webrtc/RTCRtpTransceiver-setCodecPreferences.html - external/w3c/web-platform-tests - Git at Google

 <!doctype html>
 <meta charset=utf-8>
 <title>RTCRtpTransceiver.prototype.setCodecPreferences</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <script src="./third_party/sdp/sdp.js"></script>
 <script>
  'use strict';

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  transceiver.setCodecPreferences(capabilities.codecs);
  }, `setCodecPreferences() on audio transceiver with codecs returned from RTCRtpReceiver.getCapabilities('audio') should succeed`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('video');
  const capabilities = RTCRtpReceiver.getCapabilities('video');
  transceiver.setCodecPreferences(capabilities.codecs);
  }, `setCodecPreferences() on video transceiver with codecs returned from RTCRtpReceiver.getCapabilities('video') should succeed`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  transceiver.setCodecPreferences([]);
  }, `setCodecPreferences([]) should succeed`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  const { codecs } = capabilities;

  if(codecs.length >= 2) {
  const tmp = codecs[0];
  codecs[0] = codecs[1];
  codecs[1] = tmp;
  }

  transceiver.setCodecPreferences(codecs);
  }, `setCodecPreferences() with reordered codecs should succeed`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('video');
  const capabilities = RTCRtpReceiver.getCapabilities('video');
  const { codecs } = capabilities;
  // This test verifies that the mandatory VP8 codec is present
  // and can be preferred.
  const codec = codecs.find(c => c.mimeType === 'video/VP8');
  assert_true(!!codec, 'VP8 video codec was found');
  transceiver.setCodecPreferences([codec]);
  }, `setCodecPreferences() with only VP8 should succeed`);

  test(() => {
  const pc = new RTCPeerConnection();
  const transceiver = pc.addTransceiver('video');
  const capabilities = RTCRtpReceiver.getCapabilities('video');
  const { codecs } = capabilities;
  // This test verifies that the mandatory H264 codec is present
  // and can be preferred.
  const codec = codecs.find(c => c.mimeType === 'video/H264');
  assert_true(!!codec, 'H264 video codec was found');
  transceiver.setCodecPreferences([codec]);
  }, `setCodecPreferences() with only H264 should succeed`);

  async function getRTPMapLinesWithCodecAsFirst(firstCodec)
  {
  const codecs = RTCRtpReceiver.getCapabilities('video').codecs;
  codecs.forEach((codec, idx) => {
  if (codec.mimeType === firstCodec) {
  codecs.splice(idx, 1);
  codecs.unshift(codec);
  }
  });

  const pc = new RTCPeerConnection();
  const transceiver = pc.addTransceiver('video');
  transceiver.setCodecPreferences(codecs);
  const offer = await pc.createOffer();

  return offer.sdp.split('\r\n').filter(line => line.startsWith('a=rtpmap:'));
  }

  promise_test(async () => {
  const lines = await getRTPMapLinesWithCodecAsFirst('video/H264');

  assert_greater_than(lines.length, 1);
  assert_true(lines[0].indexOf('H264') !== -1, 'H264 should be the first codec');
  }, `setCodecPreferences() should allow setting H264 as first codec`);

  promise_test(async () => {
  const lines = await getRTPMapLinesWithCodecAsFirst('video/VP8');

  assert_greater_than(lines.length, 1);
  assert_true(lines[0].indexOf('VP8') !== -1, 'VP8 should be the first codec');
  }, `setCodecPreferences() should allow setting VP8 as first codec`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('video');
  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(capabilities.codecs));
  }, `setCodecPreferences() on audio transceiver with codecs returned from getCapabilities('video') should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const codecs = [{
  mimeType: 'data',
  clockRate: 2000,
  channels: 2,
  sdpFmtpLine: '0-15'
  }];

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with user defined codec with invalid mimeType should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const codecs = [{
  mimeType: 'audio/piepiper',
  clockRate: 2000,
  channels: 2,
  sdpFmtpLine: '0-15'
  }];

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with user defined codec should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  const codecs = [
  ...capabilities.codecs,
  {
  mimeType: 'audio/piepiper',
  clockRate: 2000,
  channels: 2,
  sdpFmtpLine: '0-15'
  }];

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with user defined codec together with codecs returned from getCapabilities() should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  const codecs = [capabilities.codecs[0]];
  codecs[0].clockRate = codecs[0].clockRate / 2;

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with modified codec clock rate should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  const codecs = [capabilities.codecs[0]];
  codecs[0].channels = codecs[0].channels + 11;

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with modified codec channel count should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');
  const codecs = [capabilities.codecs[0]];
  codecs[0].sdpFmtpLine = "modifiedparameter=1";

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with modified codec parameters should throw InvalidModificationError`);

  test((t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const capabilities = RTCRtpReceiver.getCapabilities('audio');

  const { codecs } = capabilities;
  assert_greater_than(codecs.length, 0,
  'Expect at least one codec available');

  const [ codec ] = codecs;
  const { channels=2 } = codec;
  codec.channels = channels+1;

  assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
  }, `setCodecPreferences() with modified codecs returned from getCapabilities() should throw InvalidModificationError`);

  promise_test(async (t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('audio');
  const {codecs} = RTCRtpReceiver.getCapabilities('audio');
  // Reorder codecs, put PCMU/PCMA first.
  let firstCodec;
  let i;
  for (i = 0; i < codecs.length; i++) {
  const codec = codecs[i];
  if (codec.mimeType === 'audio/PCMU' || codec.mimeType === 'audio/PCMA') {
  codecs.splice(i, 1);
  codecs.unshift(codec);
  firstCodec = codec.mimeType.substr(6);
  break;
  }
  }
  assert_not_equals(firstCodec, undefined, 'PCMU or PCMA codec not found');
  transceiver.setCodecPreferences(codecs);

  const offer = await pc.createOffer();
  const mediaSection = SDPUtils.getMediaSections(offer.sdp)[0];
  const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
  assert_equals(rtpParameters.codecs[0].name, firstCodec);
  }, `setCodecPreferences() modifies the order of audio codecs in createOffer`);

  promise_test(async (t) => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  const transceiver = pc.addTransceiver('video');
  const {codecs} = RTCRtpReceiver.getCapabilities('video');
  // Reorder codecs, swap H264 and VP8.
  let vp8 = -1;
  let h264 = -1;
  let firstCodec;
  let i;
  for (i = 0; i < codecs.length; i++) {
  const codec = codecs[i];
  if (codec.mimeType === 'video/VP8' && vp8 === -1) {
  vp8 = i;
  if (h264 !== -1) {
  codecs[vp8] = codecs[h264];
  codecs[h264] = codec;
  firstCodec = 'VP8';
  break;
  }
  }
  if (codec.mimeType === 'video/H264' && h264 === -1) {
  h264 = i;
  if (vp8 !== -1) {
  codecs[h264] = codecs[vp8];
  codecs[vp8] = codec;
  firstCodec = 'H264';
  break;
  }
  }
  }
  assert_not_equals(firstCodec, undefined, 'VP8 and H264 codecs not found');
  transceiver.setCodecPreferences(codecs);

  const offer = await pc.createOffer();
  const mediaSection = SDPUtils.getMediaSections(offer.sdp)[0];
  const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
  assert_equals(rtpParameters.codecs[0].name, firstCodec);
  }, `setCodecPreferences() modifies the order of video codecs in createOffer`);

  // Tests the note removed as result of discussion in
  // https://github.com/w3c/webrtc-pc/issues/2933
  promise_test(async (t) => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const transceiver = pc1.addTransceiver('video');
  const {codecs} = RTCRtpReceiver.getCapabilities('video');
  const vp8 = codecs.find(codec => codec.mimeType === 'video/VP8');
  const h264 = codecs.find(codec => codec.mimeType === 'video/H264');
  const thirdCodec = codecs.find(codec => ['video/VP9', 'video/AV1'].includes(codec.mimeType));
  assert_true(!!vp8);
  assert_true(!!h264);
  assert_true(!!thirdCodec);

  transceiver.setCodecPreferences([vp8, thirdCodec]);
  await pc1.setLocalDescription();
  await pc2.setRemoteDescription(pc1.localDescription);
  const transceiver2 = pc2.getTransceivers()[0];
  transceiver2.setCodecPreferences([h264, thirdCodec, vp8]);
  await pc2.setLocalDescription();
  await pc1.setRemoteDescription(pc2.localDescription);
  const mediaSection = SDPUtils.getMediaSections(pc2.localDescription.sdp)[0];
  const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
  // Order is determined by pc2 but H264 is not present.
  assert_equals(rtpParameters.codecs.length, 2);
  assert_equals(rtpParameters.codecs[0].name, thirdCodec.mimeType.substring(6));
  assert_equals(rtpParameters.codecs[1].name, 'VP8');

  }, `setCodecPreferences() filters on receiver and prefers receiver order`);

  </script>
	<!doctype html>
	<meta charset=utf-8>
	<title>RTCRtpTransceiver.prototype.setCodecPreferences</title>
	<script src="/resources/testharness.js"></script>
	<script src="/resources/testharnessreport.js"></script>
	<script src="./third_party/sdp/sdp.js"></script>
	<script>
	'use strict';

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	transceiver.setCodecPreferences(capabilities.codecs);
	}, `setCodecPreferences() on audio transceiver with codecs returned from RTCRtpReceiver.getCapabilities('audio') should succeed`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('video');
	const capabilities = RTCRtpReceiver.getCapabilities('video');
	transceiver.setCodecPreferences(capabilities.codecs);
	}, `setCodecPreferences() on video transceiver with codecs returned from RTCRtpReceiver.getCapabilities('video') should succeed`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	transceiver.setCodecPreferences([]);
	}, `setCodecPreferences([]) should succeed`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	const { codecs } = capabilities;

	if(codecs.length >= 2) {
	const tmp = codecs[0];
	codecs[0] = codecs[1];
	codecs[1] = tmp;
	}

	transceiver.setCodecPreferences(codecs);
	}, `setCodecPreferences() with reordered codecs should succeed`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('video');
	const capabilities = RTCRtpReceiver.getCapabilities('video');
	const { codecs } = capabilities;
	// This test verifies that the mandatory VP8 codec is present
	// and can be preferred.
	const codec = codecs.find(c => c.mimeType === 'video/VP8');
	assert_true(!!codec, 'VP8 video codec was found');
	transceiver.setCodecPreferences([codec]);
	}, `setCodecPreferences() with only VP8 should succeed`);

	test(() => {
	const pc = new RTCPeerConnection();
	const transceiver = pc.addTransceiver('video');
	const capabilities = RTCRtpReceiver.getCapabilities('video');
	const { codecs } = capabilities;
	// This test verifies that the mandatory H264 codec is present
	// and can be preferred.
	const codec = codecs.find(c => c.mimeType === 'video/H264');
	assert_true(!!codec, 'H264 video codec was found');
	transceiver.setCodecPreferences([codec]);
	}, `setCodecPreferences() with only H264 should succeed`);

	async function getRTPMapLinesWithCodecAsFirst(firstCodec)
	{
	const codecs = RTCRtpReceiver.getCapabilities('video').codecs;
	codecs.forEach((codec, idx) => {
	if (codec.mimeType === firstCodec) {
	codecs.splice(idx, 1);
	codecs.unshift(codec);
	}
	});

	const pc = new RTCPeerConnection();
	const transceiver = pc.addTransceiver('video');
	transceiver.setCodecPreferences(codecs);
	const offer = await pc.createOffer();

	return offer.sdp.split('\r\n').filter(line => line.startsWith('a=rtpmap:'));
	}

	promise_test(async () => {
	const lines = await getRTPMapLinesWithCodecAsFirst('video/H264');

	assert_greater_than(lines.length, 1);
	assert_true(lines[0].indexOf('H264') !== -1, 'H264 should be the first codec');
	}, `setCodecPreferences() should allow setting H264 as first codec`);

	promise_test(async () => {
	const lines = await getRTPMapLinesWithCodecAsFirst('video/VP8');

	assert_greater_than(lines.length, 1);
	assert_true(lines[0].indexOf('VP8') !== -1, 'VP8 should be the first codec');
	}, `setCodecPreferences() should allow setting VP8 as first codec`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('video');
	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(capabilities.codecs));
	}, `setCodecPreferences() on audio transceiver with codecs returned from getCapabilities('video') should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const codecs = [{
	mimeType: 'data',
	clockRate: 2000,
	channels: 2,
	sdpFmtpLine: '0-15'
	}];

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with user defined codec with invalid mimeType should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const codecs = [{
	mimeType: 'audio/piepiper',
	clockRate: 2000,
	channels: 2,
	sdpFmtpLine: '0-15'
	}];

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with user defined codec should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	const codecs = [
	...capabilities.codecs,
	{
	mimeType: 'audio/piepiper',
	clockRate: 2000,
	channels: 2,
	sdpFmtpLine: '0-15'
	}];

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with user defined codec together with codecs returned from getCapabilities() should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	const codecs = [capabilities.codecs[0]];
	codecs[0].clockRate = codecs[0].clockRate / 2;

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with modified codec clock rate should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	const codecs = [capabilities.codecs[0]];
	codecs[0].channels = codecs[0].channels + 11;

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with modified codec channel count should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');
	const codecs = [capabilities.codecs[0]];
	codecs[0].sdpFmtpLine = "modifiedparameter=1";

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with modified codec parameters should throw InvalidModificationError`);

	test((t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const capabilities = RTCRtpReceiver.getCapabilities('audio');

	const { codecs } = capabilities;
	assert_greater_than(codecs.length, 0,
	'Expect at least one codec available');

	const [ codec ] = codecs;
	const { channels=2 } = codec;
	codec.channels = channels+1;

	assert_throws_dom('InvalidModificationError', () => transceiver.setCodecPreferences(codecs));
	}, `setCodecPreferences() with modified codecs returned from getCapabilities() should throw InvalidModificationError`);

	promise_test(async (t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('audio');
	const {codecs} = RTCRtpReceiver.getCapabilities('audio');
	// Reorder codecs, put PCMU/PCMA first.
	let firstCodec;
	let i;
	for (i = 0; i < codecs.length; i++) {
	const codec = codecs[i];
	if (codec.mimeType === 'audio/PCMU' \|\| codec.mimeType === 'audio/PCMA') {
	codecs.splice(i, 1);
	codecs.unshift(codec);
	firstCodec = codec.mimeType.substr(6);
	break;
	}
	}
	assert_not_equals(firstCodec, undefined, 'PCMU or PCMA codec not found');
	transceiver.setCodecPreferences(codecs);

	const offer = await pc.createOffer();
	const mediaSection = SDPUtils.getMediaSections(offer.sdp)[0];
	const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
	assert_equals(rtpParameters.codecs[0].name, firstCodec);
	}, `setCodecPreferences() modifies the order of audio codecs in createOffer`);

	promise_test(async (t) => {
	const pc = new RTCPeerConnection();
	t.add_cleanup(() => pc.close());
	const transceiver = pc.addTransceiver('video');
	const {codecs} = RTCRtpReceiver.getCapabilities('video');
	// Reorder codecs, swap H264 and VP8.
	let vp8 = -1;
	let h264 = -1;
	let firstCodec;
	let i;
	for (i = 0; i < codecs.length; i++) {
	const codec = codecs[i];
	if (codec.mimeType === 'video/VP8' && vp8 === -1) {
	vp8 = i;
	if (h264 !== -1) {
	codecs[vp8] = codecs[h264];
	codecs[h264] = codec;
	firstCodec = 'VP8';
	break;
	}
	}
	if (codec.mimeType === 'video/H264' && h264 === -1) {
	h264 = i;
	if (vp8 !== -1) {
	codecs[h264] = codecs[vp8];
	codecs[vp8] = codec;
	firstCodec = 'H264';
	break;
	}
	}
	}
	assert_not_equals(firstCodec, undefined, 'VP8 and H264 codecs not found');
	transceiver.setCodecPreferences(codecs);

	const offer = await pc.createOffer();
	const mediaSection = SDPUtils.getMediaSections(offer.sdp)[0];
	const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
	assert_equals(rtpParameters.codecs[0].name, firstCodec);
	}, `setCodecPreferences() modifies the order of video codecs in createOffer`);

	// Tests the note removed as result of discussion in
	// https://github.com/w3c/webrtc-pc/issues/2933
	promise_test(async (t) => {
	const pc1 = new RTCPeerConnection();
	t.add_cleanup(() => pc1.close());
	const pc2 = new RTCPeerConnection();
	t.add_cleanup(() => pc2.close());

	const transceiver = pc1.addTransceiver('video');
	const {codecs} = RTCRtpReceiver.getCapabilities('video');
	const vp8 = codecs.find(codec => codec.mimeType === 'video/VP8');
	const h264 = codecs.find(codec => codec.mimeType === 'video/H264');
	const thirdCodec = codecs.find(codec => ['video/VP9', 'video/AV1'].includes(codec.mimeType));
	assert_true(!!vp8);
	assert_true(!!h264);
	assert_true(!!thirdCodec);

	transceiver.setCodecPreferences([vp8, thirdCodec]);
	await pc1.setLocalDescription();
	await pc2.setRemoteDescription(pc1.localDescription);
	const transceiver2 = pc2.getTransceivers()[0];
	transceiver2.setCodecPreferences([h264, thirdCodec, vp8]);
	await pc2.setLocalDescription();
	await pc1.setRemoteDescription(pc2.localDescription);
	const mediaSection = SDPUtils.getMediaSections(pc2.localDescription.sdp)[0];
	const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
	// Order is determined by pc2 but H264 is not present.
	assert_equals(rtpParameters.codecs.length, 2);
	assert_equals(rtpParameters.codecs[0].name, thirdCodec.mimeType.substring(6));
	assert_equals(rtpParameters.codecs[1].name, 'VP8');

	}, `setCodecPreferences() filters on receiver and prefers receiver order`);

	</script>