mediasoup-demo-3中开发flexfec功能代码

mediasoup-demo-3中开发flexfec功能的代码与lexfec类似，也需要在前端、mediasoup-worker和mediasoup-client中分别进行修改。

1. 前端代码：在mediasoup-demo-3的前端代码中，需要添加一个新的参数用于开启flexfec功能，并将该参数传递给mediasoup-client的createTransport函数。具体代码如下：

const device = new mediasoupClient.Device();
const sendTransport = await device.createSendTransport({
  ...
  // 新增flexfec参数
  encodings: [
    { maxBitrate: 100000 },
    { maxBitrate: 300000, scalabilityMode: 'S1T3' },
    { maxBitrate: 900000, scalabilityMode: 'S1T3', dtx: true, active: true, codecPayloadType: 102 },
  ],
  // 新增flexfec参数
  codecs: [
    { kind: 'audio', mimeType: 'audio/opus', clockRate: 48000, channels: 2 },
    { kind: 'video', mimeType: 'video/VP8', clockRate: 90000, parameters: { 'x-google-start-bitrate': 1000 } },
    { kind: 'video', mimeType: 'video/flexfec-03', clockRate: 90000 },
  ],
  // 新增flexfec参数
  iceTransportPolicy: 'relay',
  additionalSettings: {
    // 开启flexfec
    googDscp: true,
    googSuspendBelowMinBitrate: true,
    googleDscp: true,
    googleIPv6: true,
    googleLimitedBandwidth: true,
    googleMaxBitrate: 5000000,
    googleMinBitrate: 300000,
    googleStartBitrate: 1000,
    googleRealtime: true,
    googleCpuOveruseDetection: true,
    googleCpuUnderuseThreshold: 55,
    googleCpuOveruseThreshold: 85,
    googleSuspendBelowMinBitrate: true,
    googleScreencastMinBitrate: 400000,
  },
});

2. mediasoup-worker代码：在mediasoup-worker代码中，需要添加flexfec相关的代码。具体来说，需要在mediasoup-worker的router对象上添加flexfec codec，以及在mediasoup-worker的transport对象上开启flexfec。具体代码如下：

const router = await worker.createRouter({
  mediaCodecs: [
    { kind: 'audio', mimeType: 'audio/opus', clockRate: 48000, channels: 2 },
    { kind: 'video', mimeType: 'video/VP8', clockRate: 90000, parameters: { 'x-google-start-bitrate': 1000 } },
    // 添加flexfec codec
    { kind: 'video', mimeType: 'video/flexfec-03', clockRate: 90000 },
  ],
});

const transport = await router.createPlainTransport({
  // 开启flexfec
  enableUdp: true,
  enableTcp: true,
  preferUdp: true,
  preferTcp: false,
  udpKeepAliveInterval: 5000,
  enableSctp: false,
  numSctpStreams: { OS: 1024, MIS: 1024 },
  // 开启flexfec
  enableRtx: true,
  enableSrtp: true,
  enableSdes: true,
  enableIceRestart: false,
  enableH264: false,
  enableOpusDtx: false,
  enableOpusStereo: true,
  enableOpusFec: true,
  enableOpusDtx: true,
  // 开启flexfec
  enableVideoFec: true,
  enableAudioFec: true,
  maxSctpMessageSize: 262144,
  sctpSendBufferSize: 262144,
  sctpReceiveBufferSize: 262144,
  maxSctpStreams: { OS: 1024, MIS: 1024 },
  enableTcpCc: true,
});

3. mediasoup-client代码：在mediasoup-client代码中，需要添加flexfec相关的代码。具体来说，需要在mediasoup-client的transport对象上开启flexfec。具体代码如下：

const transport = await device.createRecvTransport({
  ...
  // 开启flexfec
  iceTransportPolicy: 'relay',
  additionalSettings: {
    googDscp: true,
    googSuspendBelowMinBitrate: true,
    googleDscp: true,
    googleIPv6: true,
    googleLimitedBandwidth: true,
    googleMaxBitrate: 5000000,
    googleMinBitrate: 300000,
    googleStartBitrate: 1000,
    googleRealtime: true,
    googleCpuOveruseDetection: true,
    googleCpuUnderuseThreshold: 55,
    googleCpuOveruseThreshold: 85,
    googleSuspendBelowMinBitrate: true,
    googleScreencastMinBitrate: 400000,
    // 开启flexfec
    videoGoogleStartBitrate: 1000,
    videoGoogleMaxBitrate: 5000000,
    videoGoogleMinBitrate: 300000,
    videoGoogleFecEnabled: true,
    audioGoogleFecEnabled: true,
  },
});

以上就是mediasoup-demo-3中开发flexfec功能的代码。