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Browser affected

Browser name including version (e.g. Chrome 64.0.3282.119) Google Chrome 110.0.5481.77

Description

Add a check if SVC is supported in the current browser to the SVC sample, since even Chrome >= 101 will report supported: true in MediaCapabilities.encodingInfo() with scalabilityMode. But SVC is only supported in Chrome >= 111 (see https://chromestatus.com/feature/5769626174619648).

The only way I could find to check this, is something like:

() => {
  let supported = false;
  try {
      const pc = new RTCPeerConnection();
      const scalabilityMode = 'L2T2';
      const transceiver = pc.addTransceiver('video', { sendEncodings: [{ scalabilityMode }] });
      const parameters = transceiver.sender.getParameters();
      const [encoding] = parameters.encodings || [];
      supported = Boolean(encoding && encoding.scalabilityMode === scalabilityMode);
  } catch (error) {
      console.error(error);
  }
  return supported;
};

Steps to reproduce

Open the SVC sample https://webrtc.github.io/samples/src/content/extensions/svc/ in a Chrome browser >=101 and < 111. Click the "Start button", allow camera access, select "video/VP8" as Codec preferences.

Expected results

Since SVC is not supported in Chrome < 111, the list of scalability modes should be empty.

Actual results

The list of scalability modes include L1T1, L1T2, and L1T3.

webrtc / samples

Scalable Video Codec include an SVC support check #1597