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
|
/* deca52.c
Copyright (c) 2003-2012 HandBrake Team
This file is part of the HandBrake source code
Homepage: <http://handbrake.fr/>.
It may be used under the terms of the GNU General Public License v2.
For full terms see the file COPYING file or visit http://www.gnu.org/licenses/gpl-2.0.html
*/
#include "hb.h"
#include "audio_remap.h"
#include "a52dec/a52.h"
#include "libavutil/crc.h"
struct hb_work_private_s
{
hb_job_t * job;
/* liba52 handle */
a52_state_t * state;
int flags_in;
int flags_out;
int rate;
int bitrate;
int out_discrete_channels;
int error;
int frames; // number of good frames decoded
int crc_errors; // number of frames with crc errors
int bytes_dropped; // total bytes dropped while resyncing
float level;
float dynamic_range_compression;
double next_expected_pts;
int64_t last_buf_pts;
hb_list_t *list;
const AVCRC *crc_table;
uint8_t frame[3840];
};
static int deca52Init( hb_work_object_t *, hb_job_t * );
static int deca52Work( hb_work_object_t *, hb_buffer_t **, hb_buffer_t ** );
static void deca52Close( hb_work_object_t * );
static int deca52BSInfo( hb_work_object_t * , const hb_buffer_t *,
hb_work_info_t * );
hb_work_object_t hb_deca52 =
{
WORK_DECA52,
"AC3 decoder",
deca52Init,
deca52Work,
deca52Close,
0,
deca52BSInfo
};
/***********************************************************************
* Local prototypes
**********************************************************************/
static hb_buffer_t * Decode( hb_work_object_t * w );
/***********************************************************************
* dynrng_call
***********************************************************************
* Boosts soft audio -- taken from gbooker's work in A52Decoder, comment and all..
* Two cases
* 1) The user requested a compression of 1 or less, return the typical power rule
* 2) The user requested a compression of more than 1 (decompression):
* If the stream's requested compression is less than 1.0 (loud sound), return the normal compression
* If the stream's requested compression is more than 1.0 (soft sound), use power rule (which will make
* it louder in this case).
*
**********************************************************************/
static sample_t dynrng_call (sample_t c, void *data)
{
float *level = (float *)data;
float levelToUse = (float)*level;
if(c > 1.0 || levelToUse <= 1.0)
{
return powf(c, levelToUse);
}
else
return c;
}
/***********************************************************************
* hb_work_deca52_init
***********************************************************************
* Allocate the work object, initialize liba52
**********************************************************************/
static int deca52Init( hb_work_object_t * w, hb_job_t * job )
{
hb_work_private_t * pv = calloc( 1, sizeof( hb_work_private_t ) );
hb_audio_t * audio = w->audio;
w->private_data = pv;
pv->job = job;
pv->crc_table = av_crc_get_table( AV_CRC_16_ANSI );
pv->list = hb_list_init();
pv->state = a52_init( 0 );
pv->level = 1.0;
pv->dynamic_range_compression = audio->config.out.dynamic_range_compression;
/* Decide what format we want out of a52dec;
* work.c has already done some of this deduction for us in do_job(). */
switch( audio->config.out.mixdown )
{
case HB_AMIXDOWN_6CH:
pv->flags_out = (A52_3F2R|A52_LFE);
break;
case HB_AMIXDOWN_DOLBYPLII:
pv->flags_out = (A52_DOLBY|A52_USE_DPLII);
break;
case HB_AMIXDOWN_DOLBY:
pv->flags_out = A52_DOLBY;
break;
case HB_AMIXDOWN_MONO:
pv->flags_out = A52_MONO;
break;
default:
pv->flags_out = A52_STEREO;
break;
}
/* pass the number of channels used into the private work data */
pv->out_discrete_channels = hb_mixdown_get_discrete_channel_count( audio->config.out.mixdown );
return 0;
}
/***********************************************************************
* Close
***********************************************************************
* Free memory
**********************************************************************/
static void deca52Close( hb_work_object_t * w )
{
hb_work_private_t * pv = w->private_data;
if ( pv->crc_errors )
{
hb_log( "deca52: %d frames decoded, %d crc errors, %d bytes dropped",
pv->frames, pv->crc_errors, pv->bytes_dropped );
}
a52_free( pv->state );
hb_list_empty( &pv->list );
free( pv );
w->private_data = NULL;
}
/***********************************************************************
* Work
***********************************************************************
* Add the given buffer to the data we already have, and decode as much
* as we can
**********************************************************************/
static int deca52Work( hb_work_object_t * w, hb_buffer_t ** buf_in,
hb_buffer_t ** buf_out )
{
hb_work_private_t * pv = w->private_data;
hb_buffer_t * buf;
if ( (*buf_in)->size <= 0 )
{
/* EOF on input stream - send it downstream & say that we're done */
*buf_out = *buf_in;
*buf_in = NULL;
return HB_WORK_DONE;
}
if ( (*buf_in)->s.start < -1 && pv->next_expected_pts == 0 )
{
// discard buffers that start before video time 0
*buf_out = NULL;
return HB_WORK_OK;
}
hb_list_add( pv->list, *buf_in );
*buf_in = NULL;
/* If we got more than a frame, chain raw buffers */
*buf_out = buf = Decode( w );
while( buf )
{
buf->next = Decode( w );
buf = buf->next;
}
return HB_WORK_OK;
}
/***********************************************************************
* Decode
***********************************************************************
*
**********************************************************************/
static hb_buffer_t * Decode( hb_work_object_t * w )
{
hb_work_private_t * pv = w->private_data;
hb_buffer_t * buf;
hb_audio_t * audio = w->audio;
int i, j, k;
int size = 0;
// check that we're at the start of a valid frame and align to the
// start of a valid frame if we're not.
// we have to check the header & crc so we need at least
// 7 (the header size) + 128 (the minimum frame size) bytes
while( hb_list_bytes( pv->list ) >= 7+128 )
{
/* check if this is a valid header */
hb_list_seebytes( pv->list, pv->frame, 7 );
size = a52_syncinfo( pv->frame, &pv->flags_in, &pv->rate, &pv->bitrate );
if ( size > 0 )
{
// header looks valid - check the crc1
if( size > hb_list_bytes( pv->list ) )
{
// don't have all the frame's data yet
return NULL;
}
int crc1size = (size >> 1) + (size >> 3);
hb_list_seebytes( pv->list, pv->frame, crc1size );
if ( av_crc( pv->crc_table, 0, pv->frame + 2, crc1size - 2 ) == 0 )
{
// crc1 is ok - say we have valid frame sync
if( pv->error )
{
hb_log( "output track %d: ac3 in sync after skipping %d bytes",
audio->config.out.track, pv->error );
pv->bytes_dropped += pv->error;
pv->error = 0;
}
break;
}
}
// no sync - discard one byte then try again
hb_list_getbytes( pv->list, pv->frame, 1, NULL, NULL );
++pv->error;
}
// we exit the above loop either in error state (we didn't find sync
// or don't have enough data yet to validate sync) or in sync. If we're
// not in sync we need more data so just return.
if( pv->error || size <= 0 || hb_list_bytes( pv->list ) < size )
{
/* Need more data */
return NULL;
}
// Get the whole frame and check its CRC. If the CRC is wrong
// discard the frame - we'll resync on the next call.
uint64_t ipts;
hb_list_getbytes( pv->list, pv->frame, size, &ipts, NULL );
if ( av_crc( pv->crc_table, 0, pv->frame + 2, size - 2 ) != 0 )
{
++pv->crc_errors;
return NULL;
}
++pv->frames;
if ( ipts != pv->last_buf_pts )
{
pv->last_buf_pts = ipts;
}
else
{
// spec says that the PTS is the start time of the first frame
// that starts in the PES frame so we only use the PTS once then
// get the following frames' PTS from the frame length.
ipts = -1;
}
double pts = ( ipts != -1 ) ? ipts : pv->next_expected_pts;
double frame_dur = (6. * 256. * 90000.) / pv->rate;
/* AC3 passthrough: don't decode the AC3 frame */
if( audio->config.out.codec == HB_ACODEC_AC3_PASS )
{
buf = hb_buffer_init( size );
memcpy( buf->data, pv->frame, size );
buf->s.start = pts;
buf->s.duration = frame_dur;
pts += frame_dur;
buf->s.stop = pts;
pv->next_expected_pts = pts;
return buf;
}
/* Feed liba52 */
a52_frame( pv->state, pv->frame, &pv->flags_out, &pv->level, 0 );
/* If a user specifies strong dynamic range compression (>1), adjust it.
If a user specifies default dynamic range compression (1), leave it alone.
If a user specifies no dynamic range compression (0), call a null function. */
if( pv->dynamic_range_compression > 1.0 )
{
a52_dynrng( pv->state, dynrng_call, &pv->dynamic_range_compression );
}
else if( !pv->dynamic_range_compression )
{
a52_dynrng( pv->state, NULL, NULL );
}
/* 6 blocks per frame, 256 samples per block, channelsused channels */
buf = hb_buffer_init( 6 * 256 * pv->out_discrete_channels * sizeof( float ) );
buf->s.start = pts;
buf->s.duration = frame_dur;
pts += frame_dur;
buf->s.stop = pts;
pv->next_expected_pts = pts;
for( i = 0; i < 6; i++ )
{
sample_t * samples_in;
float * samples_out;
a52_block( pv->state );
samples_in = a52_samples( pv->state );
samples_out = ((float *) buf->data) + 256 * pv->out_discrete_channels * i;
/* Interleave */
for( j = 0; j < 256; j++ )
{
for ( k = 0; k < pv->out_discrete_channels; k++ )
{
samples_out[(pv->out_discrete_channels*j)+k] = samples_in[(256*k)+j];
}
}
}
return buf;
}
static int find_sync( const uint8_t *buf, int len )
{
int i;
// since AC3 frames don't line up with MPEG ES frames scan the
// frame for an AC3 sync pattern.
for ( i = 0; i < len - 16; ++i )
{
int rate, bitrate, flags;
int size = a52_syncinfo( (uint8_t *)buf + i, &flags, &rate, &bitrate );
if( size > 0 )
{
// we have a plausible sync header - see if crc1 checks
int crc1size = (size >> 1) + (size >> 3);
if ( i + crc1size > len )
{
// don't have enough data to check crc1
break;
}
if ( av_crc( av_crc_get_table( AV_CRC_16_ANSI ), 0,
buf + i + 2, crc1size - 2 ) == 0 )
{
// crc checks - we've got sync
return i;
}
}
}
return -1;
}
static int deca52BSInfo( hb_work_object_t *w, const hb_buffer_t *b,
hb_work_info_t *info )
{
memset( info, 0, sizeof(*info) );
// We don't know if the way that AC3 frames are fragmented into whatever
// packetization the container uses will give us enough bytes per fragment
// to check the CRC (we need at least 5/8 of the the frame). So we
// copy the fragment we got into an accumulation buffer in the audio object
// then look for sync over all the frags we've accumulated so far.
uint8_t *buf = w->audio->priv.config.a52.buf;
int len = w->audio->priv.config.a52.len, blen = b->size;
if ( len + blen > sizeof(w->audio->priv.config.a52.buf) )
{
// we don't have enough empty space in the accumulation buffer to
// hold the new frag - make room for it by discarding the oldest data.
if ( blen >= sizeof(w->audio->priv.config.a52.buf) )
{
// the frag is bigger than our accumulation buffer - copy all
// that will fit (the excess doesn't matter since the buffer
// is many times the size of a max length ac3 frame).
blen = sizeof(w->audio->priv.config.a52.buf);
len = 0;
}
else
{
// discard enough bytes from the front of the buffer to make
// room for the new stuff
int newlen = sizeof(w->audio->priv.config.a52.buf) - blen;
memmove( buf, buf + len - newlen, newlen );
len = newlen;
}
}
// add the new frag to the buffer
memcpy( buf+len, b->data, blen );
len += blen;
int i;
if ( ( i = find_sync( buf, len ) ) < 0 )
{
// didn't find sync - wait for more data
w->audio->priv.config.a52.len = len;
return 0;
}
// got sync - extract and canoncalize the bitstream parameters
int rate = 0, bitrate = 0, flags = 0;
uint8_t raw = buf[i + 5];
a52_syncinfo( buf + i, &flags, &rate, &bitrate );
if ( rate == 0 || bitrate == 0 )
{
// invalid AC-3 parameters - toss what we have so we'll start over
// with the next buf otherwise we'll keep syncing on this junk.
w->audio->priv.config.a52.len = 0;
return 0;
}
// bsid | bsmod | acmod | cmixlv | surmixlv | dsurmod | lfeon | dialnorm | compre
// 5 3 3 2 2 2 1 5 1
// byte1 | byte2 | byte3
info->name = "AC-3";
info->rate = rate;
info->rate_base = 1;
info->bitrate = bitrate;
info->flags = flags;
info->version = raw >> 3; /* bsid is the first 5 bits */
info->mode = raw & 0x7; /* bsmod is the following 3 bits */
info->samples_per_frame = 1536;
switch( flags & A52_CHANNEL_MASK )
{
/* mono sources */
case A52_MONO:
case A52_CHANNEL1:
case A52_CHANNEL2:
info->channel_layout = AV_CH_LAYOUT_MONO;
break;
/* stereo input */
case A52_CHANNEL:
case A52_STEREO:
info->channel_layout = AV_CH_LAYOUT_STEREO;
break;
/* Dolby Pro Logic (a.k.a. Dolby Surround), 4.0 channels (matrix-encoded) */
case A52_DOLBY:
info->channel_layout = AV_CH_LAYOUT_STEREO_DOWNMIX;
break;
/* 3F/2R input */
case A52_3F2R:
info->channel_layout = AV_CH_LAYOUT_5POINT0;
break;
/* 3F/1R input */
case A52_3F1R:
info->channel_layout = AV_CH_LAYOUT_4POINT0;
break;
/* other inputs */
case A52_3F:
info->channel_layout = AV_CH_LAYOUT_SURROUND;
break;
case A52_2F1R:
info->channel_layout = AV_CH_LAYOUT_2_1;
break;
case A52_2F2R:
info->channel_layout = AV_CH_LAYOUT_2_2;
break;
/* unknown */
default:
info->channel_layout = AV_CH_LAYOUT_STEREO;
}
if (flags & A52_LFE)
{
info->channel_layout |= AV_CH_LOW_FREQUENCY;
}
info->channel_map = &hb_liba52_chan_map;
return 1;
}
|