Engage in audio and video development? Several things I have to say about SRT live broadcast protocol

The protocol format of streaming media is developing rapidly , On a global scale , All formats play their own value in their application scenarios , For example, the monitoring industry has high applicability RTSP、FLV、GB28181 Such agreement , And the low latency protocol that we are currently studying webrtc etc. , Different streaming media protocols meet different business scenarios .

In addition to the agreements we talked about above , There is also a special protocol that is slowly becoming a rookie of high bit rate video transmission , namely SRT agreement .SRT Is based on UDT Transport protocol , Retain the UDT The core idea and mechanism of , Strong packet loss resistance . In recent years, you can feel , Now with the development of Technology ,RTMP The more the agreement works, the more it doesn't work , It's not just close 10 It hasn't been updated for years , Even major video websites are banned this year RTMP Protocol video streaming , In this context , We found that SRT Maybe a more reliable way out .

We mentioned before SRT Retain the UDT, The main performance is the improvement of low latency and anti packet loss ability , In the real-time field of audio and video ,SRT Time based message sending , So that it has a good ability to prevent traffic burst .SRT It provides rich congestion control statistics for the upper layer , Include RTT、 Packet loss rate 、inflight、send/receive bitrate etc. . Use this rich information , We can achieve bandwidth prediction , And according to the change of bandwidth in the coding layer to do adaptive dynamic coding and congestion control .

Before we support RTMP Protocol video streaming EasyDSS platform , There will be no packet loss , But when the network state is bad , The server will cache the package , The cumulative delay caused by , The delay time is usually a few seconds , This is a RTMP Common fault of agreement ; But through SRT When the protocol is transmitted , Because of the adoption of UDP transport , And use ARQ Packet loss recovery mechanism of , The transmission delay level based on the public network can be controlled at 1s within .

Low latency doesn't mean low quality video playback ,SRT The transmission and error correction mechanism can maximize the utilization of available bandwidth and eliminate network errors and interference , So it can transmit higher bit rate video stream in the same network environment , coordination H.264 and HEVC And so on , It can guarantee the high quality of video under the bad network condition .

In the past ,SRT It is a protocol to solve the problem of uplink live broadcasting in the field of traditional broadcast television , But at present, with the demand of high bit rate video remote transmission such as live game ,SRT The use of the protocol can effectively alleviate the cost consumption caused by the special line and satellite transmission , At the same time, it brings considerable quality in the live broadcast process , This is an improvement in the rate video remote transmission .

SRT As an open source agreement , Has been integrated into multiple platforms and architectures , meanwhile , It also has high availability in software based cloud solutions , therefore ,TSINGSEE Qingxi video will also be considered in the future SRT Protocol support , Welcome your attention and understanding .