Files
rtsp-simple-server/internal/servers/webrtc/publisher.js

395 lines
10 KiB
JavaScript

'use strict';
(() => {
const unquoteCredential = (v) => (
JSON.parse(`"${v}"`)
);
const linkToIceServers = (links) => (
(links !== null) ? links.split(', ').map((link) => {
const m = link.match(/^<(.+?)>; rel="ice-server"(; username="(.*?)"; credential="(.*?)"; credential-type="password")?/i);
const ret = {
urls: [m[1]],
};
if (m[3] !== undefined) {
ret.username = unquoteCredential(m[3]);
ret.credential = unquoteCredential(m[4]);
ret.credentialType = 'password';
}
return ret;
}) : []
);
const parseOffer = (offer) => {
const ret = {
iceUfrag: '',
icePwd: '',
medias: [],
};
for (const line of offer.split('\r\n')) {
if (line.startsWith('m=')) {
ret.medias.push(line.slice('m='.length));
} else if (ret.iceUfrag === '' && line.startsWith('a=ice-ufrag:')) {
ret.iceUfrag = line.slice('a=ice-ufrag:'.length);
} else if (ret.icePwd === '' && line.startsWith('a=ice-pwd:')) {
ret.icePwd = line.slice('a=ice-pwd:'.length);
}
}
return ret;
};
const generateSdpFragment = (od, candidates) => {
const candidatesByMedia = {};
for (const candidate of candidates) {
const mid = candidate.sdpMLineIndex;
if (candidatesByMedia[mid] === undefined) {
candidatesByMedia[mid] = [];
}
candidatesByMedia[mid].push(candidate);
}
let frag = 'a=ice-ufrag:' + od.iceUfrag + '\r\n'
+ 'a=ice-pwd:' + od.icePwd + '\r\n';
let mid = 0;
for (const media of od.medias) {
if (candidatesByMedia[mid] !== undefined) {
frag += 'm=' + media + '\r\n'
+ 'a=mid:' + mid + '\r\n';
for (const candidate of candidatesByMedia[mid]) {
frag += 'a=' + candidate.candidate + '\r\n';
}
}
mid++;
}
return frag;
};
const setCodec = (section, codec) => {
const lines = section.split('\r\n');
const lines2 = [];
const payloadFormats = [];
for (const line of lines) {
if (!line.startsWith('a=rtpmap:')) {
lines2.push(line);
} else {
if (line.toLowerCase().includes(codec)) {
payloadFormats.push(line.slice('a=rtpmap:'.length).split(' ')[0]);
lines2.push(line);
}
}
}
const lines3 = [];
let firstLine = true;
for (const line of lines2) {
if (firstLine) {
firstLine = false;
lines3.push(line.split(' ').slice(0, 3).concat(payloadFormats).join(' '));
} else if (line.startsWith('a=fmtp:')) {
if (payloadFormats.includes(line.slice('a=fmtp:'.length).split(' ')[0])) {
lines3.push(line);
}
} else if (line.startsWith('a=rtcp-fb:')) {
if (payloadFormats.includes(line.slice('a=rtcp-fb:'.length).split(' ')[0])) {
lines3.push(line);
}
} else {
lines3.push(line);
}
}
return lines3.join('\r\n');
};
const setVideoBitrate = (section, bitrate) => {
let lines = section.split('\r\n');
for (let i = 0; i < lines.length; i++) {
if (lines[i].startsWith('c=')) {
lines = [...lines.slice(0, i+1), 'b=TIAS:' + (parseInt(bitrate) * 1024).toString(), ...lines.slice(i+1)];
break
}
}
return lines.join('\r\n');
};
const setAudioBitrate = (section, bitrate, voice) => {
let opusPayloadFormat = '';
let lines = section.split('\r\n');
for (let i = 0; i < lines.length; i++) {
if (lines[i].startsWith('a=rtpmap:') && lines[i].toLowerCase().includes('opus/')) {
opusPayloadFormat = lines[i].slice('a=rtpmap:'.length).split(' ')[0];
break;
}
}
if (opusPayloadFormat === '') {
return section;
}
for (let i = 0; i < lines.length; i++) {
if (lines[i].startsWith('a=fmtp:' + opusPayloadFormat + ' ')) {
if (voice) {
lines[i] = 'a=fmtp:' + opusPayloadFormat + ' minptime=10;useinbandfec=1;maxaveragebitrate='
+ (parseInt(bitrate) * 1024).toString();
} else {
lines[i] = 'a=fmtp:' + opusPayloadFormat + ' maxplaybackrate=48000;stereo=1;sprop-stereo=1;maxaveragebitrate='
+ (parseInt(bitrate) * 1024).toString();
}
}
}
return lines.join('\r\n');
};
const editOffer = (sdp, videoCodec, audioCodec, audioBitrate, audioVoice) => {
const sections = sdp.split('m=');
for (let i = 0; i < sections.length; i++) {
if (sections[i].startsWith('video')) {
sections[i] = setCodec(sections[i], videoCodec);
} else if (sections[i].startsWith('audio')) {
sections[i] = setAudioBitrate(setCodec(sections[i], audioCodec), audioBitrate, audioVoice);
}
}
return sections.join('m=');
};
const editAnswer = (sdp, videoBitrate) => {
const sections = sdp.split('m=');
for (let i = 0; i < sections.length; i++) {
if (sections[i].startsWith('video')) {
sections[i] = setVideoBitrate(sections[i], videoBitrate);
}
}
return sections.join('m=');
};
const retryPause = 2000;
class MediaMTXWebRTCPublisher {
constructor(conf) {
this.conf = conf;
this.state = 'initializing';
this.restartTimeout = null;
this.pc = null;
this.offerData = null;
this.sessionUrl = null;
this.queuedCandidates = [];
this.start();
}
start = () => {
this.state = 'running';
this.requestICEServers()
.then((iceServers) => this.setupPeerConnection(iceServers))
.then((offer) => this.sendOffer(offer))
.then((answer) => this.setAnswer(answer))
.catch((err) => {
this.handleError(err.toString());
});
};
handleError = (err) => {
if (this.state === 'restarting' || this.state === 'error') {
return;
}
if (this.pc !== null) {
this.pc.close();
this.pc = null;
}
this.offerData = null;
if (this.sessionUrl !== null) {
fetch(this.sessionUrl, {
method: 'DELETE',
});
this.sessionUrl = null;
}
this.queuedCandidates = [];
if (this.state === 'running') {
this.state = 'restarting';
this.restartTimeout = window.setTimeout(() => {
this.restartTimeout = null;
this.start();
}, retryPause);
if (this.conf.onError !== undefined) {
this.conf.onError(err + ', retrying in some seconds');
}
} else {
this.state = 'error';
if (this.conf.onError !== undefined) {
this.conf.onError(err);
}
}
};
requestICEServers = () => {
return fetch(this.conf.url, {
method: 'OPTIONS',
})
.then((res) => linkToIceServers(res.headers.get('Link')));
};
setupPeerConnection = (iceServers) => {
this.pc = new RTCPeerConnection({
iceServers,
// https://webrtc.org/getting-started/unified-plan-transition-guide
sdpSemantics: 'unified-plan',
});
this.pc.onicecandidate = (evt) => this.onLocalCandidate(evt);
this.pc.onconnectionstatechange = () => this.onConnectionState();
this.conf.stream.getTracks().forEach((track) => {
this.pc.addTrack(track, this.conf.stream);
});
return this.pc.createOffer()
.then((offer) => {
this.offerData = parseOffer(offer.sdp);
return this.pc.setLocalDescription(offer)
.then(() => offer.sdp);
});
};
sendOffer = (offer) => {
offer = editOffer(
offer,
this.conf.videoCodec,
this.conf.audioCodec,
this.conf.audioBitrate,
this.conf.audioVoice);
return fetch(this.conf.url, {
method: 'POST',
headers: {
'Content-Type': 'application/sdp',
},
body: offer,
})
.then((res) => {
switch (res.status) {
case 201:
break;
case 400:
return res.json().then((e) => { throw new Error(e.error); });
default:
throw new Error(`bad status code ${res.status}`);
}
this.sessionUrl = new URL(res.headers.get('location'), this.conf.url).toString();
return res.text();
});
};
setAnswer = (answer) => {
if (this.state !== 'running') {
return;
}
answer = editAnswer(answer, this.conf.videoBitrate);
return this.pc.setRemoteDescription(new RTCSessionDescription({
type: 'answer',
sdp: answer,
}))
.then(() => {
if (this.queuedCandidates.length !== 0) {
this.sendLocalCandidates(this.queuedCandidates);
this.queuedCandidates = [];
}
});
};
onLocalCandidate = (evt) => {
if (this.state !== 'running') {
return;
}
if (evt.candidate !== null) {
if (this.sessionUrl === null) {
this.queuedCandidates.push(evt.candidate);
} else {
this.sendLocalCandidates([evt.candidate]);
}
}
};
sendLocalCandidates = (candidates) => {
fetch(this.sessionUrl, {
method: 'PATCH',
headers: {
'Content-Type': 'application/trickle-ice-sdpfrag',
'If-Match': '*',
},
body: generateSdpFragment(this.offerData, candidates),
})
.then((res) => {
switch (res.status) {
case 204:
break;
case 404:
throw new Error('stream not found');
default:
throw new Error(`bad status code ${res.status}`);
}
})
.catch((err) => {
this.handleError(err.toString());
});
};
onConnectionState = () => {
if (this.state !== 'running') {
return;
}
// "closed" can arrive before "failed" and without
// the close() method being called at all.
// It happens when the other peer sends a termination
// message like a DTLS CloseNotify.
if (this.pc.connectionState === 'failed'
|| this.pc.connectionState === 'closed'
) {
this.handleError('peer connection closed');
} else if (this.pc.connectionState === 'connected') {
if (this.conf.onConnected !== undefined) {
this.conf.onConnected();
}
}
};
}
window.MediaMTXWebRTCPublisher = MediaMTXWebRTCPublisher;
})();