libavcodec/adpcm.c

   1 /*
   2  * ADPCM codecs
   3  * Copyright (c) 2001-2003 The ffmpeg Project
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avcodec.h"
  20
  21 /**
  22  * @file adpcm.c
  23  * ADPCM codecs.
  24  * First version by Francois Revol revol@free.fr
  25  * Fringe ADPCM codecs (e.g., DK3 and DK4)
  26  *   by Mike Melanson (melanson@pcisys.net)
  27  *
  28  * Features and limitations:
  29  *
  30  * Reference documents:
  31  * http://www.pcisys.net/~melanson/codecs/simpleaudio.html
  32  * http://www.geocities.com/SiliconValley/8682/aud3.txt
  33  * http://openquicktime.sourceforge.net/plugins.htm
  34  * XAnim sources (xa_codec.c) http://www.rasnaimaging.com/people/lapus/download.html
  35  * http://www.cs.ucla.edu/~leec/mediabench/applications.html
  36  * SoX source code http://home.sprynet.com/~cbagwell/sox.html
  37  */
  38
  39 #define BLKSIZE 1024
  40
  41 #define CLAMP_TO_SHORT(value) \
  42 if (value > 32767) \
  43     value = 32767; \
  44 else if (value < -32768) \
  45     value = -32768; \
  46
  47 /* step_table[] and index_table[] are from the ADPCM reference source */
  48 /* This is the index table: */
  49 static const int index_table[16] = {
  50     -1, -1, -1, -1, 2, 4, 6, 8,
  51     -1, -1, -1, -1, 2, 4, 6, 8,
  52 };
  53
  54 /**
  55  * This is the step table. Note that many programs use slight deviations from
  56  * this table, but such deviations are negligible:
  57  */
  58 static const int step_table[89] = {
  59     7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
  60     19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
  61     50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
  62     130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
  63     337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
  64     876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
  65     2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
  66     5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
  67     15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
  68 };
  69
  70 /* Those are for MS-ADPCM */
  71 /* AdaptationTable[], AdaptCoeff1[], and AdaptCoeff2[] are from libsndfile */
  72 static const int AdaptationTable[] = {
  73         230, 230, 230, 230, 307, 409, 512, 614,
  74         768, 614, 512, 409, 307, 230, 230, 230
  75 };
  76
  77 static const int AdaptCoeff1[] = {
  78         256, 512, 0, 192, 240, 460, 392
  79 };
  80
  81 static const int AdaptCoeff2[] = {
  82         0, -256, 0, 64, 0, -208, -232
  83 };
  84
  85 /* end of tables */
  86
  87 typedef struct ADPCMChannelStatus {
  88     int predictor;
  89     short int step_index;
  90     int step;
  91     /* for encoding */
  92     int prev_sample;
  93
  94     /* MS version */
  95     short sample1;
  96     short sample2;
  97     int coeff1;
  98     int coeff2;
  99     int idelta;
 100 } ADPCMChannelStatus;
 101
 102 typedef struct ADPCMContext {
 103     int channel; /* for stereo MOVs, decode left, then decode right, then tell it's decoded */
 104     ADPCMChannelStatus status[2];
 105     short sample_buffer[32]; /* hold left samples while waiting for right samples */
 106 } ADPCMContext;
 107
 108 /* XXX: implement encoding */
 109
 110 static int adpcm_encode_init(AVCodecContext *avctx)
 111 {
 112     if (avctx->channels > 2)
 113         return -1; /* only stereo or mono =) */
 114     switch(avctx->codec->id) {
 115     case CODEC_ID_ADPCM_IMA_QT:
 116         fprintf(stderr, "ADPCM: codec admcp_ima_qt unsupported for encoding !\n");
 117         avctx->frame_size = 64; /* XXX: can multiple of avctx->channels * 64 (left and right blocks are interleaved) */
 118         return -1;
 119         break;
 120     case CODEC_ID_ADPCM_IMA_WAV:
 121         avctx->frame_size = (BLKSIZE - 4 * avctx->channels) * 8 / (4 * avctx->channels) + 1; /* each 16 bits sample gives one nibble */
 122                                                              /* and we have 4 bytes per channel overhead */
 123         avctx->block_align = BLKSIZE;
 124         /* seems frame_size isn't taken into account... have to buffer the samples :-( */
 125         break;
 126     case CODEC_ID_ADPCM_MS:
 127         fprintf(stderr, "ADPCM: codec admcp_ms unsupported for encoding !\n");
 128         return -1;
 129         break;
 130     default:
 131         return -1;
 132         break;
 133     }
 134
 135     avctx->coded_frame= avcodec_alloc_frame();
 136     avctx->coded_frame->key_frame= 1;
 137
 138     return 0;
 139 }
 140
 141 static int adpcm_encode_close(AVCodecContext *avctx)
 142 {
 143     av_freep(&avctx->coded_frame);
 144
 145     return 0;
 146 }
 147
 148
 149 static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, short sample)
 150 {
 151     int step_index;
 152     unsigned char nibble;
 153
 154     int sign = 0; /* sign bit of the nibble (MSB) */
 155     int delta, predicted_delta;
 156
 157     delta = sample - c->prev_sample;
 158
 159     if (delta < 0) {
 160         sign = 1;
 161         delta = -delta;
 162     }
 163
 164     step_index = c->step_index;
 165
 166     /* nibble = 4 * delta / step_table[step_index]; */
 167     nibble = (delta << 2) / step_table[step_index];
 168
 169     if (nibble > 7)
 170         nibble = 7;
 171
 172     step_index += index_table[nibble];
 173     if (step_index < 0)
 174         step_index = 0;
 175     if (step_index > 88)
 176         step_index = 88;
 177
 178     /* what the decoder will find */
 179     predicted_delta = ((step_table[step_index] * nibble) / 4) + (step_table[step_index] / 8);
 180
 181     if (sign)
 182         c->prev_sample -= predicted_delta;
 183     else
 184         c->prev_sample += predicted_delta;
 185
 186     CLAMP_TO_SHORT(c->prev_sample);
 187
 188
 189     nibble += sign << 3; /* sign * 8 */
 190
 191     /* save back */
 192     c->step_index = step_index;
 193
 194     return nibble;
 195 }
 196
 197 static int adpcm_encode_frame(AVCodecContext *avctx,
 198                             unsigned char *frame, int buf_size, void *data)
 199 {
 200     int n;
 201     short *samples;
 202     unsigned char *dst;
 203     ADPCMContext *c = avctx->priv_data;
 204
 205     dst = frame;
 206     samples = (short *)data;
 207 /*    n = (BLKSIZE - 4 * avctx->channels) / (2 * 8 * avctx->channels); */
 208
 209     switch(avctx->codec->id) {
 210     case CODEC_ID_ADPCM_IMA_QT: /* XXX: can't test until we get .mov writer */
 211         break;
 212     case CODEC_ID_ADPCM_IMA_WAV:
 213         n = avctx->frame_size / 8;
 214             c->status[0].prev_sample = (signed short)samples[0]; /* XXX */
 215 /*            c->status[0].step_index = 0; *//* XXX: not sure how to init the state machine */
 216             *dst++ = (c->status[0].prev_sample) & 0xFF; /* little endian */
 217             *dst++ = (c->status[0].prev_sample >> 8) & 0xFF;
 218             *dst++ = (unsigned char)c->status[0].step_index;
 219             *dst++ = 0; /* unknown */
 220             samples++;
 221             if (avctx->channels == 2) {
 222                 c->status[1].prev_sample = (signed short)samples[0];
 223 /*                c->status[1].step_index = 0; */
 224                 *dst++ = (c->status[1].prev_sample) & 0xFF;
 225                 *dst++ = (c->status[1].prev_sample >> 8) & 0xFF;
 226                 *dst++ = (unsigned char)c->status[1].step_index;
 227                 *dst++ = 0;
 228                 samples++;
 229             }
 230
 231             /* stereo: 4 bytes (8 samples) for left, 4 bytes for right, 4 bytes left, ... */
 232             for (; n>0; n--) {
 233                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[0]) & 0x0F;
 234                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels]) << 4) & 0xF0;
 235                 dst++;
 236                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 2]) & 0x0F;
 237                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 3]) << 4) & 0xF0;
 238                 dst++;
 239                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 4]) & 0x0F;
 240                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 5]) << 4) & 0xF0;
 241                 dst++;
 242                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 6]) & 0x0F;
 243                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 7]) << 4) & 0xF0;
 244                 dst++;
 245                 /* right channel */
 246                 if (avctx->channels == 2) {
 247                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[1]);
 248                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[3]) << 4;
 249                     dst++;
 250                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[5]);
 251                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[7]) << 4;
 252                     dst++;
 253                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[9]);
 254                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[11]) << 4;
 255                     dst++;
 256                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[13]);
 257                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[15]) << 4;
 258                     dst++;
 259                 }
 260                 samples += 8 * avctx->channels;
 261             }
 262         break;
 263     default:
 264         return -1;
 265     }
 266     return dst - frame;
 267 }
 268
 269 static int adpcm_decode_init(AVCodecContext * avctx)
 270 {
 271     ADPCMContext *c = avctx->priv_data;
 272
 273     c->channel = 0;
 274     c->status[0].predictor = c->status[1].predictor = 0;
 275     c->status[0].step_index = c->status[1].step_index = 0;
 276     c->status[0].step = c->status[1].step = 0;
 277
 278     switch(avctx->codec->id) {
 279     default:
 280         break;
 281     }
 282     return 0;
 283 }
 284
 285 static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble)
 286 {
 287     int step_index;
 288     int predictor;
 289     int sign, delta, diff, step;
 290
 291     step = step_table[c->step_index];
 292     step_index = c->step_index + index_table[(unsigned)nibble];
 293     if (step_index < 0) step_index = 0;
 294     else if (step_index > 88) step_index = 88;
 295
 296     sign = nibble & 8;
 297     delta = nibble & 7;
 298     /* perform direct multiplication instead of series of jumps proposed by
 299      * the reference ADPCM implementation since modern CPUs can do the mults
 300      * quickly enough */
 301     diff = ((2 * delta + 1) * step) >> 3;
 302     predictor = c->predictor;
 303     if (sign) predictor -= diff;
 304     else predictor += diff;
 305
 306     CLAMP_TO_SHORT(predictor);
 307     c->predictor = predictor;
 308     c->step_index = step_index;
 309
 310     return (short)predictor;
 311 }
 312
 313 static inline short adpcm_4xa_expand_nibble(ADPCMChannelStatus *c, char nibble)
 314 {
 315     int step_index;
 316     int predictor;
 317     int sign, delta, diff, step;
 318
 319     step = step_table[c->step_index];
 320     step_index = c->step_index + index_table[(unsigned)nibble];
 321     if (step_index < 0) step_index = 0;
 322     else if (step_index > 88) step_index = 88;
 323
 324     sign = nibble & 8;
 325     delta = nibble & 7;
 326
 327     diff = (delta*step + (step>>1))>>3; // difference to code above
 328
 329     predictor = c->predictor;
 330     if (sign) predictor -= diff;
 331     else predictor += diff;
 332
 333     CLAMP_TO_SHORT(predictor);
 334     c->predictor = predictor;
 335     c->step_index = step_index;
 336
 337     return (short)predictor;
 338 }
 339
 340 static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)
 341 {
 342     int predictor;
 343
 344     predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256;
 345     predictor += (signed)((nibble & 0x08)?(nibble - 0x10):(nibble)) * c->idelta;
 346     CLAMP_TO_SHORT(predictor);
 347
 348     c->sample2 = c->sample1;
 349     c->sample1 = predictor;
 350     c->idelta = (AdaptationTable[(int)nibble] * c->idelta) / 256;
 351     if (c->idelta < 16) c->idelta = 16;
 352
 353     return (short)predictor;
 354 }
 355
 356 /* DK3 ADPCM support macro */
 357 #define DK3_GET_NEXT_NIBBLE() \
 358     if (decode_top_nibble_next) \
 359     { \
 360         nibble = (last_byte >> 4) & 0x0F; \
 361         decode_top_nibble_next = 0; \
 362     } \
 363     else \
 364     { \
 365         last_byte = *src++; \
 366         if (src >= buf + buf_size) break; \
 367         nibble = last_byte & 0x0F; \
 368         decode_top_nibble_next = 1; \
 369     }
 370
 371 static int adpcm_decode_frame(AVCodecContext *avctx,
 372                             void *data, int *data_size,
 373                             uint8_t *buf, int buf_size)
 374 {
 375     ADPCMContext *c = avctx->priv_data;
 376     ADPCMChannelStatus *cs;
 377     int n, m, channel, i;
 378     int block_predictor[2];
 379     short *samples;
 380     uint8_t *src;
 381     int st; /* stereo */
 382
 383     /* DK3 ADPCM accounting variables */
 384     unsigned char last_byte = 0;
 385     unsigned char nibble;
 386     int decode_top_nibble_next = 0;
 387     int diff_channel;
 388
 389     samples = data;
 390     src = buf;
 391
 392     st = avctx->channels == 2;
 393
 394     switch(avctx->codec->id) {
 395     case CODEC_ID_ADPCM_IMA_QT:
 396         n = (buf_size - 2);/* >> 2*avctx->channels;*/
 397         channel = c->channel;
 398         cs = &(c->status[channel]);
 399         /* (pppppp) (piiiiiii) */
 400
 401         /* Bits 15-7 are the _top_ 9 bits of the 16-bit initial predictor value */
 402         cs->predictor = (*src++) << 8;
 403         cs->predictor |= (*src & 0x80);
 404         cs->predictor &= 0xFF80;
 405
 406         /* sign extension */
 407         if(cs->predictor & 0x8000)
 408             cs->predictor -= 0x10000;
 409
 410         CLAMP_TO_SHORT(cs->predictor);
 411
 412         cs->step_index = (*src++) & 0x7F;
 413
 414         if (cs->step_index > 88) fprintf(stderr, "ERROR: step_index = %i\n", cs->step_index);
 415         if (cs->step_index > 88) cs->step_index = 88;
 416
 417         cs->step = step_table[cs->step_index];
 418
 419         if (st && channel)
 420             samples++;
 421
 422         *samples++ = cs->predictor;
 423         samples += st;
 424
 425         for(m=32; n>0 && m>0; n--, m--) { /* in QuickTime, IMA is encoded by chuncks of 34 bytes (=64 samples) */
 426             *samples = adpcm_ima_expand_nibble(cs, src[0] & 0x0F);
 427             samples += avctx->channels;
 428             *samples = adpcm_ima_expand_nibble(cs, (src[0] >> 4) & 0x0F);
 429             samples += avctx->channels;
 430             src ++;
 431         }
 432
 433         if(st) { /* handle stereo interlacing */
 434             c->channel = (channel + 1) % 2; /* we get one packet for left, then one for right data */
 435             if(channel == 0) { /* wait for the other packet before outputing anything */
 436                 *data_size = 0;
 437                 return src - buf;
 438             }
 439         }
 440         break;
 441     case CODEC_ID_ADPCM_IMA_WAV:
 442         if (buf_size > BLKSIZE) {
 443             if (avctx->block_align != 0)
 444                 buf_size = avctx->block_align;
 445             else
 446                 buf_size = BLKSIZE;
 447         }
 448         // XXX: do as per-channel loop
 449         cs = &(c->status[0]);
 450         cs->predictor = (*src++) & 0x0FF;
 451         cs->predictor |= ((*src++) << 8) & 0x0FF00;
 452         if(cs->predictor & 0x8000)
 453             cs->predictor -= 0x10000;
 454         CLAMP_TO_SHORT(cs->predictor);
 455
 456         // XXX: is this correct ??: *samples++ = cs->predictor;
 457
 458         cs->step_index = *src++;
 459         if (cs->step_index < 0) cs->step_index = 0;
 460         if (cs->step_index > 88) cs->step_index = 88;
 461         if (*src++) fprintf(stderr, "unused byte should be null !!\n"); /* unused */
 462
 463         if (st) {
 464             cs = &(c->status[1]);
 465             cs->predictor = (*src++) & 0x0FF;
 466             cs->predictor |= ((*src++) << 8) & 0x0FF00;
 467             if(cs->predictor & 0x8000)
 468                 cs->predictor -= 0x10000;
 469             CLAMP_TO_SHORT(cs->predictor);
 470
 471             // XXX: is this correct ??: *samples++ = cs->predictor;
 472
 473             cs->step_index = *src++;
 474             if (cs->step_index < 0) cs->step_index = 0;
 475             if (cs->step_index > 88) cs->step_index = 88;
 476             src++; /* if != 0  -> out-of-sync */
 477         }
 478
 479         for(m=4; src < (buf + buf_size);) {
 480             *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[0] & 0x0F);
 481             if (st)
 482                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[4] & 0x0F);
 483             *samples++ = adpcm_ima_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);
 484             if (st) {
 485                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], (src[4] >> 4) & 0x0F);
 486                 if (!--m) {
 487                     m=4;
 488                     src+=4;
 489                 }
 490             }
 491             src++;
 492         }
 493         break;
 494     case CODEC_ID_ADPCM_4XM:
 495         cs = &(c->status[0]);
 496         c->status[0].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
 497         if(st){
 498             c->status[1].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;
 499         }
 500         c->status[0].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
 501         if(st){
 502             c->status[1].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;
 503         }
 504 //            if (cs->step_index < 0) cs->step_index = 0;
 505 //            if (cs->step_index > 88) cs->step_index = 88;
 506
 507         m= (buf_size - (src - buf))>>st;
 508 //printf("%d %d %d %d\n", st, m, c->status[0].predictor, c->status[0].step_index);
 509         //FIXME / XXX decode chanels individual & interleave samples
 510         for(i=0; i<m; i++) {
 511             *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] & 0x0F);
 512             if (st)
 513                 *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] & 0x0F);
 514             *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] >> 4);
 515             if (st)
 516                 *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] >> 4);
 517         }
 518
 519         src += m<<st;
 520
 521         break;
 522     case CODEC_ID_ADPCM_MS:
 523
 524         if (buf_size > BLKSIZE) {
 525             if (avctx->block_align != 0)
 526                 buf_size = avctx->block_align;
 527             else
 528                 buf_size = BLKSIZE;
 529         }
 530         n = buf_size - 7 * avctx->channels;
 531         if (n < 0)
 532             return -1;
 533         block_predictor[0] = (*src++); /* should be bound */
 534         block_predictor[0] = (block_predictor[0] < 0)?(0):((block_predictor[0] > 7)?(7):(block_predictor[0]));
 535         block_predictor[1] = 0;
 536         if (st)
 537             block_predictor[1] = (*src++);
 538         block_predictor[1] = (block_predictor[1] < 0)?(0):((block_predictor[1] > 7)?(7):(block_predictor[1]));
 539         c->status[0].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 540         if (c->status[0].idelta & 0x08000)
 541             c->status[0].idelta -= 0x10000;
 542         src+=2;
 543         if (st)
 544             c->status[1].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 545         if (st && c->status[1].idelta & 0x08000)
 546             c->status[1].idelta |= 0xFFFF0000;
 547         if (st)
 548             src+=2;
 549         c->status[0].coeff1 = AdaptCoeff1[block_predictor[0]];
 550         c->status[0].coeff2 = AdaptCoeff2[block_predictor[0]];
 551         c->status[1].coeff1 = AdaptCoeff1[block_predictor[1]];
 552         c->status[1].coeff2 = AdaptCoeff2[block_predictor[1]];
 553
 554         c->status[0].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 555         src+=2;
 556         if (st) c->status[1].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 557         if (st) src+=2;
 558         c->status[0].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 559         src+=2;
 560         if (st) c->status[1].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));
 561         if (st) src+=2;
 562
 563         *samples++ = c->status[0].sample1;
 564         if (st) *samples++ = c->status[1].sample1;
 565         *samples++ = c->status[0].sample2;
 566         if (st) *samples++ = c->status[1].sample2;
 567         for(;n>0;n--) {
 568             *samples++ = adpcm_ms_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);
 569             *samples++ = adpcm_ms_expand_nibble(&c->status[st], src[0] & 0x0F);
 570             src ++;
 571         }
 572         break;
 573     case CODEC_ID_ADPCM_IMA_DK4:
 574         if (buf_size > BLKSIZE) {
 575             if (avctx->block_align != 0)
 576                 buf_size = avctx->block_align;
 577             else
 578                 buf_size = BLKSIZE;
 579         }
 580         c->status[0].predictor = (src[0] | (src[1] << 8));
 581         c->status[0].step_index = src[2];
 582         src += 4;
 583         if(c->status[0].predictor & 0x8000)
 584             c->status[0].predictor -= 0x10000;
 585         *samples++ = c->status[0].predictor;
 586         if (st) {
 587             c->status[1].predictor = (src[0] | (src[1] << 8));
 588             c->status[1].step_index = src[2];
 589             src += 4;
 590             if(c->status[1].predictor & 0x8000)
 591                 c->status[1].predictor -= 0x10000;
 592             *samples++ = c->status[1].predictor;
 593         }
 594         while (src < buf + buf_size) {
 595
 596             /* take care of the top nibble (always left or mono channel) */
 597             *samples++ = adpcm_ima_expand_nibble(&c->status[0],
 598                 (src[0] >> 4) & 0x0F);
 599
 600             /* take care of the bottom nibble, which is right sample for
 601              * stereo, or another mono sample */
 602             if (st)
 603                 *samples++ = adpcm_ima_expand_nibble(&c->status[1],
 604                     src[0] & 0x0F);
 605             else
 606                 *samples++ = adpcm_ima_expand_nibble(&c->status[0],
 607                     src[0] & 0x0F);
 608
 609             src++;
 610         }
 611         break;
 612     case CODEC_ID_ADPCM_IMA_DK3:
 613         if (buf_size > BLKSIZE) {
 614             if (avctx->block_align != 0)
 615                 buf_size = avctx->block_align;
 616             else
 617                 buf_size = BLKSIZE;
 618         }
 619         c->status[0].predictor = (src[10] | (src[11] << 8));
 620         c->status[1].predictor = (src[12] | (src[13] << 8));
 621         c->status[0].step_index = src[14];
 622         c->status[1].step_index = src[15];
 623         /* sign extend the predictors */
 624         if(c->status[0].predictor & 0x8000)
 625             c->status[0].predictor -= 0x10000;
 626         if(c->status[1].predictor & 0x8000)
 627             c->status[1].predictor -= 0x10000;
 628         src += 16;
 629         diff_channel = c->status[1].predictor;
 630
 631         /* the DK3_GET_NEXT_NIBBLE macro issues the break statement when
 632          * the buffer is consumed */
 633         while (1) {
 634
 635             /* for this algorithm, c->status[0] is the sum channel and
 636              * c->status[1] is the diff channel */
 637
 638             /* process the first predictor of the sum channel */
 639             DK3_GET_NEXT_NIBBLE();
 640             adpcm_ima_expand_nibble(&c->status[0], nibble);
 641
 642             /* process the diff channel predictor */
 643             DK3_GET_NEXT_NIBBLE();
 644             adpcm_ima_expand_nibble(&c->status[1], nibble);
 645
 646             /* process the first pair of stereo PCM samples */
 647             diff_channel = (diff_channel + c->status[1].predictor) / 2;
 648             *samples++ = c->status[0].predictor + c->status[1].predictor;
 649             *samples++ = c->status[0].predictor - c->status[1].predictor;
 650
 651             /* process the second predictor of the sum channel */
 652             DK3_GET_NEXT_NIBBLE();
 653             adpcm_ima_expand_nibble(&c->status[0], nibble);
 654
 655             /* process the second pair of stereo PCM samples */
 656             diff_channel = (diff_channel + c->status[1].predictor) / 2;
 657             *samples++ = c->status[0].predictor + c->status[1].predictor;
 658             *samples++ = c->status[0].predictor - c->status[1].predictor;
 659         }
 660         break;
 661     default:
 662         *data_size = 0;
 663         return -1;
 664     }
 665     *data_size = (uint8_t *)samples - (uint8_t *)data;
 666     return src - buf;
 667 }
 668
 669 #define ADPCM_CODEC(id, name)                   \
 670 AVCodec name ## _encoder = {                    \
 671     #name,                                      \
 672     CODEC_TYPE_AUDIO,                           \
 673     id,                                         \
 674     sizeof(ADPCMContext),                       \
 675     adpcm_encode_init,                          \
 676     adpcm_encode_frame,                         \
 677     adpcm_encode_close,                         \
 678     NULL,                                       \
 679 };                                              \
 680 AVCodec name ## _decoder = {                    \
 681     #name,                                      \
 682     CODEC_TYPE_AUDIO,                           \
 683     id,                                         \
 684     sizeof(ADPCMContext),                       \
 685     adpcm_decode_init,                          \
 686     NULL,                                       \
 687     NULL,                                       \
 688     adpcm_decode_frame,                         \
 689 };
 690
 691 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);
 692 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);
 693 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);
 694 ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);
 695 ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);
 696 ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);
 697
 698 #undef ADPCM_CODEC