-
Notifications
You must be signed in to change notification settings - Fork 280
/
mpegts.coffee
949 lines (854 loc) · 33.7 KB
/
mpegts.coffee
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
# MPEG-TS parser
fs = require 'fs'
Bits = require './bits'
logger = require './logger'
TS_PACKET_SIZE = 188
SYNC_BYTE = 0x47
PES_STREAM_ID_PROGRAM_STREAM_MAP = 188
PES_STREAM_ID_PRIVATE_STREAM_1 = 189
PES_STREAM_ID_PADDING_STREAM = 190
PES_STREAM_ID_PRIVATE_STREAM_2 = 191
PES_STREAM_ID_ECM = 240
PES_STREAM_ID_EMM = 241
PES_STREAM_ID_PROGRAM_STREAM_DIRECTORY = 255
PES_STREAM_ID_DSMCC_STREAM = 242
PES_STREAM_ID_ITU_T_REC_H_222_1_TYPE_E_STREAM = 248
TRICK_MODE_CONTROL_FAST_FORWARD = 0
TRICK_MODE_CONTROL_SLOW_MOTION = 1
TRICK_MODE_CONTROL_FREEZE_FRAME = 2
TRICK_MODE_CONTROL_FAST_REVERSE = 3
TRICK_MODE_CONTROL_SLOW_REVERSE = 4
PID_PROGRAM_ASSOCIATION_TABLE = 0x0000
PID_CONDITIONAL_ACCESS_TABLE = 0x0001
PID_TRANSPORT_STREAM_DESCRIPTION_TABLE = 0x0002
PID_IPMP_CONTROL_INFORMATION_TABLE = 0x0003
PID_DVB_NIT_ST = 0x0010
PID_NULL_PACKET = 0x1FFF
STREAM_TYPE_MPEG2_VIDEO = 0x02 # MPEG-2 video
STREAM_TYPE_MPEG2_PES_PRIVATE = 0x06 # PES packets containing private data
STREAM_TYPE_MPEG2_DSM_CC = 0x0D
STREAM_TYPE_AUDIO_ADTS = 0x0F
STREAM_TYPE_H264 = 0x1B # AVC video
MAX_PES_PAYLOAD_SIZE = 200 * 1024
SETTIMEOUT_ADVANCE_TIME = 20
tsBits = null
tsBuf = null
isSyncByteDetermined = false
programTable = {}
programMap = {}
unparsedPESPackets = []
audioPID = null
videoPID = null
pendingVideoPesPackets = []
pendingAudioPesPackets = []
streamingStartTime = null
firstDTS = null
bufferingPESData = {}
isEOF = false
eventListeners = {}
api =
open: (file) ->
tsBuf = fs.readFileSync file # up to 1GB
close: ->
tsBuf = null
emit: (name, data...) ->
if eventListeners[name]?
for listener in eventListeners[name]
listener data...
return
on: (name, listener) ->
if eventListeners[name]?
eventListeners[name].push listener
else
eventListeners[name] = [ listener ]
startStreaming: (initialSkipTimeMs=0) ->
@resetState()
tsBits = new Bits tsBuf
streamingStartTime = Date.now() - initialSkipTimeMs
@readNext()
resetState: ->
unparsedPESPackets = []
streamingStartTime = null
bufferingPESData = {}
isEOF = false
isSyncByteDetermined = false
firstPTS = null
pts2ms: (pts) ->
pts / 90
getTimeUntilDTS: (dts) ->
if not firstDTS?
throw new Error "not yet received the first video or audio packet"
return streamingStartTime + (dts - firstDTS) / 90 - Date.now()
getCurrentPTS: ->
(Date.now() - streamingStartTime) * 90
checkEnd: ->
if isEOF and (pendingAudioPesPackets.length is 0) and
(pendingVideoPesPackets.length is 0)
@emit 'end'
return true
return false
consumeVideo: (doNotReadNext=false) ->
pendingLen = pendingVideoPesPackets.length
if pendingLen > 0
pesInfo = pendingVideoPesPackets.shift()
@emit 'video', pesInfo
if pendingLen is 1 # now the buffer is empty
if (not doNotReadNext) and (not @checkEnd())
@readNext()
else
timeDiff = Math.round @getTimeUntilDTS(pendingVideoPesPackets[0].pes.DTS) - SETTIMEOUT_ADVANCE_TIME
if timeDiff <= 0
@consumeVideo doNotReadNext
else
setTimeout =>
@consumeVideo doNotReadNext
, timeDiff
consumeAudio: (doNotReadNext=false) ->
pendingLen = pendingAudioPesPackets.length
if pendingLen > 0
pesInfo = pendingAudioPesPackets.shift()
@emit 'audio', pesInfo
if pendingLen is 1 # now the buffer is empty
if (not doNotReadNext) and (not @checkEnd())
@readNext()
else
timeDiff = Math.round @getTimeUntilDTS(pendingAudioPesPackets[0].pes.DTS) - SETTIMEOUT_ADVANCE_TIME
if timeDiff <= 0
@consumeAudio doNotReadNext
else
setTimeout =>
@consumeAudio doNotReadNext
, timeDiff
queueVideo: (pesInfo, doNotReadNext=false) ->
pendingVideoPesPackets.push pesInfo
if pendingVideoPesPackets.length is 1
timeDiff = Math.round @getTimeUntilDTS(pesInfo.pes.DTS) - SETTIMEOUT_ADVANCE_TIME
if timeDiff <= 0
setImmediate =>
@consumeVideo doNotReadNext
else
setTimeout =>
@consumeVideo doNotReadNext
, timeDiff
queueAudio: (pesInfo, doNotReadNext=false) ->
pendingAudioPesPackets.push pesInfo
if pendingAudioPesPackets.length is 1
timeDiff = Math.round @getTimeUntilDTS(pesInfo.pes.DTS) - SETTIMEOUT_ADVANCE_TIME
if timeDiff <= 0
setImmediate =>
@consumeAudio doNotReadNext
else
setTimeout =>
@consumeAudio doNotReadNext
, timeDiff
readNext: ->
pesPacket = @getNextPESPacket()
if not pesPacket? # maybe reached EOF
return
pesInfo = @parsePESPacket pesPacket.pid, pesPacket.packet, pesPacket.opts
if pesInfo.program_map? # received a program map
# parse and consume unparsedPESPackets
@consumeUnparsedPESPackets()
if pesInfo.not_parsed
# postpone the parsing process after received a program map
unparsedPESPackets.push pesPacket
if not pesInfo.pes? # not an video/audio packet
# such as program association section or program map section
return @readNext()
if not pesInfo.pes.PTS?
throw new Error "PES packet doesn't have PTS"
if not pesInfo.pes.DTS?
pesInfo.pes.DTS = pesInfo.pes.PTS
if not firstDTS?
firstDTS = pesInfo.pes.DTS
if pesInfo.pes.stream_id_type is 'video'
@queueVideo pesInfo
else if pesInfo.pes.stream_id_type is 'audio'
@queueAudio pesInfo
if (pendingAudioPesPackets.length < 2) or (pendingVideoPesPackets.length < 2)
@readNext()
startReading: ->
api.read_transport_stream tsBuf
# TODO: Check if old API is no longer used
# Described in Table 5: Service description section
read_service_description_section: (bits) ->
pointer_field = bits.read_byte()
table_id = bits.read_byte()
section_syntax_indicator = bits.read_bit()
if section_syntax_indicator isnt 1
throw new Error "section_syntax_indicator must be 1"
reserved_future_use = bits.read_bit()
reserved = bits.read_bits 2
section_length = bits.read_bits 12
if section_length > 0x3ff
throw new Error "The first two bits of section_length must be 00: #{section_length}"
transport_stream_id = bits.read_bits 16
reserved = bits.read_bits 2
version_number = bits.read_bits 5
current_next_indicator = bits.read_bit()
section_number = bits.read_byte()
last_section_number = bits.read_byte()
original_network_id = bits.read_bits 16
reserved_future_use = bits.read_byte()
remaining_section_length = section_length - 8 - 4 # 4 is for CRC
while remaining_section_length > 0
service_id = bits.read_bits 16
# service_id is the same as the program_number in the corresponding program_map_section
reserved_future_use = bits.read_bits 6
EIT_schedule_flag = bits.read_bit()
EIT_present_following_flag = bits.read_bit()
running_status = bits.read_bits 3
free_CA_mode = bits.read_bit()
descriptors_loop_length = bits.read_bits 12
remaining_descriptors_loop_length = descriptors_loop_length
descriptors = []
while remaining_descriptors_loop_length > 0
descriptor = api.read_descriptor bits
descriptors.push descriptor
remaining_descriptors_loop_length -= descriptor.total_length
remaining_section_length -= 5 + descriptors_loop_length
CRC_32 = bits.read_bits 32
read_CA_descriptor: (bits) ->
info = {}
info.descriptor_tag = bits.read_byte()
info.descriptor_length = bits.read_byte()
info.CA_system_ID = bits.read_bits 16
reserved = bits.read_bits 3
info.CA_PID = bits.read_bits 13
remainingLen = info.descriptor_length - 4
info.private_data = bits.read_bytes remainingLen
return info
read_ISO_639_language_descriptor: (bits) ->
info = {}
info.descriptor_tag = bits.read_byte()
info.descriptor_length = bits.read_byte()
# ISO_639_language_descriptor
num_loops = info.descriptor_length / 4
info.languages = []
for i in [0...num_loops]
ISO_639_language_code = bits.read_bytes(3).toString 'utf-8'
# "und" means Undetermined
audio_type = bits.read_byte()
info.languages.push
ISO_639_language_code: ISO_639_language_code
audio_type: audio_type
return info
# DVB service_descriptor, described in Table 12 in DVB spec
read_DVB_service_descriptor: (bits) ->
info = {}
info.descriptor_tag = bits.read_byte()
info.descriptor_length = bits.read_byte()
info.service_type = bits.read_byte()
info.service_provider_name_length = bits.read_byte()
info.service_provider_name = bits.read_bytes(service_provider_name_length).toString 'utf-8'
info.service_name_length = bits.read_byte()
info.service_name = bits.read_bytes(service_name_length).toString 'utf-8'
return info
read_unknown_descriptor: (bits) ->
info = {}
info.descriptor_tag = bits.read_byte()
info.descriptor_length = bits.read_byte()
bits.skip_bytes info.descriptor_length
return info
read_DVB_stream_identifier_descriptor: (bits) ->
info = {}
info.descriptor_tag = bits.read_byte()
info.descriptor_length = bits.read_byte()
info.component_tag = bits.read_byte()
return info
# Described in Section 2.6
read_descriptor: (bits) ->
descriptor_tag = bits.read_byte()
bits.push_back_byte()
# descriptor_tag table is described in Table 2-45
info = switch descriptor_tag
when 9 then api.read_CA_descriptor bits
when 10 then api.read_ISO_639_language_descriptor bits
when 0x48 then api.read_DVB_service_descriptor bits # 72
when 0x52 then api.read_DVB_stream_identifier_descriptor bits # 82
when 193, 200, 246, 253 then api.read_unknown_descriptor bits
else
throw new Error "descriptor_tag #{descriptor_tag} is not implemented"
info.total_length = info.descriptor_length + 2
return info
# Described in Table 2-33
read_program_map_section: (bits) ->
info = {}
info.pointer_field = bits.read_byte()
bits.skip_bytes info.pointer_field
info.table_id = bits.read_byte()
if info.table_id isnt 2
throw new Error "table_id must be 2: #{info.table_id}"
info.section_syntax_indicator = bits.read_bit()
if info.section_syntax_indicator isnt 1
throw new Error "section_syntax_indicator must be 1: #{info.section_syntax_indicator}"
bit_0 = bits.read_bit()
if bit_0 isnt 0
throw new Error "bit_0 must be 0: #{bit_0}"
reserved = bits.read_bits 2
info.section_length = bits.read_bits 12
info.program_number = bits.read_bits 16
reserved = bits.read_bits 2
info.version_number = bits.read_bits 5
info.current_next_indicator = bits.read_bit()
info.section_number = bits.read_byte()
if info.section_number isnt 0
throw new Error "section_number must be 0: #{section_number}"
info.last_section_number = bits.read_byte()
if info.last_section_number isnt 0
throw new Error "last_section_number must be 0: #{last_section_number}"
reserved = bits.read_bits 3
info.PCR_PID = bits.read_bits 13
reserved = bits.read_bits 4
info.program_info_length = bits.read_bits 12
if info.program_info_length > 0x3ff
throw new Error "The first two bits of program_info_length must be 00: #{info.program_info_length}"
remaining_program_info_length = info.program_info_length
info.descriptors = []
while remaining_program_info_length > 0
descriptor = api.read_descriptor bits
info.descriptors.push descriptor
remaining_program_info_length -= descriptor.total_length
remaining_section_length = info.section_length - 9 - info.program_info_length - 4 # 4 for CRC
info.streams = []
while remaining_section_length > 0
stream_type = bits.read_byte()
reserved = bits.read_bits 3
elementary_PID = bits.read_bits 13
switch stream_type
when STREAM_TYPE_H264
videoPID = elementary_PID
when STREAM_TYPE_AUDIO_ADTS
audioPID = elementary_PID
reserved = bits.read_bits 4
ES_info_length = bits.read_bits 12
remaining_ES_info_length = ES_info_length
descriptors = []
while remaining_ES_info_length > 0
descriptor = api.read_descriptor bits
descriptors.push descriptor
remaining_ES_info_length -= descriptor.total_length
remaining_section_length -= 5 + ES_info_length
info.streams.push
stream_type: stream_type
elementary_PID: elementary_PID
ES_info_length: ES_info_length
descriptors: descriptors
CRC_32 = bits.read_bits 32
return info
# Described in Table-2-29 and Table 2-30
read_program_association_section: (bits) ->
info = {}
info.pointer_field = bits.read_byte()
info.table_id = bits.read_byte()
if info.table_id isnt 0x00
throw new Error "table_id for program_association_section must be 0x00"
info.section_syntax_indicator = bits.read_bit()
if info.section_syntax_indicator isnt 1
throw new Error "section_syntax_indicator must be 1: #{info.section_syntax_indicator}"
bit_0 = bits.read_bit()
if bit_0 isnt 0
throw new Error "bit_0 must be 0: #{bit_0}"
reserved = bits.read_bits 2
info.section_length = bits.read_bits 12
if info.section_length > 1021
throw new Error "section_length shall not exceed 1021 (0x3FD)"
info.transport_stream_id = bits.read_bits 16
reserved = bits.read_bits 2
info.version_number = bits.read_bits 5
info.current_next_indicator = bits.read_bit()
info.section_number = bits.read_byte()
info.last_section_number = bits.read_byte()
num_programs = (info.section_length - 9) / 4
info.programTable = {}
for i in [0...num_programs]
program_number = bits.read_bits 16
reserved = bits.read_bits 3
if program_number is 0
info.programTable[program_number] =
network_PID: bits.read_bits 13
else
info.programTable[program_number] =
program_map_PID: bits.read_bits 13
programTable = info.programTable
CRC_32 = bits.read_bits 32
return info
consumeUnparsedPESPackets: ->
for pesPacket in unparsedPESPackets
pesInfo = @parsePESPacket pesPacket.pid, pesPacket.packet, pesPacket.opts
if pesInfo.not_parsed
continue
if not pesInfo.pes? # not an video/audio packet
continue
if not pesInfo.pes.PTS?
throw new Error "PES packet doesn't have PTS"
if not pesInfo.pes.DTS?
pesInfo.pes.DTS = pesInfo.pes.PTS
if not firstDTS?
firstDTS = pesInfo.pes.DTS
if pesInfo.pes.stream_id_type is 'video'
@queueVideo pesInfo, true
else if pesInfo.pes.stream_id_type is 'audio'
@queueAudio pesInfo, true
unparsedPESPackets = []
parsePESPacket: (pid, packet, opts) ->
info = {}
pes_data = Buffer.concat packet.data
# Described in Table 2-3 - PID table
switch pid
when PID_PROGRAM_ASSOCIATION_TABLE # 0
bits = new Bits pes_data
info.program_association = api.read_program_association_section bits
when videoPID, audioPID
bits = new Bits pes_data
if not opts?
opts = {}
opts.pid = pid
info.pes = api.read_pes_packet bits, opts
else
isParsed = false
for programNumber, pidInfo of programTable
if pid is pidInfo.program_map_PID
bits = new Bits pes_data
info.program_map = api.read_program_map_section bits
programMap = info.program_map
isParsed = true
if not isParsed
info.not_parsed = true
return info
read_system_header: (bits) ->
info = {}
system_header_start_code = bits.read_bits 32
if system_header_start_code isnt 0x000001BB
throw new Error "system_header_start_code must be 0x000001BB"
info.header_length = bits.read_bits 16
marker_bit = bits.read_bit()
info.rate_bound = bits.read_bits 22
marker_bit = bits.read_bit()
info.audio_bound = bits.read_bits 6
info.fixed_flag = bits.read_bit()
info.CSPS_flag = bits.read_bit()
info.system_audio_lock_flag = bits.read_bit()
info.system_video_lock_flag = bits.read_bit()
marker_bit = bits.read_bit()
info.video_bound = bits.read_bits 5
info.packet_rate_restriction_flag = bits.read_bit()
reserved_bits = bits.read_bits 7
info.total_length = 12
info.bufferBounds = {}
while ((nextByte = bits.read_byte()) & 0x80) is 0x80
stream_id = nextByte
bits_11 = bits.read_bits 2
if bits_11 isnt 3
throw new Error "bits must be '11': #{bits_11}"
P_STD_buffer_bound_scale = bits.read_bit()
P_STD_buffer_size_bound = bits.read_bits 13
info.bufferBounds[stream_id] =
P_STD_buffer_bound_scale: P_STD_buffer_bound_scale
P_STD_buffer_size_bound: P_STD_buffer_size_bound
info.total_length += 3
bits.push_back_byte()
return info
# pack_header()
read_pack_header: (bits) ->
info = {}
pack_start_code = bits.read_bits 32
if pack_start_code isnt 0x000001BA
throw new Error "pack_start_code must be 0x000001BA"
bits_01 = bits.read_bits 2
if bits_01 isnt 1
throw new Error "bits must be '01': #{bits_01}"
info.system_clock_reference_base = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.system_clock_reference_base += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.system_clock_reference_base += bits.read_bits(15)
marker_bit = bits.read_bit()
info.system_clock_reference_extension = bits.read_bits 9
marker_bit = bits.read_bit()
info.program_mux_rate = bits.read_bits 22
marker_bit = bits.read_bit()
marker_bit = bits.read_bit()
reserved = bits.read_bits 5
info.pack_stuffing_length = bits.read_bits 3
# skip stuffing bytes
bits.skip_bytes info.pack_stuffing_length
info.total_length = 14 + info.pack_stuffing_length
# check if system_header() exists
system_header_start_code = bits.read_bits 32
if system_header_start_code is 0x000001BB
bits.push_back_bits 32
info.system_header = api.read_system_header bits
info.total_length += info.system_header.total_length
return info
# PES_packet()
read_pes_packet: (bits, opts) ->
info = {}
# Start code emulation is not possible in video elementary streams.
# It is possible in audio and data elementary streams.
packet_start_code_prefix = bits.read_bits 24 # must be 0x000001
if packet_start_code_prefix isnt 0x000001
bits.push_back_bytes 3
bits.peek()
bits.print_position()
throw new Error "packet_start_code_prefix must be 0x000001: #{packet_start_code_prefix}"
info.stream_id = bits.read_byte()
# PES_packet_length is the length between the last byte of
# PES_packet_length and the first byte of PES_packet_data.
info.PES_packet_length = bits.read_bits 16 # do not use read_bytes(2)!
remaining_pes_len = info.PES_packet_length
# PES_packet_length == 0 indicates that the PES packet length is unbounded.
# Unbounded length is allowed only for video elementary streams because
# start code emulation (false positive) is prevented in video streams.
if info.PES_packet_length is 0
remaining_pes_len = MAX_PES_PAYLOAD_SIZE
if info.stream_id not in [
PES_STREAM_ID_PROGRAM_STREAM_MAP
PES_STREAM_ID_PADDING_STREAM
PES_STREAM_ID_PRIVATE_STREAM_2
PES_STREAM_ID_ECM
PES_STREAM_ID_EMM
PES_STREAM_ID_PROGRAM_STREAM_DIRECTORY
PES_STREAM_ID_DSMCC_STREAM
PES_STREAM_ID_ITU_T_REC_H_222_1_TYPE_E_STREAM
]
bits_10 = bits.read_bits 2
if bits_10 isnt 2
throw new Error "bits must be '10': #{bits_10}"
info.PES_scrambling_control = bits.read_bits 2
info.PES_priority = bits.read_bit()
info.data_alignment_indicator = bits.read_bit()
info.copyright = bits.read_bit()
info.original_or_copy = bits.read_bit()
info.PTS_DTS_flags = bits.read_bits 2
info.ESCR_flag = bits.read_bit()
info.ES_rate_flag = bits.read_bit()
info.DSM_trick_mode_flag = bits.read_bit()
info.additional_copy_info_flag = bits.read_bit()
info.PES_CRC_flag = bits.read_bit()
info.PES_extension_flag = bits.read_bit()
info.PES_header_data_length = bits.read_byte()
remaining_header_len = info.PES_header_data_length
remaining_pes_len -= 3
if info.PTS_DTS_flags is 2
bits_0010 = bits.read_bits 4
if bits_0010 isnt 2
throw new Error "Bits must be '0010': #{bits_0010}"
info.PTS = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.PTS += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.PTS += bits.read_bits(15)
marker_bit = bits.read_bit()
remaining_pes_len -= 5
remaining_header_len -= 5
if info.PTS_DTS_flags is 3
bits_0011 = bits.read_bits 4
if bits_0011 isnt 3
throw new Error "Bits must be '0011': #{bits_0011}"
info.PTS = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.PTS += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.PTS += bits.read_bits(15)
marker_bit = bits.read_bit()
bits_0001 = bits.read_bits 4
if bits_0001 isnt 1
throw new Error "Bits must be '0001': #{bits_0001}"
info.DTS = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.DTS += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.DTS += bits.read_bits(15)
marker_bit = bits.read_bit()
remaining_pes_len -= 10
remaining_header_len -= 10
if info.ESCR_flag is 1
reserved = bits.read_bits 2
info.ESCR_base = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.ESCR_base += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.ESCR_base += bits.read_bits(15)
marker_bit = bits.read_bit()
info.ESCR_extension = bits.read_bits 9
marker_bit = bits.read_bit()
remaining_pes_len -= 6
remaining_header_len -= 6
if info.ES_rate_flag is 1
marker_bit = bits.read_bit()
info.ES_rate = bits.read_bits 22
marker_bit = bits.read_bit()
remaining_pes_len -= 3
remaining_header_len -= 3
if info.DSM_trick_mode_flag is 1
info.trick_mode_control = bits.read_bits 3
if info.trick_mode_control is TRICK_MODE_CONTROL_FAST_FORWARD
info.field_id = bits.read_bits 2
info.intra_slice_refresh = bits.read_bit()
info.frequency_truncation = bits.read_bits 2
else if info.trick_mode_control is TRICK_MODE_CONTROL_SLOW_MOTION
info.rep_cntrl = bits.read_bits 5
else if info.trick_mode_control is TRICK_MODE_CONTROL_FREEZE_FRAME
info.field_id = bits.read_bits 2
reserved = bits.read_bits 3
else if info.trick_mode_control is TRICK_MODE_CONTROL_FAST_REVERSE
info.field_id = bits.read_bits 2
info.intra_slice_refresh = bits.read_bit()
info.frequency_truncation = bits.read_bits 2
else if info.trick_mode_control is TRICK_MODE_CONTROL_SLOW_REVERSE
info.rep_cntrl = bits.read_bits 5
else
reserved = bits.read_bits 5
remaining_pes_len--
remaining_header_len--
if info.additional_copy_info_flag is 1
marker_bit = bits.read_bit()
info.additional_copy_info = bits.read_bits 7
remaining_pes_len--
remaining_header_len--
if info.PES_CRC_flag is 1
info.previous_PES_packet_CRC = bits.read_bits 16
remaining_pes_len -= 2
remaining_header_len -= 2
if info.PES_extension_flag is 1
info.PES_private_data_flag = bits.read_bit()
info.pack_header_field_flag = bits.read_bit()
info.program_packet_sequence_counter_flag = bits.read_bit()
info.P_STD_buffer_flag = bits.read_bit()
reserved = bits.read_bits 3
info.PES_extension_flag_2 = bits.read_bit()
remaining_pes_len--
remaining_header_len--
if info.PES_private_data_flag is 1
info.PES_private_data = bits.read_bytes 16
remaining_pes_len -= 16
remaining_header_len -= 16
if info.pack_header_field_flag is 1
info.pack_field_length = bits.read_byte()
info.pack_header = api.read_pack_header bits
remaining_pes_len -= info.pack_header.total_length
remaining_header_len -= info.pack_header.total_length
if info.program_packet_sequence_counter_flag is 1
marker_bit = bits.read_bit()
info.program_packet_sequence_counter = bits.read_bits 7
marker_bit = bits.read_bit()
info.MPEG1_MPEG2_identifier = bits.read_bit()
info.original_stuff_length = bits.read_bits 6
remaining_pes_len -= 2
remaining_header_len -= 2
if info.P_STD_buffer_flag is 1
bits_01 = bits.read_bits 2
if bits_01 isnt 1
throw new Error "bits must be '01': #{bits_01}"
info.P_STD_buffer_scale = bits.read_bit()
info.P_STD_buffer_size = bits.read_bits 13
remaining_pes_len -= 2
remaining_header_len -= 2
if info.PES_extension_flag_2 is 1
marker_bit = bits.read_bit()
info.PES_extension_field_length = bits.read_bits 7
info.stream_id_extension_flag = bits.read_bit()
if info.stream_id_extension_flag is 0
info.stream_id_extension = bits.read_bits 7
bits.skip_bytes info.PES_extension_field_length # reserved
remaining_pes_len -= 2 + info.PES_extension_field_length
remaining_header_len -= 2 + info.PES_extension_field_length
else
throw new Error "stream_id_extension_flag == 1 is reserved"
# skip stuffing bytes
bits.skip_bytes remaining_header_len
remaining_pes_len -= remaining_header_len
# content
PES_packet_data_byte = bits.read_bytes remaining_pes_len, 1
info.data = PES_packet_data_byte
if (info.stream_id & 0b11110000) is 0b11100000 # video stream
info.stream_id_type = 'video'
else if (info.stream_id & 0b11100000) is 0b11000000 # audio stream
info.stream_id_type = 'audio'
else if info.stream_id in [
PES_STREAM_ID_PROGRAM_STREAM_MAP
PES_STREAM_ID_PRIVATE_STREAM_2
PES_STREAM_ID_ECM
PES_STREAM_ID_EMM
PES_STREAM_ID_PROGRAM_STREAM_DIRECTORY
PES_STREAM_ID_DSMCC_STREAM
PES_STREAM_ID_ITU_T_REC_H_222_1_TYPE_E_STREAM
]
throw new Error "stream_id type 2"
PES_packet_data_byte = bits.read_bytes remaining_pes_len, 1
info.data = PES_packet_data_byte
else if (info.stream_id is PES_STREAM_ID_PADDING_STREAM)
throw new Error "stream_id type padding"
padding_byte = bits.read_bytes remaining_pes_len, 1 # all 0xff
return info
# Sync byte (0x47) may occur within data byte.
# It appears that there is no emulation mechanism in MPEG-TS level.
# According to the spec, emulation of the sync byte is permitted
# to occur in the same position of the packet header for a maximum of
# 4-consecutive transport packets, though this is a recommendation.
search_sync_byte: (bits) ->
if isSyncByteDetermined
if not bits.is_byte_aligned()
throw new Error "search_sync_byte: byte is not aligned"
if bits.get_current_byte() isnt SYNC_BYTE
throw new Error "sync byte must be here: #{bits.get_current_byte()}"
else
read_len = 0
loop
if bits.read_byte() is SYNC_BYTE
# Check if 5 consecutive transport packets have
# sync byte at the same position.
for i in [1..4]
if bits.get_byte_at(i * TS_PACKET_SIZE - 1) isnt SYNC_BYTE
logger.debug "mpegts: sync byte was false positive"
# false positive (sync byte emulation)
continue
isSyncByteDetermined = true
if read_len > 0
logger.debug "mpegts: skipped #{read_len} bytes before sync byte"
bits.push_back_bytes 1
return
read_len++
read_adaptation_field: (bits) ->
info = {}
info.adaptation_field_length = bits.read_byte()
consumed_bytes = 0
if info.adaptation_field_length > 0
info.discontinuity_indicator = bits.read_bit()
info.random_access_indicator = bits.read_bit()
info.elementary_stream_priority_indicator = bits.read_bit()
info.pcr_flag = bits.read_bit()
info.opcr_flag = bits.read_bit()
info.splicing_point_flag = bits.read_bit()
info.transport_private_data_flag = bits.read_bit()
info.adaptation_field_extension_flag = bits.read_bit()
consumed_bytes++
if info.pcr_flag is 1
info.program_clock_reference_base = bits.read_bits 33
reserved = bits.read_bits 6
info.program_clock_reference_extension = bits.read_bits 9
consumed_bytes += 6
if info.opcr_flag is 1
info.original_program_clock_reference_base = bits.read_bits 33
reserved = read_bits 6
info.original_program_clock_reference_extension = bits.read_bits 9
consumed_bytes += 6
if info.splicing_point_flag is 1
info.splice_countdown = bits.read_byte()
consumed_bytes++
if info.transport_private_data_flag is 1
transport_private_data_length = bits.read_byte()
consumed_bytes++
info.private_data = bits.read_bytes transport_private_data_length
consumed_bytes += transport_private_data_length
if info.adaptation_field_extension_flag is 1
info.adaptation_field_extension_length = bits.read_byte()
info.ltw_flag = bits.read_bit()
info.piecewise_rate_flag = bits.read_bit()
info.seamless_splice_flag = bits.read_bit()
reserved = bits.read_bits 5
consumed_bytes += 2
if info.ltw_flag is 1
info.ltw_valid_flag = bits.read_bit()
info.ltw_offset = bits.read_bits 15
consumed_bytes += 2
if info.piecewise_rate_flag is 1
reserved = bits.read_bits 2
info.piecewise_rate = bits.read_bits 22
consumed_bytes += 3
if info.seamless_splice_flag is 1
info.splice_type = bits.read_bits 4
info.DTS_next_AU = bits.read_bits(3) * Math.pow(2, 30)
marker_bit = bits.read_bit()
info.DTS_next_AU += bits.read_bits(15) * Math.pow(2, 15)
marker_bit = bits.read_bit()
info.DTS_next_AU += bits.read_bits(15)
marker_bit = bits.read_bit()
consumed_bytes += 5
# skip stuffing bytes
bits.skip_bytes info.adaptation_field_length - consumed_bytes
return info
# Table 2-2 transport_packet()
read_transport_packet: (bits) ->
info = {}
api.search_sync_byte bits
sync_byte = bits.read_byte()
info.transport_error_indicator = bits.read_bit()
info.payload_unit_start_indicator = bits.read_bit()
transport_priority = bits.read_bit()
info.pid = bits.read_bits 13
# PID 0: Program Association Table
# PID 1: Conditional Access Table
# PID 2: Transport Stream Description Table
# PID 3: IPMP Control Information Table
# PID 4-15: reserved
# PID 8191: reserved for null packets
info.transport_scrambling_control = bits.read_bits 2
info.adaptation_field_control = bits.read_bits 2
info.continuity_counter = bits.read_bits 4
# at here, already consumed 4 bytes. remaining is 184 bytes.
remaining_bytes = TS_PACKET_SIZE - 4
if info.adaptation_field_control in [2, 3]
info.adaptation_field = api.read_adaptation_field bits
remaining_bytes -= info.adaptation_field.adaptation_field_length + 1
if info.adaptation_field_control in [1, 3]
info.data = bits.read_bytes remaining_bytes
# payload
return info
getNextPESPacket: ->
bits = tsBits
pesPacket = null
if not isEOF
loop
try
if not bits.has_more_data()
isEOF = true
break
ts_packet = api.read_transport_packet bits
if bufferingPESData[ts_packet.pid]?
pid_pes = bufferingPESData[ts_packet.pid]
if ts_packet.payload_unit_start_indicator
if pid_pes.tmp.data.length > 0
pid_pes.packets.push pid_pes.tmp
pesPacket = {
pid: ts_packet.pid
packet: pid_pes.tmp
opts:
adaptation_field: ts_packet.adaptation_field
}
pid_pes.tmp =
data: []
adaptation_field: ts_packet.adaptation_field
pid_pes.tmp.data.push ts_packet.data
if pesPacket?
return pesPacket
else
if not ts_packet.payload_unit_start_indicator
logger.warn "mpegts: dropping residual PES packet for PID #{ts_packet.pid}"
else
bufferingPESData[ts_packet.pid] =
packets: []
tmp:
data: [ts_packet.data]
adaptation_field: ts_packet.adaptation_field
catch e
isEOF = true
logger.error e.stack
break
for pid, pid_pes of bufferingPESData
delete bufferingPESData[pid]
if pid_pes.tmp.data.length > 0
pid_pes.packets.push pid_pes.tmp
pesPacket = {
pid: parseInt(pid)
packet: pid_pes.tmp
opts:
adaptation_field: pid_pes.adaptation_field
is_last: true
}
pid_pes.tmp = null
if pesPacket?
return pesPacket
return null
module.exports = api