The MediaTrackSupportedConstraints dictionary's suppressLocalAudioPlayback property indicates whether or not the suppressLocalAudioPlayback constraint is supported by the user agent and the device on which the content is being used.

The supported constraints list is obtained by calling navigator.mediaDevices.getSupportedConstraints().

A boolean value which is true if the suppressLocalAudioPlayback constraint is supported by the device and user agent.

The function below sets up the options object for the call to getDisplayMedia(). It adds the suppressLocalAudioPlayback constraint (requesting that captured audio is not played out of the user's local speakers) only if it is known to be supported by the browser. Capturing is then started by calling getDisplayMedia() and attaching the returned stream to the video element referenced by the variable videoElem.

async function capture() {
  const supportedConstraints = navigator.mediaDevices.getSupportedConstraints();
  const displayMediaOptions = {
    audio: {},
  };

  if (supportedConstraints.suppressLocalAudioPlayback) {
    displayMediaOptions.audio.suppressLocalAudioPlayback = true;
  }

  try {
    videoElem.srcObject =
      await navigator.mediaDevices.getDisplayMedia(displayMediaOptions);
  } catch (err) {
    /* handle the error */
  }
}

• Screen Capture API
• Using the screen capture API
• Capabilities, constraints, and settings
• MediaDevices.getDisplayMedia()
• MediaStreamTrack.getConstraints()
• MediaStreamTrack.applyConstraints()
• MediaStreamTrack.getSettings()