libavcodec/flac.c

   1 /*
   2  * FLAC (Free Lossless Audio Codec) decoder
   3  * Copyright (c) 2003 Alex Beregszaszi
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file flac.c
  24  * FLAC (Free Lossless Audio Codec) decoder
  25  * @author Alex Beregszaszi
  26  *
  27  * For more information on the FLAC format, visit:
  28  *  http://flac.sourceforge.net/
  29  *
  30  * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
  31  * through, starting from the initial 'fLaC' signature; or by passing the
  32  * 34-byte streaminfo structure through avctx->extradata[_size] followed
  33  * by data starting with the 0xFFF8 marker.
  34  */
  35
  36 #include <limits.h>
  37
  38 #define ALT_BITSTREAM_READER
  39 #include "libavutil/crc.h"
  40 #include "avcodec.h"
  41 #include "bitstream.h"
  42 #include "golomb.h"
  43 #include "flac.h"
  44
  45 #undef NDEBUG
  46 #include <assert.h>
  47
  48 #define MAX_CHANNELS 8
  49 #define MAX_BLOCKSIZE 65535
  50 #define FLAC_STREAMINFO_SIZE 34
  51
  52 enum decorrelation_type {
  53     INDEPENDENT,
  54     LEFT_SIDE,
  55     RIGHT_SIDE,
  56     MID_SIDE,
  57 };
  58
  59 typedef struct FLACContext {
  60     FLACSTREAMINFO
  61
  62     AVCodecContext *avctx;
  63     GetBitContext gb;
  64
  65     int blocksize/*, last_blocksize*/;
  66     int curr_bps;
  67     enum decorrelation_type decorrelation;
  68
  69     int32_t *decoded[MAX_CHANNELS];
  70     uint8_t *bitstream;
  71     unsigned int bitstream_size;
  72     unsigned int bitstream_index;
  73     unsigned int allocated_bitstream_size;
  74 } FLACContext;
  75
  76 #define METADATA_TYPE_STREAMINFO 0
  77
  78 static const int sample_rate_table[] =
  79 { 0, 0, 0, 0,
  80   8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
  81   0, 0, 0, 0 };
  82
  83 static const int sample_size_table[] =
  84 { 0, 8, 12, 0, 16, 20, 24, 0 };
  85
  86 static const int blocksize_table[] = {
  87      0,    192, 576<<0, 576<<1, 576<<2, 576<<3,      0,      0,
  88 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
  89 };
  90
  91 static int64_t get_utf8(GetBitContext *gb){
  92     int64_t val;
  93     GET_UTF8(val, get_bits(gb, 8), return -1;)
  94     return val;
  95 }
  96
  97 static void allocate_buffers(FLACContext *s);
  98 static int metadata_parse(FLACContext *s);
  99
 100 static av_cold int flac_decode_init(AVCodecContext * avctx)
 101 {
 102     FLACContext *s = avctx->priv_data;
 103     s->avctx = avctx;
 104
 105     if (avctx->extradata_size > 4) {
 106         /* initialize based on the demuxer-supplied streamdata header */
 107         if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
 108             ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, avctx->extradata);
 109             allocate_buffers(s);
 110         } else {
 111             init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
 112             metadata_parse(s);
 113         }
 114     }
 115
 116     avctx->sample_fmt = SAMPLE_FMT_S16;
 117     return 0;
 118 }
 119
 120 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
 121 {
 122     av_log(avctx, AV_LOG_DEBUG, "  Blocksize: %d .. %d\n", s->min_blocksize, s->max_blocksize);
 123     av_log(avctx, AV_LOG_DEBUG, "  Max Framesize: %d\n", s->max_framesize);
 124     av_log(avctx, AV_LOG_DEBUG, "  Samplerate: %d\n", s->samplerate);
 125     av_log(avctx, AV_LOG_DEBUG, "  Channels: %d\n", s->channels);
 126     av_log(avctx, AV_LOG_DEBUG, "  Bits: %d\n", s->bps);
 127 }
 128
 129 static void allocate_buffers(FLACContext *s){
 130     int i;
 131
 132     assert(s->max_blocksize);
 133
 134     if(s->max_framesize == 0 && s->max_blocksize){
 135         s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
 136     }
 137
 138     for (i = 0; i < s->channels; i++)
 139     {
 140         s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
 141     }
 142
 143     if(s->allocated_bitstream_size < s->max_framesize)
 144         s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
 145 }
 146
 147 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
 148                               const uint8_t *buffer)
 149 {
 150     GetBitContext gb;
 151     init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
 152
 153     /* mandatory streaminfo */
 154     s->min_blocksize = get_bits(&gb, 16);
 155     s->max_blocksize = get_bits(&gb, 16);
 156
 157     skip_bits(&gb, 24); /* skip min frame size */
 158     s->max_framesize = get_bits_long(&gb, 24);
 159
 160     s->samplerate = get_bits_long(&gb, 20);
 161     s->channels = get_bits(&gb, 3) + 1;
 162     s->bps = get_bits(&gb, 5) + 1;
 163
 164     avctx->channels = s->channels;
 165     avctx->sample_rate = s->samplerate;
 166
 167     skip_bits(&gb, 36); /* total num of samples */
 168
 169     skip_bits(&gb, 64); /* md5 sum */
 170     skip_bits(&gb, 64); /* md5 sum */
 171
 172     dump_headers(avctx, s);
 173 }
 174
 175 /**
 176  * Parse a list of metadata blocks. This list of blocks must begin with
 177  * the fLaC marker.
 178  * @param s the flac decoding context containing the gb bit reader used to
 179  *          parse metadata
 180  * @return 1 if some metadata was read, 0 if no fLaC marker was found
 181  */
 182 static int metadata_parse(FLACContext *s)
 183 {
 184     int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
 185     int initial_pos= get_bits_count(&s->gb);
 186
 187     if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
 188         skip_bits(&s->gb, 32);
 189
 190         av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
 191         do {
 192             metadata_last = get_bits1(&s->gb);
 193             metadata_type = get_bits(&s->gb, 7);
 194             metadata_size = get_bits_long(&s->gb, 24);
 195
 196             if(get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits){
 197                 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
 198                 break;
 199             }
 200
 201             av_log(s->avctx, AV_LOG_DEBUG,
 202                    " metadata block: flag = %d, type = %d, size = %d\n",
 203                    metadata_last, metadata_type, metadata_size);
 204             if (metadata_size) {
 205                 switch (metadata_type) {
 206                 case METADATA_TYPE_STREAMINFO:
 207                     ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, s->gb.buffer+get_bits_count(&s->gb)/8);
 208                     streaminfo_updated = 1;
 209
 210                 default:
 211                     for (i=0; i<metadata_size; i++)
 212                         skip_bits(&s->gb, 8);
 213                 }
 214             }
 215         } while (!metadata_last);
 216
 217         if (streaminfo_updated)
 218             allocate_buffers(s);
 219         return 1;
 220     }
 221     return 0;
 222 }
 223
 224 static int decode_residuals(FLACContext *s, int channel, int pred_order)
 225 {
 226     int i, tmp, partition, method_type, rice_order;
 227     int sample = 0, samples;
 228
 229     method_type = get_bits(&s->gb, 2);
 230     if (method_type > 1){
 231         av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
 232         return -1;
 233     }
 234
 235     rice_order = get_bits(&s->gb, 4);
 236
 237     samples= s->blocksize >> rice_order;
 238     if (pred_order > samples) {
 239         av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n", pred_order, samples);
 240         return -1;
 241     }
 242
 243     sample=
 244     i= pred_order;
 245     for (partition = 0; partition < (1 << rice_order); partition++)
 246     {
 247         tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
 248         if (tmp == (method_type == 0 ? 15 : 31))
 249         {
 250             av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
 251             tmp = get_bits(&s->gb, 5);
 252             for (; i < samples; i++, sample++)
 253                 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
 254         }
 255         else
 256         {
 257 //            av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
 258             for (; i < samples; i++, sample++){
 259                 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
 260             }
 261         }
 262         i= 0;
 263     }
 264
 265 //    av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
 266
 267     return 0;
 268 }
 269
 270 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
 271 {
 272     const int blocksize = s->blocksize;
 273     int32_t *decoded = s->decoded[channel];
 274     int a, b, c, d, i;
 275
 276 //    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME FIXED\n");
 277
 278     /* warm up samples */
 279 //    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
 280
 281     for (i = 0; i < pred_order; i++)
 282     {
 283         decoded[i] = get_sbits(&s->gb, s->curr_bps);
 284 //        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
 285     }
 286
 287     if (decode_residuals(s, channel, pred_order) < 0)
 288         return -1;
 289
 290     if(pred_order > 0)
 291         a = decoded[pred_order-1];
 292     if(pred_order > 1)
 293         b = a - decoded[pred_order-2];
 294     if(pred_order > 2)
 295         c = b - decoded[pred_order-2] + decoded[pred_order-3];
 296     if(pred_order > 3)
 297         d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
 298
 299     switch(pred_order)
 300     {
 301         case 0:
 302             break;
 303         case 1:
 304             for (i = pred_order; i < blocksize; i++)
 305                 decoded[i] = a += decoded[i];
 306             break;
 307         case 2:
 308             for (i = pred_order; i < blocksize; i++)
 309                 decoded[i] = a += b += decoded[i];
 310             break;
 311         case 3:
 312             for (i = pred_order; i < blocksize; i++)
 313                 decoded[i] = a += b += c += decoded[i];
 314             break;
 315         case 4:
 316             for (i = pred_order; i < blocksize; i++)
 317                 decoded[i] = a += b += c += d += decoded[i];
 318             break;
 319         default:
 320             av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
 321             return -1;
 322     }
 323
 324     return 0;
 325 }
 326
 327 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
 328 {
 329     int i, j;
 330     int coeff_prec, qlevel;
 331     int coeffs[pred_order];
 332     int32_t *decoded = s->decoded[channel];
 333
 334 //    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME LPC\n");
 335
 336     /* warm up samples */
 337 //    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
 338
 339     for (i = 0; i < pred_order; i++)
 340     {
 341         decoded[i] = get_sbits(&s->gb, s->curr_bps);
 342 //        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, decoded[i]);
 343     }
 344
 345     coeff_prec = get_bits(&s->gb, 4) + 1;
 346     if (coeff_prec == 16)
 347     {
 348         av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
 349         return -1;
 350     }
 351 //    av_log(s->avctx, AV_LOG_DEBUG, "   qlp coeff prec: %d\n", coeff_prec);
 352     qlevel = get_sbits(&s->gb, 5);
 353 //    av_log(s->avctx, AV_LOG_DEBUG, "   quant level: %d\n", qlevel);
 354     if(qlevel < 0){
 355         av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
 356         return -1;
 357     }
 358
 359     for (i = 0; i < pred_order; i++)
 360     {
 361         coeffs[i] = get_sbits(&s->gb, coeff_prec);
 362 //        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, coeffs[i]);
 363     }
 364
 365     if (decode_residuals(s, channel, pred_order) < 0)
 366         return -1;
 367
 368     if (s->bps > 16) {
 369         int64_t sum;
 370         for (i = pred_order; i < s->blocksize; i++)
 371         {
 372             sum = 0;
 373             for (j = 0; j < pred_order; j++)
 374                 sum += (int64_t)coeffs[j] * decoded[i-j-1];
 375             decoded[i] += sum >> qlevel;
 376         }
 377     } else {
 378         for (i = pred_order; i < s->blocksize-1; i += 2)
 379         {
 380             int c;
 381             int d = decoded[i-pred_order];
 382             int s0 = 0, s1 = 0;
 383             for (j = pred_order-1; j > 0; j--)
 384             {
 385                 c = coeffs[j];
 386                 s0 += c*d;
 387                 d = decoded[i-j];
 388                 s1 += c*d;
 389             }
 390             c = coeffs[0];
 391             s0 += c*d;
 392             d = decoded[i] += s0 >> qlevel;
 393             s1 += c*d;
 394             decoded[i+1] += s1 >> qlevel;
 395         }
 396         if (i < s->blocksize)
 397         {
 398             int sum = 0;
 399             for (j = 0; j < pred_order; j++)
 400                 sum += coeffs[j] * decoded[i-j-1];
 401             decoded[i] += sum >> qlevel;
 402         }
 403     }
 404
 405     return 0;
 406 }
 407
 408 static inline int decode_subframe(FLACContext *s, int channel)
 409 {
 410     int type, wasted = 0;
 411     int i, tmp;
 412
 413     s->curr_bps = s->bps;
 414     if(channel == 0){
 415         if(s->decorrelation == RIGHT_SIDE)
 416             s->curr_bps++;
 417     }else{
 418         if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
 419             s->curr_bps++;
 420     }
 421
 422     if (get_bits1(&s->gb))
 423     {
 424         av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
 425         return -1;
 426     }
 427     type = get_bits(&s->gb, 6);
 428 //    wasted = get_bits1(&s->gb);
 429
 430 //    if (wasted)
 431 //    {
 432 //        while (!get_bits1(&s->gb))
 433 //            wasted++;
 434 //        if (wasted)
 435 //            wasted++;
 436 //        s->curr_bps -= wasted;
 437 //    }
 438 #if 0
 439     wasted= 16 - av_log2(show_bits(&s->gb, 17));
 440     skip_bits(&s->gb, wasted+1);
 441     s->curr_bps -= wasted;
 442 #else
 443     if (get_bits1(&s->gb))
 444     {
 445         wasted = 1;
 446         while (!get_bits1(&s->gb))
 447             wasted++;
 448         s->curr_bps -= wasted;
 449         av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
 450     }
 451 #endif
 452 //FIXME use av_log2 for types
 453     if (type == 0)
 454     {
 455         av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
 456         tmp = get_sbits(&s->gb, s->curr_bps);
 457         for (i = 0; i < s->blocksize; i++)
 458             s->decoded[channel][i] = tmp;
 459     }
 460     else if (type == 1)
 461     {
 462         av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
 463         for (i = 0; i < s->blocksize; i++)
 464             s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
 465     }
 466     else if ((type >= 8) && (type <= 12))
 467     {
 468 //        av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
 469         if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
 470             return -1;
 471     }
 472     else if (type >= 32)
 473     {
 474 //        av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
 475         if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
 476             return -1;
 477     }
 478     else
 479     {
 480         av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
 481         return -1;
 482     }
 483
 484     if (wasted)
 485     {
 486         int i;
 487         for (i = 0; i < s->blocksize; i++)
 488             s->decoded[channel][i] <<= wasted;
 489     }
 490
 491     return 0;
 492 }
 493
 494 static int decode_frame(FLACContext *s, int alloc_data_size)
 495 {
 496     int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
 497     int decorrelation, bps, blocksize, samplerate;
 498
 499     blocksize_code = get_bits(&s->gb, 4);
 500
 501     sample_rate_code = get_bits(&s->gb, 4);
 502
 503     assignment = get_bits(&s->gb, 4); /* channel assignment */
 504     if (assignment < 8 && s->channels == assignment+1)
 505         decorrelation = INDEPENDENT;
 506     else if (assignment >=8 && assignment < 11 && s->channels == 2)
 507         decorrelation = LEFT_SIDE + assignment - 8;
 508     else
 509     {
 510         av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
 511         return -1;
 512     }
 513
 514     sample_size_code = get_bits(&s->gb, 3);
 515     if(sample_size_code == 0)
 516         bps= s->bps;
 517     else if((sample_size_code != 3) && (sample_size_code != 7))
 518         bps = sample_size_table[sample_size_code];
 519     else
 520     {
 521         av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
 522         return -1;
 523     }
 524
 525     if (get_bits1(&s->gb))
 526     {
 527         av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
 528         return -1;
 529     }
 530
 531     if(get_utf8(&s->gb) < 0){
 532         av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
 533         return -1;
 534     }
 535 #if 0
 536     if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
 537         (s->min_blocksize != s->max_blocksize)){
 538     }else{
 539     }
 540 #endif
 541
 542     if (blocksize_code == 0)
 543         blocksize = s->min_blocksize;
 544     else if (blocksize_code == 6)
 545         blocksize = get_bits(&s->gb, 8)+1;
 546     else if (blocksize_code == 7)
 547         blocksize = get_bits(&s->gb, 16)+1;
 548     else
 549         blocksize = blocksize_table[blocksize_code];
 550
 551     if(blocksize > s->max_blocksize){
 552         av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
 553         return -1;
 554     }
 555
 556     if(blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
 557         return -1;
 558
 559     if (sample_rate_code == 0){
 560         samplerate= s->samplerate;
 561     }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
 562         samplerate = sample_rate_table[sample_rate_code];
 563     else if (sample_rate_code == 12)
 564         samplerate = get_bits(&s->gb, 8) * 1000;
 565     else if (sample_rate_code == 13)
 566         samplerate = get_bits(&s->gb, 16);
 567     else if (sample_rate_code == 14)
 568         samplerate = get_bits(&s->gb, 16) * 10;
 569     else{
 570         av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
 571         return -1;
 572     }
 573
 574     skip_bits(&s->gb, 8);
 575     crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
 576                   s->gb.buffer, get_bits_count(&s->gb)/8);
 577     if(crc8){
 578         av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
 579         return -1;
 580     }
 581
 582     s->blocksize    = blocksize;
 583     s->samplerate   = samplerate;
 584     s->bps          = bps;
 585     s->decorrelation= decorrelation;
 586
 587 //    dump_headers(s->avctx, (FLACStreaminfo *)s);
 588
 589     /* subframes */
 590     for (i = 0; i < s->channels; i++)
 591     {
 592 //        av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
 593         if (decode_subframe(s, i) < 0)
 594             return -1;
 595     }
 596
 597     align_get_bits(&s->gb);
 598
 599     /* frame footer */
 600     skip_bits(&s->gb, 16); /* data crc */
 601
 602     return 0;
 603 }
 604
 605 static int flac_decode_frame(AVCodecContext *avctx,
 606                             void *data, int *data_size,
 607                             const uint8_t *buf, int buf_size)
 608 {
 609     FLACContext *s = avctx->priv_data;
 610     int tmp = 0, i, j = 0, input_buf_size = 0;
 611     int16_t *samples = data;
 612     int alloc_data_size= *data_size;
 613
 614     *data_size=0;
 615
 616     if(s->max_framesize == 0){
 617         s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
 618         s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
 619     }
 620
 621     if(1 && s->max_framesize){//FIXME truncated
 622             if(s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
 623                 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
 624             input_buf_size= buf_size;
 625
 626             if(s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
 627                 return -1;
 628
 629             if(s->allocated_bitstream_size < s->bitstream_size + buf_size)
 630                 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
 631
 632             if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
 633 //                printf("memmove\n");
 634                 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
 635                 s->bitstream_index=0;
 636             }
 637             memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
 638             buf= &s->bitstream[s->bitstream_index];
 639             buf_size += s->bitstream_size;
 640             s->bitstream_size= buf_size;
 641
 642             if(buf_size < s->max_framesize && input_buf_size){
 643 //                printf("wanna more data ...\n");
 644                 return input_buf_size;
 645             }
 646     }
 647
 648     init_get_bits(&s->gb, buf, buf_size*8);
 649
 650     if(metadata_parse(s))
 651         goto end;
 652
 653         tmp = show_bits(&s->gb, 16);
 654         if((tmp & 0xFFFE) != 0xFFF8){
 655             av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
 656             while(get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
 657                 skip_bits(&s->gb, 8);
 658             goto end; // we may not have enough bits left to decode a frame, so try next time
 659         }
 660         skip_bits(&s->gb, 16);
 661         if (decode_frame(s, alloc_data_size) < 0){
 662             av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
 663             s->bitstream_size=0;
 664             s->bitstream_index=0;
 665             return -1;
 666         }
 667
 668
 669 #if 0
 670     /* fix the channel order here */
 671     if (s->order == MID_SIDE)
 672     {
 673         short *left = samples;
 674         short *right = samples + s->blocksize;
 675         for (i = 0; i < s->blocksize; i += 2)
 676         {
 677             uint32_t x = s->decoded[0][i];
 678             uint32_t y = s->decoded[0][i+1];
 679
 680             right[i] = x - (y / 2);
 681             left[i] = right[i] + y;
 682         }
 683         *data_size = 2 * s->blocksize;
 684     }
 685     else
 686     {
 687     for (i = 0; i < s->channels; i++)
 688     {
 689         switch(s->order)
 690         {
 691             case INDEPENDENT:
 692                 for (j = 0; j < s->blocksize; j++)
 693                     samples[(s->blocksize*i)+j] = s->decoded[i][j];
 694                 break;
 695             case LEFT_SIDE:
 696             case RIGHT_SIDE:
 697                 if (i == 0)
 698                     for (j = 0; j < s->blocksize; j++)
 699                         samples[(s->blocksize*i)+j] = s->decoded[0][j];
 700                 else
 701                     for (j = 0; j < s->blocksize; j++)
 702                         samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
 703                 break;
 704 //            case MID_SIDE:
 705 //                av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
 706         }
 707         *data_size += s->blocksize;
 708     }
 709     }
 710 #else
 711 #define DECORRELATE(left, right)\
 712             assert(s->channels == 2);\
 713             for (i = 0; i < s->blocksize; i++)\
 714             {\
 715                 int a= s->decoded[0][i];\
 716                 int b= s->decoded[1][i];\
 717                 *samples++ = ((left)  << (24 - s->bps)) >> 8;\
 718                 *samples++ = ((right) << (24 - s->bps)) >> 8;\
 719             }\
 720             break;
 721
 722     switch(s->decorrelation)
 723     {
 724         case INDEPENDENT:
 725             for (j = 0; j < s->blocksize; j++)
 726             {
 727                 for (i = 0; i < s->channels; i++)
 728                     *samples++ = (s->decoded[i][j] << (24 - s->bps)) >> 8;
 729             }
 730             break;
 731         case LEFT_SIDE:
 732             DECORRELATE(a,a-b)
 733         case RIGHT_SIDE:
 734             DECORRELATE(a+b,b)
 735         case MID_SIDE:
 736             DECORRELATE( (a-=b>>1) + b, a)
 737     }
 738 #endif
 739
 740     *data_size = (int8_t *)samples - (int8_t *)data;
 741 //    av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
 742
 743 //    s->last_blocksize = s->blocksize;
 744 end:
 745     i= (get_bits_count(&s->gb)+7)/8;
 746     if(i > buf_size){
 747         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
 748         s->bitstream_size=0;
 749         s->bitstream_index=0;
 750         return -1;
 751     }
 752
 753     if(s->bitstream_size){
 754         s->bitstream_index += i;
 755         s->bitstream_size  -= i;
 756         return input_buf_size;
 757     }else
 758         return i;
 759 }
 760
 761 static av_cold int flac_decode_close(AVCodecContext *avctx)
 762 {
 763     FLACContext *s = avctx->priv_data;
 764     int i;
 765
 766     for (i = 0; i < s->channels; i++)
 767     {
 768         av_freep(&s->decoded[i]);
 769     }
 770     av_freep(&s->bitstream);
 771
 772     return 0;
 773 }
 774
 775 static void flac_flush(AVCodecContext *avctx){
 776     FLACContext *s = avctx->priv_data;
 777
 778     s->bitstream_size=
 779     s->bitstream_index= 0;
 780 }
 781
 782 AVCodec flac_decoder = {
 783     "flac",
 784     CODEC_TYPE_AUDIO,
 785     CODEC_ID_FLAC,
 786     sizeof(FLACContext),
 787     flac_decode_init,
 788     NULL,
 789     flac_decode_close,
 790     flac_decode_frame,
 791     CODEC_CAP_DELAY,
 792     .flush= flac_flush,
 793     .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
 794 };