js

const videoPlayer = document.getElementById("player");

// ...

await window.documentPictureInPicture.requestWindow({
  width: videoPlayer.clientWidth,
  height: videoPlayer.clientHeight,
});

// ...

const pipWindow = window.documentPictureInPicture.window;
if (pipWindow) {
  // Mute video playing in the Picture-in-Picture window.
  const pipVideo = pipWindow.document.querySelector("#video");
  pipVideo.muted = true;
}