chrome simulcast in screenshare

mediasoup libraries
1

Hi. Does simulcast work with latest chrome version? I can publish screen without simulcast but with any simulcast settings even “bytesSent” is always 0 for producer stats with type “outbound-rtp”.

index.js:3565 mediasoup-client:Device constructor() +0ms
index.js:3565 mediasoup-client:Device constructor() | detected handler: Chrome74 +8ms
index.js:3565 mediasoup-client:Chrome74 close() +0ms
index.js:3565 mediasoup-client:Device load() [routerRtpCapabilities:{codecs: Array(3), headerExtensions: Array(12)}] +114ms
index.js:3565 mediasoup-client:Chrome74 getNativeRtpCapabilities() +114ms
index.js:3565 mediasoup-client:Device load() | got native RTP capabilities:{codecs: Array(30), headerExtensions: Array(18)} +20ms
index.js:3565 mediasoup-client:Device load() | got extended RTP capabilities:{codecs: Array(2), headerExtensions: Array(11)} +2ms
index.js:3565 mediasoup-client:Device load() | got receiving RTP capabilities:{codecs: Array(3), headerExtensions: Array(6)} +0ms
index.js:3565 mediasoup-client:Chrome74 getNativeSctpCapabilities() +22ms
index.js:3565 mediasoup-client:Device load() | got native SCTP capabilities:{numStreams: {…}} +1ms
index.js:3565 mediasoup-client:Device load() succeeded +0ms
index.js:3565 mediasoup-client:Chrome74 close() +1ms
index.js:3565 mediasoup-client:Device createSendTransport() +83ms
index.js:3565 mediasoup-client:Transport constructor() [id:41488910-4205-4251-9190-c460dc21dd11, direction:send] +0ms
index.js:3565 mediasoup-client:Chrome74 run() +85ms
index.js:3565 mediasoup-client:Transport produce() [track:MediaStreamTrack {kind: "video", id: "a8f112e1-4d28-42be-aa34-991b5b7c5eb4", label: "screen:0:0", enabled: true, muted: false, …}] +5ms
index.js:3565 mediasoup-client:Chrome74 send() [kind:video, track.id:a8f112e1-4d28-42be-aa34-991b5b7c5eb4] +7ms
index.js:3565 mediasoup-client:RemoteSdp updateDtlsRole() [role:client] +0ms
index.js:3565 mediasoup-client:Chrome74 send() | calling pc.setLocalDescription() [offer:RTCSessionDescription {type: "offer", sdp: "v=0
↵o=- 3245799165224049695 2 IN IP4 127.0.0.1
↵s…:r0 send
↵a=rid:r1 send
↵a=simulcast:send r0;r1
↵"}] +76ms
index.js:3565 mediasoup-client:Chrome74 send() | calling pc.setRemoteDescription() [answer:{type: "answer", sdp: "v=0
↵o=mediasoup-client 10000 1 IN IP4 0.0.0.0
↵s=…:r0 recv
↵a=rid:r1 recv
↵a=simulcast:recv r0;r1
↵"}] +10ms
index.js:3565 mediasoup-client:Transport connection state changed to connecting +93ms
index.js:3565 mediasoup-client:Producer constructor() +0ms
index.js:3565 mediasoup-client:Transport connection state changed to connected +99ms

P.S.: it works with Chrome55 handler but can’t check stats there because it’s not implemented

2

What about making this question in Chrome forums? Yes, there are tons of issues and limitations in Chrome when doing screen sharing with simulcast. It depends on the given encodings, chose codec, etc etc. We cannot give support about Chrome. There are plenty of related issues reported in Chrome/libwebrtc issue tracker.