aboutsummaryrefslogtreecommitdiffstats
path: root/codecs/codec_adpcm.c
blob: 892847683daa88e420ba72db3bc64567f7ba0144 (plain)
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
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Based on frompcm.c and topcm.c from the Emiliano MIPL browser/
 * interpreter.  See http://www.bsdtelephony.com.mx
 *
 * Copyright (c) 2001 - 2005 Digium, Inc.
 * All rights reserved.
 *
 * Karl Sackett <krs@linux-support.net>, 2001-03-21
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/* 
 *
 * codec_adpcm.c - translate between signed linear and Dialogic ADPCM
 * 
 */

#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision$")

#include "asterisk/lock.h"
#include "asterisk/logger.h"
#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/options.h"
#include "asterisk/translate.h"
#include "asterisk/channel.h"

/* define NOT_BLI to use a faster but not bit-level identical version */
/* #define NOT_BLI */

#define BUFFER_SIZE   8096	/* size for the translation buffers */

AST_MUTEX_DEFINE_STATIC(localuser_lock);
static int localusecnt = 0;

static char *tdesc = "Adaptive Differential PCM Coder/Decoder";

static int useplc = 0;

/* Sample frame data */

#include "slin_adpcm_ex.h"
#include "adpcm_slin_ex.h"

/*
 * Step size index shift table 
 */

static int indsft[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };

/*
 * Step size table, where stpsz[i]=floor[16*(11/10)^i]
 */

static int stpsz[49] = {
  16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73,
  80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279,
  307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963,
  1060, 1166, 1282, 1411, 1552
};

/*
 * Decoder/Encoder state
 *   States for both encoder and decoder are synchronized
 */
struct adpcm_state {
	int ssindex;
	int signal;
	int zero_count;
	int next_flag;
};

/*
 * Decode(encoded)
 *  Decodes the encoded nibble from the adpcm file.
 *
 * Results:
 *  Returns the encoded difference.
 *
 * Side effects:
 *  Sets the index to the step size table for the next encode.
 */

static inline short
decode(int encoded, struct adpcm_state* state)
{
	int diff;
	int step;
	int sign;

	step = stpsz[state->ssindex];

	sign = encoded & 0x08;
	encoded &= 0x07;
#ifdef NOT_BLI
	diff = (((encoded << 1) + 1) * step) >> 3;
#else /* BLI code */
	diff = step >> 3;
	if (encoded & 4) diff += step;
	if (encoded & 2) diff += step >> 1;
	if (encoded & 1) diff += step >> 2;
	if ((encoded >> 1) & step & 0x1)
		diff++;
#endif
	if (sign)
		diff = -diff;

	if (state->next_flag & 0x1)
		state->signal -= 8;
	else if (state->next_flag & 0x2)
		state->signal += 8;

	state->signal += diff;

	if (state->signal > 2047)
		state->signal = 2047;
	else if (state->signal < -2047)
		state->signal = -2047;

	state->next_flag = 0;

#ifdef AUTO_RETURN
	if (encoded)
		state->zero_count = 0;
	else if (++(state->zero_count) == 24)
	{
		state->zero_count = 0;
		if (state->signal > 0)
			state->next_flag = 0x1;
		else if (state->signal < 0)
			state->next_flag = 0x2;
	}
#endif

	state->ssindex += indsft[encoded];
	if (state->ssindex < 0)
		state->ssindex = 0;
	else if (state->ssindex > 48)
		state->ssindex = 48;

	return state->signal << 4;
}

/*
 * Adpcm
 *  Takes a signed linear signal and encodes it as ADPCM
 *  For more information see http://support.dialogic.com/appnotes/adpcm.pdf
 *
 * Results:
 *  Foo.
 *
 * Side effects:
 *  signal gets updated with each pass.
 */

static inline int
adpcm(short csig, struct adpcm_state* state)
{
	int diff;
	int step;
	int encoded;

	/* 
	* Clip csig if too large or too small
	*/
	csig >>= 4;

	step = stpsz[state->ssindex];
	diff = csig - state->signal;

#ifdef NOT_BLI
	if (diff < 0)
	{
		encoded = (-diff << 2) / step;
		if (encoded > 7)
			encoded = 7;
		encoded |= 0x08;
	}
	else
	{
		encoded = (diff << 2) / step;
		if (encoded > 7)
			encoded = 7;
	}
#else /* BLI code */
	if (diff < 0)
	{
		encoded = 8;
		diff = -diff;
	}
	else
		encoded = 0;
	if (diff >= step)
	{
		encoded |= 4;
		diff -= step;
	}
	step >>= 1;
	if (diff >= step)
	{
		encoded |= 2;
		diff -= step;
	}
	step >>= 1;
	if (diff >= step)
		encoded |= 1;
#endif /* NOT_BLI */

	/* feedback to state */
	decode(encoded, state);
	
	return encoded;
}

/*
 * Private workspace for translating signed linear signals to ADPCM.
 */

struct adpcm_encoder_pvt
{
  struct ast_frame f;
  char offset[AST_FRIENDLY_OFFSET];   /* Space to build offset */
  short inbuf[BUFFER_SIZE];           /* Unencoded signed linear values */
  unsigned char outbuf[BUFFER_SIZE];  /* Encoded ADPCM, two nibbles to a word */
  struct adpcm_state state;
  int tail;
};

/*
 * Private workspace for translating ADPCM signals to signed linear.
 */

struct adpcm_decoder_pvt
{
  struct ast_frame f;
  char offset[AST_FRIENDLY_OFFSET];	/* Space to build offset */
  short outbuf[BUFFER_SIZE];	/* Decoded signed linear values */
  struct adpcm_state state;
  int tail;
  plc_state_t plc;
};

/*
 * AdpcmToLin_New
 *  Create a new instance of adpcm_decoder_pvt.
 *
 * Results:
 *  Returns a pointer to the new instance.
 *
 * Side effects:
 *  None.
 */

static struct ast_translator_pvt *
adpcmtolin_new (void)
{
  struct adpcm_decoder_pvt *tmp;
  tmp = malloc (sizeof (struct adpcm_decoder_pvt));
  if (tmp)
    {
	  memset(tmp, 0, sizeof(*tmp));
      tmp->tail = 0;
      plc_init(&tmp->plc);
      localusecnt++;
      ast_update_use_count ();
    }
  return (struct ast_translator_pvt *) tmp;
}

/*
 * LinToAdpcm_New
 *  Create a new instance of adpcm_encoder_pvt.
 *
 * Results:
 *  Returns a pointer to the new instance.
 *
 * Side effects:
 *  None.
 */

static struct ast_translator_pvt *
lintoadpcm_new (void)
{
  struct adpcm_encoder_pvt *tmp;
  tmp = malloc (sizeof (struct adpcm_encoder_pvt));
  if (tmp)
    {
	  memset(tmp, 0, sizeof(*tmp));
      localusecnt++;
      ast_update_use_count ();
      tmp->tail = 0;
    }
  return (struct ast_translator_pvt *) tmp;
}

/*
 * AdpcmToLin_FrameIn
 *  Take an input buffer with packed 4-bit ADPCM values and put decoded PCM in outbuf, 
 *  if there is room left.
 *
 * Results:
 *  Foo
 *
 * Side effects:
 *  tmp->tail is the number of packed values in the buffer.
 */

static int
adpcmtolin_framein (struct ast_translator_pvt *pvt, struct ast_frame *f)
{
  struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt;
  int x;
  unsigned char *b;

  if(f->datalen == 0) { /* perform PLC with nominal framesize of 20ms/160 samples */
        if((tmp->tail + 160) > sizeof(tmp->outbuf) / 2) {
            ast_log(LOG_WARNING, "Out of buffer space\n");
            return -1;
        }
        if(useplc) {
	  plc_fillin(&tmp->plc, tmp->outbuf+tmp->tail, 160);
	  tmp->tail += 160;
	}
        return 0;
  }

  if (f->datalen * 4 + tmp->tail * 2 > sizeof(tmp->outbuf)) {
  	ast_log(LOG_WARNING, "Out of buffer space\n");
	return -1;
  }

  b = f->data;

  for (x=0;x<f->datalen;x++) {
	tmp->outbuf[tmp->tail++] = decode((b[x] >> 4) & 0xf, &tmp->state);
	tmp->outbuf[tmp->tail++] = decode(b[x] & 0x0f, &tmp->state);
  }

  if(useplc) plc_rx(&tmp->plc, tmp->outbuf+tmp->tail-f->datalen*2, f->datalen*2);

  return 0;
}

/*
 * AdpcmToLin_FrameOut
 *  Convert 4-bit ADPCM encoded signals to 16-bit signed linear.
 *
 * Results:
 *  Converted signals are placed in tmp->f.data, tmp->f.datalen
 *  and tmp->f.samples are calculated.
 *
 * Side effects:
 *  None.
 */

static struct ast_frame *
adpcmtolin_frameout (struct ast_translator_pvt *pvt)
{
  struct adpcm_decoder_pvt *tmp = (struct adpcm_decoder_pvt *) pvt;

  if (!tmp->tail)
    return NULL;

  tmp->f.frametype = AST_FRAME_VOICE;
  tmp->f.subclass = AST_FORMAT_SLINEAR;
  tmp->f.datalen = tmp->tail *2;
  tmp->f.samples = tmp->tail;
  tmp->f.mallocd = 0;
  tmp->f.offset = AST_FRIENDLY_OFFSET;
  tmp->f.src = __PRETTY_FUNCTION__;
  tmp->f.data = tmp->outbuf;
  tmp->tail = 0;
  return &tmp->f;
}

/*
 * LinToAdpcm_FrameIn
 *  Fill an input buffer with 16-bit signed linear PCM values.
 *
 * Results:
 *  None.
 *
 * Side effects:
 *  tmp->tail is number of signal values in the input buffer.
 */

static int
lintoadpcm_framein (struct ast_translator_pvt *pvt, struct ast_frame *f)
{
  struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt;

  if ((tmp->tail + f->datalen / 2) < (sizeof (tmp->inbuf) / 2))
    {
      memcpy (&tmp->inbuf[tmp->tail], f->data, f->datalen);
      tmp->tail += f->datalen / 2;
    }
  else
    {
      ast_log (LOG_WARNING, "Out of buffer space\n");
      return -1;
    }
  return 0;
}

/*
 * LinToAdpcm_FrameOut
 *  Convert a buffer of raw 16-bit signed linear PCM to a buffer
 *  of 4-bit ADPCM packed two to a byte (Big Endian).
 *
 * Results:
 *  Foo
 *
 * Side effects:
 *  Leftover inbuf data gets packed, tail gets updated.
 */

static struct ast_frame *
lintoadpcm_frameout (struct ast_translator_pvt *pvt)
{
  struct adpcm_encoder_pvt *tmp = (struct adpcm_encoder_pvt *) pvt;
  int i_max, i;
  
  if (tmp->tail < 2) return NULL;


  i_max = tmp->tail & ~1; /* atomic size is 2 samples */

  /* What is this, state debugging? should be #ifdef'd then
  tmp->outbuf[0] = tmp->ssindex & 0xff;
  tmp->outbuf[1] = (tmp->signal >> 8) & 0xff;
  tmp->outbuf[2] = (tmp->signal & 0xff);
  tmp->outbuf[3] = tmp->zero_count;
  tmp->outbuf[4] = tmp->next_flag;
  */
  for (i = 0; i < i_max; i+=2)
  {
    tmp->outbuf[i/2] =
      (adpcm(tmp->inbuf[i  ], &tmp->state) << 4) |
	  (adpcm(tmp->inbuf[i+1], &tmp->state)     );
  };


  tmp->f.frametype = AST_FRAME_VOICE;
  tmp->f.subclass = AST_FORMAT_ADPCM;
  tmp->f.samples = i_max;
  tmp->f.mallocd = 0;
  tmp->f.offset = AST_FRIENDLY_OFFSET;
  tmp->f.src = __PRETTY_FUNCTION__;
  tmp->f.data = tmp->outbuf;
  tmp->f.datalen = i_max / 2;

  /*
   * If there is a signal left over (there should be no more than
   * one) move it to the beginning of the input buffer.
   */

  if (tmp->tail == i_max)
    tmp->tail = 0;
  else
    {
      tmp->inbuf[0] = tmp->inbuf[tmp->tail];
      tmp->tail = 1;
    }
  return &tmp->f;
}


/*
 * AdpcmToLin_Sample
 */

static struct ast_frame *
adpcmtolin_sample (void)
{
  static struct ast_frame f;
  f.frametype = AST_FRAME_VOICE;
  f.subclass = AST_FORMAT_ADPCM;
  f.datalen = sizeof (adpcm_slin_ex);
  f.samples = sizeof(adpcm_slin_ex) * 2;
  f.mallocd = 0;
  f.offset = 0;
  f.src = __PRETTY_FUNCTION__;
  f.data = adpcm_slin_ex;
  return &f;
}

/*
 * LinToAdpcm_Sample
 */

static struct ast_frame *
lintoadpcm_sample (void)
{
  static struct ast_frame f;
  f.frametype = AST_FRAME_VOICE;
  f.subclass = AST_FORMAT_SLINEAR;
  f.datalen = sizeof (slin_adpcm_ex);
  /* Assume 8000 Hz */
  f.samples = sizeof (slin_adpcm_ex) / 2;
  f.mallocd = 0;
  f.offset = 0;
  f.src = __PRETTY_FUNCTION__;
  f.data = slin_adpcm_ex;
  return &f;
}

/*
 * Adpcm_Destroy
 *  Destroys a private workspace.
 *
 * Results:
 *  It's gone!
 *
 * Side effects:
 *  None.
 */

static void
adpcm_destroy (struct ast_translator_pvt *pvt)
{
  free (pvt);
  localusecnt--;
  ast_update_use_count ();
}

/*
 * The complete translator for ADPCMToLin.
 */

static struct ast_translator adpcmtolin = {
  "adpcmtolin",
  AST_FORMAT_ADPCM,
  AST_FORMAT_SLINEAR,
  adpcmtolin_new,
  adpcmtolin_framein,
  adpcmtolin_frameout,
  adpcm_destroy,
  /* NULL */
  adpcmtolin_sample
};

/*
 * The complete translator for LinToADPCM.
 */

static struct ast_translator lintoadpcm = {
  "lintoadpcm",
  AST_FORMAT_SLINEAR,
  AST_FORMAT_ADPCM,
  lintoadpcm_new,
  lintoadpcm_framein,
  lintoadpcm_frameout,
  adpcm_destroy,
  /* NULL */
  lintoadpcm_sample
};

static void 
parse_config(void)
{
  struct ast_config *cfg;
  struct ast_variable *var;
  if ((cfg = ast_config_load("codecs.conf"))) {
    if ((var = ast_variable_browse(cfg, "plc"))) {
      while (var) {
       if (!strcasecmp(var->name, "genericplc")) {
         useplc = ast_true(var->value) ? 1 : 0;
         if (option_verbose > 2)
           ast_verbose(VERBOSE_PREFIX_3 "codec_adpcm: %susing generic PLC\n", useplc ? "" : "not ");
       }
       var = var->next;
      }
    }
    ast_config_destroy(cfg);
  }
}

int
reload(void)
{
  parse_config();
  return 0;
}

int
unload_module (void)
{
  int res;
  ast_mutex_lock (&localuser_lock);
  res = ast_unregister_translator (&lintoadpcm);
  if (!res)
    res = ast_unregister_translator (&adpcmtolin);
  if (localusecnt)
    res = -1;
  ast_mutex_unlock (&localuser_lock);
  return res;
}

int
load_module (void)
{
  int res;
  parse_config();
  res = ast_register_translator (&adpcmtolin);
  if (!res)
    res = ast_register_translator (&lintoadpcm);
  else
    ast_unregister_translator (&adpcmtolin);
  return res;
}

/*
 * Return a description of this module.
 */

char *
description (void)
{
  return tdesc;
}

int
usecount (void)
{
  int res;
  STANDARD_USECOUNT (res);
  return res;
}

char *
key ()
{
  return ASTERISK_GPL_KEY;
}