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Function Description

This article mainly introduces the advanced usage of custom capture and custom rendering.

Custom Capture

By default, trtc.startLocalVideo() and trtc.startLocalAudio() enable camera and microphone capture.
If you need to customize the capture, you can specify the option.videoTrack/option.audioTrack parameter of the trtc.startLocalVideo() / trtc.startLocalAudio() method.
There are usually several ways to obtain audioTrack and videoTrack:
Use getUserMedia to capture the camera and microphone.
Use getDisplayMedia to capture screen sharing.
Use videoElement.captureStream to capture the audio and video being played in the video tag.
Use canvas.captureStream to capture the animation in the canvas.

Capture the video being played in the video tag

// Check if your current browser supports capturing streams from video elements
if (!HTMLVideoElement.prototype.captureStream) {
  console.log('your browser does not support capturing stream from video element');
  return
}
// Get the video tag that is playing video on your page
const video = document.getElementByID('your-video-element-ID');
// Capture the video stream from the playing video
const stream = video.captureStream();
const audioTrack = stream.getAudioTracks()[0];
const videoTrack = stream.getVideoTracks()[0];

trtc.startLocalVideo({ option:{ videoTrack } });
trtc.startLocalAudio({ option:{ audioTrack } });

Capture the animation in the canvas

// Check if your current browser supports capturing streams from canvas elements
if (!HTMLCanvasElement.prototype.captureStream) {
  console.log('your browser does not support capturing stream from canvas element');
  return
}
// Get your canvas tag
const canvas = document.getElementByID('your-canvas-element-ID');

// Capture a 15 fps video stream from the canvas
const fps = 15;
const stream = canvas.captureStream(fps);
const videoTrack = stream.getVideoTracks()[0];

trtc.startLocalVideo({ option:{ videoTrack } });

Custom Rendering

By default, when calling trtc.startLocalVideo(view) or trtc.startRemoteVideo(view, streamType, userId), you need to pass in the view parameter. The SDK will create a video tag under the specified element tag to play the video.
If you need to customize the rendering, and do not need the SDK to play the video, you can refer to the following steps:
Do not fill in the view parameter or pass in null when calling the startLocalVideo or startRemoteVideo method.
Use the trtc.getVideoTrack(userId, streamType) method to obtain the corresponding videoTrack.
Use your own player for video rendering.
After using this custom rendering method, the EVENT.VIDEO_PLAY_STATE_CHANGED event will not be triggered. You need to listen to the mute/unmute/ended events of the video track MediaStreamTrack to determine the status of the current video data stream.
For remote video, you also need to listen to the EVENT.REMOTE_VIDEO_AVAILABLE and EVENT.REMOTE_VIDEO_UNAVAILABLE events to handle the lifecycle of remote video.

Custom rendering of local video

await trtc.startLocalVideo();
const videoTrack = trtc.getVideoTrack();

// Use your own player for video rendering
const videoElement = document.getElementById('video-element');
videoElement.srcObject = new MediaStream([videoTrack]);
videoElement.play();


Custom rendering of remote video

trtc.on(TRTC.EVENT.REMOTE_VIDEO_AVAILABLE, async ({ userId, streamType }) => {
  // Only pull the stream, do not play it
  await trtc.startRemoteVideo({ userId, streamType })
  const videoTrack = trtc.getVideoTrack({ userId, streamType });

  // Use your own player for video rendering
  const videoElement = document.getElementById('remote-video-element');
  videoElement.srcObject = new MediaStream([videoTrack]);
  videoElement.play();
});