Simulcast in WebRTC

This WebRTC sample shows how to use simulcast on a video application.

Requirements

• Node v14+

How to run locally

1. Clone this repository

git clone https://github.com/muriware/simulcast-in-webrtc.git

2. Copy the .env.example file into a file named .env in the server folder

cp .env.example server/.env

STATIC_DIR tells the server where to the client files are located and does not need to be modified.

3. Install dependencies

cd server && yarn

4. Run the application

yarn start

5. Go to localhost:4242 to see the demo

How to test

Disable second layer

var sender = pc1.getSenders()[0];
var parameters = sender.getParameters();

parameters.encodings[1].active = false;

sender.setParameters(parameters);

Enable second layer

var sender = pc1.getSenders()[0];
var parameters = sender.getParameters();

parameters.encodings[1].active = true;

sender.setParameters(parameters);

Limit first layer bitrate to 100kbps, and second layer to 300kbps.

var sender = pc1.getSenders()[0];
var parameters = sender.getParameters();

parameters.encodings[0].maxBitrate = 100000;
parameters.encodings[1].maxBitrate = 300000;

sender.setParameters(parameters);

Set the resolution of the second layer to be a quarter of the original resolution.

var sender = pc1.getSenders()[0];
var parameters = sender.getParameters();

parameters.encodings[1].scaleResolutionDownBy = 4;

sender.setParameters(parameters);

Set the resolution of the second layer to be a half of the original resolution.

var sender = pc1.getSenders()[0];
var parameters = sender.getParameters();

parameters.encodings[1].scaleResolutionDownBy = 2;

sender.setParameters(parameters);

Limit the bandwidth available to 800kbps on the remote end

await pc1.setLocalDescription()
pc1.setRemoteDescription({type: 'answer', sdp: pc1.remoteDescription.sdp + "b=AS:800\r\n"})