/
m3u8-parser.js
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/
m3u8-parser.js
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import * as URLToolkit from 'url-toolkit';
import Fragment from './fragment';
import Level from './level';
import LevelKey from './level-key';
import AttrList from '../utils/attr-list';
import { logger } from '../utils/logger';
import { isCodecType } from '../utils/codecs';
/**
* M3U8 parser
* @module
*/
// https://regex101.com is your friend
const MASTER_PLAYLIST_REGEX = /#EXT-X-STREAM-INF:([^\n\r]*)[\r\n]+([^\r\n]+)/g;
const MASTER_PLAYLIST_MEDIA_REGEX = /#EXT-X-MEDIA:(.*)/g;
const LEVEL_PLAYLIST_REGEX_FAST = new RegExp([
/#EXTINF:\s*(\d*(?:\.\d+)?)(?:,(.*)\s+)?/.source, // duration (#EXTINF:<duration>,<title>), group 1 => duration, group 2 => title
/|(?!#)([\S+ ?]+)/.source, // segment URI, group 3 => the URI (note newline is not eaten)
/|#EXT-X-BYTERANGE:*(.+)/.source, // next segment's byterange, group 4 => range spec (x@y)
/|#EXT-X-PROGRAM-DATE-TIME:(.+)/.source, // next segment's program date/time group 5 => the datetime spec
/|#.*/.source // All other non-segment oriented tags will match with all groups empty
].join(''), 'g');
const LEVEL_PLAYLIST_REGEX_SLOW = /(?:(?:#(EXTM3U))|(?:#EXT-X-(PLAYLIST-TYPE):(.+))|(?:#EXT-X-(MEDIA-SEQUENCE): *(\d+))|(?:#EXT-X-(TARGETDURATION): *(\d+))|(?:#EXT-X-(KEY):(.+))|(?:#EXT-X-(START):(.+))|(?:#EXT-X-(ENDLIST))|(?:#EXT-X-(DISCONTINUITY-SEQ)UENCE:(\d+))|(?:#EXT-X-(DIS)CONTINUITY))|(?:#EXT-X-(VERSION):(\d+))|(?:#EXT-X-(MAP):(.+))|(?:(#)([^:]*):(.*))|(?:(#)(.*))(?:.*)\r?\n?/;
const MP4_REGEX_SUFFIX = /\.(mp4|m4s|m4v|m4a)$/i;
export default class M3U8Parser {
static findGroup (groups, mediaGroupId) {
if (!groups) {
return null;
}
let matchingGroup = null;
for (let i = 0; i < groups.length; i++) {
const group = groups[i];
if (group.id === mediaGroupId) {
matchingGroup = group;
}
}
return matchingGroup;
}
static convertAVC1ToAVCOTI (codec) {
let avcdata = codec.split('.');
let result;
if (avcdata.length > 2) {
result = avcdata.shift() + '.';
result += parseInt(avcdata.shift()).toString(16);
result += ('000' + parseInt(avcdata.shift()).toString(16)).substr(-4);
} else {
result = codec;
}
return result;
}
static resolve (url, baseUrl) {
return URLToolkit.buildAbsoluteURL(baseUrl, url, { alwaysNormalize: true });
}
static parseMasterPlaylist (string, baseurl) {
let levels = [];
MASTER_PLAYLIST_REGEX.lastIndex = 0;
function setCodecs (codecs, level) {
['video', 'audio'].forEach((type) => {
const filtered = codecs.filter((codec) => isCodecType(codec, type));
if (filtered.length) {
const preferred = filtered.filter((codec) => {
return codec.lastIndexOf('avc1', 0) === 0 || codec.lastIndexOf('mp4a', 0) === 0;
});
level[`${type}Codec`] = preferred.length > 0 ? preferred[0] : filtered[0];
// remove from list
codecs = codecs.filter((codec) => filtered.indexOf(codec) === -1);
}
});
level.unknownCodecs = codecs;
}
let result;
while ((result = MASTER_PLAYLIST_REGEX.exec(string)) != null) {
const level = {};
const attrs = level.attrs = new AttrList(result[1]);
level.url = M3U8Parser.resolve(result[2], baseurl);
const resolution = attrs.decimalResolution('RESOLUTION');
if (resolution) {
level.width = resolution.width;
level.height = resolution.height;
}
level.bitrate = attrs.decimalInteger('AVERAGE-BANDWIDTH') || attrs.decimalInteger('BANDWIDTH');
level.name = attrs.NAME;
setCodecs([].concat((attrs.CODECS || '').split(/[ ,]+/)), level);
if (level.videoCodec && level.videoCodec.indexOf('avc1') !== -1) {
level.videoCodec = M3U8Parser.convertAVC1ToAVCOTI(level.videoCodec);
}
levels.push(level);
}
return levels;
}
static parseMasterPlaylistMedia (string, baseurl, type, audioGroups = []) {
let result;
let medias = [];
let id = 0;
MASTER_PLAYLIST_MEDIA_REGEX.lastIndex = 0;
while ((result = MASTER_PLAYLIST_MEDIA_REGEX.exec(string)) !== null) {
const media = {};
const attrs = new AttrList(result[1]);
if (attrs.TYPE === type) {
media.groupId = attrs['GROUP-ID'];
media.name = attrs.NAME;
media.type = type;
media.default = (attrs.DEFAULT === 'YES');
media.autoselect = (attrs.AUTOSELECT === 'YES');
media.forced = (attrs.FORCED === 'YES');
if (attrs.URI) {
media.url = M3U8Parser.resolve(attrs.URI, baseurl);
}
media.lang = attrs.LANGUAGE;
if (!media.name) {
media.name = media.lang;
}
if (audioGroups.length) {
const groupCodec = M3U8Parser.findGroup(audioGroups, media.groupId);
media.audioCodec = groupCodec ? groupCodec.codec : audioGroups[0].codec;
}
media.id = id++;
medias.push(media);
}
}
return medias;
}
static parseLevelPlaylist (string, baseurl, id, type, levelUrlId) {
let currentSN = 0;
let totalduration = 0;
let level = new Level(baseurl);
let levelkey = new LevelKey();
let cc = 0;
let prevFrag = null;
let frag = new Fragment();
let result;
let i;
let firstPdtIndex = null;
LEVEL_PLAYLIST_REGEX_FAST.lastIndex = 0;
while ((result = LEVEL_PLAYLIST_REGEX_FAST.exec(string)) !== null) {
const duration = result[1];
if (duration) { // INF
frag.duration = parseFloat(duration);
// avoid sliced strings https://github.com/video-dev/hls.js/issues/939
const title = (' ' + result[2]).slice(1);
frag.title = title || null;
frag.tagList.push(title ? [ 'INF', duration, title ] : [ 'INF', duration ]);
} else if (result[3]) { // url
if (Number.isFinite(frag.duration)) {
const sn = currentSN++;
frag.type = type;
frag.start = totalduration;
frag.levelkey = levelkey;
frag.sn = sn;
frag.level = id;
frag.cc = cc;
frag.urlId = levelUrlId;
frag.baseurl = baseurl;
// avoid sliced strings https://github.com/video-dev/hls.js/issues/939
frag.relurl = (' ' + result[3]).slice(1);
assignProgramDateTime(frag, prevFrag);
level.fragments.push(frag);
prevFrag = frag;
totalduration += frag.duration;
frag = new Fragment();
}
} else if (result[4]) { // X-BYTERANGE
frag.rawByteRange = (' ' + result[4]).slice(1);
if (prevFrag) {
const lastByteRangeEndOffset = prevFrag.byteRangeEndOffset;
if (lastByteRangeEndOffset) {
frag.lastByteRangeEndOffset = lastByteRangeEndOffset;
}
}
} else if (result[5]) { // PROGRAM-DATE-TIME
// avoid sliced strings https://github.com/video-dev/hls.js/issues/939
frag.rawProgramDateTime = (' ' + result[5]).slice(1);
frag.tagList.push(['PROGRAM-DATE-TIME', frag.rawProgramDateTime]);
if (firstPdtIndex === null) {
firstPdtIndex = level.fragments.length;
}
} else {
result = result[0].match(LEVEL_PLAYLIST_REGEX_SLOW);
for (i = 1; i < result.length; i++) {
if (typeof result[i] !== 'undefined') {
break;
}
}
// avoid sliced strings https://github.com/video-dev/hls.js/issues/939
const value1 = (' ' + result[i + 1]).slice(1);
const value2 = (' ' + result[i + 2]).slice(1);
switch (result[i]) {
case '#':
frag.tagList.push(value2 ? [ value1, value2 ] : [ value1 ]);
break;
case 'PLAYLIST-TYPE':
level.type = value1.toUpperCase();
break;
case 'MEDIA-SEQUENCE':
currentSN = level.startSN = parseInt(value1);
break;
case 'TARGETDURATION':
level.targetduration = parseFloat(value1);
break;
case 'VERSION':
level.version = parseInt(value1);
break;
case 'EXTM3U':
break;
case 'ENDLIST':
level.live = false;
break;
case 'DIS':
cc++;
frag.tagList.push(['DIS']);
break;
case 'DISCONTINUITY-SEQ':
cc = parseInt(value1);
break;
case 'KEY': {
// https://tools.ietf.org/html/draft-pantos-http-live-streaming-08#section-3.4.4
const decryptparams = value1;
const keyAttrs = new AttrList(decryptparams);
const decryptmethod = keyAttrs.enumeratedString('METHOD');
const decrypturi = keyAttrs.URI;
const decryptiv = keyAttrs.hexadecimalInteger('IV');
if (decryptmethod) {
levelkey = new LevelKey();
if ((decrypturi) && (['AES-128', 'SAMPLE-AES', 'SAMPLE-AES-CENC'].indexOf(decryptmethod) >= 0)) {
levelkey.method = decryptmethod;
// URI to get the key
levelkey.baseuri = baseurl;
levelkey.reluri = decrypturi;
levelkey.key = null;
// Initialization Vector (IV)
levelkey.iv = decryptiv;
}
}
break;
}
case 'START': {
const startAttrs = new AttrList(value1);
const startTimeOffset = startAttrs.decimalFloatingPoint('TIME-OFFSET');
// TIME-OFFSET can be 0
if (Number.isFinite(startTimeOffset)) {
level.startTimeOffset = startTimeOffset;
}
break;
}
case 'MAP': {
const mapAttrs = new AttrList(value1);
frag.relurl = mapAttrs.URI;
frag.rawByteRange = mapAttrs.BYTERANGE;
frag.baseurl = baseurl;
frag.level = id;
frag.type = type;
frag.sn = 'initSegment';
level.initSegment = frag;
frag = new Fragment();
frag.rawProgramDateTime = level.initSegment.rawProgramDateTime;
break;
}
default:
logger.warn(`line parsed but not handled: ${result}`);
break;
}
}
}
frag = prevFrag;
// logger.log('found ' + level.fragments.length + ' fragments');
if (frag && !frag.relurl) {
level.fragments.pop();
totalduration -= frag.duration;
}
level.totalduration = totalduration;
level.averagetargetduration = totalduration / level.fragments.length;
level.endSN = currentSN - 1;
level.startCC = level.fragments[0] ? level.fragments[0].cc : 0;
level.endCC = cc;
if (!level.initSegment && level.fragments.length) {
// this is a bit lurky but HLS really has no other way to tell us
// if the fragments are TS or MP4, except if we download them :/
// but this is to be able to handle SIDX.
if (level.fragments.every((frag) => MP4_REGEX_SUFFIX.test(frag.relurl))) {
logger.warn('MP4 fragments found but no init segment (probably no MAP, incomplete M3U8), trying to fetch SIDX');
frag = new Fragment();
frag.relurl = level.fragments[0].relurl;
frag.baseurl = baseurl;
frag.level = id;
frag.type = type;
frag.sn = 'initSegment';
level.initSegment = frag;
level.needSidxRanges = true;
}
}
/**
* Backfill any missing PDT values
"If the first EXT-X-PROGRAM-DATE-TIME tag in a Playlist appears after
one or more Media Segment URIs, the client SHOULD extrapolate
backward from that tag (using EXTINF durations and/or media
timestamps) to associate dates with those segments."
* We have already extrapolated forward, but all fragments up to the first instance of PDT do not have their PDTs
* computed.
*/
if (firstPdtIndex) {
backfillProgramDateTimes(level.fragments, firstPdtIndex);
}
return level;
}
}
function backfillProgramDateTimes (fragments, startIndex) {
let fragPrev = fragments[startIndex];
for (let i = startIndex - 1; i >= 0; i--) {
const frag = fragments[i];
frag.programDateTime = fragPrev.programDateTime - (frag.duration * 1000);
fragPrev = frag;
}
}
function assignProgramDateTime (frag, prevFrag) {
if (frag.rawProgramDateTime) {
frag.programDateTime = Date.parse(frag.rawProgramDateTime);
} else if (prevFrag && prevFrag.programDateTime) {
frag.programDateTime = prevFrag.endProgramDateTime;
}
if (!Number.isFinite(frag.programDateTime)) {
frag.programDateTime = null;
frag.rawProgramDateTime = null;
}
}