streaming-client-api.js

'use strict';
const fetchJsonFile = await fetch("./api.json")
const DID_API = await fetchJsonFile.json()

if (DID_API.key == '🤫') alert('Please put your api key inside ./api.json and restart..');

const RTCPeerConnection = (
  window.RTCPeerConnection ||
  window.webkitRTCPeerConnection ||
  window.mozRTCPeerConnection
).bind(window);

let peerConnection;
let pcDataChannel;
let streamId;
let sessionId;
let sessionClientAnswer;

let statsIntervalId;
let lastBytesReceived;
let videoIsPlaying = false;
let streamVideoOpacity = 0;

// Set this variable to true to request stream warmup upon connection to mitigate potential jittering issues
const stream_warmup = true;
let isStreamReady = !stream_warmup;

const idleVideoElement = document.getElementById('idle-video-element');
const streamVideoElement = document.getElementById('stream-video-element');
idleVideoElement.setAttribute('playsinline', '');
streamVideoElement.setAttribute('playsinline', '');
const peerStatusLabel = document.getElementById('peer-status-label');
const iceStatusLabel = document.getElementById('ice-status-label');
const iceGatheringStatusLabel = document.getElementById('ice-gathering-status-label');
const signalingStatusLabel = document.getElementById('signaling-status-label');
const streamingStatusLabel = document.getElementById('streaming-status-label');
const streamEventLabel = document.getElementById('stream-event-label');

const presenterInputByService = {
  talks: {
    source_url: 'jpg/or-roman.jpg',
  },
  clips: {
    presenter_id: 'rian-lZC6MmWfC1',
    driver_id: 'mXra4jY38i',
  },
};

const connectButton = document.getElementById('connect-button');
connectButton.onclick = async () => {
  if (peerConnection && peerConnection.connectionState === 'connected') {
    return;
  }

  stopAllStreams();
  closePC();

  /**
   * Set 'stream_warmup' to 'true' in the payload to initiate idle streaming at the beginning of the connection, addressing jittering issues.
   * The idle streaming process is transparent to the user and is concealed by triggering a 'stream/ready' event on the data channel,
   * indicating that idle streaming has concluded and the stream channel is ready for use.
   */
  const sessionResponse = await fetchWithRetries(`${DID_API.url}/${DID_API.service}/streams`, {
    method: 'POST',
    headers: {
      Authorization: `Basic ${DID_API.key}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ ...presenterInputByService[DID_API.service], stream_warmup }),
  });

  const { id: newStreamId, offer, ice_servers: iceServers, session_id: newSessionId } = await sessionResponse.json();
  streamId = newStreamId;
  sessionId = newSessionId;

  try {
    sessionClientAnswer = await createPeerConnection(offer, iceServers);
  } catch (e) {
    console.log('error during streaming setup', e);
    stopAllStreams();
    closePC();
    return;
  }

  const sdpResponse = await fetch(`${DID_API.url}/${DID_API.service}/streams/${streamId}/sdp`, {
    method: 'POST',
    headers: {
      Authorization: `Basic ${DID_API.key}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({
      answer: sessionClientAnswer,
      session_id: sessionId,
    }),
  });
};

const startButton = document.getElementById('start-button');
startButton.onclick = async () => {
  // connectionState not supported in firefox
  if (
    (peerConnection?.signalingState === 'stable' || peerConnection?.iceConnectionState === 'connected') &&
    isStreamReady
  ) {
    const playResponse = await fetchWithRetries(`${DID_API.url}/${DID_API.service}/streams/${streamId}`, {
      method: 'POST',
      headers: {
        Authorization: `Basic ${DID_API.key}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        script: {
          type: 'audio',
          audio_url: 'https://d-id-public-bucket.s3.us-west-2.amazonaws.com/webrtc.mp3',
        },
        ...(DID_API.service === 'clips' && {
          background: {
            color: '#FFFFFF',
          },
        }),
        config: {
          stitch: true,
        },
        session_id: sessionId,
      }),
    });
  }
};

const destroyButton = document.getElementById('destroy-button');
destroyButton.onclick = async () => {
  await fetch(`${DID_API.url}/${DID_API.service}/streams/${streamId}`, {
    method: 'DELETE',
    headers: {
      Authorization: `Basic ${DID_API.key}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ session_id: sessionId }),
  });

  stopAllStreams();
  closePC();
};

function onIceGatheringStateChange() {
  iceGatheringStatusLabel.innerText = peerConnection.iceGatheringState;
  iceGatheringStatusLabel.className = 'iceGatheringState-' + peerConnection.iceGatheringState;
}
function onIceCandidate(event) {
  console.log('onIceCandidate', event);
  if (event.candidate) {
    const { candidate, sdpMid, sdpMLineIndex } = event.candidate;

    fetch(`${DID_API.url}/${DID_API.service}/streams/${streamId}/ice`, {
      method: 'POST',
      headers: {
        Authorization: `Basic ${DID_API.key}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        candidate,
        sdpMid,
        sdpMLineIndex,
        session_id: sessionId,
      }),
    });
  } else {
    // For the initial 2 sec idle stream at the beginning of the connection, we utilize a null ice candidate.
    fetch(`${DID_API.url}/${DID_API.service}/streams/${streamId}/ice`, {
      method: 'POST',
      headers: {
        Authorization: `Basic ${DID_API.key}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        session_id: sessionId,
      }),
    });
  }
}
function onIceConnectionStateChange() {
  iceStatusLabel.innerText = peerConnection.iceConnectionState;
  iceStatusLabel.className = 'iceConnectionState-' + peerConnection.iceConnectionState;
  if (peerConnection.iceConnectionState === 'failed' || peerConnection.iceConnectionState === 'closed') {
    stopAllStreams();
    closePC();
  }
}
function onConnectionStateChange() {
  // not supported in firefox
  peerStatusLabel.innerText = peerConnection.connectionState;
  peerStatusLabel.className = 'peerConnectionState-' + peerConnection.connectionState;
  if (peerConnection.connectionState === 'connected') {
    playIdleVideo();
    /**
     * A fallback mechanism: if the 'stream/ready' event isn't received within 5 seconds after asking for stream warmup,
     * it updates the UI to indicate that the system is ready to start streaming data.
     */
    setTimeout(() => {
      if (!isStreamReady) {
        console.log('forcing stream/ready');
        isStreamReady = true;
        streamEventLabel.innerText = 'ready';
        streamEventLabel.className = 'streamEvent-ready';
      }
    }, 5000);
  }
}
function onSignalingStateChange() {
  signalingStatusLabel.innerText = peerConnection.signalingState;
  signalingStatusLabel.className = 'signalingState-' + peerConnection.signalingState;
}

function onVideoStatusChange(videoIsPlaying, stream) {
  let status;

  if (videoIsPlaying) {
    status = 'streaming';
    streamVideoOpacity = isStreamReady ? 1 : 0;
    setStreamVideoElement(stream);
  } else {
    status = 'empty';
    streamVideoOpacity = 0;
  }

  streamVideoElement.style.opacity = streamVideoOpacity;
  idleVideoElement.style.opacity = 1 - streamVideoOpacity;

  streamingStatusLabel.innerText = status;
  streamingStatusLabel.className = 'streamingState-' + status;
}

function onTrack(event) {
  /**
   * The following code is designed to provide information about wether currently there is data
   * that's being streamed - It does so by periodically looking for changes in total stream data size
   *
   * This information in our case is used in order to show idle video while no video is streaming.
   * To create this idle video use the POST https://api.d-id.com/talks (or clips) endpoint with a silent audio file or a text script with only ssml breaks
   * https://docs.aws.amazon.com/polly/latest/dg/supportedtags.html#break-tag
   * for seamless results use `config.fluent: true` and provide the same configuration as the streaming video
   */

  if (!event.track) return;

  statsIntervalId = setInterval(async () => {
    const stats = await peerConnection.getStats(event.track);
    stats.forEach((report) => {
     if (report.type === 'inbound-rtp' && report.kind === 'video') {
        const videoStatusChanged = videoIsPlaying !== report.bytesReceived > lastBytesReceived;

        if (videoStatusChanged) {
          videoIsPlaying = report.bytesReceived > lastBytesReceived;
          onVideoStatusChange(videoIsPlaying, event.streams[0]);
        }
        lastBytesReceived = report.bytesReceived;
      }
    });
  }, 500);
}

function onStreamEvent(message) {
  /**
   * This function handles stream events received on the data channel.
   * The 'stream/ready' event received on the data channel signals the end of the 2sec idle streaming.
   * Upon receiving the 'ready' event, we can display the streamed video if one is available on the stream channel.
   * Until the 'ready' event is received, we hide any streamed video.
   * Additionally, this function processes events for stream start, completion, and errors. Other data events are disregarded.
   */

  if (pcDataChannel.readyState === 'open') {
    let status;
    const [event, _] = message.data.split(':');

    switch (event) {
      case 'stream/started':
        status = 'started';
        break;
      case 'stream/done':
        status = 'done';
        break;
      case 'stream/ready':
        status = 'ready';
        break;
      case 'stream/error':
        status = 'error';
        break;
      default:
        status = 'dont-care';
        break;
    }

    // Set stream ready after a short delay, adjusting for potential timing differences between data and stream channels
    if (status === 'ready') {
      setTimeout(() => {
        console.log('stream/ready');
        isStreamReady = true;
        streamEventLabel.innerText = 'ready';
        streamEventLabel.className = 'streamEvent-ready';
      }, 1000);
    } else {
      console.log(event);
      streamEventLabel.innerText = status === 'dont-care' ? event : status;
      streamEventLabel.className = 'streamEvent-' + status;
    }
  }
}

async function createPeerConnection(offer, iceServers) {
  if (!peerConnection) {
    peerConnection = new RTCPeerConnection({ iceServers });
    pcDataChannel = peerConnection.createDataChannel('JanusDataChannel');
    peerConnection.addEventListener('icegatheringstatechange', onIceGatheringStateChange, true);
    peerConnection.addEventListener('icecandidate', onIceCandidate, true);
    peerConnection.addEventListener('iceconnectionstatechange', onIceConnectionStateChange, true);
    peerConnection.addEventListener('connectionstatechange', onConnectionStateChange, true);
    peerConnection.addEventListener('signalingstatechange', onSignalingStateChange, true);
    peerConnection.addEventListener('track', onTrack, true);
    pcDataChannel.addEventListener('message', onStreamEvent, true);
  }

  await peerConnection.setRemoteDescription(offer);
  console.log('set remote sdp OK');

  const sessionClientAnswer = await peerConnection.createAnswer();
  console.log('create local sdp OK');

  await peerConnection.setLocalDescription(sessionClientAnswer);
  console.log('set local sdp OK');

  return sessionClientAnswer;
}

function setStreamVideoElement(stream) {
  if (!stream) return;

  streamVideoElement.srcObject = stream;
  streamVideoElement.loop = false;
  streamVideoElement.mute = !isStreamReady;

  // safari hotfix
  if (streamVideoElement.paused) {
    streamVideoElement
      .play()
      .then((_) => {})
      .catch((e) => {});
  }
}

function playIdleVideo() {
  idleVideoElement.src = DID_API.service == 'clips' ? 'rian_idle.mp4' : 'or_idle.mp4';
}

function stopAllStreams() {
  if (streamVideoElement.srcObject) {
    console.log('stopping video streams');
    streamVideoElement.srcObject.getTracks().forEach((track) => track.stop());
    streamVideoElement.srcObject = null;
    streamVideoOpacity = 0;
  }
}

function closePC(pc = peerConnection) {
  if (!pc) return;
  console.log('stopping peer connection');
  pc.close();
  pc.removeEventListener('icegatheringstatechange', onIceGatheringStateChange, true);
  pc.removeEventListener('icecandidate', onIceCandidate, true);
  pc.removeEventListener('iceconnectionstatechange', onIceConnectionStateChange, true);
  pc.removeEventListener('connectionstatechange', onConnectionStateChange, true);
  pc.removeEventListener('signalingstatechange', onSignalingStateChange, true);
  pc.removeEventListener('track', onTrack, true);
  pc.removeEventListener('onmessage', onStreamEvent, true);

  clearInterval(statsIntervalId);
  isStreamReady = !stream_warmup;
  streamVideoOpacity = 0;
  iceGatheringStatusLabel.innerText = '';
  signalingStatusLabel.innerText = '';
  iceStatusLabel.innerText = '';
  peerStatusLabel.innerText = '';
  streamEventLabel.innerText = '';
  console.log('stopped peer connection');
  if (pc === peerConnection) {
    peerConnection = null;
  }
}

const maxRetryCount = 3;
const maxDelaySec = 4;

async function fetchWithRetries(url, options, retries = 1) {
  try {
    return await fetch(url, options);
  } catch (err) {
    if (retries <= maxRetryCount) {
      const delay = Math.min(Math.pow(2, retries) / 4 + Math.random(), maxDelaySec) * 1000;

      await new Promise((resolve) => setTimeout(resolve, delay));

      console.log(`Request failed, retrying ${retries}/${maxRetryCount}. Error ${err}`);
      return fetchWithRetries(url, options, retries + 1);
    } else {
      throw new Error(`Max retries exceeded. error: ${err}`);
    }
  }
}