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   1 /*
   2  * Shorten decoder
   3  * Copyright (c) 2005 Jeff Muizelaar
   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 shorten.c
  24  * Shorten decoder
  25  * @author Jeff Muizelaar
  26  *
  27  */
  28
  29 #define DEBUG
  30 #include <limits.h>
  31 #include "avcodec.h"
  32 #include "bitstream.h"
  33 #include "golomb.h"
  34
  35 #define MAX_CHANNELS 8
  36 #define MAX_BLOCKSIZE 65535
  37
  38 #define OUT_BUFFER_SIZE 16384
  39
  40 #define ULONGSIZE 2
  41
  42 #define WAVE_FORMAT_PCM 0x0001
  43
  44 #define DEFAULT_BLOCK_SIZE 256
  45
  46 #define TYPESIZE 4
  47 #define CHANSIZE 0
  48 #define LPCQSIZE 2
  49 #define ENERGYSIZE 3
  50 #define BITSHIFTSIZE 2
  51
  52 #define TYPE_S16HL 3
  53 #define TYPE_S16LH 5
  54
  55 #define NWRAP 3
  56 #define NSKIPSIZE 1
  57
  58 #define LPCQUANT 5
  59 #define V2LPCQOFFSET (1 << LPCQUANT)
  60
  61 #define FNSIZE 2
  62 #define FN_DIFF0        0
  63 #define FN_DIFF1        1
  64 #define FN_DIFF2        2
  65 #define FN_DIFF3        3
  66 #define FN_QUIT         4
  67 #define FN_BLOCKSIZE    5
  68 #define FN_BITSHIFT     6
  69 #define FN_QLPC         7
  70 #define FN_ZERO         8
  71 #define FN_VERBATIM     9
  72
  73 #define VERBATIM_CKSIZE_SIZE 5
  74 #define VERBATIM_BYTE_SIZE 8
  75 #define CANONICAL_HEADER_SIZE 44
  76
  77 typedef struct ShortenContext {
  78     AVCodecContext *avctx;
  79     GetBitContext gb;
  80
  81     int min_framesize, max_framesize;
  82     int channels;
  83
  84     int32_t *decoded[MAX_CHANNELS];
  85     int32_t *offset[MAX_CHANNELS];
  86     uint8_t *bitstream;
  87     int bitstream_size;
  88     int bitstream_index;
  89     unsigned int allocated_bitstream_size;
  90     int header_size;
  91     uint8_t header[OUT_BUFFER_SIZE];
  92     int version;
  93     int cur_chan;
  94     int bitshift;
  95     int nmean;
  96     int internal_ftype;
  97     int nwrap;
  98     int blocksize;
  99     int bitindex;
 100     int32_t lpcqoffset;
 101 } ShortenContext;
 102
 103 static int shorten_decode_init(AVCodecContext * avctx)
 104 {
 105     ShortenContext *s = avctx->priv_data;
 106     s->avctx = avctx;
 107
 108     return 0;
 109 }
 110
 111 static int allocate_buffers(ShortenContext *s)
 112 {
 113     int i, chan;
 114     for (chan=0; chan<s->channels; chan++) {
 115         if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
 116             av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
 117             return -1;
 118         }
 119         if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
 120             av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
 121             return -1;
 122         }
 123
 124         s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
 125
 126         s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
 127         for (i=0; i<s->nwrap; i++)
 128             s->decoded[chan][i] = 0;
 129         s->decoded[chan] += s->nwrap;
 130     }
 131     return 0;
 132 }
 133
 134
 135 static inline unsigned int get_uint(ShortenContext *s, int k)
 136 {
 137     if (s->version != 0)
 138         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
 139     return get_ur_golomb_shorten(&s->gb, k);
 140 }
 141
 142
 143 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
 144 {
 145     int i;
 146
 147     if (s->bitshift != 0)
 148         for (i = 0; i < s->blocksize; i++)
 149             buffer[s->nwrap + i] <<= s->bitshift;
 150 }
 151
 152
 153 static void init_offset(ShortenContext *s)
 154 {
 155     int32_t mean = 0;
 156     int  chan, i;
 157     int nblock = FFMAX(1, s->nmean);
 158     /* initialise offset */
 159     switch (s->internal_ftype)
 160     {
 161         case TYPE_S16HL:
 162         case TYPE_S16LH:
 163             mean = 0;
 164             break;
 165         default:
 166             av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
 167             abort();
 168     }
 169
 170     for (chan = 0; chan < s->channels; chan++)
 171         for (i = 0; i < nblock; i++)
 172             s->offset[chan][i] = mean;
 173 }
 174
 175 static int inline get_le32(GetBitContext *gb)
 176 {
 177     return bswap_32(get_bits_long(gb, 32));
 178 }
 179
 180 static short inline get_le16(GetBitContext *gb)
 181 {
 182     return bswap_16(get_bits_long(gb, 16));
 183 }
 184
 185 static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
 186 {
 187     GetBitContext hb;
 188     int len;
 189     int chunk_size;
 190     short wave_format;
 191
 192     init_get_bits(&hb, header, header_size*8);
 193     if (get_le32(&hb) != MKTAG('R','I','F','F')) {
 194         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
 195         return -1;
 196     }
 197
 198     chunk_size = get_le32(&hb);
 199
 200     if (get_le32(&hb) != MKTAG('W','A','V','E')) {
 201         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
 202         return -1;
 203     }
 204
 205     while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
 206         len = get_le32(&hb);
 207         skip_bits(&hb, 8*len);
 208     }
 209     len = get_le32(&hb);
 210
 211     if (len < 16) {
 212         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
 213         return -1;
 214     }
 215
 216     wave_format = get_le16(&hb);
 217
 218     switch (wave_format) {
 219         case WAVE_FORMAT_PCM:
 220             break;
 221         default:
 222             av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
 223             return -1;
 224     }
 225
 226     avctx->channels = get_le16(&hb);
 227     avctx->sample_rate = get_le32(&hb);
 228     avctx->bit_rate = get_le32(&hb) * 8;
 229     avctx->block_align = get_le16(&hb);
 230     avctx->bits_per_sample = get_le16(&hb);
 231
 232     if (avctx->bits_per_sample != 16) {
 233         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
 234         return -1;
 235     }
 236
 237     len -= 16;
 238     if (len > 0)
 239         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
 240
 241     return 0;
 242 }
 243
 244 static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
 245     int i, chan;
 246     for (i=0; i<blocksize; i++)
 247         for (chan=0; chan < nchan; chan++)
 248             *samples++ = FFMIN(buffer[chan][i], 32768);
 249     return samples;
 250 }
 251
 252 static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
 253 {
 254     int sum, i, j;
 255     int coeffs[pred_order];
 256
 257     for (i=0; i<pred_order; i++)
 258         coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
 259
 260     for (i=0; i < s->blocksize; i++) {
 261         sum = s->lpcqoffset;
 262         for (j=0; j<pred_order; j++)
 263             sum += coeffs[j] * s->decoded[channel][i-j-1];
 264         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
 265     }
 266 }
 267
 268
 269 static int shorten_decode_frame(AVCodecContext *avctx,
 270         void *data, int *data_size,
 271         uint8_t *buf, int buf_size)
 272 {
 273     ShortenContext *s = avctx->priv_data;
 274     int i, input_buf_size = 0;
 275     int16_t *samples = data;
 276     if(s->max_framesize == 0){
 277         s->max_framesize= 1024; // should hopefully be enough for the first header
 278         s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
 279     }
 280
 281     if(1 && s->max_framesize){//FIXME truncated
 282         buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
 283         input_buf_size= buf_size;
 284
 285         if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
 286             //                printf("memmove\n");
 287             memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
 288             s->bitstream_index=0;
 289         }
 290         memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
 291         buf= &s->bitstream[s->bitstream_index];
 292         buf_size += s->bitstream_size;
 293         s->bitstream_size= buf_size;
 294
 295         if(buf_size < s->max_framesize){
 296             //dprintf("wanna more data ... %d\n", buf_size);
 297             return input_buf_size;
 298         }
 299     }
 300     init_get_bits(&s->gb, buf, buf_size*8);
 301     get_bits(&s->gb, s->bitindex);
 302     if (!s->blocksize)
 303     {
 304         int maxnlpc = 0;
 305         /* shorten signature */
 306         if (get_bits_long(&s->gb, 32) != bswap_32(ff_get_fourcc("ajkg"))) {
 307             av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
 308             return -1;
 309         }
 310
 311         s->lpcqoffset = 0;
 312         s->blocksize = DEFAULT_BLOCK_SIZE;
 313         s->channels = 1;
 314         s->nmean = -1;
 315         s->version = get_bits(&s->gb, 8);
 316         s->internal_ftype = get_uint(s, TYPESIZE);
 317
 318         s->channels = get_uint(s, CHANSIZE);
 319         if (s->channels > MAX_CHANNELS) {
 320             av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
 321             return -1;
 322         }
 323
 324         /* get blocksize if version > 0 */
 325         if (s->version > 0) {
 326             int skip_bytes;
 327             s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
 328             maxnlpc = get_uint(s, LPCQSIZE);
 329             s->nmean = get_uint(s, 0);
 330
 331             skip_bytes = get_uint(s, NSKIPSIZE);
 332             for (i=0; i<skip_bytes; i++) {
 333                 skip_bits(&s->gb, 8);
 334             }
 335         }
 336         s->nwrap = FFMAX(NWRAP, maxnlpc);
 337
 338         if (allocate_buffers(s))
 339             return -1;
 340
 341         init_offset(s);
 342
 343         if (s->version > 1)
 344             s->lpcqoffset = V2LPCQOFFSET;
 345
 346         if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
 347             av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at begining of stream\n");
 348             return -1;
 349         }
 350
 351         s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 352         if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
 353             av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
 354             return -1;
 355         }
 356
 357         for (i=0; i<s->header_size; i++)
 358             s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 359
 360         if (decode_wave_header(avctx, s->header, s->header_size) < 0)
 361             return -1;
 362
 363         s->cur_chan = 0;
 364         s->bitshift = 0;
 365     }
 366     else
 367     {
 368         int cmd;
 369         int len;
 370         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
 371         switch (cmd) {
 372             case FN_ZERO:
 373             case FN_DIFF0:
 374             case FN_DIFF1:
 375             case FN_DIFF2:
 376             case FN_DIFF3:
 377             case FN_QLPC:
 378                 {
 379                     int residual_size = 0;
 380                     int channel = s->cur_chan;
 381                     int32_t coffset;
 382                     if (cmd != FN_ZERO) {
 383                         residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
 384                         /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
 385                         if (s->version == 0)
 386                             residual_size--;
 387                     }
 388
 389                     if (s->nmean == 0)
 390                         coffset = s->offset[channel][0];
 391                     else {
 392                         int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
 393                         for (i=0; i<s->nmean; i++)
 394                             sum += s->offset[channel][i];
 395                         coffset = sum / s->nmean;
 396                         if (s->version >= 2)
 397                             coffset >>= FFMIN(1, s->bitshift);
 398                     }
 399                     switch (cmd) {
 400                         case FN_ZERO:
 401                             for (i=0; i<s->blocksize; i++)
 402                                 s->decoded[channel][i] = 0;
 403                             break;
 404                         case FN_DIFF0:
 405                             for (i=0; i<s->blocksize; i++)
 406                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
 407                             break;
 408                         case FN_DIFF1:
 409                             for (i=0; i<s->blocksize; i++)
 410                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
 411                             break;
 412                         case FN_DIFF2:
 413                             for (i=0; i<s->blocksize; i++)
 414                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
 415                                                                                                       -   s->decoded[channel][i-2];
 416                             break;
 417                         case FN_DIFF3:
 418                             for (i=0; i<s->blocksize; i++)
 419                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
 420                                                                                                       - 3*s->decoded[channel][i-2]
 421                                                                                                       +   s->decoded[channel][i-3];
 422                             break;
 423                         case FN_QLPC:
 424                             {
 425                                 int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
 426                                 for (i=0; i<pred_order; i++)
 427                                     s->decoded[channel][i - pred_order] -= coffset;
 428                                 decode_subframe_lpc(s, channel, residual_size, pred_order);
 429                                 if (coffset != 0)
 430                                     for (i=0; i < s->blocksize; i++)
 431                                         s->decoded[channel][i] += coffset;
 432                             }
 433                     }
 434                     if (s->nmean > 0) {
 435                         int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
 436                         for (i=0; i<s->blocksize; i++)
 437                             sum += s->decoded[channel][i];
 438
 439                         for (i=1; i<s->nmean; i++)
 440                             s->offset[channel][i-1] = s->offset[channel][i];
 441
 442                         if (s->version < 2)
 443                             s->offset[channel][s->nmean - 1] = sum / s->blocksize;
 444                         else
 445                             s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
 446                     }
 447                     for (i=-s->nwrap; i<0; i++)
 448                         s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
 449
 450                     fix_bitshift(s, s->decoded[channel]);
 451
 452                     s->cur_chan++;
 453                     if (s->cur_chan == s->channels) {
 454                         samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
 455                         s->cur_chan = 0;
 456                         goto frame_done;
 457                     }
 458                     break;
 459                 }
 460                 break;
 461             case FN_VERBATIM:
 462                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 463                 while (len--) {
 464                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 465                 }
 466                 break;
 467             case FN_BITSHIFT:
 468                 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
 469                 break;
 470             case FN_BLOCKSIZE:
 471                 s->blocksize = get_uint(s, av_log2(s->blocksize));
 472                 break;
 473             case FN_QUIT:
 474                 return buf_size;
 475                 break;
 476             default:
 477                 av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
 478                 return -1;
 479                 break;
 480         }
 481     }
 482 frame_done:
 483     *data_size = (int8_t *)samples - (int8_t *)data;
 484
 485     //    s->last_blocksize = s->blocksize;
 486     s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
 487     i= (get_bits_count(&s->gb))/8;
 488     if (i > buf_size) {
 489         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
 490         s->bitstream_size=0;
 491         s->bitstream_index=0;
 492         return -1;
 493     }
 494     if (s->bitstream_size) {
 495         s->bitstream_index += i;
 496         s->bitstream_size  -= i;
 497         return input_buf_size;
 498     } else
 499         return i;
 500 }
 501
 502 static int shorten_decode_close(AVCodecContext *avctx)
 503 {
 504     ShortenContext *s = avctx->priv_data;
 505     int i;
 506
 507     for (i = 0; i < s->channels; i++) {
 508         s->decoded[i] -= s->nwrap;
 509         av_freep(&s->decoded[i]);
 510         av_freep(&s->offset[i]);
 511     }
 512     av_freep(&s->bitstream);
 513     return 0;
 514 }
 515
 516 static void shorten_flush(AVCodecContext *avctx){
 517     ShortenContext *s = avctx->priv_data;
 518
 519     s->bitstream_size=
 520         s->bitstream_index= 0;
 521 }
 522
 523 AVCodec shorten_decoder = {
 524     "shorten",
 525     CODEC_TYPE_AUDIO,
 526     CODEC_ID_SHORTEN,
 527     sizeof(ShortenContext),
 528     shorten_decode_init,
 529     NULL,
 530     shorten_decode_close,
 531     shorten_decode_frame,
 532     .flush= shorten_flush,
 533 };