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g726.c
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1 /*
2  * G.726 ADPCM audio codec
3  * Copyright (c) 2004 Roman Shaposhnik
4  *
5  * This is a very straightforward rendition of the G.726
6  * Section 4 "Computational Details".
7  *
8  * This file is part of FFmpeg.
9  *
10  * FFmpeg is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * FFmpeg is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with FFmpeg; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 #include <limits.h>
25 
27 #include "libavutil/opt.h"
28 #include "avcodec.h"
29 #include "internal.h"
30 #include "get_bits.h"
31 #include "put_bits.h"
32 
33 /**
34  * G.726 11bit float.
35  * G.726 Standard uses rather odd 11bit floating point arithmetic for
36  * numerous occasions. It's a mystery to me why they did it this way
37  * instead of simply using 32bit integer arithmetic.
38  */
39 typedef struct Float11 {
40  uint8_t sign; /**< 1bit sign */
41  uint8_t exp; /**< 4bit exponent */
42  uint8_t mant; /**< 6bit mantissa */
43 } Float11;
44 
45 static inline Float11* i2f(int i, Float11* f)
46 {
47  f->sign = (i < 0);
48  if (f->sign)
49  i = -i;
50  f->exp = av_log2_16bit(i) + !!i;
51  f->mant = i? (i<<6) >> f->exp : 1<<5;
52  return f;
53 }
54 
55 static inline int16_t mult(Float11* f1, Float11* f2)
56 {
57  int res, exp;
58 
59  exp = f1->exp + f2->exp;
60  res = (((f1->mant * f2->mant) + 0x30) >> 4);
61  res = exp > 19 ? res << (exp - 19) : res >> (19 - exp);
62  return (f1->sign ^ f2->sign) ? -res : res;
63 }
64 
65 static inline int sgn(int value)
66 {
67  return (value < 0) ? -1 : 1;
68 }
69 
70 typedef struct G726Tables {
71  const int* quant; /**< quantization table */
72  const int16_t* iquant; /**< inverse quantization table */
73  const int16_t* W; /**< special table #1 ;-) */
74  const uint8_t* F; /**< special table #2 */
75 } G726Tables;
76 
77 typedef struct G726Context {
78  AVClass *class;
79  G726Tables tbls; /**< static tables needed for computation */
80 
81  Float11 sr[2]; /**< prev. reconstructed samples */
82  Float11 dq[6]; /**< prev. difference */
83  int a[2]; /**< second order predictor coeffs */
84  int b[6]; /**< sixth order predictor coeffs */
85  int pk[2]; /**< signs of prev. 2 sez + dq */
86 
87  int ap; /**< scale factor control */
88  int yu; /**< fast scale factor */
89  int yl; /**< slow scale factor */
90  int dms; /**< short average magnitude of F[i] */
91  int dml; /**< long average magnitude of F[i] */
92  int td; /**< tone detect */
93 
94  int se; /**< estimated signal for the next iteration */
95  int sez; /**< estimated second order prediction */
96  int y; /**< quantizer scaling factor for the next iteration */
97  int code_size;
98  int little_endian; /**< little-endian bitstream as used in aiff and Sun AU */
99 } G726Context;
100 
101 static const int quant_tbl16[] = /**< 16kbit/s 2bits per sample */
102  { 260, INT_MAX };
103 static const int16_t iquant_tbl16[] =
104  { 116, 365, 365, 116 };
105 static const int16_t W_tbl16[] =
106  { -22, 439, 439, -22 };
107 static const uint8_t F_tbl16[] =
108  { 0, 7, 7, 0 };
109 
110 static const int quant_tbl24[] = /**< 24kbit/s 3bits per sample */
111  { 7, 217, 330, INT_MAX };
112 static const int16_t iquant_tbl24[] =
113  { INT16_MIN, 135, 273, 373, 373, 273, 135, INT16_MIN };
114 static const int16_t W_tbl24[] =
115  { -4, 30, 137, 582, 582, 137, 30, -4 };
116 static const uint8_t F_tbl24[] =
117  { 0, 1, 2, 7, 7, 2, 1, 0 };
118 
119 static const int quant_tbl32[] = /**< 32kbit/s 4bits per sample */
120  { -125, 79, 177, 245, 299, 348, 399, INT_MAX };
121 static const int16_t iquant_tbl32[] =
122  { INT16_MIN, 4, 135, 213, 273, 323, 373, 425,
123  425, 373, 323, 273, 213, 135, 4, INT16_MIN };
124 static const int16_t W_tbl32[] =
125  { -12, 18, 41, 64, 112, 198, 355, 1122,
126  1122, 355, 198, 112, 64, 41, 18, -12};
127 static const uint8_t F_tbl32[] =
128  { 0, 0, 0, 1, 1, 1, 3, 7, 7, 3, 1, 1, 1, 0, 0, 0 };
129 
130 static const int quant_tbl40[] = /**< 40kbit/s 5bits per sample */
131  { -122, -16, 67, 138, 197, 249, 297, 338,
132  377, 412, 444, 474, 501, 527, 552, INT_MAX };
133 static const int16_t iquant_tbl40[] =
134  { INT16_MIN, -66, 28, 104, 169, 224, 274, 318,
135  358, 395, 429, 459, 488, 514, 539, 566,
136  566, 539, 514, 488, 459, 429, 395, 358,
137  318, 274, 224, 169, 104, 28, -66, INT16_MIN };
138 static const int16_t W_tbl40[] =
139  { 14, 14, 24, 39, 40, 41, 58, 100,
140  141, 179, 219, 280, 358, 440, 529, 696,
141  696, 529, 440, 358, 280, 219, 179, 141,
142  100, 58, 41, 40, 39, 24, 14, 14 };
143 static const uint8_t F_tbl40[] =
144  { 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 6,
145  6, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
146 
147 static const G726Tables G726Tables_pool[] =
152 
153 
154 /**
155  * Para 4.2.2 page 18: Adaptive quantizer.
156  */
157 static inline uint8_t quant(G726Context* c, int d)
158 {
159  int sign, exp, i, dln;
160 
161  sign = i = 0;
162  if (d < 0) {
163  sign = 1;
164  d = -d;
165  }
166  exp = av_log2_16bit(d);
167  dln = ((exp<<7) + (((d<<7)>>exp)&0x7f)) - (c->y>>2);
168 
169  while (c->tbls.quant[i] < INT_MAX && c->tbls.quant[i] < dln)
170  ++i;
171 
172  if (sign)
173  i = ~i;
174  if (c->code_size != 2 && i == 0) /* I'm not sure this is a good idea */
175  i = 0xff;
176 
177  return i;
178 }
179 
180 /**
181  * Para 4.2.3 page 22: Inverse adaptive quantizer.
182  */
183 static inline int16_t inverse_quant(G726Context* c, int i)
184 {
185  int dql, dex, dqt;
186 
187  dql = c->tbls.iquant[i] + (c->y >> 2);
188  dex = (dql>>7) & 0xf; /* 4bit exponent */
189  dqt = (1<<7) + (dql & 0x7f); /* log2 -> linear */
190  return (dql < 0) ? 0 : ((dqt<<dex) >> 7);
191 }
192 
193 static int16_t g726_decode(G726Context* c, int I)
194 {
195  int dq, re_signal, pk0, fa1, i, tr, ylint, ylfrac, thr2, al, dq0;
196  Float11 f;
197  int I_sig= I >> (c->code_size - 1);
198 
199  dq = inverse_quant(c, I);
200 
201  /* Transition detect */
202  ylint = (c->yl >> 15);
203  ylfrac = (c->yl >> 10) & 0x1f;
204  thr2 = (ylint > 9) ? 0x1f << 10 : (0x20 + ylfrac) << ylint;
205  tr= (c->td == 1 && dq > ((3*thr2)>>2));
206 
207  if (I_sig) /* get the sign */
208  dq = -dq;
209  re_signal = c->se + dq;
210 
211  /* Update second order predictor coefficient A2 and A1 */
212  pk0 = (c->sez + dq) ? sgn(c->sez + dq) : 0;
213  dq0 = dq ? sgn(dq) : 0;
214  if (tr) {
215  c->a[0] = 0;
216  c->a[1] = 0;
217  for (i=0; i<6; i++)
218  c->b[i] = 0;
219  } else {
220  /* This is a bit crazy, but it really is +255 not +256 */
221  fa1 = av_clip_intp2((-c->a[0]*c->pk[0]*pk0)>>5, 8);
222 
223  c->a[1] += 128*pk0*c->pk[1] + fa1 - (c->a[1]>>7);
224  c->a[1] = av_clip(c->a[1], -12288, 12288);
225  c->a[0] += 64*3*pk0*c->pk[0] - (c->a[0] >> 8);
226  c->a[0] = av_clip(c->a[0], -(15360 - c->a[1]), 15360 - c->a[1]);
227 
228  for (i=0; i<6; i++)
229  c->b[i] += 128*dq0*sgn(-c->dq[i].sign) - (c->b[i]>>8);
230  }
231 
232  /* Update Dq and Sr and Pk */
233  c->pk[1] = c->pk[0];
234  c->pk[0] = pk0 ? pk0 : 1;
235  c->sr[1] = c->sr[0];
236  i2f(re_signal, &c->sr[0]);
237  for (i=5; i>0; i--)
238  c->dq[i] = c->dq[i-1];
239  i2f(dq, &c->dq[0]);
240  c->dq[0].sign = I_sig; /* Isn't it crazy ?!?! */
241 
242  c->td = c->a[1] < -11776;
243 
244  /* Update Ap */
245  c->dms += (c->tbls.F[I]<<4) + ((- c->dms) >> 5);
246  c->dml += (c->tbls.F[I]<<4) + ((- c->dml) >> 7);
247  if (tr)
248  c->ap = 256;
249  else {
250  c->ap += (-c->ap) >> 4;
251  if (c->y <= 1535 || c->td || abs((c->dms << 2) - c->dml) >= (c->dml >> 3))
252  c->ap += 0x20;
253  }
254 
255  /* Update Yu and Yl */
256  c->yu = av_clip(c->y + c->tbls.W[I] + ((-c->y)>>5), 544, 5120);
257  c->yl += c->yu + ((-c->yl)>>6);
258 
259  /* Next iteration for Y */
260  al = (c->ap >= 256) ? 1<<6 : c->ap >> 2;
261  c->y = (c->yl + (c->yu - (c->yl>>6))*al) >> 6;
262 
263  /* Next iteration for SE and SEZ */
264  c->se = 0;
265  for (i=0; i<6; i++)
266  c->se += mult(i2f(c->b[i] >> 2, &f), &c->dq[i]);
267  c->sez = c->se >> 1;
268  for (i=0; i<2; i++)
269  c->se += mult(i2f(c->a[i] >> 2, &f), &c->sr[i]);
270  c->se >>= 1;
271 
272  return av_clip(re_signal << 2, -0xffff, 0xffff);
273 }
274 
276 {
277  int i;
278 
279  c->tbls = G726Tables_pool[c->code_size - 2];
280  for (i=0; i<2; i++) {
281  c->sr[i].mant = 1<<5;
282  c->pk[i] = 1;
283  }
284  for (i=0; i<6; i++) {
285  c->dq[i].mant = 1<<5;
286  }
287  c->yu = 544;
288  c->yl = 34816;
289 
290  c->y = 544;
291 
292  return 0;
293 }
294 
295 #if CONFIG_ADPCM_G726_ENCODER
296 static int16_t g726_encode(G726Context* c, int16_t sig)
297 {
298  uint8_t i;
299 
300  i = av_mod_uintp2(quant(c, sig/4 - c->se), c->code_size);
301  g726_decode(c, i);
302  return i;
303 }
304 
305 /* Interfacing to the libavcodec */
306 
307 static av_cold int g726_encode_init(AVCodecContext *avctx)
308 {
309  G726Context* c = avctx->priv_data;
310 
312  avctx->sample_rate != 8000) {
313  av_log(avctx, AV_LOG_ERROR, "Sample rates other than 8kHz are not "
314  "allowed when the compliance level is higher than unofficial. "
315  "Resample or reduce the compliance level.\n");
316  return AVERROR(EINVAL);
317  }
318  if (avctx->sample_rate <= 0) {
319  av_log(avctx, AV_LOG_ERROR, "Invalid sample rate %d\n",
320  avctx->sample_rate);
321  return AVERROR(EINVAL);
322  }
323 
324  if(avctx->channels != 1){
325  av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");
326  return AVERROR(EINVAL);
327  }
328 
329  if (avctx->bit_rate)
330  c->code_size = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate;
331 
332  c->code_size = av_clip(c->code_size, 2, 5);
333  avctx->bit_rate = c->code_size * avctx->sample_rate;
334  avctx->bits_per_coded_sample = c->code_size;
335 
336  g726_reset(c);
337 
338  /* select a frame size that will end on a byte boundary and have a size of
339  approximately 1024 bytes */
340  avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[c->code_size - 2];
341 
342  return 0;
343 }
344 
345 static int g726_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
346  const AVFrame *frame, int *got_packet_ptr)
347 {
348  G726Context *c = avctx->priv_data;
349  const int16_t *samples = (const int16_t *)frame->data[0];
350  PutBitContext pb;
351  int i, ret, out_size;
352 
353  out_size = (frame->nb_samples * c->code_size + 7) / 8;
354  if ((ret = ff_alloc_packet2(avctx, avpkt, out_size, 0)) < 0)
355  return ret;
356  init_put_bits(&pb, avpkt->data, avpkt->size);
357 
358  for (i = 0; i < frame->nb_samples; i++)
359  put_bits(&pb, c->code_size, g726_encode(c, *samples++));
360 
361  flush_put_bits(&pb);
362 
363  avpkt->size = out_size;
364  *got_packet_ptr = 1;
365  return 0;
366 }
367 
368 #define OFFSET(x) offsetof(G726Context, x)
369 #define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
370 static const AVOption options[] = {
371  { "code_size", "Bits per code", OFFSET(code_size), AV_OPT_TYPE_INT, { .i64 = 4 }, 2, 5, AE },
372  { NULL },
373 };
374 
375 static const AVClass g726_class = {
376  .class_name = "g726",
377  .item_name = av_default_item_name,
378  .option = options,
379  .version = LIBAVUTIL_VERSION_INT,
380 };
381 
382 static const AVCodecDefault defaults[] = {
383  { "b", "0" },
384  { NULL },
385 };
386 
387 AVCodec ff_adpcm_g726_encoder = {
388  .name = "g726",
389  .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM"),
390  .type = AVMEDIA_TYPE_AUDIO,
392  .priv_data_size = sizeof(G726Context),
393  .init = g726_encode_init,
394  .encode2 = g726_encode_frame,
395  .capabilities = AV_CODEC_CAP_SMALL_LAST_FRAME,
396  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
398  .priv_class = &g726_class,
399  .defaults = defaults,
400 };
401 #endif
402 
403 #if CONFIG_ADPCM_G726_DECODER || CONFIG_ADPCM_G726LE_DECODER
404 static av_cold int g726_decode_init(AVCodecContext *avctx)
405 {
406  G726Context* c = avctx->priv_data;
407 
408  if(avctx->channels > 1){
409  avpriv_request_sample(avctx, "Decoding more than one channel");
410  return AVERROR_PATCHWELCOME;
411  }
412  avctx->channels = 1;
414 
415  c->little_endian = !strcmp(avctx->codec->name, "g726le");
416 
417  c->code_size = avctx->bits_per_coded_sample;
418  if (c->code_size < 2 || c->code_size > 5) {
419  av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
420  return AVERROR(EINVAL);
421  }
422  g726_reset(c);
423 
424  avctx->sample_fmt = AV_SAMPLE_FMT_S16;
425 
426  return 0;
427 }
428 
429 static int g726_decode_frame(AVCodecContext *avctx, void *data,
430  int *got_frame_ptr, AVPacket *avpkt)
431 {
432  AVFrame *frame = data;
433  const uint8_t *buf = avpkt->data;
434  int buf_size = avpkt->size;
435  G726Context *c = avctx->priv_data;
436  int16_t *samples;
437  GetBitContext gb;
438  int out_samples, ret;
439 
440  out_samples = buf_size * 8 / c->code_size;
441 
442  /* get output buffer */
443  frame->nb_samples = out_samples;
444  if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
445  return ret;
446  samples = (int16_t *)frame->data[0];
447 
448  init_get_bits(&gb, buf, buf_size * 8);
449 
450  while (out_samples--)
451  *samples++ = g726_decode(c, c->little_endian ?
452  get_bits_le(&gb, c->code_size) :
453  get_bits(&gb, c->code_size));
454 
455  if (get_bits_left(&gb) > 0)
456  av_log(avctx, AV_LOG_ERROR, "Frame invalidly split, missing parser?\n");
457 
458  *got_frame_ptr = 1;
459 
460  return buf_size;
461 }
462 
463 static void g726_decode_flush(AVCodecContext *avctx)
464 {
465  G726Context *c = avctx->priv_data;
466  g726_reset(c);
467 }
468 #endif
469 
470 #if CONFIG_ADPCM_G726_DECODER
471 AVCodec ff_adpcm_g726_decoder = {
472  .name = "g726",
473  .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM"),
474  .type = AVMEDIA_TYPE_AUDIO,
476  .priv_data_size = sizeof(G726Context),
477  .init = g726_decode_init,
478  .decode = g726_decode_frame,
479  .flush = g726_decode_flush,
480  .capabilities = AV_CODEC_CAP_DR1,
481 };
482 #endif
483 
484 #if CONFIG_ADPCM_G726LE_DECODER
485 AVCodec ff_adpcm_g726le_decoder = {
486  .name = "g726le",
487  .type = AVMEDIA_TYPE_AUDIO,
489  .priv_data_size = sizeof(G726Context),
490  .init = g726_decode_init,
491  .decode = g726_decode_frame,
492  .flush = g726_decode_flush,
493  .capabilities = AV_CODEC_CAP_DR1,
494  .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM little-endian"),
495 };
496 #endif
static av_cold int g726_reset(G726Context *c)
Definition: g726.c:275
#define NULL
Definition: coverity.c:32
const struct AVCodec * codec
Definition: avcodec.h:1648
This structure describes decoded (raw) audio or video data.
Definition: frame.h:180
AVOption.
Definition: opt.h:245
const int16_t * W
special table #1 ;-)
Definition: g726.c:73
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
static void flush(AVCodecContext *avctx)
int pk[2]
signs of prev.
Definition: g726.c:85
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:206
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:260
int64_t bit_rate
the average bitrate
Definition: avcodec.h:1704
#define LIBAVUTIL_VERSION_INT
Definition: version.h:70
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
uint8_t exp
4bit exponent
Definition: g726.c:41
static int16_t g726_decode(G726Context *c, int I)
Definition: g726.c:193
int yl
slow scale factor
Definition: g726.c:89
static Float11 * i2f(int i, Float11 *f)
Definition: g726.c:45
int size
Definition: avcodec.h:1575
static const int16_t iquant_tbl32[]
Definition: g726.c:121
static const G726Tables G726Tables_pool[]
Definition: g726.c:147
const uint8_t * F
special table #2
Definition: g726.c:74
static const uint8_t F_tbl32[]
Definition: g726.c:127
int b[6]
sixth order predictor coeffs
Definition: g726.c:84
Float11 dq[6]
prev.
Definition: g726.c:82
int av_log2_16bit(unsigned v)
Definition: intmath.c:31
AVCodec.
Definition: avcodec.h:3531
static int sgn(int value)
Definition: g726.c:65
static const int quant_tbl40[]
40kbit/s 5bits per sample
Definition: g726.c:130
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
const int * quant
quantization table
Definition: g726.c:71
static const int quant_tbl16[]
16kbit/s 2bits per sample
Definition: g726.c:101
void void avpriv_request_sample(void *avc, const char *msg,...) av_printf_format(2
Log a generic warning message about a missing feature.
int yu
fast scale factor
Definition: g726.c:88
static const uint8_t F_tbl24[]
Definition: g726.c:116
enum AVSampleFormat sample_fmt
audio sample format
Definition: avcodec.h:2408
uint8_t
#define av_cold
Definition: attributes.h:82
AVOptions.
static AVFrame * frame
uint8_t * data
Definition: avcodec.h:1574
bitstream reader API header.
int bits_per_coded_sample
bits per sample/pixel from the demuxer (needed for huffyuv).
Definition: avcodec.h:3032
static const int16_t W_tbl32[]
Definition: g726.c:124
const OptionDef options[]
Definition: ffserver.c:3967
#define av_log(a,...)
G.726 11bit float.
Definition: g726.c:39
int ap
scale factor control
Definition: g726.c:87
G726Tables tbls
static tables needed for computation
Definition: g726.c:79
#define FF_COMPLIANCE_UNOFFICIAL
Allow unofficial extensions.
Definition: avcodec.h:2860
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:607
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
av_default_item_name
static const int quant_tbl24[]
24kbit/s 3bits per sample
Definition: g726.c:110
#define AVERROR(e)
Definition: error.h:43
static const int16_t iquant_tbl16[]
Definition: g726.c:103
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
static uint8_t quant(G726Context *c, int d)
Para 4.2.2 page 18: Adaptive quantizer.
Definition: g726.c:157
int out_size
Definition: movenc-test.c:55
const char * name
Name of the codec implementation.
Definition: avcodec.h:3538
#define AE
Definition: alacenc.c:653
int8_t exp
Definition: eval.c:64
uint64_t channel_layout
Audio channel layout.
Definition: avcodec.h:2451
audio channel layout utility functions
uint8_t sign
1bit sign
Definition: g726.c:40
#define AV_CODEC_CAP_SMALL_LAST_FRAME
Codec can be fed a final frame with a smaller size.
Definition: avcodec.h:980
static const int16_t W_tbl24[]
Definition: g726.c:114
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:109
static const int16_t W_tbl40[]
Definition: g726.c:138
static const int16_t iquant_tbl24[]
Definition: g726.c:112
int se
estimated signal for the next iteration
Definition: g726.c:94
int a[2]
second order predictor coeffs
Definition: g726.c:83
int td
tone detect
Definition: g726.c:92
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2420
Libavcodec external API header.
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
int sample_rate
samples per second
Definition: avcodec.h:2400
uint8_t mant
6bit mantissa
Definition: g726.c:42
main external API structure.
Definition: avcodec.h:1639
static const int16_t W_tbl16[]
Definition: g726.c:105
int ff_get_buffer(AVCodecContext *avctx, AVFrame *frame, int flags)
Get a buffer for a frame.
Definition: utils.c:928
void * buf
Definition: avisynth_c.h:553
Float11 sr[2]
prev.
Definition: g726.c:81
static int16_t mult(Float11 *f1, Float11 *f2)
Definition: g726.c:55
int little_endian
little-endian bitstream as used in aiff and Sun AU
Definition: g726.c:98
Describe the class of an AVClass context structure.
Definition: log.h:67
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:418
int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size)
Check AVPacket size and/or allocate data.
Definition: utils.c:1683
static unsigned int get_bits_le(GetBitContext *s, int n)
Definition: get_bits.h:280
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:194
static const uint8_t F_tbl16[]
Definition: g726.c:107
int code_size
Definition: g726.c:97
#define OFFSET(x)
Definition: ffmpeg_opt.c:3093
static int decode(AVCodecContext *avctx, void *data, int *got_sub, AVPacket *avpkt)
Definition: ccaption_dec.c:722
common internal api header.
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:101
int dml
long average magnitude of F[i]
Definition: g726.c:91
signed 16 bits
Definition: samplefmt.h:61
static double c[64]
static const int16_t iquant_tbl40[]
Definition: g726.c:133
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:48
static const uint8_t F_tbl40[]
Definition: g726.c:143
void * priv_data
Definition: avcodec.h:1681
int y
quantizer scaling factor for the next iteration
Definition: g726.c:96
const int16_t * iquant
inverse quantization table
Definition: g726.c:72
int channels
number of audio channels
Definition: avcodec.h:2401
int sez
estimated second order prediction
Definition: g726.c:95
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:701
static int16_t inverse_quant(G726Context *c, int i)
Para 4.2.3 page 22: Inverse adaptive quantizer.
Definition: g726.c:183
static const int quant_tbl32[]
32kbit/s 4bits per sample
Definition: g726.c:119
static const AVCodecDefault defaults[]
Definition: dcaenc.c:975
int dms
short average magnitude of F[i]
Definition: g726.c:90
#define AV_CH_LAYOUT_MONO
This structure stores compressed data.
Definition: avcodec.h:1551
int nb_samples
number of audio samples (per channel) described by this frame
Definition: frame.h:237
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() for allocating buffers and supports custom allocators.
Definition: avcodec.h:950
int strict_std_compliance
strictly follow the standard (MPEG4, ...).
Definition: avcodec.h:2856
bitstream writer API