test_peerConnection_simulcastAnswer.html

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<html>

<head>

  <script type="application/javascript" src="pc.js"></script>

  <script type="application/javascript" src="/tests/dom/canvas/test/captureStream_common.js"></script>

  <script type="application/javascript" src="helpers_from_wpt/sdp.js"></script>

  <script type="application/javascript" src="simulcast.js"></script>

  <script type="application/javascript" src="stats.js"></script>

</head>

<body>

<pre id="test">

<script type="application/javascript">

  createHTML({

    bug: "1231507",

    title: "Basic video-only peer connection with Simulcast answer",

    visible: true

});

  runNetworkTest(async () => {

    await pushPrefs(

        // 180Kbps was determined empirically, set well-higher than

        // the 80Kbps+overhead needed for the two simulcast streams.

        // 100Kbps was apparently too low.

        ['media.peerconnection.video.min_bitrate_estimate', 180*1000]);

    const offerer = new RTCPeerConnection();

    const answerer = new RTCPeerConnection();

    const add = (pc, can, failed) => can && pc.addIceCandidate(can).catch(failed);

    offerer.onicecandidate = e => add(answerer, e.candidate, generateErrorCallback());

    answerer.onicecandidate = e => add(offerer, e.candidate, generateErrorCallback());

    const metadataToBeLoaded = [];

    offerer.ontrack = (e) => {

      metadataToBeLoaded.push(getPlaybackWithLoadedMetadata(e.track));

};

    // Two recv transceivers, one for each simulcast stream

    offerer.addTransceiver('video', { direction: 'recvonly' });

    offerer.addTransceiver('video', { direction: 'recvonly' });

    const offer = await offerer.createOffer();

    const mungedOffer = midToRid(offer);

    info(`Transformed recv offer to simulcast: ${offer.sdp} to ${mungedOffer}`);

    await answerer.setRemoteDescription({type: 'offer', sdp: mungedOffer});

    // One send transceiver, that will be used to send both simulcast streams

    const emitter = new VideoFrameEmitter();

    const videoStream = emitter.stream();

    const sender = answerer.addTrack(videoStream.getVideoTracks()[0], videoStream);

    let parameters = sender.getParameters();

    is(parameters.encodings.length, 2);

    is(answerer.getSenders().length, 1);

    emitter.start();

    await offerer.setLocalDescription(offer);

    const rids = offerer.getTransceivers().map(t => t.mid);

    is(rids.length, 2, 'Should have 2 mids in offer');

    ok(rids[0] != '', 'First mid should be non-empty');

    ok(rids[1] != '', 'Second mid should be non-empty');

    info(`rids: ${JSON.stringify(rids)}`);

    parameters = sender.getParameters();

    info(`parameters: ${JSON.stringify(parameters)}`);

    const observedRids = parameters.encodings.map(({rid}) => rid);

    isDeeply(observedRids, rids);

    parameters.encodings[0].maxBitrate = 40000;

    parameters.encodings[0].scaleResolutionDownBy = 1;

    parameters.encodings[1].maxBitrate = 40000;

    parameters.encodings[1].scaleResolutionDownBy = 2;

    await sender.setParameters(parameters);

    const answer = await answerer.createAnswer();

    const mungedAnswer = ridToMid(answer);

    info(`Transformed send simulcast answer to multiple m-sections: ${answer.sdp} to ${mungedAnswer}`);

    await offerer.setRemoteDescription({type: 'answer', sdp: mungedAnswer});

    await answerer.setLocalDescription(answer);

    is(metadataToBeLoaded.length, 2, 'Offerer should have gotten 2 ontrack events');

    info('Waiting for 2 loadedmetadata events');

    const videoElems = await Promise.all(metadataToBeLoaded);

    const statsReady =

      Promise.all([waitForSyncedRtcp(offerer), waitForSyncedRtcp(answerer)]);

    const helper = new VideoStreamHelper();

    info('Waiting for first video element to start playing');

    await helper.checkVideoPlaying(videoElems[0]);

    info('Waiting for second video element to start playing');

    await helper.checkVideoPlaying(videoElems[1]);

    is(videoElems[0].videoWidth, 50,

       "sink is same width as source, modulo our cropping algorithm");

    is(videoElems[0].videoHeight, 50,

       "sink is same height as source, modulo our cropping algorithm");

    is(videoElems[1].videoWidth, 25,

       "sink is 1/2 width of source, modulo our cropping algorithm");

    is(videoElems[1].videoHeight, 25,

       "sink is 1/2 height of source, modulo our cropping algorithm");

    await statsReady;

    info("Stats ready");

    const senderStats = await sender.getStats();

    checkSenderStats(senderStats, 2);

    checkExpectedFields(senderStats);

    pedanticChecks(senderStats);

    emitter.stop();

    videoStream.getVideoTracks()[0].stop();

    offerer.close();

    answerer.close();

});

</script>

</pre>

</body>

</html>