/**
* @file m3u8/parser.js
*/
import Stream from '../stream' ;
import LineStream from './line-stream';
import ParseStream from './parse-stream';
import {mergeOptions} from 'video.js';
/**
* A parser for M3U8 files. The current interpretation of the input is
* exposed as a property `manifest` on parser objects. It's just two lines to
* create and parse a manifest once you have the contents available as a string:
*
* ```js
* var parser = new videojs.m3u8.Parser();
* parser.push(xhr.responseText);
* ```
*
* New input can later be applied to update the manifest object by calling
* `push` again.
*
* The parser attempts to create a usable manifest object even if the
* underlying input is somewhat nonsensical. It emits `info` and `warning`
* events during the parse if it encounters input that seems invalid or
* requires some property of the manifest object to be defaulted.
*
* @class Parser
* @extends Stream
*/
export default class Parser extends Stream {
constructor() {
super();
this.lineStream = new LineStream();
this.parseStream = new ParseStream();
this.lineStream.pipe(this.parseStream);
/* eslint-disable consistent-this */
let self = this;
/* eslint-enable consistent-this */
let uris = [];
let currentUri = {};
let key;
let noop = function() {};
let defaultMediaGroups = {
'AUDIO': {},
'VIDEO': {},
'CLOSED-CAPTIONS': {},
'SUBTITLES': {}
};
// group segments into numbered timelines delineated by discontinuities
let currentTimeline = 0;
// the manifest is empty until the parse stream begins delivering data
this.manifest = {
allowCache: true,
discontinuityStarts: []
};
// update the manifest with the m3u8 entry from the parse stream
this.parseStream.on('data', function(entry) {
let mediaGroup;
let rendition;
({
tag() {
// switch based on the tag type
(({
'allow-cache'() {
this.manifest.allowCache = entry.allowed;
if (!('allowed' in entry)) {
this.trigger('info', {
message: 'defaulting allowCache to YES'
});
this.manifest.allowCache = true;
}
},
byterange() {
let byterange = {};
if ('length' in entry) {
currentUri.byterange = byterange;
byterange.length = entry.length;
if (!('offset' in entry)) {
this.trigger('info', {
message: 'defaulting offset to zero'
});
entry.offset = 0;
}
}
if ('offset' in entry) {
currentUri.byterange = byterange;
byterange.offset = entry.offset;
}
},
endlist() {
this.manifest.endList = true;
},
inf() {
if (!('mediaSequence' in this.manifest)) {
this.manifest.mediaSequence = 0;
this.trigger('info', {
message: 'defaulting media sequence to zero'
});
}
if (!('discontinuitySequence' in this.manifest)) {
this.manifest.discontinuitySequence = 0;
this.trigger('info', {
message: 'defaulting discontinuity sequence to zero'
});
}
if (entry.duration > 0) {
currentUri.duration = entry.duration;
}
if (entry.duration === 0) {
currentUri.duration = 0.01;
this.trigger('info', {
message: 'updating zero segment duration to a small value'
});
}
this.manifest.segments = uris;
},
key() {
if (!entry.attributes) {
this.trigger('warn', {
message: 'ignoring key declaration without attribute list'
});
return;
}
// clear the active encryption key
if (entry.attributes.METHOD === 'NONE') {
key = null;
return;
}
if (!entry.attributes.URI) {
this.trigger('warn', {
message: 'ignoring key declaration without URI'
});
return;
}
if (!entry.attributes.METHOD) {
this.trigger('warn', {
message: 'defaulting key method to AES-128'
});
}
// setup an encryption key for upcoming segments
key = {
method: entry.attributes.METHOD || 'AES-128',
uri: entry.attributes.URI
};
if (typeof entry.attributes.IV !== 'undefined') {
key.iv = entry.attributes.IV;
}
},
'media-sequence'() {
if (!isFinite(entry.number)) {
this.trigger('warn', {
message: 'ignoring invalid media sequence: ' + entry.number
});
return;
}
this.manifest.mediaSequence = entry.number;
},
'discontinuity-sequence'() {
if (!isFinite(entry.number)) {
this.trigger('warn', {
message: 'ignoring invalid discontinuity sequence: ' + entry.number
});
return;
}
this.manifest.discontinuitySequence = entry.number;
currentTimeline = entry.number;
},
'playlist-type'() {
if (!(/VOD|EVENT/).test(entry.playlistType)) {
this.trigger('warn', {
message: 'ignoring unknown playlist type: ' + entry.playlist
});
return;
}
this.manifest.playlistType = entry.playlistType;
},
'stream-inf'() {
this.manifest.playlists = uris;
this.manifest.mediaGroups =
this.manifest.mediaGroups || defaultMediaGroups;
if (!entry.attributes) {
this.trigger('warn', {
message: 'ignoring empty stream-inf attributes'
});
return;
}
if (!currentUri.attributes) {
currentUri.attributes = {};
}
currentUri.attributes = mergeOptions(currentUri.attributes,
entry.attributes);
},
media() {
this.manifest.mediaGroups =
this.manifest.mediaGroups || defaultMediaGroups;
if (!(entry.attributes &&
entry.attributes.TYPE &&
entry.attributes['GROUP-ID'] &&
entry.attributes.NAME)) {
this.trigger('warn', {
message: 'ignoring incomplete or missing media group'
});
return;
}
// find the media group, creating defaults as necessary
let mediaGroupType = this.manifest.mediaGroups[entry.attributes.TYPE];
mediaGroupType[entry.attributes['GROUP-ID']] =
mediaGroupType[entry.attributes['GROUP-ID']] || {};
mediaGroup = mediaGroupType[entry.attributes['GROUP-ID']];
// collect the rendition metadata
rendition = {
default: (/yes/i).test(entry.attributes.DEFAULT)
};
if (rendition.default) {
rendition.autoselect = true;
} else {
rendition.autoselect = (/yes/i).test(entry.attributes.AUTOSELECT);
}
if (entry.attributes.LANGUAGE) {
rendition.language = entry.attributes.LANGUAGE;
}
if (entry.attributes.URI) {
rendition.uri = entry.attributes.URI;
}
// insert the new rendition
mediaGroup[entry.attributes.NAME] = rendition;
},
discontinuity() {
currentTimeline += 1;
currentUri.discontinuity = true;
this.manifest.discontinuityStarts.push(uris.length);
},
targetduration() {
if (!isFinite(entry.duration) || entry.duration < 0) {
this.trigger('warn', {
message: 'ignoring invalid target duration: ' + entry.duration
});
return;
}
this.manifest.targetDuration = entry.duration;
},
totalduration() {
if (!isFinite(entry.duration) || entry.duration < 0) {
this.trigger('warn', {
message: 'ignoring invalid total duration: ' + entry.duration
});
return;
}
this.manifest.totalDuration = entry.duration;
}
})[entry.tagType] || noop).call(self);
},
uri() {
currentUri.uri = entry.uri;
uris.push(currentUri);
// if no explicit duration was declared, use the target duration
if (this.manifest.targetDuration &&
!('duration' in currentUri)) {
this.trigger('warn', {
message: 'defaulting segment duration to the target duration'
});
currentUri.duration = this.manifest.targetDuration;
}
// annotate with encryption information, if necessary
if (key) {
currentUri.key = key;
}
currentUri.timeline = currentTimeline;
// prepare for the next URI
currentUri = {};
},
comment() {
// comments are not important for playback
}
})[entry.type].call(self);
});
}
/**
* Parse the input string and update the manifest object.
*
* @param {String} chunk a potentially incomplete portion of the manifest
*/
push(chunk) {
this.lineStream.push(chunk);
}
/**
* Flush any remaining input. This can be handy if the last line of an M3U8
* manifest did not contain a trailing newline but the file has been
* completely received.
*/
end() {
// flush any buffered input
this.lineStream.push('\n');
}
}