simulcast-answer.html

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This WPT test may be referenced by the following Test IDs:
- /webrtc/protocol/simulcast-answer.html - WPT Dashboard Interop Dashboard

<!doctype html>

<meta charset=utf-8>

<title>RTCPeerConnection Simulcast Answer</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script>

'use strict';

const offer_sdp = `v=0

o=- 3840232462471583827 2 IN IP4 127.0.0.1

s=-

t=0 0

a=group:BUNDLE 0

a=msid-semantic: WMS

m=video 9 UDP/TLS/RTP/SAVPF 96

c=IN IP4 0.0.0.0

a=rtcp:9 IN IP4 0.0.0.0

a=ice-ufrag:Li6+

a=ice-pwd:3C05CTZBRQVmGCAq7hVasHlT

a=ice-options:trickle

a=fingerprint:sha-256 5B:D3:8E:66:0E:7D:D3:F3:8E:E6:80:28:19:FC:55:AD:58:5D:B9:3D:A8:DE:45:4A:E7:87:02:F8:3C:0B:3B:B3

a=setup:actpass

a=mid:0

a=extmap:1 urn:ietf:params:rtp-hdrext:sdes:mid

a=extmap:2 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id

a=recvonly

a=rtcp-mux

a=rtpmap:96 VP8/90000

a=rtcp-fb:96 goog-remb

a=rtcp-fb:96 transport-cc

a=rtcp-fb:96 ccm fir

a=rid:foo recv

a=rid:bar recv

a=rid:baz recv

a=simulcast:recv foo;bar;baz

`;

// Tests for the construction of answers with simulcast according to:

// draft-ietf-mmusic-sdp-simulcast-13

// draft-ietf-mmusic-rid-15

promise_test(async t => {

  const pc = new RTCPeerConnection();

  t.add_cleanup(() => pc.close());

  const expected_rids = ['foo', 'bar', 'baz'];

  await pc.setRemoteDescription({type: 'offer', sdp: offer_sdp});

  const transceiver = pc.getTransceivers()[0];

  // The created transceiver should be in "recvonly" state. Allow it to send.

  transceiver.direction = 'sendonly';

  const answer = await pc.createAnswer();

  const answer_lines = answer.sdp.split('\r\n');

  // Check for a RID line for each layer.

  for (const rid of expected_rids) {

    const result = answer_lines.find(line => line.startsWith(`a=rid:${rid}`));

    assert_not_equals(result, undefined, `RID attribute for '${rid}' missing.`);

  // Check for simulcast attribute with send direction and all RIDs.

  const result = answer_lines.find(

      line => line.startsWith(`a=simulcast:send ${expected_rids.join(';')}`));

  assert_not_equals(result, undefined, 'Could not find simulcast attribute.');

}, 'createAnswer() with multiple send encodings should create simulcast answer');

promise_test(async t => {

  const pc = new RTCPeerConnection();

  t.add_cleanup(() => pc.close());

  const expected_rids = ['foo', 'bar', 'baz'];

  // Try to disable the `bar` encoding in a=simulcast by prefixing it with the

  // `~` character.

  await pc.setRemoteDescription({type: 'offer', sdp: offer_sdp.replace(/(a=simulcast:.*)bar/, '$1~bar')});

  const transceiver = pc.getTransceivers()[0];

  transceiver.direction = 'sendonly';

  await pc.setLocalDescription();

  const parameters = pc.getSenders()[0].getParameters();

  const barEncoding = parameters.encodings.find(encoding => encoding.rid === 'bar');

  assert_not_equals(barEncoding, undefined);

  assert_not_equals(barEncoding.active, false);

}, 'Using the ~rid SDP syntax in a remote offer does not control the local encodings active flag');

promise_test(async t => {

  const pc = new RTCPeerConnection();

  t.add_cleanup(() => pc.close());

  const expected_rids = ['foo', 'bar', 'baz'];

  await pc.setRemoteDescription({type: 'offer', sdp: offer_sdp});

  const transceiver = pc.getTransceivers()[0];

  transceiver.direction = 'sendonly';

  await pc.setLocalDescription();

  // Disabling the encoding should not change the rid to ~rid.

  const parameters = pc.getSenders()[0].getParameters();

  parameters.encodings.forEach(e => e.active = false);

  await pc.getSenders()[0].setParameters(parameters);

  const offer = await pc.createOffer();

  const offer_lines = offer.sdp.split('\r\n');

  const result = offer_lines.find(

      line => line.startsWith(`a=simulcast:send ${expected_rids.join(';')}`));

  assert_not_equals(result, undefined, 'Could not find simulcast attribute.');

}, 'Disabling encodings locally does not change the SDP');

</script>