upstream-pion-webrtc/examples/play-from-disk-fec/jsfiddle/demo.js

/* eslint-env browser */

// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
// SPDX-License-Identifier: MIT

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

pc.ontrack = function (event) {
  const el = document.createElement(event.track.kind)
  el.srcObject = event.streams[0]
  el.autoplay = true
  el.controls = true

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

pc.oniceconnectionstatechange = (e) => log(pc.iceConnectionState)
pc.onicecandidate = (event) => {
  if (event.candidate === null) {
    document.getElementById('localSessionDescription').value = btoa(
      JSON.stringify(pc.localDescription)
    )
  }
}

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

  try {
    // Set the remote offer
    pc.setRemoteDescription(JSON.parse(atob(sd)))
      .then(() => {
        // Create answer
        return pc.createAnswer()
      })
      .then((answer) => {
        // Set local description with the answer
        return pc.setLocalDescription(answer)
      })
      .catch(log)
  } catch (e) {
    alert(e)
  }
}

window.copySessionDescription = () => {
  const browserSessionDescription = document.getElementById(
    'localSessionDescription'
  )

  browserSessionDescription.focus()
  browserSessionDescription.select()

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