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<title>RTCPeerConnection Simulcast Tests - negotiation/encodings</title>
<meta name="timeout" content="long">
<script src="../third_party/sdp/sdp.js"></script>
<script src="simulcast.js"></script>
<script src="../RTCPeerConnection-helper.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="../../mediacapture-streams/permission-helper.js"></script>
<script>

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const sender = pc1.addTrack(stream.getTracks()[0]);
  // pc1 is unicast right now
  pc2.addTrack(stream.getTracks()[0]);

  await doOfferToRecvSimulcastAndAnswer(pc2, pc1, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  const {encodings} = sender.getParameters();
  const rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'addTrack, then sRD(simulcast recv offer) results in simulcast');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({audio: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const sender = pc1.addTrack(stream.getTracks()[0]);
  // pc1 is unicast right now
  pc2.addTrack(stream.getTracks()[0]);

  await doOfferToRecvSimulcastAndAnswer(pc2, pc1, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  const {encodings} = sender.getParameters();
  const rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, [undefined]);
}, 'simulcast is not supported for audio');

// We do not have a test case for sRD(offer) narrowing a simulcast envelope
// from addTransceiver, since that transceiver cannot be paired up with a remote
// offer m-section
promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  const rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [2]);
}, 'sRD(recv simulcast answer) can narrow the simulcast envelope specified by addTransceiver');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [2]);
}, 'sRD(recv simulcast answer) can narrow the simulcast envelope from a previous negotiation');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  // doAnswerToSendSimulcast causes pc2 to barf unless we set the direction to
  // sendrecv
  pc2.getTransceivers()[0].direction = "sendrecv";
  pc2.getTransceivers()[1].direction = "sendrecv";

  await doOfferToRecvSimulcast(pc2, pc1, ["foo"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"], "[[SendEncodings]] is not updated in have-remote-offer for reoffers");

  await doAnswerToSendSimulcast(pc2, pc1);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [2]);
}, 'sRD(simulcast offer) can narrow the simulcast envelope from a previous negotiation');

// https://github.com/w3c/webrtc-pc/issues/2780
promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const sender = pc1.addTrack(stream.getTracks()[0]);
  pc2.addTrack(stream.getTracks()[0]);

  await doOfferToRecvSimulcastAndAnswer(pc2, pc1, ["foo", "bar", "foo"]);
  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
  assert_true(pc1.remoteDescription.sdp.includes("a=simulcast:recv foo;bar;foo"), "Duplicate rids should be present in offer");
  assert_false(pc1.localDescription.sdp.includes("a=simulcast:send foo;bar;foo"), "Duplicate rids should not be present in answer");
  assert_true(pc1.localDescription.sdp.includes("a=simulcast:send foo;bar"), "Answer should use the correct rids");
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'Duplicate rids in sRD(offer) are ignored');

// https://github.com/w3c/webrtc-pc/issues/2769
promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const sender = pc1.addTrack(stream.getTracks()[0]);
  pc2.addTrack(stream.getTracks()[0]);

  await doOfferToRecvSimulcastAndAnswer(pc2, pc1, ["foo,bar", "1,2"]);
  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "1"]);
  assert_true(pc1.remoteDescription.sdp.includes("a=simulcast:recv foo,bar;1,2"), "Choices of rids should be present in offer");
  assert_true(pc1.localDescription.sdp.includes("a=simulcast:send foo;1\r\n"), "Choices of rids should not be present in answer");
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "1"]);
}, 'Choices in rids in sRD(offer) are ignored');

// https://github.com/w3c/webrtc-pc/issues/2764
promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const sender = pc1.addTrack(stream.getTracks()[0]);
  pc2.addTrack(stream.getTracks()[0]);

  await doOfferToRecvSimulcast(pc2, pc1, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await pc1.setRemoteDescription({sdp: "", type: "rollback"});

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, [undefined]);
}, 'addTrack, then rollback of sRD(simulcast offer), brings us back to having a single encoding without a rid');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  pc2.addTrack(stream.getTracks()[0]);
  await doOfferToRecvSimulcast(pc2, pc1, ["foo", "bar"]);
  const sender = pc1.addTrack(stream.getTracks()[0]);
  assert_equals(pc1.getTransceivers().length, 1);

  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await pc1.setRemoteDescription({sdp: "", type: "rollback"});

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, [undefined]);
}, 'sRD(simulcast offer), addTrack, then rollback brings us back to having a single encoding');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const {sender} = pc1.addTransceiver(stream.getTracks()[0], {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});

  await doOfferToSendSimulcast(pc1, pc2);
  await doAnswerToRecvSimulcast(pc1, pc2, ["bar", "foo"]);
  assert_true(pc1.remoteDescription.sdp.includes("a=simulcast:recv bar;foo"), "Answer should have reordered rids");

  assert_equals(pc1.getTransceivers().length, 1);
  const {encodings} = sender.getParameters();
  const rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'Reordering of rids in sRD(answer) is ignored');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const {sender} = pc1.addTransceiver(stream.getTracks()[0], {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await doOfferToSendSimulcast(pc1, pc2);
  await doAnswerToRecvSimulcast(pc1, pc2, ["bar", "foo"]);
  assert_true(pc1.remoteDescription.sdp.includes("a=simulcast:recv bar;foo"), "Answer should have reordered rids");

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'Reordering of rids in sRD(reanswer) is ignored');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const {sender} = pc1.addTransceiver(stream.getTracks()[0], {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  let {encodings} = sender.getParameters();
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  // doAnswerToSendSimulcast causes pc2 to barf unless we set the direction to
  // sendrecv
  pc2.getTransceivers()[0].direction = "sendrecv";
  pc2.getTransceivers()[1].direction = "sendrecv";

  await doOfferToRecvSimulcast(pc2, pc1, ["bar", "foo"]);
  await doAnswerToSendSimulcast(pc2, pc1);
  assert_true(pc1.remoteDescription.sdp.includes("a=simulcast:recv bar;foo"), "Reoffer should have reordered rids");

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'Reordering of rids in sRD(reoffer) is ignored');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const stream = await getNoiseStream({video: true});
  t.add_cleanup(() => stream.getTracks().forEach(track => track.stop()));
  const {sender} = pc1.addTransceiver(stream.getTracks()[0], {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  let encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  // doAnswerToSendSimulcast causes pc2 to barf unless we set the direction to
  // sendrecv
  pc2.getTransceivers()[0].direction = "sendrecv";
  pc2.getTransceivers()[1].direction = "sendrecv";

  // Keep the second encoding!
  await doOfferToRecvSimulcast(pc2, pc1, ["bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await pc1.setRemoteDescription({sdp: "", type: "rollback"});

  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'Rollback of sRD(reoffer) with a single rid results in all previous encodings');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  const rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["bar"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [1]);
}, 'sRD(recv simulcast answer) can narrow the simulcast envelope specified by addTransceiver by removing the first encoding');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["bar"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [1]);
}, 'sRD(recv simulcast answer) can narrow the simulcast envelope from a previous negotiation by removing the first encoding');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  // doAnswerToSendSimulcast causes pc2 to barf unless we set the direction to
  // sendrecv
  pc2.getTransceivers()[0].direction = "sendrecv";
  pc2.getTransceivers()[1].direction = "sendrecv";

  await doOfferToRecvSimulcast(pc2, pc1, ["bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"], "[[SendEncodings]] is not updated in have-remote-offer for reoffers");

  await doAnswerToSendSimulcast(pc2, pc1);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["bar"]);
  const scaleDownByValues = encodings.map(({scaleResolutionDownBy}) => scaleResolutionDownBy);
  assert_array_equals(scaleDownByValues, [1]);
}, 'sRD(simulcast offer) can narrow the simulcast envelope from a previous negotiation by removing the first encoding');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  pc1.getTransceivers()[0].direction = "inactive";
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'sender renegotiation to inactive does not disable simulcast');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  pc1.getTransceivers()[0].direction = "recvonly";
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'sender renegotiation to recvonly does not disable simulcast');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  pc2.getTransceivers()[0].direction = "inactive";
  pc2.getTransceivers()[1].direction = "inactive";
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'receiver renegotiation to inactive does not disable simulcast');

promise_test(async t => {
  const pc1 = new RTCPeerConnection();
  t.add_cleanup(() => pc1.close());
  const pc2 = new RTCPeerConnection();
  t.add_cleanup(() => pc2.close());

  const {sender} = pc1.addTransceiver("video", {sendEncodings: [{rid: "foo"}, {rid: "bar"}]});
  let {encodings} = sender.getParameters();

  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);

  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  let rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);

  pc2.getTransceivers()[0].direction = "sendonly";
  pc2.getTransceivers()[1].direction = "sendonly";
  await doOfferToSendSimulcastAndAnswer(pc1, pc2, ["foo", "bar"]);
  assert_equals(pc1.getTransceivers().length, 1);
  encodings = sender.getParameters().encodings;
  rids = encodings.map(({rid}) => rid);
  assert_array_equals(rids, ["foo", "bar"]);
}, 'receiver renegotiation to sendonly does not disable simulcast');

</script>
