snapshot of https://github.com/pion/webrtc.git (main, 2026-09-15; blobs > 131072B omitted)

examples/swap-tracks/jsfiddle/demo.css

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+/*
+    SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+    SPDX-License-Identifier: MIT
+*/
+textarea {
+    width: 500px;
+    min-height: 75px;
+}

examples/swap-tracks/jsfiddle/demo.details

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+---
+# SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+# SPDX-License-Identifier: MIT
+
+name: swap-tracks
+description: Example of how to have Pion swap incoming tracks on a single outgoing track
+authors:
+  - Chad Retz

examples/swap-tracks/jsfiddle/demo.html

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+<!--
+	SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+	SPDX-License-Identifier: MIT
+-->
+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 />
+
+<div style="display: flex">
+  <div>
+    Browser stream 1<br />
+    <canvas id="canvasOne" height="200" width="200"></canvas>
+  </div>
+  <div>
+    Browser stream 2<br />
+    <canvas id="canvasTwo" height="200" width="200"></canvas>
+  </div>
+  <div>
+    Browser stream 3<br />
+    <canvas id="canvasThree" height="200" width="200"></canvas>
+  </div>
+</div>
+
+Video from server<br />
+<video id="serverVideo" width="200" height="200" autoplay muted></video> <br />

examples/swap-tracks/jsfiddle/demo.js

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+/* eslint-env browser */
+
+// SPDX-FileCopyrightText: 2026 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+// Create peer conn
+const pc = new RTCPeerConnection({
+  iceServers: [
+    {
+      urls: 'stun:stun.l.google.com:19302'
+    }
+  ]
+})
+
+pc.oniceconnectionstatechange = e => {
+  console.debug('connection state change', pc.iceConnectionState)
+}
+pc.onicecandidate = event => {
+  if (event.candidate === null) {
+    document.getElementById('localSessionDescription').value = btoa(JSON.stringify(pc.localDescription))
+  }
+}
+
+pc.onnegotiationneeded = e =>
+  pc.createOffer().then(d => pc.setLocalDescription(d)).catch(console.error)
+
+pc.ontrack = event => {
+  console.log('Got track event', event)
+  document.getElementById('serverVideo').srcObject = new MediaStream([event.track])
+}
+
+const canvases = [
+  document.getElementById('canvasOne'),
+  document.getElementById('canvasTwo'),
+  document.getElementById('canvasThree')
+]
+
+// Firefox requires getContext to be invoked on an HTML Canvas Element
+// prior to captureStream
+const canvasContexts = canvases.map(c => c.getContext('2d'))
+
+// Capture canvas streams and add to peer conn
+const streams = canvases.map(c => c.captureStream())
+streams.forEach(stream => stream.getVideoTracks().forEach(track => pc.addTrack(track, stream)))
+
+// Start circles
+requestAnimationFrame(() => drawCircle(canvasContexts[0], '#006699', 0))
+requestAnimationFrame(() => drawCircle(canvasContexts[1], '#cf635f', 0))
+requestAnimationFrame(() => drawCircle(canvasContexts[2], '#46c240', 0))
+
+function drawCircle (ctx, color, angle) {
+  // Background
+  ctx.clearRect(0, 0, 200, 200)
+  ctx.fillStyle = '#eeeeee'
+  ctx.fillRect(0, 0, 200, 200)
+  // Draw and fill in circle
+  ctx.beginPath()
+  const radius = 25 + 50 * Math.abs(Math.cos(angle))
+  ctx.arc(100, 100, radius, 0, Math.PI * 2, false)
+  ctx.closePath()
+  ctx.fillStyle = color
+  ctx.fill()
+  // Call again
+  requestAnimationFrame(() => drawCircle(ctx, color, angle + (Math.PI / 64)))
+}
+
+window.startSession = () => {
+  const 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'
+    console.log('Copying SDP was ' + msg)
+  } catch (err) {
+    console.log('Unable to copy SDP ' + err)
+  }
+}