Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / g726.c
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
26 #include "libavutil/avassert.h"
27 #include "libavutil/channel_layout.h"
28 #include "libavutil/opt.h"
29 #include "avcodec.h"
30 #include "internal.h"
31 #include "get_bits.h"
32 #include "put_bits.h"
33
34 /**
35 * G.726 11bit float.
36 * G.726 Standard uses rather odd 11bit floating point arithmentic for
37 * numerous occasions. It's a mystery to me why they did it this way
38 * instead of simply using 32bit integer arithmetic.
39 */
40 typedef struct Float11 {
41 uint8_t sign; /**< 1bit sign */
42 uint8_t exp; /**< 4bit exponent */
43 uint8_t mant; /**< 6bit mantissa */
44 } Float11;
45
46 static inline Float11* i2f(int i, Float11* f)
47 {
48 f->sign = (i < 0);
49 if (f->sign)
50 i = -i;
51 f->exp = av_log2_16bit(i) + !!i;
52 f->mant = i? (i<<6) >> f->exp : 1<<5;
53 return f;
54 }
55
56 static inline int16_t mult(Float11* f1, Float11* f2)
57 {
58 int res, exp;
59
60 exp = f1->exp + f2->exp;
61 res = (((f1->mant * f2->mant) + 0x30) >> 4);
62 res = exp > 19 ? res << (exp - 19) : res >> (19 - exp);
63 return (f1->sign ^ f2->sign) ? -res : res;
64 }
65
66 static inline int sgn(int value)
67 {
68 return (value < 0) ? -1 : 1;
69 }
70
71 typedef struct G726Tables {
72 const int* quant; /**< quantization table */
73 const int16_t* iquant; /**< inverse quantization table */
74 const int16_t* W; /**< special table #1 ;-) */
75 const uint8_t* F; /**< special table #2 */
76 } G726Tables;
77
78 typedef struct G726Context {
79 AVClass *class;
80 G726Tables tbls; /**< static tables needed for computation */
81
82 Float11 sr[2]; /**< prev. reconstructed samples */
83 Float11 dq[6]; /**< prev. difference */
84 int a[2]; /**< second order predictor coeffs */
85 int b[6]; /**< sixth order predictor coeffs */
86 int pk[2]; /**< signs of prev. 2 sez + dq */
87
88 int ap; /**< scale factor control */
89 int yu; /**< fast scale factor */
90 int yl; /**< slow scale factor */
91 int dms; /**< short average magnitude of F[i] */
92 int dml; /**< long average magnitude of F[i] */
93 int td; /**< tone detect */
94
95 int se; /**< estimated signal for the next iteration */
96 int sez; /**< estimated second order prediction */
97 int y; /**< quantizer scaling factor for the next iteration */
98 int code_size;
99 int little_endian; /**< little-endian bitstream as used in aiff and Sun AU */
100 } G726Context;
101
102 static const int quant_tbl16[] = /**< 16kbit/s 2bits per sample */
103 { 260, INT_MAX };
104 static const int16_t iquant_tbl16[] =
105 { 116, 365, 365, 116 };
106 static const int16_t W_tbl16[] =
107 { -22, 439, 439, -22 };
108 static const uint8_t F_tbl16[] =
109 { 0, 7, 7, 0 };
110
111 static const int quant_tbl24[] = /**< 24kbit/s 3bits per sample */
112 { 7, 217, 330, INT_MAX };
113 static const int16_t iquant_tbl24[] =
114 { INT16_MIN, 135, 273, 373, 373, 273, 135, INT16_MIN };
115 static const int16_t W_tbl24[] =
116 { -4, 30, 137, 582, 582, 137, 30, -4 };
117 static const uint8_t F_tbl24[] =
118 { 0, 1, 2, 7, 7, 2, 1, 0 };
119
120 static const int quant_tbl32[] = /**< 32kbit/s 4bits per sample */
121 { -125, 79, 177, 245, 299, 348, 399, INT_MAX };
122 static const int16_t iquant_tbl32[] =
123 { INT16_MIN, 4, 135, 213, 273, 323, 373, 425,
124 425, 373, 323, 273, 213, 135, 4, INT16_MIN };
125 static const int16_t W_tbl32[] =
126 { -12, 18, 41, 64, 112, 198, 355, 1122,
127 1122, 355, 198, 112, 64, 41, 18, -12};
128 static const uint8_t F_tbl32[] =
129 { 0, 0, 0, 1, 1, 1, 3, 7, 7, 3, 1, 1, 1, 0, 0, 0 };
130
131 static const int quant_tbl40[] = /**< 40kbit/s 5bits per sample */
132 { -122, -16, 67, 138, 197, 249, 297, 338,
133 377, 412, 444, 474, 501, 527, 552, INT_MAX };
134 static const int16_t iquant_tbl40[] =
135 { INT16_MIN, -66, 28, 104, 169, 224, 274, 318,
136 358, 395, 429, 459, 488, 514, 539, 566,
137 566, 539, 514, 488, 459, 429, 395, 358,
138 318, 274, 224, 169, 104, 28, -66, INT16_MIN };
139 static const int16_t W_tbl40[] =
140 { 14, 14, 24, 39, 40, 41, 58, 100,
141 141, 179, 219, 280, 358, 440, 529, 696,
142 696, 529, 440, 358, 280, 219, 179, 141,
143 100, 58, 41, 40, 39, 24, 14, 14 };
144 static const uint8_t F_tbl40[] =
145 { 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 6,
146 6, 6, 5, 4, 3, 2, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
147
148 static const G726Tables G726Tables_pool[] =
149 {{ quant_tbl16, iquant_tbl16, W_tbl16, F_tbl16 },
150 { quant_tbl24, iquant_tbl24, W_tbl24, F_tbl24 },
151 { quant_tbl32, iquant_tbl32, W_tbl32, F_tbl32 },
152 { quant_tbl40, iquant_tbl40, W_tbl40, F_tbl40 }};
153
154
155 /**
156 * Para 4.2.2 page 18: Adaptive quantizer.
157 */
158 static inline uint8_t quant(G726Context* c, int d)
159 {
160 int sign, exp, i, dln;
161
162 sign = i = 0;
163 if (d < 0) {
164 sign = 1;
165 d = -d;
166 }
167 exp = av_log2_16bit(d);
168 dln = ((exp<<7) + (((d<<7)>>exp)&0x7f)) - (c->y>>2);
169
170 while (c->tbls.quant[i] < INT_MAX && c->tbls.quant[i] < dln)
171 ++i;
172
173 if (sign)
174 i = ~i;
175 if (c->code_size != 2 && i == 0) /* I'm not sure this is a good idea */
176 i = 0xff;
177
178 return i;
179 }
180
181 /**
182 * Para 4.2.3 page 22: Inverse adaptive quantizer.
183 */
184 static inline int16_t inverse_quant(G726Context* c, int i)
185 {
186 int dql, dex, dqt;
187
188 dql = c->tbls.iquant[i] + (c->y >> 2);
189 dex = (dql>>7) & 0xf; /* 4bit exponent */
190 dqt = (1<<7) + (dql & 0x7f); /* log2 -> linear */
191 return (dql < 0) ? 0 : ((dqt<<dex) >> 7);
192 }
193
194 static int16_t g726_decode(G726Context* c, int I)
195 {
196 int dq, re_signal, pk0, fa1, i, tr, ylint, ylfrac, thr2, al, dq0;
197 Float11 f;
198 int I_sig= I >> (c->code_size - 1);
199
200 dq = inverse_quant(c, I);
201
202 /* Transition detect */
203 ylint = (c->yl >> 15);
204 ylfrac = (c->yl >> 10) & 0x1f;
205 thr2 = (ylint > 9) ? 0x1f << 10 : (0x20 + ylfrac) << ylint;
206 tr= (c->td == 1 && dq > ((3*thr2)>>2));
207
208 if (I_sig) /* get the sign */
209 dq = -dq;
210 re_signal = c->se + dq;
211
212 /* Update second order predictor coefficient A2 and A1 */
213 pk0 = (c->sez + dq) ? sgn(c->sez + dq) : 0;
214 dq0 = dq ? sgn(dq) : 0;
215 if (tr) {
216 c->a[0] = 0;
217 c->a[1] = 0;
218 for (i=0; i<6; i++)
219 c->b[i] = 0;
220 } else {
221 /* This is a bit crazy, but it really is +255 not +256 */
222 fa1 = av_clip((-c->a[0]*c->pk[0]*pk0)>>5, -256, 255);
223
224 c->a[1] += 128*pk0*c->pk[1] + fa1 - (c->a[1]>>7);
225 c->a[1] = av_clip(c->a[1], -12288, 12288);
226 c->a[0] += 64*3*pk0*c->pk[0] - (c->a[0] >> 8);
227 c->a[0] = av_clip(c->a[0], -(15360 - c->a[1]), 15360 - c->a[1]);
228
229 for (i=0; i<6; i++)
230 c->b[i] += 128*dq0*sgn(-c->dq[i].sign) - (c->b[i]>>8);
231 }
232
233 /* Update Dq and Sr and Pk */
234 c->pk[1] = c->pk[0];
235 c->pk[0] = pk0 ? pk0 : 1;
236 c->sr[1] = c->sr[0];
237 i2f(re_signal, &c->sr[0]);
238 for (i=5; i>0; i--)
239 c->dq[i] = c->dq[i-1];
240 i2f(dq, &c->dq[0]);
241 c->dq[0].sign = I_sig; /* Isn't it crazy ?!?! */
242
243 c->td = c->a[1] < -11776;
244
245 /* Update Ap */
246 c->dms += (c->tbls.F[I]<<4) + ((- c->dms) >> 5);
247 c->dml += (c->tbls.F[I]<<4) + ((- c->dml) >> 7);
248 if (tr)
249 c->ap = 256;
250 else {
251 c->ap += (-c->ap) >> 4;
252 if (c->y <= 1535 || c->td || abs((c->dms << 2) - c->dml) >= (c->dml >> 3))
253 c->ap += 0x20;
254 }
255
256 /* Update Yu and Yl */
257 c->yu = av_clip(c->y + c->tbls.W[I] + ((-c->y)>>5), 544, 5120);
258 c->yl += c->yu + ((-c->yl)>>6);
259
260 /* Next iteration for Y */
261 al = (c->ap >= 256) ? 1<<6 : c->ap >> 2;
262 c->y = (c->yl + (c->yu - (c->yl>>6))*al) >> 6;
263
264 /* Next iteration for SE and SEZ */
265 c->se = 0;
266 for (i=0; i<6; i++)
267 c->se += mult(i2f(c->b[i] >> 2, &f), &c->dq[i]);
268 c->sez = c->se >> 1;
269 for (i=0; i<2; i++)
270 c->se += mult(i2f(c->a[i] >> 2, &f), &c->sr[i]);
271 c->se >>= 1;
272
273 return av_clip(re_signal << 2, -0xffff, 0xffff);
274 }
275
276 static av_cold int g726_reset(G726Context *c)
277 {
278 int i;
279
280 c->tbls = G726Tables_pool[c->code_size - 2];
281 for (i=0; i<2; i++) {
282 c->sr[i].mant = 1<<5;
283 c->pk[i] = 1;
284 }
285 for (i=0; i<6; i++) {
286 c->dq[i].mant = 1<<5;
287 }
288 c->yu = 544;
289 c->yl = 34816;
290
291 c->y = 544;
292
293 return 0;
294 }
295
296 #if CONFIG_ADPCM_G726_ENCODER
297 static int16_t g726_encode(G726Context* c, int16_t sig)
298 {
299 uint8_t i;
300
301 i = quant(c, sig/4 - c->se) & ((1<<c->code_size) - 1);
302 g726_decode(c, i);
303 return i;
304 }
305
306 /* Interfacing to the libavcodec */
307
308 static av_cold int g726_encode_init(AVCodecContext *avctx)
309 {
310 G726Context* c = avctx->priv_data;
311
312 if (avctx->strict_std_compliance > FF_COMPLIANCE_UNOFFICIAL &&
313 avctx->sample_rate != 8000) {
314 av_log(avctx, AV_LOG_ERROR, "Sample rates other than 8kHz are not "
315 "allowed when the compliance level is higher than unofficial. "
316 "Resample or reduce the compliance level.\n");
317 return AVERROR(EINVAL);
318 }
319 av_assert0(avctx->sample_rate > 0);
320
321 if(avctx->channels != 1){
322 av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");
323 return AVERROR(EINVAL);
324 }
325
326 if (avctx->bit_rate)
327 c->code_size = (avctx->bit_rate + avctx->sample_rate/2) / avctx->sample_rate;
328
329 c->code_size = av_clip(c->code_size, 2, 5);
330 avctx->bit_rate = c->code_size * avctx->sample_rate;
331 avctx->bits_per_coded_sample = c->code_size;
332
333 g726_reset(c);
334
335 /* select a frame size that will end on a byte boundary and have a size of
336 approximately 1024 bytes */
337 avctx->frame_size = ((int[]){ 4096, 2736, 2048, 1640 })[c->code_size - 2];
338
339 return 0;
340 }
341
342 static int g726_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
343 const AVFrame *frame, int *got_packet_ptr)
344 {
345 G726Context *c = avctx->priv_data;
346 const int16_t *samples = (const int16_t *)frame->data[0];
347 PutBitContext pb;
348 int i, ret, out_size;
349
350 out_size = (frame->nb_samples * c->code_size + 7) / 8;
351 if ((ret = ff_alloc_packet2(avctx, avpkt, out_size)) < 0)
352 return ret;
353 init_put_bits(&pb, avpkt->data, avpkt->size);
354
355 for (i = 0; i < frame->nb_samples; i++)
356 put_bits(&pb, c->code_size, g726_encode(c, *samples++));
357
358 flush_put_bits(&pb);
359
360 avpkt->size = out_size;
361 *got_packet_ptr = 1;
362 return 0;
363 }
364
365 #define OFFSET(x) offsetof(G726Context, x)
366 #define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
367 static const AVOption options[] = {
368 { "code_size", "Bits per code", OFFSET(code_size), AV_OPT_TYPE_INT, { .i64 = 4 }, 2, 5, AE },
369 { NULL },
370 };
371
372 static const AVClass g726_class = {
373 .class_name = "g726",
374 .item_name = av_default_item_name,
375 .option = options,
376 .version = LIBAVUTIL_VERSION_INT,
377 };
378
379 static const AVCodecDefault defaults[] = {
380 { "b", "0" },
381 { NULL },
382 };
383
384 AVCodec ff_adpcm_g726_encoder = {
385 .name = "g726",
386 .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM"),
387 .type = AVMEDIA_TYPE_AUDIO,
388 .id = AV_CODEC_ID_ADPCM_G726,
389 .priv_data_size = sizeof(G726Context),
390 .init = g726_encode_init,
391 .encode2 = g726_encode_frame,
392 .capabilities = CODEC_CAP_SMALL_LAST_FRAME,
393 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
394 AV_SAMPLE_FMT_NONE },
395 .priv_class = &g726_class,
396 .defaults = defaults,
397 };
398 #endif
399
400 #if CONFIG_ADPCM_G726_DECODER || CONFIG_ADPCM_G726LE_DECODER
401 static av_cold int g726_decode_init(AVCodecContext *avctx)
402 {
403 G726Context* c = avctx->priv_data;
404
405 if(avctx->channels > 1){
406 avpriv_request_sample(avctx, "Decoding more than one channel");
407 return AVERROR_PATCHWELCOME;
408 }
409 avctx->channels = 1;
410 avctx->channel_layout = AV_CH_LAYOUT_MONO;
411
412 c->little_endian = !strcmp(avctx->codec->name, "g726le");
413
414 c->code_size = avctx->bits_per_coded_sample;
415 if (c->code_size < 2 || c->code_size > 5) {
416 av_log(avctx, AV_LOG_ERROR, "Invalid number of bits %d\n", c->code_size);
417 return AVERROR(EINVAL);
418 }
419 g726_reset(c);
420
421 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
422
423 return 0;
424 }
425
426 static int g726_decode_frame(AVCodecContext *avctx, void *data,
427 int *got_frame_ptr, AVPacket *avpkt)
428 {
429 AVFrame *frame = data;
430 const uint8_t *buf = avpkt->data;
431 int buf_size = avpkt->size;
432 G726Context *c = avctx->priv_data;
433 int16_t *samples;
434 GetBitContext gb;
435 int out_samples, ret;
436
437 out_samples = buf_size * 8 / c->code_size;
438
439 /* get output buffer */
440 frame->nb_samples = out_samples;
441 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
442 return ret;
443 samples = (int16_t *)frame->data[0];
444
445 init_get_bits(&gb, buf, buf_size * 8);
446
447 while (out_samples--)
448 *samples++ = g726_decode(c, c->little_endian ?
449 get_bits_le(&gb, c->code_size) :
450 get_bits(&gb, c->code_size));
451
452 if (get_bits_left(&gb) > 0)
453 av_log(avctx, AV_LOG_ERROR, "Frame invalidly split, missing parser?\n");
454
455 *got_frame_ptr = 1;
456
457 return buf_size;
458 }
459
460 static void g726_decode_flush(AVCodecContext *avctx)
461 {
462 G726Context *c = avctx->priv_data;
463 g726_reset(c);
464 }
465 #endif
466
467 #if CONFIG_ADPCM_G726_DECODER
468 AVCodec ff_adpcm_g726_decoder = {
469 .name = "g726",
470 .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM"),
471 .type = AVMEDIA_TYPE_AUDIO,
472 .id = AV_CODEC_ID_ADPCM_G726,
473 .priv_data_size = sizeof(G726Context),
474 .init = g726_decode_init,
475 .decode = g726_decode_frame,
476 .flush = g726_decode_flush,
477 .capabilities = CODEC_CAP_DR1,
478 };
479 #endif
480
481 #if CONFIG_ADPCM_G726LE_DECODER
482 AVCodec ff_adpcm_g726le_decoder = {
483 .name = "g726le",
484 .type = AVMEDIA_TYPE_AUDIO,
485 .id = AV_CODEC_ID_ADPCM_G726LE,
486 .priv_data_size = sizeof(G726Context),
487 .init = g726_decode_init,
488 .decode = g726_decode_frame,
489 .flush = g726_decode_flush,
490 .capabilities = CODEC_CAP_DR1,
491 .long_name = NULL_IF_CONFIG_SMALL("G.726 ADPCM little-endian"),
492 };
493 #endif