-
Notifications
You must be signed in to change notification settings - Fork 2.5k
/
stream-controller.js
1376 lines (1253 loc) · 52.8 KB
/
stream-controller.js
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Stream Controller
*/
import BinarySearch from '../utils/binary-search';
import { BufferHelper } from '../utils/buffer-helper';
import Demuxer from '../demux/demuxer';
import Event from '../events';
import { FragmentState } from './fragment-tracker';
import { ElementaryStreamTypes } from '../loader/fragment';
import { PlaylistLevelType } from '../types/loader';
import * as LevelHelper from './level-helper';
import TimeRanges from '../utils/time-ranges';
import { ErrorDetails } from '../errors';
import { logger } from '../utils/logger';
import { alignStream } from '../utils/discontinuities';
import { findFragmentByPDT, findFragmentByPTS } from './fragment-finders';
import GapController, { MAX_START_GAP_JUMP } from './gap-controller';
import BaseStreamController, { State } from './base-stream-controller';
const TICK_INTERVAL = 100; // how often to tick in ms
class StreamController extends BaseStreamController {
constructor (hls, fragmentTracker) {
super(hls,
Event.MEDIA_ATTACHED,
Event.MEDIA_DETACHING,
Event.MANIFEST_LOADING,
Event.MANIFEST_PARSED,
Event.LEVEL_LOADED,
Event.LEVELS_UPDATED,
Event.KEY_LOADED,
Event.FRAG_LOADED,
Event.FRAG_LOAD_EMERGENCY_ABORTED,
Event.FRAG_PARSING_INIT_SEGMENT,
Event.FRAG_PARSING_DATA,
Event.FRAG_PARSED,
Event.ERROR,
Event.AUDIO_TRACK_SWITCHING,
Event.AUDIO_TRACK_SWITCHED,
Event.BUFFER_CREATED,
Event.BUFFER_APPENDED,
Event.BUFFER_FLUSHED);
this.fragmentTracker = fragmentTracker;
this.config = hls.config;
this.audioCodecSwap = false;
this._state = State.STOPPED;
this.stallReported = false;
this.gapController = null;
this.altAudio = false;
this.audioOnly = false;
this.bitrateTest = false;
}
startLoad (startPosition) {
if (this.levels) {
let lastCurrentTime = this.lastCurrentTime, hls = this.hls;
this.stopLoad();
this.setInterval(TICK_INTERVAL);
this.level = -1;
this.fragLoadError = 0;
if (!this.startFragRequested) {
// determine load level
let startLevel = hls.startLevel;
if (startLevel === -1) {
if (hls.config.testBandwidth) {
// -1 : guess start Level by doing a bitrate test by loading first fragment of lowest quality level
startLevel = 0;
this.bitrateTest = true;
} else {
startLevel = hls.nextAutoLevel;
}
}
// set new level to playlist loader : this will trigger start level load
// hls.nextLoadLevel remains until it is set to a new value or until a new frag is successfully loaded
this.level = hls.nextLoadLevel = startLevel;
this.loadedmetadata = false;
}
// if startPosition undefined but lastCurrentTime set, set startPosition to last currentTime
if (lastCurrentTime > 0 && startPosition === -1) {
logger.log(`override startPosition with lastCurrentTime @${lastCurrentTime.toFixed(3)}`);
startPosition = lastCurrentTime;
}
this.state = State.IDLE;
this.nextLoadPosition = this.startPosition = this.lastCurrentTime = startPosition;
this.tick();
} else {
this.forceStartLoad = true;
this.state = State.STOPPED;
}
}
stopLoad () {
this.forceStartLoad = false;
super.stopLoad();
}
doTick () {
switch (this.state) {
case State.BUFFER_FLUSHING:
// in buffer flushing state, reset fragLoadError counter
this.fragLoadError = 0;
break;
case State.IDLE:
this._doTickIdle();
break;
case State.WAITING_LEVEL:
var level = this.levels[this.level];
// check if playlist is already loaded
if (level && level.details) {
this.state = State.IDLE;
}
break;
case State.FRAG_LOADING_WAITING_RETRY:
var now = window.performance.now();
var retryDate = this.retryDate;
// if current time is gt than retryDate, or if media seeking let's switch to IDLE state to retry loading
if (!retryDate || (now >= retryDate) || (this.media && this.media.seeking)) {
logger.log('mediaController: retryDate reached, switch back to IDLE state');
this.state = State.IDLE;
}
break;
case State.ERROR:
case State.STOPPED:
case State.FRAG_LOADING:
case State.PARSING:
case State.PARSED:
case State.ENDED:
break;
default:
break;
}
// check buffer
this._checkBuffer();
// check/update current fragment
this._checkFragmentChanged();
}
// Ironically the "idle" state is the on we do the most logic in it seems ....
// NOTE: Maybe we could rather schedule a check for buffer length after half of the currently
// played segment, or on pause/play/seek instead of naively checking every 100ms?
_doTickIdle () {
const hls = this.hls,
config = hls.config,
media = this.media;
// if start level not parsed yet OR
// if video not attached AND start fragment already requested OR start frag prefetch disable
// exit loop, as we either need more info (level not parsed) or we need media to be attached to load new fragment
if (this.levelLastLoaded === undefined || (
!media && (this.startFragRequested || !config.startFragPrefetch))) {
return;
}
// If the "main" level is audio-only but we are loading an alternate track in the same group, do not load anything
if (this.altAudio && this.audioOnly) {
// Clear audio demuxer state so when switching back to main audio we're not still appending where we left off
this.demuxer.frag = null;
return;
}
// if we have not yet loaded any fragment, start loading from start position
let pos;
if (this.loadedmetadata) {
pos = media.currentTime;
} else {
pos = this.nextLoadPosition;
}
// determine next load level
let level = hls.nextLoadLevel,
levelInfo = this.levels[level];
if (!levelInfo) {
return;
}
let levelBitrate = levelInfo.bitrate,
maxBufLen;
// compute max Buffer Length that we could get from this load level, based on level bitrate.
if (levelBitrate) {
maxBufLen = Math.max(8 * config.maxBufferSize / levelBitrate, config.maxBufferLength);
} else {
maxBufLen = config.maxBufferLength;
}
maxBufLen = Math.min(maxBufLen, config.maxMaxBufferLength);
// determine next candidate fragment to be loaded, based on current position and end of buffer position
// ensure up to `config.maxMaxBufferLength` of buffer upfront
const maxBufferHole = pos < config.maxBufferHole ? Math.max(MAX_START_GAP_JUMP, config.maxBufferHole) : config.maxBufferHole;
const bufferInfo = BufferHelper.bufferInfo(this.mediaBuffer ? this.mediaBuffer : media, pos, maxBufferHole);
const bufferLen = bufferInfo.len;
// Stay idle if we are still with buffer margins
if (bufferLen >= maxBufLen) {
return;
}
// if buffer length is less than maxBufLen try to load a new fragment ...
logger.trace(`buffer length of ${bufferLen.toFixed(3)} is below max of ${maxBufLen.toFixed(3)}. checking for more payload ...`);
// set next load level : this will trigger a playlist load if needed
this.level = hls.nextLoadLevel = level;
const levelDetails = levelInfo.details;
// if level info not retrieved yet, switch state and wait for level retrieval
// if live playlist, ensure that new playlist has been refreshed to avoid loading/try to load
// a useless and outdated fragment (that might even introduce load error if it is already out of the live playlist)
if (!levelDetails || (levelDetails.live && this.levelLastLoaded !== level)) {
this.state = State.WAITING_LEVEL;
return;
}
if (this._streamEnded(bufferInfo, levelDetails)) {
const data = {};
if (this.altAudio) {
data.type = 'video';
}
this.hls.trigger(Event.BUFFER_EOS, data);
this.state = State.ENDED;
return;
}
// if we have the levelDetails for the selected variant, lets continue enrichen our stream (load keys/fragments or trigger EOS, etc..)
this._fetchPayloadOrEos(pos, bufferInfo, levelDetails);
}
_fetchPayloadOrEos (pos, bufferInfo, levelDetails) {
const fragPrevious = this.fragPrevious,
level = this.level,
fragments = levelDetails.fragments,
fragLen = fragments.length;
// empty playlist
if (fragLen === 0) {
return;
}
// find fragment index, contiguous with end of buffer position
let start = fragments[0].start,
end = fragments[fragLen - 1].start + fragments[fragLen - 1].duration,
bufferEnd = bufferInfo.end,
frag;
if (levelDetails.initSegment && !levelDetails.initSegment.data) {
frag = levelDetails.initSegment;
} else {
// in case of live playlist we need to ensure that requested position is not located before playlist start
if (levelDetails.live) {
let initialLiveManifestSize = this.config.initialLiveManifestSize;
if (fragLen < initialLiveManifestSize) {
logger.warn(`Can not start playback of a level, reason: not enough fragments ${fragLen} < ${initialLiveManifestSize}`);
return;
}
frag = this._ensureFragmentAtLivePoint(levelDetails, bufferEnd, start, end, fragPrevious, fragments);
// if it explicitely returns null don't load any fragment and exit function now
if (frag === null) {
return;
}
} else {
// VoD playlist: if bufferEnd before start of playlist, load first fragment
if (bufferEnd < start) {
frag = fragments[0];
}
}
}
if (!frag) {
frag = this._findFragment(start, fragPrevious, fragLen, fragments, bufferEnd, end, levelDetails);
}
if (frag) {
if (frag.encrypted) {
this._loadKey(frag, levelDetails);
} else {
this._loadFragment(frag, levelDetails, pos, bufferEnd);
}
}
}
_ensureFragmentAtLivePoint (levelDetails, bufferEnd, start, end, fragPrevious, fragments) {
const config = this.hls.config, media = this.media;
let frag;
// check if requested position is within seekable boundaries :
// logger.log(`start/pos/bufEnd/seeking:${start.toFixed(3)}/${pos.toFixed(3)}/${bufferEnd.toFixed(3)}/${this.media.seeking}`);
let maxLatency = Infinity;
if (config.liveMaxLatencyDuration !== undefined) {
maxLatency = config.liveMaxLatencyDuration;
} else if (Number.isFinite(config.liveMaxLatencyDurationCount)) {
maxLatency = config.liveMaxLatencyDurationCount * levelDetails.targetduration;
}
if (bufferEnd < Math.max(start - config.maxFragLookUpTolerance, end - maxLatency)) {
let liveSyncPosition = this.liveSyncPosition = this.computeLivePosition(start, levelDetails);
bufferEnd = liveSyncPosition;
if (media && !media.paused && media.readyState && media.duration > liveSyncPosition && liveSyncPosition > media.currentTime) {
logger.log(`buffer end: ${bufferEnd.toFixed(3)} is located too far from the end of live sliding playlist, reset currentTime to : ${liveSyncPosition.toFixed(3)}`);
media.currentTime = liveSyncPosition;
}
this.nextLoadPosition = liveSyncPosition;
}
// if end of buffer greater than live edge, don't load any fragment
// this could happen if live playlist intermittently slides in the past.
// level 1 loaded [182580161,182580167]
// level 1 loaded [182580162,182580169]
// Loading 182580168 of [182580162 ,182580169],level 1 ..
// Loading 182580169 of [182580162 ,182580169],level 1 ..
// level 1 loaded [182580162,182580168] <============= here we should have bufferEnd > end. in that case break to avoid reloading 182580168
// level 1 loaded [182580164,182580171]
//
// don't return null in case media not loaded yet (readystate === 0)
if (levelDetails.PTSKnown && bufferEnd > end && media && media.readyState) {
return null;
}
if (this.startFragRequested && !levelDetails.PTSKnown) {
/* we are switching level on live playlist, but we don't have any PTS info for that quality level ...
try to load frag matching with next SN.
even if SN are not synchronized between playlists, loading this frag will help us
compute playlist sliding and find the right one after in case it was not the right consecutive one */
if (fragPrevious) {
if (levelDetails.hasProgramDateTime) {
// Relies on PDT in order to switch bitrates (Support EXT-X-DISCONTINUITY without EXT-X-DISCONTINUITY-SEQUENCE)
logger.log(`live playlist, switching playlist, load frag with same PDT: ${fragPrevious.programDateTime}`);
frag = findFragmentByPDT(fragments, fragPrevious.endProgramDateTime, config.maxFragLookUpTolerance);
} else {
// Uses buffer and sequence number to calculate switch segment (required if using EXT-X-DISCONTINUITY-SEQUENCE)
const targetSN = fragPrevious.sn + 1;
if (targetSN >= levelDetails.startSN && targetSN <= levelDetails.endSN) {
const fragNext = fragments[targetSN - levelDetails.startSN];
if (fragPrevious.cc === fragNext.cc) {
frag = fragNext;
logger.log(`live playlist, switching playlist, load frag with next SN: ${frag.sn}`);
}
}
// next frag SN not available (or not with same continuity counter)
// look for a frag sharing the same CC
if (!frag) {
frag = BinarySearch.search(fragments, function (frag) {
return fragPrevious.cc - frag.cc;
});
if (frag) {
logger.log(`live playlist, switching playlist, load frag with same CC: ${frag.sn}`);
}
}
}
}
}
return frag;
}
_findFragment (start, fragPreviousLoad, fragmentIndexRange, fragments, bufferEnd, end, levelDetails) {
const config = this.hls.config;
let fragNextLoad;
if (bufferEnd < end) {
const lookupTolerance = (bufferEnd > end - config.maxFragLookUpTolerance) ? 0 : config.maxFragLookUpTolerance;
// Remove the tolerance if it would put the bufferEnd past the actual end of stream
// Uses buffer and sequence number to calculate switch segment (required if using EXT-X-DISCONTINUITY-SEQUENCE)
fragNextLoad = findFragmentByPTS(fragPreviousLoad, fragments, bufferEnd, lookupTolerance);
} else {
// reach end of playlist
fragNextLoad = fragments[fragmentIndexRange - 1];
}
if (fragNextLoad) {
const curSNIdx = fragNextLoad.sn - levelDetails.startSN;
const sameLevel = fragPreviousLoad && fragNextLoad.level === fragPreviousLoad.level;
const prevSnFrag = fragments[curSNIdx - 1];
const nextSnFrag = fragments[curSNIdx + 1];
// logger.log('find SN matching with pos:' + bufferEnd + ':' + frag.sn);
if (fragPreviousLoad && fragNextLoad.sn === fragPreviousLoad.sn) {
if (sameLevel && !fragNextLoad.backtracked) {
if (fragNextLoad.sn < levelDetails.endSN) {
let deltaPTS = fragPreviousLoad.deltaPTS;
// if there is a significant delta between audio and video, larger than max allowed hole,
// and if previous remuxed fragment did not start with a keyframe. (fragPrevious.dropped)
// let's try to load previous fragment again to get last keyframe
// then we will reload again current fragment (that way we should be able to fill the buffer hole ...)
if (deltaPTS && deltaPTS > config.maxBufferHole && fragPreviousLoad.dropped && curSNIdx) {
fragNextLoad = prevSnFrag;
logger.warn('Previous fragment was dropped with large PTS gap between audio and video. Maybe fragment is not starting with a keyframe? Loading previous one to try to overcome this');
} else {
fragNextLoad = nextSnFrag;
logger.log(`Re-loading fragment with SN: ${fragNextLoad.sn}`);
}
} else {
fragNextLoad = null;
}
} else if (fragNextLoad.backtracked) {
// Only backtrack a max of 1 consecutive fragment to prevent sliding back too far when little or no frags start with keyframes
if (nextSnFrag && nextSnFrag.backtracked) {
logger.warn(`Already backtracked from fragment ${nextSnFrag.sn}, will not backtrack to fragment ${fragNextLoad.sn}. Loading fragment ${nextSnFrag.sn}`);
fragNextLoad = nextSnFrag;
} else {
// If a fragment has dropped frames and it's in a same level/sequence, load the previous fragment to try and find the keyframe
// Reset the dropped count now since it won't be reset until we parse the fragment again, which prevents infinite backtracking on the same segment
logger.warn('Loaded fragment with dropped frames, backtracking 1 segment to find a keyframe');
fragNextLoad.dropped = 0;
if (prevSnFrag) {
fragNextLoad = prevSnFrag;
fragNextLoad.backtracked = true;
} else if (curSNIdx) {
// can't backtrack on very first fragment
fragNextLoad = null;
}
}
}
}
}
return fragNextLoad;
}
_loadKey (frag, levelDetails) {
logger.log(`Loading key for ${frag.sn} of [${levelDetails.startSN} ,${levelDetails.endSN}],level ${this.level}`);
this.state = State.KEY_LOADING;
this.hls.trigger(Event.KEY_LOADING, { frag });
}
_loadFragment (frag, levelDetails, pos, bufferEnd) {
// Check if fragment is not loaded
let fragState = this.fragmentTracker.getState(frag);
this.fragCurrent = frag;
if (frag.sn !== 'initSegment') {
this.startFragRequested = true;
}
// Don't update nextLoadPosition for fragments which are not buffered
if (Number.isFinite(frag.sn) && !frag.bitrateTest) {
this.nextLoadPosition = frag.start + frag.duration;
}
// Allow backtracked fragments to load
if (frag.backtracked || fragState === FragmentState.NOT_LOADED || fragState === FragmentState.PARTIAL) {
frag.autoLevel = this.hls.autoLevelEnabled;
frag.bitrateTest = this.bitrateTest;
logger.log(`Loading ${frag.sn} of [${levelDetails.startSN} ,${levelDetails.endSN}],level ${this.level}, currentTime:${pos.toFixed(3)},bufferEnd:${bufferEnd.toFixed(3)}`);
this.hls.trigger(Event.FRAG_LOADING, { frag });
// lazy demuxer init, as this could take some time ... do it during frag loading
if (!this.demuxer) {
this.demuxer = new Demuxer(this.hls, 'main');
}
this.state = State.FRAG_LOADING;
} else if (fragState === FragmentState.APPENDING) {
// Lower the buffer size and try again
if (this._reduceMaxBufferLength(frag.duration)) {
this.fragmentTracker.removeFragment(frag);
}
}
}
set state (nextState) {
if (this.state !== nextState) {
const previousState = this.state;
this._state = nextState;
logger.log(`main stream-controller: ${previousState}->${nextState}`);
this.hls.trigger(Event.STREAM_STATE_TRANSITION, { previousState, nextState });
}
}
get state () {
return this._state;
}
getBufferedFrag (position) {
return this.fragmentTracker.getBufferedFrag(position, PlaylistLevelType.MAIN);
}
get currentLevel () {
let media = this.media;
if (media) {
const frag = this.getBufferedFrag(media.currentTime);
if (frag) {
return frag.level;
}
}
return -1;
}
get nextBufferedFrag () {
let media = this.media;
if (media) {
// first get end range of current fragment
return this.followingBufferedFrag(this.getBufferedFrag(media.currentTime));
} else {
return null;
}
}
followingBufferedFrag (frag) {
if (frag) {
// try to get range of next fragment (500ms after this range)
return this.getBufferedFrag(frag.endPTS + 0.5);
}
return null;
}
get nextLevel () {
const frag = this.nextBufferedFrag;
if (frag) {
return frag.level;
} else {
return -1;
}
}
_checkFragmentChanged () {
let fragPlayingCurrent, currentTime, video = this.media;
if (video && video.readyState && video.seeking === false) {
currentTime = video.currentTime;
/* if video element is in seeked state, currentTime can only increase.
(assuming that playback rate is positive ...)
As sometimes currentTime jumps back to zero after a
media decode error, check this, to avoid seeking back to
wrong position after a media decode error
*/
if (currentTime > this.lastCurrentTime) {
this.lastCurrentTime = currentTime;
}
if (BufferHelper.isBuffered(video, currentTime)) {
fragPlayingCurrent = this.getBufferedFrag(currentTime);
} else if (BufferHelper.isBuffered(video, currentTime + 0.1)) {
/* ensure that FRAG_CHANGED event is triggered at startup,
when first video frame is displayed and playback is paused.
add a tolerance of 100ms, in case current position is not buffered,
check if current pos+100ms is buffered and use that buffer range
for FRAG_CHANGED event reporting */
fragPlayingCurrent = this.getBufferedFrag(currentTime + 0.1);
}
if (fragPlayingCurrent) {
let fragPlaying = fragPlayingCurrent;
if (fragPlaying !== this.fragPlaying) {
this.hls.trigger(Event.FRAG_CHANGED, { frag: fragPlaying });
const fragPlayingLevel = fragPlaying.level;
if (!this.fragPlaying || this.fragPlaying.level !== fragPlayingLevel) {
this.hls.trigger(Event.LEVEL_SWITCHED, { level: fragPlayingLevel });
}
this.fragPlaying = fragPlaying;
}
}
}
}
/*
on immediate level switch :
- pause playback if playing
- cancel any pending load request
- and trigger a buffer flush
*/
immediateLevelSwitch () {
logger.log('immediateLevelSwitch');
if (!this.immediateSwitch) {
this.immediateSwitch = true;
let media = this.media, previouslyPaused;
if (media) {
previouslyPaused = media.paused;
media.pause();
} else {
// don't restart playback after instant level switch in case media not attached
previouslyPaused = true;
}
this.previouslyPaused = previouslyPaused;
}
let fragCurrent = this.fragCurrent;
if (fragCurrent && fragCurrent.loader) {
fragCurrent.loader.abort();
}
this.fragCurrent = null;
// flush everything
this.flushMainBuffer(0, Number.POSITIVE_INFINITY);
}
/**
* on immediate level switch end, after new fragment has been buffered:
* - nudge video decoder by slightly adjusting video currentTime (if currentTime buffered)
* - resume the playback if needed
*/
immediateLevelSwitchEnd () {
const media = this.media;
if (media && media.buffered.length) {
this.immediateSwitch = false;
if (BufferHelper.isBuffered(media, media.currentTime)) {
// only nudge if currentTime is buffered
media.currentTime -= 0.0001;
}
if (!this.previouslyPaused) {
media.play();
}
}
}
/**
* try to switch ASAP without breaking video playback:
* in order to ensure smooth but quick level switching,
* we need to find the next flushable buffer range
* we should take into account new segment fetch time
*/
nextLevelSwitch () {
const media = this.media;
// ensure that media is defined and that metadata are available (to retrieve currentTime)
if (media && media.readyState) {
let fetchdelay, fragPlayingCurrent, nextBufferedFrag;
fragPlayingCurrent = this.getBufferedFrag(media.currentTime);
if (fragPlayingCurrent && fragPlayingCurrent.startPTS > 1) {
// flush buffer preceding current fragment (flush until current fragment start offset)
// minus 1s to avoid video freezing, that could happen if we flush keyframe of current video ...
this.flushMainBuffer(0, fragPlayingCurrent.startPTS - 1);
}
if (!media.paused) {
// add a safety delay of 1s
let nextLevelId = this.hls.nextLoadLevel, nextLevel = this.levels[nextLevelId], fragLastKbps = this.fragLastKbps;
if (fragLastKbps && this.fragCurrent) {
fetchdelay = this.fragCurrent.duration * nextLevel.bitrate / (1000 * fragLastKbps) + 1;
} else {
fetchdelay = 0;
}
} else {
fetchdelay = 0;
}
// logger.log('fetchdelay:'+fetchdelay);
// find buffer range that will be reached once new fragment will be fetched
nextBufferedFrag = this.getBufferedFrag(media.currentTime + fetchdelay);
if (nextBufferedFrag) {
// we can flush buffer range following this one without stalling playback
nextBufferedFrag = this.followingBufferedFrag(nextBufferedFrag);
if (nextBufferedFrag) {
// if we are here, we can also cancel any loading/demuxing in progress, as they are useless
let fragCurrent = this.fragCurrent;
if (fragCurrent && fragCurrent.loader) {
fragCurrent.loader.abort();
}
this.fragCurrent = null;
// start flush position is the start PTS of next buffered frag.
// we use frag.naxStartPTS which is max(audio startPTS, video startPTS).
// in case there is a small PTS Delta between audio and video, using maxStartPTS avoids flushing last samples from current fragment
this.flushMainBuffer(nextBufferedFrag.maxStartPTS, Number.POSITIVE_INFINITY);
}
}
}
}
flushMainBuffer (startOffset, endOffset) {
this.state = State.BUFFER_FLUSHING;
let flushScope = { startOffset: startOffset, endOffset: endOffset };
// if alternate audio tracks are used, only flush video, otherwise flush everything
if (this.altAudio) {
flushScope.type = 'video';
}
this.hls.trigger(Event.BUFFER_FLUSHING, flushScope);
}
onMediaAttached (data) {
let media = this.media = this.mediaBuffer = data.media;
this.onvseeking = this.onMediaSeeking.bind(this);
this.onvseeked = this.onMediaSeeked.bind(this);
this.onvended = this.onMediaEnded.bind(this);
media.addEventListener('seeking', this.onvseeking);
media.addEventListener('seeked', this.onvseeked);
media.addEventListener('ended', this.onvended);
let config = this.config;
if (this.levels && config.autoStartLoad) {
this.hls.startLoad(config.startPosition);
}
this.gapController = new GapController(config, media, this.fragmentTracker, this.hls);
}
onMediaDetaching () {
let media = this.media;
if (media && media.ended) {
logger.log('MSE detaching and video ended, reset startPosition');
this.startPosition = this.lastCurrentTime = 0;
}
// reset fragment backtracked flag
let levels = this.levels;
if (levels) {
levels.forEach(level => {
if (level.details) {
level.details.fragments.forEach(fragment => {
fragment.backtracked = undefined;
});
}
});
}
// remove video listeners
if (media) {
media.removeEventListener('seeking', this.onvseeking);
media.removeEventListener('seeked', this.onvseeked);
media.removeEventListener('ended', this.onvended);
this.onvseeking = this.onvseeked = this.onvended = null;
}
this.fragmentTracker.removeAllFragments();
this.media = this.mediaBuffer = null;
this.loadedmetadata = false;
this.stopLoad();
}
onMediaSeeked () {
const media = this.media;
const currentTime = media ? media.currentTime : undefined;
if (Number.isFinite(currentTime)) {
logger.log(`media seeked to ${currentTime.toFixed(3)}`);
}
// tick to speed up FRAGMENT_PLAYING triggering
this.tick();
}
onManifestLoading () {
// reset buffer on manifest loading
logger.log('trigger BUFFER_RESET');
this.hls.trigger(Event.BUFFER_RESET);
this.fragmentTracker.removeAllFragments();
this.stalled = false;
this.startPosition = this.lastCurrentTime = 0;
}
onManifestParsed (data) {
let aac = false, heaac = false, codec;
data.levels.forEach(level => {
// detect if we have different kind of audio codecs used amongst playlists
codec = level.audioCodec;
if (codec) {
if (codec.indexOf('mp4a.40.2') !== -1) {
aac = true;
}
if (codec.indexOf('mp4a.40.5') !== -1) {
heaac = true;
}
}
});
this.audioCodecSwitch = (aac && heaac);
if (this.audioCodecSwitch) {
logger.log('both AAC/HE-AAC audio found in levels; declaring level codec as HE-AAC');
}
this.altAudio = data.altAudio;
this.levels = data.levels;
this.startFragRequested = false;
let config = this.config;
if (config.autoStartLoad || this.forceStartLoad) {
this.hls.startLoad(config.startPosition);
}
}
onLevelLoaded (data) {
const newDetails = data.details;
const newLevelId = data.level;
const lastLevel = this.levels[this.levelLastLoaded];
const curLevel = this.levels[newLevelId];
const duration = newDetails.totalduration;
let sliding = 0;
logger.log(`level ${newLevelId} loaded [${newDetails.startSN},${newDetails.endSN}],duration:${duration}`);
if (newDetails.live) {
let curDetails = curLevel.details;
if (curDetails && newDetails.fragments.length > 0) {
// we already have details for that level, merge them
LevelHelper.mergeDetails(curDetails, newDetails);
sliding = newDetails.fragments[0].start;
this.liveSyncPosition = this.computeLivePosition(sliding, curDetails);
if (newDetails.PTSKnown && Number.isFinite(sliding)) {
logger.log(`live playlist sliding:${sliding.toFixed(3)}`);
} else {
logger.log('live playlist - outdated PTS, unknown sliding');
alignStream(this.fragPrevious, lastLevel, newDetails);
}
} else {
logger.log('live playlist - first load, unknown sliding');
newDetails.PTSKnown = false;
alignStream(this.fragPrevious, lastLevel, newDetails);
}
} else {
newDetails.PTSKnown = false;
}
// override level info
curLevel.details = newDetails;
this.levelLastLoaded = newLevelId;
this.hls.trigger(Event.LEVEL_UPDATED, { details: newDetails, level: newLevelId });
if (this.startFragRequested === false) {
// compute start position if set to -1. use it straight away if value is defined
if (this.startPosition === -1 || this.lastCurrentTime === -1) {
// first, check if start time offset has been set in playlist, if yes, use this value
let startTimeOffset = newDetails.startTimeOffset;
if (Number.isFinite(startTimeOffset)) {
if (startTimeOffset < 0) {
logger.log(`negative start time offset ${startTimeOffset}, count from end of last fragment`);
startTimeOffset = sliding + duration + startTimeOffset;
}
logger.log(`start time offset found in playlist, adjust startPosition to ${startTimeOffset}`);
this.startPosition = startTimeOffset;
} else {
// if live playlist, set start position to be fragment N-this.config.liveSyncDurationCount (usually 3)
if (newDetails.live) {
this.startPosition = this.computeLivePosition(sliding, newDetails);
logger.log(`configure startPosition to ${this.startPosition}`);
} else {
this.startPosition = 0;
}
}
this.lastCurrentTime = this.startPosition;
}
this.nextLoadPosition = this.startPosition;
}
// only switch batck to IDLE state if we were waiting for level to start downloading a new fragment
if (this.state === State.WAITING_LEVEL) {
this.state = State.IDLE;
}
// trigger handler right now
this.tick();
}
onKeyLoaded () {
if (this.state === State.KEY_LOADING) {
this.state = State.IDLE;
this.tick();
}
}
onFragLoaded (data) {
const { fragCurrent, hls, levels, media } = this;
const fragLoaded = data.frag;
if (this.state === State.FRAG_LOADING &&
fragCurrent &&
fragLoaded.type === 'main' &&
fragLoaded.level === fragCurrent.level &&
fragLoaded.sn === fragCurrent.sn) {
const stats = data.stats;
const currentLevel = levels[fragCurrent.level];
const details = currentLevel.details;
// reset frag bitrate test in any case after frag loaded event
// if this frag was loaded to perform a bitrate test AND if hls.nextLoadLevel is greater than 0
// then this means that we should be able to load a fragment at a higher quality level
this.bitrateTest = false;
this.stats = stats;
logger.log(`Loaded ${fragCurrent.sn} of [${details.startSN} ,${details.endSN}],level ${fragCurrent.level}`);
if (fragLoaded.bitrateTest && hls.nextLoadLevel) {
// switch back to IDLE state ... we just loaded a fragment to determine adequate start bitrate and initialize autoswitch algo
this.state = State.IDLE;
this.startFragRequested = false;
stats.tparsed = stats.tbuffered = window.performance.now();
hls.trigger(Event.FRAG_BUFFERED, { stats: stats, frag: fragCurrent, id: 'main' });
this.tick();
} else if (fragLoaded.sn === 'initSegment') {
this.state = State.IDLE;
stats.tparsed = stats.tbuffered = window.performance.now();
details.initSegment.data = data.payload;
hls.trigger(Event.FRAG_BUFFERED, { stats: stats, frag: fragCurrent, id: 'main' });
this.tick();
} else {
logger.log(`Parsing ${fragCurrent.sn} of [${details.startSN} ,${details.endSN}],level ${fragCurrent.level}, cc ${fragCurrent.cc}`);
this.state = State.PARSING;
this.pendingBuffering = true;
this.appended = false;
// Bitrate test frags are not usually buffered so the fragment tracker ignores them. If Hls.js decides to buffer
// it (and therefore ends up at this line), then the fragment tracker needs to be manually informed.
if (fragLoaded.bitrateTest) {
fragLoaded.bitrateTest = false;
this.fragmentTracker.onFragLoaded({
frag: fragLoaded
});
}
// time Offset is accurate if level PTS is known, or if playlist is not sliding (not live) and if media is not seeking (this is to overcome potential timestamp drifts between playlists and fragments)
const accurateTimeOffset = !(media && media.seeking) && (details.PTSKnown || !details.live);
const initSegmentData = details.initSegment ? details.initSegment.data : [];
const audioCodec = this._getAudioCodec(currentLevel);
// transmux the MPEG-TS data to ISO-BMFF segments
const demuxer = this.demuxer = this.demuxer || new Demuxer(this.hls, 'main');
demuxer.push(
data.payload,
initSegmentData,
audioCodec,
currentLevel.videoCodec,
fragCurrent,
details.totalduration,
accurateTimeOffset
);
}
}
this.fragLoadError = 0;
}
onFragParsingInitSegment (data) {
const fragCurrent = this.fragCurrent;
const fragNew = data.frag;
if (fragCurrent &&
data.id === 'main' &&
fragNew.sn === fragCurrent.sn &&
fragNew.level === fragCurrent.level &&
this.state === State.PARSING) {
let tracks = data.tracks, trackName, track;
this.audioOnly = tracks.audio && !tracks.video;
// if audio track is expected to come from audio stream controller, discard any coming from main
if (this.altAudio && !this.audioOnly) {
delete tracks.audio;
}
// include levelCodec in audio and video tracks
track = tracks.audio;
if (track) {
let audioCodec = this.levels[this.level].audioCodec,
ua = navigator.userAgent.toLowerCase();
if (audioCodec && this.audioCodecSwap) {
logger.log('swapping playlist audio codec');
if (audioCodec.indexOf('mp4a.40.5') !== -1) {
audioCodec = 'mp4a.40.2';
} else {
audioCodec = 'mp4a.40.5';
}
}
// in case AAC and HE-AAC audio codecs are signalled in manifest
// force HE-AAC , as it seems that most browsers prefers that way,
// except for mono streams OR on FF
// these conditions might need to be reviewed ...
if (this.audioCodecSwitch) {
// don't force HE-AAC if mono stream
if (track.metadata.channelCount !== 1 &&
// don't force HE-AAC if firefox
ua.indexOf('firefox') === -1) {
audioCodec = 'mp4a.40.5';
}
}
// HE-AAC is broken on Android, always signal audio codec as AAC even if variant manifest states otherwise
if (ua.indexOf('android') !== -1 && track.container !== 'audio/mpeg') { // Exclude mpeg audio
audioCodec = 'mp4a.40.2';
logger.log(`Android: force audio codec to ${audioCodec}`);
}
track.levelCodec = audioCodec;
track.id = data.id;
}
track = tracks.video;
if (track) {
track.levelCodec = this.levels[this.level].videoCodec;
track.id = data.id;
}
this.hls.trigger(Event.BUFFER_CODECS, tracks);
// loop through tracks that are going to be provided to bufferController
for (trackName in tracks) {
track = tracks[trackName];
logger.log(`main track:${trackName},container:${track.container},codecs[level/parsed]=[${track.levelCodec}/${track.codec}]`);
let initSegment = track.initSegment;
if (initSegment) {
this.appended = true;
// arm pending Buffering flag before appending a segment
this.pendingBuffering = true;
this.hls.trigger(Event.BUFFER_APPENDING, { type: trackName, data: initSegment, parent: 'main', content: 'initSegment' });
}
}
// trigger handler right now
this.tick();
}
}
onFragParsingData (data) {
const fragCurrent = this.fragCurrent;
const fragNew = data.frag;
if (fragCurrent &&
data.id === 'main' &&
fragNew.sn === fragCurrent.sn &&
fragNew.level === fragCurrent.level &&
!(data.type === 'audio' && this.altAudio) && // filter out main audio if audio track is loaded through audio stream controller
this.state === State.PARSING) {
let level = this.levels[this.level],
frag = fragCurrent;
if (!Number.isFinite(data.endPTS)) {
data.endPTS = data.startPTS + fragCurrent.duration;