803 lines
25 KiB
JavaScript
803 lines
25 KiB
JavaScript
/* eslint-env node */
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'use strict';
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// SDP helpers.
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const SDPUtils = {};
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// Generate an alphanumeric identifier for cname or mids.
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// TODO: use UUIDs instead? https://gist.github.com/jed/982883
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SDPUtils.generateIdentifier = function() {
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return Math.random().toString(36).substring(2, 12);
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};
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// The RTCP CNAME used by all peerconnections from the same JS.
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SDPUtils.localCName = SDPUtils.generateIdentifier();
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// Splits SDP into lines, dealing with both CRLF and LF.
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SDPUtils.splitLines = function(blob) {
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return blob.trim().split('\n').map(line => line.trim());
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};
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// Splits SDP into sessionpart and mediasections. Ensures CRLF.
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SDPUtils.splitSections = function(blob) {
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const parts = blob.split('\nm=');
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return parts.map((part, index) => (index > 0 ?
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'm=' + part : part).trim() + '\r\n');
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};
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// Returns the session description.
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SDPUtils.getDescription = function(blob) {
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const sections = SDPUtils.splitSections(blob);
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return sections && sections[0];
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};
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// Returns the individual media sections.
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SDPUtils.getMediaSections = function(blob) {
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const sections = SDPUtils.splitSections(blob);
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sections.shift();
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return sections;
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};
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// Returns lines that start with a certain prefix.
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SDPUtils.matchPrefix = function(blob, prefix) {
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return SDPUtils.splitLines(blob).filter(line => line.indexOf(prefix) === 0);
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};
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// Parses an ICE candidate line. Sample input:
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// candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
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// rport 55996"
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// Input can be prefixed with a=.
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SDPUtils.parseCandidate = function(line) {
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let parts;
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// Parse both variants.
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if (line.indexOf('a=candidate:') === 0) {
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parts = line.substring(12).split(' ');
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} else {
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parts = line.substring(10).split(' ');
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}
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const candidate = {
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foundation: parts[0],
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component: {1: 'rtp', 2: 'rtcp'}[parts[1]] || parts[1],
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protocol: parts[2].toLowerCase(),
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priority: parseInt(parts[3], 10),
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ip: parts[4],
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address: parts[4], // address is an alias for ip.
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port: parseInt(parts[5], 10),
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// skip parts[6] == 'typ'
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type: parts[7],
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};
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for (let i = 8; i < parts.length; i += 2) {
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switch (parts[i]) {
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case 'raddr':
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candidate.relatedAddress = parts[i + 1];
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break;
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case 'rport':
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candidate.relatedPort = parseInt(parts[i + 1], 10);
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break;
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case 'tcptype':
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candidate.tcpType = parts[i + 1];
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break;
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case 'ufrag':
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candidate.ufrag = parts[i + 1]; // for backward compatibility.
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candidate.usernameFragment = parts[i + 1];
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break;
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default: // extension handling, in particular ufrag. Don't overwrite.
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if (candidate[parts[i]] === undefined) {
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candidate[parts[i]] = parts[i + 1];
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}
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break;
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}
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}
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return candidate;
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};
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// Translates a candidate object into SDP candidate attribute.
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// This does not include the a= prefix!
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SDPUtils.writeCandidate = function(candidate) {
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const sdp = [];
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sdp.push(candidate.foundation);
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const component = candidate.component;
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if (component === 'rtp') {
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sdp.push(1);
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} else if (component === 'rtcp') {
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sdp.push(2);
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} else {
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sdp.push(component);
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}
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sdp.push(candidate.protocol.toUpperCase());
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sdp.push(candidate.priority);
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sdp.push(candidate.address || candidate.ip);
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sdp.push(candidate.port);
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const type = candidate.type;
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sdp.push('typ');
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sdp.push(type);
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if (type !== 'host' && candidate.relatedAddress &&
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candidate.relatedPort) {
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sdp.push('raddr');
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sdp.push(candidate.relatedAddress);
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sdp.push('rport');
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sdp.push(candidate.relatedPort);
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}
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if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
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sdp.push('tcptype');
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sdp.push(candidate.tcpType);
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}
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if (candidate.usernameFragment || candidate.ufrag) {
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sdp.push('ufrag');
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sdp.push(candidate.usernameFragment || candidate.ufrag);
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}
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return 'candidate:' + sdp.join(' ');
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};
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// Parses an ice-options line, returns an array of option tags.
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// Sample input:
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// a=ice-options:foo bar
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SDPUtils.parseIceOptions = function(line) {
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return line.substring(14).split(' ');
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};
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// Parses a rtpmap line, returns RTCRtpCoddecParameters. Sample input:
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// a=rtpmap:111 opus/48000/2
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SDPUtils.parseRtpMap = function(line) {
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let parts = line.substring(9).split(' ');
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const parsed = {
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payloadType: parseInt(parts.shift(), 10), // was: id
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};
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parts = parts[0].split('/');
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parsed.name = parts[0];
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parsed.clockRate = parseInt(parts[1], 10); // was: clockrate
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parsed.channels = parts.length === 3 ? parseInt(parts[2], 10) : 1;
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// legacy alias, got renamed back to channels in ORTC.
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parsed.numChannels = parsed.channels;
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return parsed;
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};
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// Generates a rtpmap line from RTCRtpCodecCapability or
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// RTCRtpCodecParameters.
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SDPUtils.writeRtpMap = function(codec) {
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let pt = codec.payloadType;
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if (codec.preferredPayloadType !== undefined) {
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pt = codec.preferredPayloadType;
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}
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const channels = codec.channels || codec.numChannels || 1;
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return 'a=rtpmap:' + pt + ' ' + codec.name + '/' + codec.clockRate +
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(channels !== 1 ? '/' + channels : '') + '\r\n';
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};
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// Parses a extmap line (headerextension from RFC 5285). Sample input:
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// a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
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// a=extmap:2/sendonly urn:ietf:params:rtp-hdrext:toffset
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SDPUtils.parseExtmap = function(line) {
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const parts = line.substring(9).split(' ');
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return {
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id: parseInt(parts[0], 10),
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direction: parts[0].indexOf('/') > 0 ? parts[0].split('/')[1] : 'sendrecv',
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uri: parts[1],
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attributes: parts.slice(2).join(' '),
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};
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};
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// Generates an extmap line from RTCRtpHeaderExtensionParameters or
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// RTCRtpHeaderExtension.
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SDPUtils.writeExtmap = function(headerExtension) {
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return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
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(headerExtension.direction && headerExtension.direction !== 'sendrecv'
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? '/' + headerExtension.direction
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: '') +
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' ' + headerExtension.uri +
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(headerExtension.attributes ? ' ' + headerExtension.attributes : '') +
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'\r\n';
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};
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// Parses a fmtp line, returns dictionary. Sample input:
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// a=fmtp:96 vbr=on;cng=on
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// Also deals with vbr=on; cng=on
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SDPUtils.parseFmtp = function(line) {
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const parsed = {};
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let kv;
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const parts = line.substring(line.indexOf(' ') + 1).split(';');
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for (let j = 0; j < parts.length; j++) {
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kv = parts[j].trim().split('=');
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parsed[kv[0].trim()] = kv[1];
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}
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return parsed;
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};
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// Generates a fmtp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
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SDPUtils.writeFmtp = function(codec) {
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let line = '';
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let pt = codec.payloadType;
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if (codec.preferredPayloadType !== undefined) {
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pt = codec.preferredPayloadType;
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}
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if (codec.parameters && Object.keys(codec.parameters).length) {
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const params = [];
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Object.keys(codec.parameters).forEach(param => {
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if (codec.parameters[param] !== undefined) {
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params.push(param + '=' + codec.parameters[param]);
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} else {
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params.push(param);
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}
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});
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line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n';
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}
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return line;
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};
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// Parses a rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
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// a=rtcp-fb:98 nack rpsi
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SDPUtils.parseRtcpFb = function(line) {
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const parts = line.substring(line.indexOf(' ') + 1).split(' ');
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return {
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type: parts.shift(),
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parameter: parts.join(' '),
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};
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};
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// Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
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SDPUtils.writeRtcpFb = function(codec) {
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let lines = '';
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let pt = codec.payloadType;
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if (codec.preferredPayloadType !== undefined) {
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pt = codec.preferredPayloadType;
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}
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if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
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// FIXME: special handling for trr-int?
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codec.rtcpFeedback.forEach(fb => {
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lines += 'a=rtcp-fb:' + pt + ' ' + fb.type +
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(fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
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'\r\n';
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});
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}
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return lines;
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};
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// Parses a RFC 5576 ssrc media attribute. Sample input:
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// a=ssrc:3735928559 cname:something
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SDPUtils.parseSsrcMedia = function(line) {
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const sp = line.indexOf(' ');
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const parts = {
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ssrc: parseInt(line.substring(7, sp), 10),
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};
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const colon = line.indexOf(':', sp);
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if (colon > -1) {
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parts.attribute = line.substring(sp + 1, colon);
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parts.value = line.substring(colon + 1);
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} else {
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parts.attribute = line.substring(sp + 1);
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}
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return parts;
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};
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// Parse a ssrc-group line (see RFC 5576). Sample input:
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// a=ssrc-group:semantics 12 34
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SDPUtils.parseSsrcGroup = function(line) {
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const parts = line.substring(13).split(' ');
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return {
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semantics: parts.shift(),
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ssrcs: parts.map(ssrc => parseInt(ssrc, 10)),
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};
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};
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// Extracts the MID (RFC 5888) from a media section.
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// Returns the MID or undefined if no mid line was found.
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SDPUtils.getMid = function(mediaSection) {
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const mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:')[0];
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if (mid) {
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return mid.substring(6);
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}
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};
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// Parses a fingerprint line for DTLS-SRTP.
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SDPUtils.parseFingerprint = function(line) {
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const parts = line.substring(14).split(' ');
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return {
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algorithm: parts[0].toLowerCase(), // algorithm is case-sensitive in Edge.
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value: parts[1].toUpperCase(), // the definition is upper-case in RFC 4572.
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};
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};
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// Extracts DTLS parameters from SDP media section or sessionpart.
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// FIXME: for consistency with other functions this should only
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// get the fingerprint line as input. See also getIceParameters.
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SDPUtils.getDtlsParameters = function(mediaSection, sessionpart) {
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const lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
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'a=fingerprint:');
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// Note: a=setup line is ignored since we use the 'auto' role in Edge.
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return {
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role: 'auto',
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fingerprints: lines.map(SDPUtils.parseFingerprint),
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};
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};
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// Serializes DTLS parameters to SDP.
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SDPUtils.writeDtlsParameters = function(params, setupType) {
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let sdp = 'a=setup:' + setupType + '\r\n';
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params.fingerprints.forEach(fp => {
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sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n';
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});
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return sdp;
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};
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// Parses a=crypto lines into
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// https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#dictionary-rtcsrtpsdesparameters-members
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SDPUtils.parseCryptoLine = function(line) {
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const parts = line.substring(9).split(' ');
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return {
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tag: parseInt(parts[0], 10),
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cryptoSuite: parts[1],
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keyParams: parts[2],
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sessionParams: parts.slice(3),
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};
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};
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SDPUtils.writeCryptoLine = function(parameters) {
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return 'a=crypto:' + parameters.tag + ' ' +
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parameters.cryptoSuite + ' ' +
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(typeof parameters.keyParams === 'object'
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? SDPUtils.writeCryptoKeyParams(parameters.keyParams)
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: parameters.keyParams) +
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(parameters.sessionParams ? ' ' + parameters.sessionParams.join(' ') : '') +
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'\r\n';
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};
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// Parses the crypto key parameters into
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// https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#rtcsrtpkeyparam*
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SDPUtils.parseCryptoKeyParams = function(keyParams) {
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if (keyParams.indexOf('inline:') !== 0) {
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return null;
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}
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const parts = keyParams.substring(7).split('|');
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return {
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keyMethod: 'inline',
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keySalt: parts[0],
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lifeTime: parts[1],
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mkiValue: parts[2] ? parts[2].split(':')[0] : undefined,
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mkiLength: parts[2] ? parts[2].split(':')[1] : undefined,
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};
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};
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SDPUtils.writeCryptoKeyParams = function(keyParams) {
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return keyParams.keyMethod + ':'
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+ keyParams.keySalt +
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(keyParams.lifeTime ? '|' + keyParams.lifeTime : '') +
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(keyParams.mkiValue && keyParams.mkiLength
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? '|' + keyParams.mkiValue + ':' + keyParams.mkiLength
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: '');
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};
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// Extracts all SDES parameters.
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SDPUtils.getCryptoParameters = function(mediaSection, sessionpart) {
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const lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
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'a=crypto:');
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return lines.map(SDPUtils.parseCryptoLine);
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};
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// Parses ICE information from SDP media section or sessionpart.
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// FIXME: for consistency with other functions this should only
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// get the ice-ufrag and ice-pwd lines as input.
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SDPUtils.getIceParameters = function(mediaSection, sessionpart) {
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const ufrag = SDPUtils.matchPrefix(mediaSection + sessionpart,
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'a=ice-ufrag:')[0];
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const pwd = SDPUtils.matchPrefix(mediaSection + sessionpart,
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'a=ice-pwd:')[0];
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if (!(ufrag && pwd)) {
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return null;
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}
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return {
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usernameFragment: ufrag.substring(12),
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password: pwd.substring(10),
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};
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};
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// Serializes ICE parameters to SDP.
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SDPUtils.writeIceParameters = function(params) {
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let sdp = 'a=ice-ufrag:' + params.usernameFragment + '\r\n' +
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'a=ice-pwd:' + params.password + '\r\n';
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if (params.iceLite) {
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sdp += 'a=ice-lite\r\n';
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}
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return sdp;
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};
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// Parses the SDP media section and returns RTCRtpParameters.
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SDPUtils.parseRtpParameters = function(mediaSection) {
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const description = {
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codecs: [],
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headerExtensions: [],
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fecMechanisms: [],
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rtcp: [],
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};
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const lines = SDPUtils.splitLines(mediaSection);
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const mline = lines[0].split(' ');
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description.profile = mline[2];
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for (let i = 3; i < mline.length; i++) { // find all codecs from mline[3..]
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const pt = mline[i];
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const rtpmapline = SDPUtils.matchPrefix(
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mediaSection, 'a=rtpmap:' + pt + ' ')[0];
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if (rtpmapline) {
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const codec = SDPUtils.parseRtpMap(rtpmapline);
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const fmtps = SDPUtils.matchPrefix(
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mediaSection, 'a=fmtp:' + pt + ' ');
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// Only the first a=fmtp:<pt> is considered.
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codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {};
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codec.rtcpFeedback = SDPUtils.matchPrefix(
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mediaSection, 'a=rtcp-fb:' + pt + ' ')
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.map(SDPUtils.parseRtcpFb);
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description.codecs.push(codec);
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// parse FEC mechanisms from rtpmap lines.
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switch (codec.name.toUpperCase()) {
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case 'RED':
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case 'ULPFEC':
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description.fecMechanisms.push(codec.name.toUpperCase());
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break;
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default: // only RED and ULPFEC are recognized as FEC mechanisms.
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break;
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}
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}
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}
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SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(line => {
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description.headerExtensions.push(SDPUtils.parseExtmap(line));
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});
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const wildcardRtcpFb = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-fb:* ')
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.map(SDPUtils.parseRtcpFb);
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description.codecs.forEach(codec => {
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wildcardRtcpFb.forEach(fb=> {
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const duplicate = codec.rtcpFeedback.find(existingFeedback => {
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return existingFeedback.type === fb.type &&
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existingFeedback.parameter === fb.parameter;
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});
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if (!duplicate) {
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codec.rtcpFeedback.push(fb);
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}
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});
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});
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// FIXME: parse rtcp.
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return description;
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};
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// Generates parts of the SDP media section describing the capabilities /
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// parameters.
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SDPUtils.writeRtpDescription = function(kind, caps) {
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let sdp = '';
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// Build the mline.
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sdp += 'm=' + kind + ' ';
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sdp += caps.codecs.length > 0 ? '9' : '0'; // reject if no codecs.
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sdp += ' ' + (caps.profile || 'UDP/TLS/RTP/SAVPF') + ' ';
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sdp += caps.codecs.map(codec => {
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if (codec.preferredPayloadType !== undefined) {
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return codec.preferredPayloadType;
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}
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return codec.payloadType;
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}).join(' ') + '\r\n';
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||
|
||
sdp += 'c=IN IP4 0.0.0.0\r\n';
|
||
sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n';
|
||
|
||
// Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
|
||
caps.codecs.forEach(codec => {
|
||
sdp += SDPUtils.writeRtpMap(codec);
|
||
sdp += SDPUtils.writeFmtp(codec);
|
||
sdp += SDPUtils.writeRtcpFb(codec);
|
||
});
|
||
let maxptime = 0;
|
||
caps.codecs.forEach(codec => {
|
||
if (codec.maxptime > maxptime) {
|
||
maxptime = codec.maxptime;
|
||
}
|
||
});
|
||
if (maxptime > 0) {
|
||
sdp += 'a=maxptime:' + maxptime + '\r\n';
|
||
}
|
||
|
||
if (caps.headerExtensions) {
|
||
caps.headerExtensions.forEach(extension => {
|
||
sdp += SDPUtils.writeExtmap(extension);
|
||
});
|
||
}
|
||
// FIXME: write fecMechanisms.
|
||
return sdp;
|
||
};
|
||
|
||
// Parses the SDP media section and returns an array of
|
||
// RTCRtpEncodingParameters.
|
||
SDPUtils.parseRtpEncodingParameters = function(mediaSection) {
|
||
const encodingParameters = [];
|
||
const description = SDPUtils.parseRtpParameters(mediaSection);
|
||
const hasRed = description.fecMechanisms.indexOf('RED') !== -1;
|
||
const hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1;
|
||
|
||
// filter a=ssrc:... cname:, ignore PlanB-msid
|
||
const ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
|
||
.map(line => SDPUtils.parseSsrcMedia(line))
|
||
.filter(parts => parts.attribute === 'cname');
|
||
const primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc;
|
||
let secondarySsrc;
|
||
|
||
const flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID')
|
||
.map(line => {
|
||
const parts = line.substring(17).split(' ');
|
||
return parts.map(part => parseInt(part, 10));
|
||
});
|
||
if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
|
||
secondarySsrc = flows[0][1];
|
||
}
|
||
|
||
description.codecs.forEach(codec => {
|
||
if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
|
||
let encParam = {
|
||
ssrc: primarySsrc,
|
||
codecPayloadType: parseInt(codec.parameters.apt, 10),
|
||
};
|
||
if (primarySsrc && secondarySsrc) {
|
||
encParam.rtx = {ssrc: secondarySsrc};
|
||
}
|
||
encodingParameters.push(encParam);
|
||
if (hasRed) {
|
||
encParam = JSON.parse(JSON.stringify(encParam));
|
||
encParam.fec = {
|
||
ssrc: primarySsrc,
|
||
mechanism: hasUlpfec ? 'red+ulpfec' : 'red',
|
||
};
|
||
encodingParameters.push(encParam);
|
||
}
|
||
}
|
||
});
|
||
if (encodingParameters.length === 0 && primarySsrc) {
|
||
encodingParameters.push({
|
||
ssrc: primarySsrc,
|
||
});
|
||
}
|
||
|
||
// we support both b=AS and b=TIAS but interpret AS as TIAS.
|
||
let bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=');
|
||
if (bandwidth.length) {
|
||
if (bandwidth[0].indexOf('b=TIAS:') === 0) {
|
||
bandwidth = parseInt(bandwidth[0].substring(7), 10);
|
||
} else if (bandwidth[0].indexOf('b=AS:') === 0) {
|
||
// use formula from JSEP to convert b=AS to TIAS value.
|
||
bandwidth = parseInt(bandwidth[0].substring(5), 10) * 1000 * 0.95
|
||
- (50 * 40 * 8);
|
||
} else {
|
||
bandwidth = undefined;
|
||
}
|
||
encodingParameters.forEach(params => {
|
||
params.maxBitrate = bandwidth;
|
||
});
|
||
}
|
||
return encodingParameters;
|
||
};
|
||
|
||
// parses http://draft.ortc.org/#rtcrtcpparameters*
|
||
SDPUtils.parseRtcpParameters = function(mediaSection) {
|
||
const rtcpParameters = {};
|
||
|
||
// Gets the first SSRC. Note that with RTX there might be multiple
|
||
// SSRCs.
|
||
const remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
|
||
.map(line => SDPUtils.parseSsrcMedia(line))
|
||
.filter(obj => obj.attribute === 'cname')[0];
|
||
if (remoteSsrc) {
|
||
rtcpParameters.cname = remoteSsrc.value;
|
||
rtcpParameters.ssrc = remoteSsrc.ssrc;
|
||
}
|
||
|
||
// Edge uses the compound attribute instead of reducedSize
|
||
// compound is !reducedSize
|
||
const rsize = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-rsize');
|
||
rtcpParameters.reducedSize = rsize.length > 0;
|
||
rtcpParameters.compound = rsize.length === 0;
|
||
|
||
// parses the rtcp-mux attrіbute.
|
||
// Note that Edge does not support unmuxed RTCP.
|
||
const mux = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-mux');
|
||
rtcpParameters.mux = mux.length > 0;
|
||
|
||
return rtcpParameters;
|
||
};
|
||
|
||
SDPUtils.writeRtcpParameters = function(rtcpParameters) {
|
||
let sdp = '';
|
||
if (rtcpParameters.reducedSize) {
|
||
sdp += 'a=rtcp-rsize\r\n';
|
||
}
|
||
if (rtcpParameters.mux) {
|
||
sdp += 'a=rtcp-mux\r\n';
|
||
}
|
||
if (rtcpParameters.ssrc !== undefined && rtcpParameters.cname) {
|
||
sdp += 'a=ssrc:' + rtcpParameters.ssrc +
|
||
' cname:' + rtcpParameters.cname + '\r\n';
|
||
}
|
||
return sdp;
|
||
};
|
||
|
||
|
||
// parses either a=msid: or a=ssrc:... msid lines and returns
|
||
// the id of the MediaStream and MediaStreamTrack.
|
||
SDPUtils.parseMsid = function(mediaSection) {
|
||
let parts;
|
||
const spec = SDPUtils.matchPrefix(mediaSection, 'a=msid:');
|
||
if (spec.length === 1) {
|
||
parts = spec[0].substring(7).split(' ');
|
||
return {stream: parts[0], track: parts[1]};
|
||
}
|
||
const planB = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
|
||
.map(line => SDPUtils.parseSsrcMedia(line))
|
||
.filter(msidParts => msidParts.attribute === 'msid');
|
||
if (planB.length > 0) {
|
||
parts = planB[0].value.split(' ');
|
||
return {stream: parts[0], track: parts[1]};
|
||
}
|
||
};
|
||
|
||
// SCTP
|
||
// parses draft-ietf-mmusic-sctp-sdp-26 first and falls back
|
||
// to draft-ietf-mmusic-sctp-sdp-05
|
||
SDPUtils.parseSctpDescription = function(mediaSection) {
|
||
const mline = SDPUtils.parseMLine(mediaSection);
|
||
const maxSizeLine = SDPUtils.matchPrefix(mediaSection, 'a=max-message-size:');
|
||
let maxMessageSize;
|
||
if (maxSizeLine.length > 0) {
|
||
maxMessageSize = parseInt(maxSizeLine[0].substring(19), 10);
|
||
}
|
||
if (isNaN(maxMessageSize)) {
|
||
maxMessageSize = 65536;
|
||
}
|
||
const sctpPort = SDPUtils.matchPrefix(mediaSection, 'a=sctp-port:');
|
||
if (sctpPort.length > 0) {
|
||
return {
|
||
port: parseInt(sctpPort[0].substring(12), 10),
|
||
protocol: mline.fmt,
|
||
maxMessageSize,
|
||
};
|
||
}
|
||
const sctpMapLines = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:');
|
||
if (sctpMapLines.length > 0) {
|
||
const parts = sctpMapLines[0]
|
||
.substring(10)
|
||
.split(' ');
|
||
return {
|
||
port: parseInt(parts[0], 10),
|
||
protocol: parts[1],
|
||
maxMessageSize,
|
||
};
|
||
}
|
||
};
|
||
|
||
// SCTP
|
||
// outputs the draft-ietf-mmusic-sctp-sdp-26 version that all browsers
|
||
// support by now receiving in this format, unless we originally parsed
|
||
// as the draft-ietf-mmusic-sctp-sdp-05 format (indicated by the m-line
|
||
// protocol of DTLS/SCTP -- without UDP/ or TCP/)
|
||
SDPUtils.writeSctpDescription = function(media, sctp) {
|
||
let output = [];
|
||
if (media.protocol !== 'DTLS/SCTP') {
|
||
output = [
|
||
'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.protocol + '\r\n',
|
||
'c=IN IP4 0.0.0.0\r\n',
|
||
'a=sctp-port:' + sctp.port + '\r\n',
|
||
];
|
||
} else {
|
||
output = [
|
||
'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.port + '\r\n',
|
||
'c=IN IP4 0.0.0.0\r\n',
|
||
'a=sctpmap:' + sctp.port + ' ' + sctp.protocol + ' 65535\r\n',
|
||
];
|
||
}
|
||
if (sctp.maxMessageSize !== undefined) {
|
||
output.push('a=max-message-size:' + sctp.maxMessageSize + '\r\n');
|
||
}
|
||
return output.join('');
|
||
};
|
||
|
||
// Generate a session ID for SDP.
|
||
// https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-20#section-5.2.1
|
||
// recommends using a cryptographically random +ve 64-bit value
|
||
// but right now this should be acceptable and within the right range
|
||
SDPUtils.generateSessionId = function() {
|
||
return Math.random().toString().substr(2, 22);
|
||
};
|
||
|
||
// Write boiler plate for start of SDP
|
||
// sessId argument is optional - if not supplied it will
|
||
// be generated randomly
|
||
// sessVersion is optional and defaults to 2
|
||
// sessUser is optional and defaults to 'thisisadapterortc'
|
||
SDPUtils.writeSessionBoilerplate = function(sessId, sessVer, sessUser) {
|
||
let sessionId;
|
||
const version = sessVer !== undefined ? sessVer : 2;
|
||
if (sessId) {
|
||
sessionId = sessId;
|
||
} else {
|
||
sessionId = SDPUtils.generateSessionId();
|
||
}
|
||
const user = sessUser || 'thisisadapterortc';
|
||
// FIXME: sess-id should be an NTP timestamp.
|
||
return 'v=0\r\n' +
|
||
'o=' + user + ' ' + sessionId + ' ' + version +
|
||
' IN IP4 127.0.0.1\r\n' +
|
||
's=-\r\n' +
|
||
't=0 0\r\n';
|
||
};
|
||
|
||
// Gets the direction from the mediaSection or the sessionpart.
|
||
SDPUtils.getDirection = function(mediaSection, sessionpart) {
|
||
// Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
|
||
const lines = SDPUtils.splitLines(mediaSection);
|
||
for (let i = 0; i < lines.length; i++) {
|
||
switch (lines[i]) {
|
||
case 'a=sendrecv':
|
||
case 'a=sendonly':
|
||
case 'a=recvonly':
|
||
case 'a=inactive':
|
||
return lines[i].substring(2);
|
||
default:
|
||
// FIXME: What should happen here?
|
||
}
|
||
}
|
||
if (sessionpart) {
|
||
return SDPUtils.getDirection(sessionpart);
|
||
}
|
||
return 'sendrecv';
|
||
};
|
||
|
||
SDPUtils.getKind = function(mediaSection) {
|
||
const lines = SDPUtils.splitLines(mediaSection);
|
||
const mline = lines[0].split(' ');
|
||
return mline[0].substring(2);
|
||
};
|
||
|
||
SDPUtils.isRejected = function(mediaSection) {
|
||
return mediaSection.split(' ', 2)[1] === '0';
|
||
};
|
||
|
||
SDPUtils.parseMLine = function(mediaSection) {
|
||
const lines = SDPUtils.splitLines(mediaSection);
|
||
const parts = lines[0].substring(2).split(' ');
|
||
return {
|
||
kind: parts[0],
|
||
port: parseInt(parts[1], 10),
|
||
protocol: parts[2],
|
||
fmt: parts.slice(3).join(' '),
|
||
};
|
||
};
|
||
|
||
SDPUtils.parseOLine = function(mediaSection) {
|
||
const line = SDPUtils.matchPrefix(mediaSection, 'o=')[0];
|
||
const parts = line.substring(2).split(' ');
|
||
return {
|
||
username: parts[0],
|
||
sessionId: parts[1],
|
||
sessionVersion: parseInt(parts[2], 10),
|
||
netType: parts[3],
|
||
addressType: parts[4],
|
||
address: parts[5],
|
||
};
|
||
};
|
||
|
||
// a very naive interpretation of a valid SDP.
|
||
SDPUtils.isValidSDP = function(blob) {
|
||
if (typeof blob !== 'string' || blob.length === 0) {
|
||
return false;
|
||
}
|
||
const lines = SDPUtils.splitLines(blob);
|
||
for (let i = 0; i < lines.length; i++) {
|
||
if (lines[i].length < 2 || lines[i].charAt(1) !== '=') {
|
||
return false;
|
||
}
|
||
// TODO: check the modifier a bit more.
|
||
}
|
||
return true;
|
||
};
|
||
|
||
// Expose public methods.
|
||
if (typeof module === 'object') {
|
||
module.exports = SDPUtils;
|
||
}
|