Pion Echo Example

Example of how to have Pion send back to the user exactly what it receives using the same PeerConnection.

HTML

Browser base64 Session Description<br />
<textarea id="localSessionDescription" readonly="true"></textarea> <br />
<button onclick="window.copySDP()">
        Copy browser SDP to clipboard
</button>
<br />
<br />

Golang base64 Session Description<br />
<textarea id="remoteSessionDescription"></textarea> <br/>
<button onclick="window.startSession()"> Start Session </button><br />

<br />

Video<br />
<div id="remoteVideos"></div> <br />

Logs<br />
<div id="logs"></div>

CSS

textarea {
    width: 500px;
    min-height: 75px;
}

JavaScript

/* eslint-env browser */

let pc = new RTCPeerConnection({
  iceServers: [
    {
      urls: 'stun:stun.l.google.com:19302'
    }
  ]
})
var log = msg => {
  document.getElementById('logs').innerHTML += msg + '<br>'
}

navigator.mediaDevices.getUserMedia({ video: true, audio: true })
  .then(stream => {
    stream.getTracks().forEach(track => pc.addTrack(track, stream));
    pc.createOffer().then(d => pc.setLocalDescription(d)).catch(log)
  }).catch(log)

pc.oniceconnectionstatechange = e => log(pc.iceConnectionState)
pc.onicecandidate = event => {
  if (event.candidate === null) {
    document.getElementById('localSessionDescription').value = btoa(JSON.stringify(pc.localDescription))
  }
}
pc.ontrack = function (event) {
  var el = document.createElement(event.track.kind)
  el.srcObject = event.streams[0]
  el.autoplay = true
  el.controls = true

  document.getElementById('remoteVideos').appendChild(el)
}

window.startSession = () => {
  let sd = document.getElementById('remoteSessionDescription').value
  if (sd === '') {
    return alert('Session Description must not be empty')
  }

  try {
    pc.setRemoteDescription(JSON.parse(atob(sd)))
  } catch (e) {
    alert(e)
  }
}

window.copySDP = () => {
  const browserSDP = document.getElementById('localSessionDescription')

  browserSDP.focus()
  browserSDP.select()

  try {
    const successful = document.execCommand('copy')
    const msg = successful ? 'successful' : 'unsuccessful'
    log('Copying SDP was ' + msg)
  } catch (err) {
    log('Unable to copy SDP ' + err)
  }
}