existing broadcast infrastructure are output and sent to the receiver through the network (broadband network, cellular network, broadcast network, etc.). The receiving end then performs reciprocal packet conversion with the sending end to obtain the MMTP packet encapsulated based on the MMT protocol, thereby providing a richer, more flexible and personalized media service.

The MMTP packet in this embodiment is generated according to the MMT protocol standard encapsulation, and then it is subjected to ULE (Unidirectional Lightweight Encapsulation) encapsulation and TS encapsulation in order to complete the MMT-TS packet conversion. The TS packet obtained after conversion is sent to the receiving end through the broadcast network, and the TS-MMT packet conversion can be completed after the receiving end performs decapsulation. The specific implementation of the MMT-TS packet conversion at the transmitting end will be described below. The packet conversion step of the TS-MMT at the receiving end is the opposite, that is, TS decapsulation is performed first and then ULE decapsulation is performed to obtain the original MMTP packet.

ULE package:

Media resources that are fragmented and encapsulated according to the MMT protocol can be transmitted in a wide range of networks such as broadband, cellular, and broadcast networks after being packaged into MMTP packets, and support multiple services such as multi-view simultaneous presentation and multi-terminal associated presentation. mode. MMT encapsulation has the advantages of flexibility and support for heterogeneous networks and personalized customization scenarios. Therefore, the present invention does not change the standard MMT encapsulation format, but performs packet conversion at the MMTP packet level, and finally converts it into TS packets.

As shown in Figure 1, MMTP packets are encapsulated twice during packet conversion. The first thing to do is a lightweight (can be ULE or MLE) ULE package. The structure of the encapsulated ULE packet is shown in Figure 3, and its syntax format is shown in Table 1.

The semantics of the related fields are as follows:

mmtp_length: 16 bits, indicating the byte length of the MMTP data packet encapsulated in the ULE;

mmtp_type: 16 bits, indicating the type of the MMTP packet;

MMTP_data: ULE packet payload, that is, MMTP packet;

CRC: Cyclic Redundancy Check, 32 bits, used for data transmission error detection.

TS package:

After the MMTP package is ULE encapsulated and converted into a ULE package, it needs to be further encapsulated to be converted into a TS package. As shown in FIG. 4, a TS packet usually includes a fixed-length header of 4 bytes and an adaptive field of a variable-length header, and a data segment not exceeding 184 bytes. For each ULE packet, the present invention cuts it into a plurality of data segments not exceeding 184 bytes, and places each data segment into the payload of the TS packet. In particular, if the TS receiver in the transmission system is not only used to accept the converted ULE data segment containing MMTP data, the present invention occupies 9 bytes in a variable-length header adaptive field (AdaptionField) to insert an indication The information enables the TS receiver to determine that the currently accepted content is a ULE data segment, and describes the attributes of the encapsulated content. If this adaptive field is enabled, the size of the ULE data segment will be reduced to 175 bytes. For the header of the converted TS packet, the fields are set as follows:

Sync byte: 8 bits, set here to 0x47;

Error code indicates: 1 bit, set to "1" when there is an uncorrectable bit error in the TS packet;

Unit start indication: 1 bit, set to "1" when the payload data is the first data segment after ULE packet segmentation;

Priority: 1 bit. In packets with the same PID, the priority is set to "1".

PID: 13 bits, corresponding to packet_id in MMTP;

Scrambling control: 2 bits, indicating the scrambling mode of the load;

AF control: 2 bits, indicating whether the header adaptive field (Adaption Field) is included after the header;

Continuous counter: 4 bits, incremented with packets with the same PID.

If needed, the fields in the header adaptive field (AdptationField) that need special settings are as follows:

Adaptive field length: 1 byte, used to indicate the length of the extended field, counted as 9 bytes, that is, set to "0x09";

Discontinuity status indicator: 1 bit, used to indicate the discontinuity status of the currently transmitted data packet;

Random access indicator: 1 bit, used to indicate whether the currently transmitted stream packet contains information to help random access;

Elementary stream priority indicator: 1 bit, used to indicate the priority of the payload in the same packet;

PCR identifier: 1 bit, used to indicate whether this adaptive field contains a PCR field, set to "0";

OPCR identifier: 1 bit, used to indicate whether this adaptive field contains the OPCR field, set to "0";

Splice point identifier: 1 bit, used to indicate whether this adaptive field contains the splice_countdown field, and is set to "0";

Transmission private data identifier: 1 bit, used to indicate whether this adaptive field contains a private data field, set to "1";

Adaptive field extension identifier: 1 bit, used to indicate whether the adaptive field contains an extension field, set to "0";

In the private data field, the field length (transport_private_data_length) is calculated as "6" and is set to "0x06", and the field byte (transport_private_data_byte) is set to "IS_ULE", which is used to indicate that the data in the TS packet is a ULE data segment. After unpacking and splicing, the ULE packet should be unpacked again to obtain the MMTP and handed over to the MMT receiver for media operations.

Based on the foregoing transmission protocol conversion method based on a broadcast system, the present invention also provides a transmission protocol conversion system based on a broadcast system, including:

Preliminary encapsulation module: Encapsulates media resources into a first protocol package according to a first protocol.

Packet conversion module: converts the first protocol packet into a packet, and obtains a TS packet for network transmission.

Those skilled in the art know that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in a pure computer-readable program code manner, it is entirely possible to make the system and its various devices provided by the present invention logically program the method steps , Modules, and units implement the same functions in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system provided by the present invention and its various devices, modules, and units can be considered as a hardware component, and the devices, modules, and units included in it to implement various functions can also be considered as hardware components. The device, module, and unit for implementing various functions can also be regarded as a structure that can be either a software module for implementing the method or a hardware component.

The 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 can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

A transmission protocol conversion method based on a broadcast system, which includes:

Initial encapsulation step: encapsulating media resources into a first protocol package according to the first protocol;

Packet conversion step: perform packet conversion on the first protocol packet to obtain a TS packet for network transmission.
The transmission protocol conversion method based on a broadcast system according to claim 1, wherein the first protocol is an MMT protocol.
The method for converting a transmission system based on a broadcast system according to claim 1, wherein the packet conversion step comprises:

Light-weight packaging step: Light-weight packaging of the first protocol package to obtain a light-weight packaging package;

TS encapsulation step: TS encapsulation of the lightweight encapsulation packet to obtain a TS packet.
The method of claim 3, wherein the packet structure of the lightweight package includes a header field (HDR), a first protocol data segment, and a CRC segment;

The first protocol data segment is a lightweight encapsulated packet load, that is, a first protocol packet;

The CRC segment is a cyclic redundancy check code;

The header field includes: length: indicates a byte length of the first protocol packet encapsulated in the lightweight encapsulation packet.
The method of claim 4, wherein the header field further comprises:

type: indicates the type of the first protocol packet.
The method for converting a transmission system based on a broadcast system according to claim 4, wherein:

The CRC segment is 32 bits;

The length in the header field is 16 bits.
The method of claim 3, wherein the TS packet comprises: a header and a payload segment;

The header includes:

Sync byte

Error code indicates: "1" is set when there is an uncorrectable bit error in the TS packet;

Unit start indication: Set "1" when the load segment is the first data segment after the lightweight package packet is split;

Priority: In packets with the same PID, set to "1" when the priority is higher;

PID: corresponding to the first protocol package;

Scrambling control: indicates the scrambling mode of the load;

AF control: indicates whether the header adaptive field is included after the header;

Continuous counter: increments with packets with the same PID.
The method for converting a transmission system based on a broadcast system according to claim 7, wherein:

The synchronization byte is 8 bits;

The error code is represented as 1 bit;

The unit start indication is 1 bit;

The priority is 1 bit;

The PID is 13 bits;

The scrambling control is 2 bits;

The AF control is 2 bits;

The continuous counter is 4 bits.
The method of claim 1, further comprising:

Decapsulation step: The received TS packet is converted into a packet that is inverse to the packet conversion step to obtain a first protocol packet.
A transmission protocol conversion method based on a broadcast system, which includes:

Packet conversion step: reversely convert the received TS packet into a packet;

De-encapsulation step: De-encapsulating the first protocol packet obtained through reverse packet conversion to obtain the first protocol.
The method for converting a transmission system based on a broadcast system according to claim 10, wherein the reverse packet conversion comprises:

TS encapsulation and decapsulation step: Decapsulating the received TS packet to obtain a lightweight encapsulation packet;

Lightweight encapsulation and decapsulation step: Decapsulating the received lightweight encapsulation package to obtain a first protocol package.
A transmission protocol conversion system based on a broadcast system, which includes:

Preliminary encapsulation module: encapsulating media resources into a first protocol package according to the first protocol;

Packet conversion module: perform packet conversion on the first protocol packet to obtain a TS packet for network transmission.
The transmission protocol conversion system based on a broadcast system according to claim 12, wherein the first protocol is an MMT protocol.
The transmission protocol conversion system based on a broadcast system according to claim 12, wherein the packet conversion module comprises:

Lightweight packaging module: performing lightweight packaging on the first protocol package to obtain a lightweight packaging package;

TS packaging module: TS packaging the lightweight packaging package to obtain a TS package.
The transmission protocol conversion system based on a broadcast system according to claim 14, wherein the packet structure of the lightweight package includes a header field (HDR), a first protocol data segment, and a CRC segment;

The first protocol data segment is a lightweight encapsulated packet load, that is, a first protocol packet;

The CRC segment is a cyclic redundancy check code;

The header field includes:

length: indicates the byte length of the first protocol packet encapsulated in the lightweight package.
The transmission protocol conversion system based on a broadcast system according to claim 15, wherein the header field further comprises:

type: indicates the type of the first protocol packet.
The transmission protocol conversion system based on a broadcast system according to claim 15, wherein:

The CRC segment is 32 bits;

The length in the header field is 16 bits.
The transmission protocol conversion system based on a broadcast system according to claim 14, wherein the TS packet comprises: a header and a payload segment;

The header includes:

Sync byte

Error code indicates: "1" is set when there is an uncorrectable bit error in the TS packet;

Unit start indication: Set "1" when the load segment is the first data segment after the lightweight package packet is split;

Priority: In packets with the same PID, set to "1" when the priority is higher;

PID: corresponding to the first protocol package;

Scrambling control: indicates the scrambling mode of the load;

AF control: indicates whether the header adaptive field is included after the header;

Continuous counter: increments with packets with the same PID.
The transmission protocol conversion system based on a broadcasting system according to claim 18, wherein,

The synchronization byte is 8 bits;

The error code is represented as 1 bit;

The unit start indication is 1 bit;

The priority is 1 bit;

The PID is 13 bits;

The scrambling control is 2 bits;

The AF control is 2 bits;

The continuous counter is 4 bits.
The transmission protocol conversion system based on a broadcast system according to claim 12, further comprising:

Decapsulation module: The received TS packet is converted into a packet that is inverse to the packet conversion module to obtain a first protocol packet.
A transmission protocol conversion system based on a broadcast system, which includes:

Packet conversion module: performs reverse packet conversion on the received TS packet;

Decapsulation module: Decapsulates the first protocol packet obtained by reverse packet conversion to obtain the first protocol.
The transmission protocol conversion system based on a broadcast system according to claim 21, wherein the reverse packet conversion comprises:

TS encapsulation and decapsulation module: Decapsulates the received TS packet to obtain a lightweight encapsulation packet;

Lightweight encapsulation and decapsulation module: Decapsulates the received lightweight encapsulation package to obtain a first protocol package.