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openvidu-browser: enable simulcast for SDP Offers

pull/635/head
Juan Navarro 2021-06-22 19:01:07 +02:00
parent 6d624209a0
commit 0a34c2d752
1 changed files with 53 additions and 3 deletions
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56
openvidu-browser/src/OpenViduInternal/WebRtcPeer/WebRtcPeer.ts
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@ -30,6 +30,49 @@ const logger: OpenViduLogger = OpenViduLogger.getInstance();
*/
let platform: PlatformUtils;
/*
* Table of sender video encodings for simulcast.
* Note that this is just a polite request, but the browser is free to honor it
* or just play by its own rules.
*
* Chrome imposes some restrictions based on the size of the video, max bitrate,
* and available bandwidth. Check here for the video size table:
* https://chromium.googlesource.com/external/webrtc/+/master/media/engine/simulcast.cc#90
*
* | Size (px) | Bitrate (kbps) | Max Layers |
* |----------:|---------------:|-----------:|
* | 1920x1080 | 5000 | 3 |
* | 1280x720 | 2500 | 3 |
* | 960x540 | 1200 | 3 |
* | 640x360 | 700 | 2 |
* | 480x270 | 450 | 2 |
* | 320x180 | 200 | 1 |
*/
const simulcastVideoEncodings: RTCRtpEncodingParameters[] = [
{
rid: "r0",
maxBitrate: 700000,
// TODO: Remove for final version; leave the browser decide:
// https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-addtransceiver
// > If the scaleResolutionDownBy attribues of sendEncodings are still
// > undefined, initialize each encoding's scaleResolutionDownBy to
// > 2^(length of sendEncodings - encoding index - 1). This results in
// > smaller-to-larger resolutions where the last encoding has no scaling
// > applied to it, e.g. 4:2:1 if the length is 3.
scaleResolutionDownBy: 16,
},
{
rid: "r1",
maxBitrate: 800000,
scaleResolutionDownBy: 8,
},
{
rid: "r2",
maxBitrate: 900000,
scaleResolutionDownBy: 1,
},
];
export interface WebRtcPeerConfiguration {
mediaConstraints: {
@ -127,6 +170,8 @@ export class WebRtcPeer {
if ("addTransceiver" in this.pc) {
logger.debug("[createOffer] Method RTCPeerConnection.addTransceiver() is available; using it");
// Spec doc: https://w3c.github.io/webrtc-pc/#dom-rtcpeerconnection-addtransceiver
if (this.configuration.mode !== "recvonly") {
// To send media, assume that all desired media tracks
// have been already added by higher level code to our
@ -138,11 +183,16 @@ export class WebRtcPeer {
}
for (const track of this.configuration.mediaStream.getTracks()) {
this.pc.addTransceiver(track, {
const tcInit: RTCRtpTransceiverInit = {
direction: this.configuration.mode,
streams: [this.configuration.mediaStream],
sendEncodings: [],
});
};
if (track.kind === "video") {
tcInit.sendEncodings = simulcastVideoEncodings;
}
this.pc.addTransceiver(track, tcInit);
}
} else {
// To just receive media, create new recvonly transceivers.