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'use strict';
// This file depends on `webrtc/RTCPeerConnection-helper.js`
// which should be loaded from the main HTML file.
var kAbsCaptureTime =
'http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time';
function addHeaderExtensionToSdp(sdp, uri) {
const extmap = new RegExp('a=extmap:(\\d+)');
let sdpLines = sdp.split('\r\n');
// This assumes at most one audio m= section and one video m= section.
// If more are present, only the first section of each kind is munged.
for (const section of ['audio', 'video']) {
let found_section = false;
let maxId = undefined;
let maxIdLine = undefined;
let extmapAllowMixed = false;
// find the largest header extension id for section.
for (let i = 0; i < sdpLines.length; ++i) {
if (!found_section) {
if (sdpLines[i].startsWith('m=' + section)) {
found_section = true;
}
continue;
} else {
if (sdpLines[i].startsWith('m=')) {
// end of section
break;
}
}
if (sdpLines[i] === 'a=extmap-allow-mixed') {
extmapAllowMixed = true;
}
let result = sdpLines[i].match(extmap);
if (result && result.length === 2) {
if (maxId == undefined || result[1] > maxId) {
maxId = parseInt(result[1]);
maxIdLine = i;
}
}
}
if (maxId == 14 && !extmapAllowMixed) {
// Reaching the limit of one byte header extension. Adding two byte header
// extension support.
sdpLines.splice(maxIdLine + 1, 0, 'a=extmap-allow-mixed');
}
if (maxIdLine !== undefined) {
sdpLines.splice(maxIdLine + 1, 0,
'a=extmap:' + (maxId + 1).toString() + ' ' + uri);
}
}
return sdpLines.join('\r\n');
}
// TODO(crbug.com/1051821): Use RTP header extension API instead of munging
// when the RTP header extension API is implemented.
async function addAbsCaptureTimeAndExchangeOffer(caller, callee) {
let offer = await caller.createOffer();
// Absolute capture time header extension may not be offered by default,
// in such case, munge the SDP.
offer.sdp = addHeaderExtensionToSdp(offer.sdp, kAbsCaptureTime);
await caller.setLocalDescription(offer);
return callee.setRemoteDescription(offer);
}
// TODO(crbug.com/1051821): Use RTP header extension API instead of munging
// when the RTP header extension API is implemented.
async function checkAbsCaptureTimeAndExchangeAnswer(caller, callee,
absCaptureTimeAnswered) {
let answer = await callee.createAnswer();
const extmap = new RegExp('a=extmap:\\d+ ' + kAbsCaptureTime + '\r\n', 'g');
if (answer.sdp.match(extmap) == null) {
// We expect that absolute capture time RTP header extension is answered.
// But if not, there is no need to proceed with the test.
assert_false(absCaptureTimeAnswered, 'Absolute capture time RTP ' +
'header extension is not answered');
} else {
if (!absCaptureTimeAnswered) {
// We expect that absolute capture time RTP header extension is not
// answered, but it is, then we munge the answer to remove it.
answer.sdp = answer.sdp.replace(extmap, '');
}
}
await callee.setLocalDescription(answer);
return caller.setRemoteDescription(answer);
}
async function exchangeOfferAndListenToOntrack(t, caller, callee,
absCaptureTimeOffered) {
const ontrackPromise = addEventListenerPromise(t, callee, 'track');
// Absolute capture time header extension is expected not offered by default,
// and thus munging is needed to enable it.
await absCaptureTimeOffered
? addAbsCaptureTimeAndExchangeOffer(caller, callee)
: exchangeOffer(caller, callee);
return ontrackPromise;
}
async function initiateSingleTrackCall(t, cap, absCaptureTimeOffered,
absCaptureTimeAnswered) {
const caller = new RTCPeerConnection();
t.add_cleanup(() => caller.close());
const callee = new RTCPeerConnection();
t.add_cleanup(() => callee.close());
const stream = await getNoiseStream(cap);
stream.getTracks().forEach(track => {
caller.addTrack(track, stream);
t.add_cleanup(() => track.stop());
});
// TODO(crbug.com/988432): `getSynchronizationSources() on the audio side
// needs a hardware sink for the returned dictionary entries to get updated.
const remoteVideo = document.getElementById('remote');
callee.ontrack = e => {
remoteVideo.srcObject = e.streams[0];
}
exchangeIceCandidates(caller, callee);
await exchangeOfferAndListenToOntrack(t, caller, callee,
absCaptureTimeOffered);
// Exchange answer and check whether the absolute capture time RTP header
// extension is answered.
await checkAbsCaptureTimeAndExchangeAnswer(caller, callee,
absCaptureTimeAnswered);
return [caller, callee];
}
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