webrtc/protocol/rtx-codecs.https.html

<!doctype html>
<meta charset=utf-8>
<title>RTX codec integrity checks</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../RTCPeerConnection-helper.js"></script>
<script src="../third_party/sdp/sdp.js"></script>
<script>
'use strict';

// Tests for conformance to rules for RTX codecs.
// Basic rule: Offers and answers must contain RTX codecs, and the
// RTX codecs must have an a=fmtp line that points to a non-RTX codec.

// Helper function for doing one round of offer/answer exchange
// between two local peer connections.
// Calls setRemoteDescription(offer/answer) before
// setLocalDescription(offer/answer) to ensure the remote description
// is set and candidates can be added before the local peer connection
// starts generating candidates and ICE checks.
async function doSignalingHandshake(localPc, remotePc, options={}) {
  let offer = await localPc.createOffer();
  // Modify offer if callback has been provided
  if (options.modifyOffer) {
    offer = await options.modifyOffer(offer);
  }

  // Apply offer.
  await remotePc.setRemoteDescription(offer);
  await localPc.setLocalDescription(offer);

  let answer = await remotePc.createAnswer();
  // Modify answer if callback has been provided
  if (options.modifyAnswer) {
    answer = await options.modifyAnswer(answer);
  }

  // Apply answer.
  await localPc.setRemoteDescription(answer);
  await remotePc.setLocalDescription(answer);
}

function verifyRtxReferences(description) {
  const mediaSection = SDPUtils.getMediaSections(description.sdp)[0];
  const rtpParameters = SDPUtils.parseRtpParameters(mediaSection);
  for (const codec of rtpParameters.codecs) {
    if (codec.name === 'rtx') {
      assert_own_property(codec.parameters, 'apt', 'rtx codec has apt parameter');
      const referenced_codec = rtpParameters.codecs.find(
        c => c.payloadType === parseInt(codec.parameters.apt));
      assert_true(referenced_codec !== undefined, `Found referenced codec`);
    }
  }
}



promise_test(async t => {
  const pc = new RTCPeerConnection();
  const offer = await generateVideoReceiveOnlyOffer(pc);
  verifyRtxReferences(offer);
}, 'Initial offer should have sensible RTX mappings');

async function negotiateAndReturnAnswer(t) {
  const pc1 = new RTCPeerConnection();
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  t.add_cleanup(() => pc2.close());
  let [track, streams] = await getTrackFromUserMedia('video');
  const sender = pc1.addTrack(track);
  await doSignalingHandshake(pc1, pc2);
  return pc2.localDescription;
}

promise_test(async t => {
  const answer = await negotiateAndReturnAnswer(t);
  verifyRtxReferences(answer);
}, 'Self-negotiated answer should have sensible RTX parameters');

promise_test(async t => {
  const sampleOffer = `v=0
o=- 1878890426675213188 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE video
a=msid-semantic: WMS
m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:RGPK
a=ice-pwd:rAyHEAKC7ckxQgWaRZXukz+Z
a=ice-options:trickle
a=fingerprint:sha-256 8C:29:0A:8F:11:06:BF:1C:58:B3:CA:E6:F1:F1:DC:99:4C:6C:89:E9:FF:BC:D4:38:11:18:1F:40:19:C8:49:37
a=setup:actpass
a=mid:video
a=recvonly
a=rtcp-mux
a=rtpmap:97 rtx/90000
a=fmtp:97 apt=98
a=rtpmap:98 VP8/90000
a=rtcp-fb:98 ccm fir
a=rtcp-fb:98 nack
a=rtcp-fb:98 nack pli
a=rtcp-fb:98 goog-remb
a=rtcp-fb:98 transport-cc
`;
  const pc = new RTCPeerConnection();
  let [track, streams] = await getTrackFromUserMedia('video');
  const sender = pc.addTrack(track);
  await pc.setRemoteDescription({type: 'offer', sdp: sampleOffer});
  const answer = await pc.createAnswer();
  verifyRtxReferences(answer);
}, 'A remote offer generates sensible RTX references in answer');

promise_test(async t => {
  const sampleOffer = `v=0
o=- 1878890426675213188 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE video
a=msid-semantic: WMS
m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:RGPK
a=ice-pwd:rAyHEAKC7ckxQgWaRZXukz+Z
a=ice-options:trickle
a=fingerprint:sha-256 8C:29:0A:8F:11:06:BF:1C:58:B3:CA:E6:F1:F1:DC:99:4C:6C:89:E9:FF:BC:D4:38:11:18:1F:40:19:C8:49:37
a=setup:actpass
a=mid:video
a=recvonly
a=rtcp-mux
a=rtpmap:96 VP8/90000
a=rtpmap:97 rtx/90000
a=fmtp:97 apt=98
a=rtpmap:98 VP8/90000
a=rtcp-fb:98 ccm fir
a=rtcp-fb:98 nack
a=rtcp-fb:98 nack pli
a=rtcp-fb:98 goog-remb
a=rtcp-fb:98 transport-cc
a=rtpmap:99 rtx/90000
a=fmtp:99 apt=96
`;
  const pc = new RTCPeerConnection();
  let [track, streams] = await getTrackFromUserMedia('video');
  const sender = pc.addTrack(track);
  await pc.setRemoteDescription({type: 'offer', sdp: sampleOffer});
  const answer = await pc.createAnswer();
  verifyRtxReferences(answer);
}, 'A remote offer with duplicate codecs generates sensible RTX references in answer');

</script>