mediasoup基础介绍

一、简介

webrtc:谷歌开源，跨平台，用于浏览器之间的实时传输音视频引擎(一对一)

mediasoup:流媒体服务器，实现多人在线实时互动。

二、mediasoup架构图(from web)

三、vrvmeeting中c++代码

启动mediasoup

worker.js构造函数中调用spawn，启动mediasoup-worker

// Create the mediasoup-worker child process.
this._child = spawn(workerPath, spawnArgs, spawnOptions);

运行worker

一、初始化，配置相关项

二、创建channel，用于接收及发生数据

int channelFd  = std::stoi(std::getenv("MEDIASOUP_CHANNEL_FD"));
// Initialize libuv stuff (we need it for the Channel).
DepLibUV::ClassInit();
// Set the Channel socket (this will be handled and deleted by the Worker).
auto* channel = new Channel::UnixStreamSocket(channelFd);

三、运行worker

// Run the Worker.
Worker worker(channel);

mediasoup channel的创建

js:worker.js

// Channel instance.
this._channel = new Channel(this._child.stdio[CHANNEL_FD]);

c++:main.cpp（channelFd为3）

// Set the Channel socket (this will be handled and deleted by the Worker).
auto* channel = new Channel::UnixStreamSocket(channelFd);
var code = "f40d1b26-d2ee-4104-9ecc-42f58dfcb640"

注:实际实现的地方为handles/UnixStreamSocket.cpp中:

UnixStreamSocket.cpp详情

uv_pipe_init -> uv_pipe_open -> uv_read_start

// Start reading.
    err = uv_read_start(
      reinterpret_cast<uv_stream_t*>(this->uvHandle),
      static_cast<uv_alloc_cb>(onAlloc),
      static_cast<uv_read_cb>(onRead));

实际真正读取的接口:channel/UnixStreamSocket.cpp

int nsRet = netstring_read(reinterpret_cast<char*>(this->buffer + this->msgStart), readLen, &jsonStart, &jsonLen);

转成json,将相关数据解析并放到request类中(id，method，internal，data)

request = new Channel::Request(this, json);

将request传给worker

// Notify the listener.
this->listener->OnChannelRequest(this, request);

调用worker.cpp中的OnChannelRequest，根据requset的MethodId做不同的执行动作

1.WORKER_DUMP:拿到workerid和routers的数据值并返回

2.WORKER_UPDATE_SETTINGS:更新相关配置

3:WORKER_CPUWOEKSPEED:拿到CpuSpeed并返回

4:WORKER_NETWOEKSPEED:拿到NetName，上传速度，下载速度，并返回

5:WORKER_CREATE_ROUTER:创建router

6:ROUTER_CLOSE；关闭房间

7:ROUTER_CREATE_SYNCHRONIZATION_TRANSPORT

8:WORKER_REMOTE_BITRATE

9:其他MethodId:从request中拿到router，然后在router中执行HandleRequest

1:router = GetRouterFromRequest(request);
2:router->HandleRequest(request);

注意:信令返回方式:

request->Accept();//无返回数据时
request->Accept(json);//有返回数据时

accept()实现:libuv库的uv_write接口

router房间类

Request::MethodId为ROUTER_CREATE_WEBRTC_TRANSPORT:创建webrtc transport

从request中获取transportId,peerName,udpsocket，将其他数据存入RTC::WebRtcTransport::Options中，然后创建WebRtcTransport

if(Settings::configuration.isSinglePort){
webrtcTransport = new RTC::WebRtcTransport(this, this->notifier, transportId,   options,udpSocket,peerName);
}else{
webrtcTransport = new RTC::WebRtcTransport(this, this->notifier, transportId, options);
webrtcTransport->m_peername = peerName;
}

Request::MethodId为ROUTER_CREATE_PRODUCER:创建producer

获取producerId,获取peerName，transport，Media::Kind，RTC::RtpParameters，RtpMapping rtpMapping，然后创建producer

auto* producer = new RTC::Producer(this->notifier, producerId, kind, transport, rtpParameters, rtpMapping, paused); 

//Tell the Transport to handle the new Producer         
transport->HandleProducer(producer);

this->mapProducerConsumers[producer];
//添加producer和peer关系
this->mapProducerPeers[producerId] = peerName;

Request::MethodId为ROUTER_CREATE_CONSUMER:创建consumer

获取consumerId，peerName，producer，创建一个cunsumer:

auto* consumer = new RTC::Consumer(this->notifier, consumerId, kind, producer->producerId);
//将consumer和producer进行关联
this->mapConsumerProducer[consumer] = producer;

//consumer 和peer关联
this->mapConsumerPeers[consumerId] = peerName;

WebRtcTransport类

auto* udpSocket = new RTC::UdpSocket(this, AF_INET);//创建udpsocket

OnPacketRecv()中根据data中不同的类型数据分别接收并处理
OnStunDataRecv();//stun协议数据接收处理
OnRtcpDataRecv();//Rtcp协议数据接收处理
OnRtpDataRecv();//Rtp协议数据接收处理
OnDtlsDataRecv();//Dtls协议数据接收处理

mediasoup类整理

1:mediasoup类简介

类名	解释	详细介绍
Worker	进程类	进程启动，业务入口，主要业务接口
Router	房间类	创建消费者，生产者，transport
Request	消息类	用于接收和发送数据(send)
Notifier	通知类	用于通知(Emit)
UnixStreamSocket	数据传输类	libuv的上层封装
Transport	通道类	将终端与MediaSoup Router连接起来，创建producer和consumer进行传输
producer	生产者类	⽣产媒体数据，⾳频或视频
consumer	消费者类	消费媒体数据，音频或视频

2:主要业务图