CN107147916B

CN107147916B - Method for transmitting H.265 coding video data on transmission layer

Info

Publication number: CN107147916B
Application number: CN201710431382.7A
Authority: CN
Inventors: 高扬; 杨爱芳
Original assignee: Suzhou Snail Digital Technology Co Ltd
Current assignee: Suzhou Snail Digital Technology Co Ltd
Priority date: 2017-06-09
Filing date: 2017-06-09
Publication date: 2021-01-29
Anticipated expiration: 2037-06-09
Also published as: CN107147916A

Abstract

A method of transmitting h.265 encoded video data on a transport layer comprising the steps of h.265 encoding a live video; modifying the codecID field and metadata information of the header of the RTMP or HTTP-FLV protocol, and modifying the data structure of the RTMP protocol or HTTP-FLV protocol; the modified RTMP or HTTP-FLV protocol is adopted to transmit H.265 coded video data; and selecting an H.265 decoder for decoding and video playing. The method for transmitting H.265 coded video data on the transmission layer uses the H.265 coding mode to reduce the code rate on the premise of ensuring that the image quality is not changed, thereby being capable of transmitting the video data with high image quality under the condition of not consuming high bandwidth resources.

Description

Method for transmitting H.265 coding video data on transmission layer

Technical Field

The invention relates to the technical field of video data transmission, in particular to a method for transmitting H.265 coded video data on a transmission layer.

Background

In recent years, due to the spread of high-bit-rate and high-quality video, in particular, video requiring an extremely experienced visual viewing experience, such as VR video, has been transmitted with a higher network bandwidth. One method is that the user actively upgrades the network bandwidth size, and the other method is that a new video coding mode is used to reduce the code rate on the premise of ensuring the image quality to be unchanged, so that the video data with high image quality can be transmitted without consuming high bandwidth resources. The present invention is a solution to transmit the super-high quality video data at a relatively not very high bit rate using a second idea.

Disclosure of Invention

In order to solve the defects of the prior art, the invention aims to provide a method for transmitting H.265 encoded video data on a transmission layer, which distributes and transmits pictures with higher image quality on a video live streaming layer protocol by using an H.265 encoding mode with higher compression rate.

To achieve the above object, the present invention provides a method for transmitting h.265 encoded video data on a transport layer, comprising the steps of:

1) h.265 coding the live video;

2) modifying the codecID field and metadata information of the header of the RTMP or HTTP-FLV protocol, and modifying the data structure of the RTMP protocol or HTTP-FLV protocol;

3) the modified RTMP or HTTP-FLV protocol is adopted to transmit H.265 coded video data;

4) and selecting an H.265 decoder for decoding and video playing.

Further, the step 2) modifies the codecID field and the metadata information of the RTMP or HTTP-FLV protocol header, including,

adding data with the codec ID of 10 in a protocol header of an RTMP protocol or an HTTP-FLV protocol to identify that the encoding type of the stream is H.265;

adding codecID to metadata information of RTMP protocol to be 10 indicates that H.265 encoding is used.

Further, the method also comprises the following steps:

if the HevcPacketType field is 0, increasing VPS data;

and encapsulating 265 frame data into video packet payloads of RTMP or HTTP-FLV.

Still further, the step 4) further comprises,

judging whether a protocol header of an RTMP protocol or an HTTP-FLV protocol has a codecID (10 identifier);

judging whether the identifier codecID in the RTMP protocol or the HTTP-FLV protocol metadata is 10 or not;

the player selects the h.265 decoder for video data decoding.

The method for transmitting H.265 coded video data on the transmission layer provided by the invention uses the H.265 coding mode to reduce the code rate on the premise of ensuring that the image quality is not changed, thereby being capable of transmitting the video data with high image quality under the condition of not consuming high bandwidth resources.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic diagram of a message structure of a message in the conventional RTMP protocol;

fig. 2 is a schematic diagram of a message structure of a message block in the existing RTMP protocol;

FIG. 3 is a diagram illustrating a message blocking process in the RTMP protocol;

fig. 4 is a flow chart of a method of transmitting h.265 encoded video data over a transport layer in accordance with the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The RTMP (HTTP-FLV is the same as RTMP protocol, and will not be described in detail later) protocol is a protocol of an application layer in an Internet TCP/IP five-layer architecture. The basic data unit in the RTMP protocol is called a Message (Message). When the RTMP protocol transmits data over the internet, a message is broken up into smaller units called message blocks (chunks).

1 message

A message is a basic data unit in the RTMP protocol. Different kinds of messages contain different Message Type IDs, representing different functions. A total of more than ten message types are defined in the RTMP protocol and each plays a different role. Fig. 1 is a schematic diagram of a Message structure of a Message in an existing RTMP protocol, and as shown in fig. 1, messages with Message Type IDs of 1 to 7 are used for protocol control, and these messages are generally messages to be used by management of the RTMP protocol itself, and a user generally does not need to operate data therein. Messages with Message Type IDs of 8, 9 are used to transmit audio and video data, respectively. The Message with Message Type ID 15-20 is used to send AMF encoded commands, responsible for the interaction between the user and the server, such as play, pause, etc. The Message Header (Message Header) is composed of four parts: message Type ID for marking Message Type, Payload Length for marking Message Length, Timestamp for marking Timestamp, and Stream ID for marking media Stream to which the Message belongs.

2 message block

When data is transmitted on a network, a message needs to be split into smaller data blocks to be suitable for transmission on the corresponding network environment. The RTMP protocol provides that messages are split into message blocks (Chunk) when transmitted over a network. Fig. 2 is a schematic diagram of a message structure of a message block in the existing RTMP protocol, and as shown in fig. 2, a message block Header (Chunk Header) is composed of three parts: a Chunk Basic Header for identifying the Chunk, a Chunk Message Header for identifying the Message to which the Chunk belongs, and Extended Timestamp which occurs when the Timestamp overflows.

3 message chunking

In the process of dividing a Message into several Message blocks, a Message payload (Message Body) is divided into fixed-size data blocks (default is 128 bytes, and the last data block can be smaller than the fixed length), and a Message block Header (Chunk Header) is added to the Header of the fixed-size data blocks to form corresponding Message blocks. Fig. 3 is a schematic diagram of a message blocking process in the conventional RTMP protocol, and as shown in fig. 3, a message with a size of 307 bytes is divided into message blocks of 128 bytes (except for the last one).

In the process of RTMP transmitting media data, a transmitting end firstly encapsulates the media data into messages, then divides the messages into message blocks, and finally transmits the divided message blocks through a TCP protocol. After receiving data through TCP protocol, the receiving end firstly recombines the message blocks into message, and then recovers the media data by de-encapsulating the message.

Fig. 4 is a flowchart of a method for transmitting h.265 encoded video data on a transport layer according to the present invention, and the method for transmitting h.265 encoded video data on a transport layer according to the present invention will be described in detail with reference to fig. 4.

Firstly, in step 401, encoding a live video by adopting an H.265 video encoding standard;

h.265 is a new video coding standard established by ITU-T VCEG following H.264. The h.265 standard surrounds the existing video coding standard h.264, retains some of the original techniques, and improves some related techniques, using advanced techniques to improve the relationship between the code stream, coding quality, delay, and algorithm complexity, to achieve an optimal setting. The specific research contents comprise: the method has the advantages of improving compression efficiency, robustness and error recovery capability, reducing real-time delay, reducing channel acquisition time and random access time delay, reducing complexity and the like. Due to algorithm optimization, the H264 can realize standard definition digital image transmission at the speed lower than 1 Mbps; h.265 can realize the transmission of 720P (with the resolution of 1280 x 720) common high-definition audio and video by using the transmission speed of 1-2 Mbps.

At step 402, modifying a data structure of the RTMP protocol;

the Frame type field of the RTMP protocol Header is not changed, and data with a new codec id of 10 is added to the codec id field of the RTMP protocol Header (RTMP Header) to identify the encoding type of the stream as h.265(264 uses 7). And adding codecID of 10 (the adopted 264 code is 7) in metadata information of the RTMP protocol indicates that H.265 code is used for enabling a player to select an H.265 decoder for video data decoding.

If the HEVC packettype field is 0 (indicating the sequence header of HEVC), i.e. some configuration information of 265 Video stream, the VPS data [ VPS: Video Parameter Set ] is added to the sequence header of the original 264 (sps + pps data), to assist decoding.

The video packet payload at RTMP encapsulates 265 frames of data. This mechanism is the same as 264, except that the payload content is different.

In step 403, modifying the data structure of the HTTP-FLV protocol;

the HTTP-FLV protocol supports the same H.265 protocol as the RTMP protocol, and a new codecID is enabled to represent the H.265 encoding mode.

In step 404, the modified RTMP and HTTP-FLV protocols are adopted to transmit H.265 coded video data;

in step 405, the player selects the h.265 decoder to decode and play the video data.

The RTMP protocol and the HTTP-FLV protocol are added with a codecID of 10 to identify the H.265 coder. The need to identify the codec id as 10 in the protocol metadata indicates that h.265 encoding is used to let the player select the h.265 decoder for video data decoding.

RTMP video packet payload data structure RTMP Header + RTMP Body (5 byte Header +4 bytes NALU size + true video data), where the Body Header structure is as follows:

byte[0]＝[1-byte header]

byte[1]＝[1-byte codec config indicator(1-video data,0-codec config packet)]

byte[2..4]＝[3-byte time difference between dts and pts in milliseconds]byte[5..8]＝[4-byte nalu size]

wherein the NALU field size is determined by length sizeminusone.

The HEVC field is defined as shown in the following table:

HEVC video decoding configuration information data structure:

Those of ordinary skill in the art will understand that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method of transmitting h.265 encoded video data on a transport layer, comprising the steps of:

1) h.265 coding the live video;

2) adding data with codecID =10 in a protocol header of an RTMP or HTTP-FLV protocol to identify that the editing type of the stream is H.265, adding data with codecID of 10 in metadata of the RTMP or HTTP-FLV protocol to indicate that H.265 coding is used, and modifying a data structure of the RTMP protocol or the HTTP-FLV protocol;

4) and judging that the protocol header of the RTMP protocol or the HTTP-FLV protocol has a codeCID =10 identifier, judging that the identifier of the RTMP protocol or the HTTP-FLV protocol metadata is 10, and selecting an H.265 decoder by the player for decoding the video data.

2. The method for transmitting h.265 encoded video data over a transport layer as claimed in claim 1 further comprising the steps of:

if the HevcPacketType field is 0, increasing VPS data;

the H.265 frame data is encapsulated into video packet payloads of RTMP or HTTP-FLV.