libavcodec/shorten.c

   1 /*
   2  * Shorten decoder
   3  * Copyright (c) 2005 Jeff Muizelaar
   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
  20 /**
  21  * @file shorten.c
  22  * Shorten decoder
  23  * @author Jeff Muizelaar
  24  *
  25  */
  26
  27 #define DEBUG
  28 #include <limits.h>
  29 #include "avcodec.h"
  30 #include "bitstream.h"
  31 #include "golomb.h"
  32
  33 #define MAX_CHANNELS 8
  34 #define MAX_BLOCKSIZE 65535
  35
  36 #define OUT_BUFFER_SIZE 16384
  37
  38 #define ULONGSIZE 2
  39
  40 #define WAVE_FORMAT_PCM 0x0001
  41
  42 #define DEFAULT_BLOCK_SIZE 256
  43
  44 #define TYPESIZE 4
  45 #define CHANSIZE 0
  46 #define LPCQSIZE 2
  47 #define ENERGYSIZE 3
  48 #define BITSHIFTSIZE 2
  49
  50 #define TYPE_S16HL 3
  51 #define TYPE_S16LH 5
  52
  53 #define NWRAP 3
  54 #define NSKIPSIZE 1
  55
  56 #define LPCQUANT 5
  57 #define V2LPCQOFFSET (1 << LPCQUANT)
  58
  59 #define FNSIZE 2
  60 #define FN_DIFF0        0
  61 #define FN_DIFF1        1
  62 #define FN_DIFF2        2
  63 #define FN_DIFF3        3
  64 #define FN_QUIT         4
  65 #define FN_BLOCKSIZE    5
  66 #define FN_BITSHIFT     6
  67 #define FN_QLPC         7
  68 #define FN_ZERO         8
  69 #define FN_VERBATIM     9
  70
  71 #define VERBATIM_CKSIZE_SIZE 5
  72 #define VERBATIM_BYTE_SIZE 8
  73 #define CANONICAL_HEADER_SIZE 44
  74
  75 typedef struct ShortenContext {
  76     AVCodecContext *avctx;
  77     GetBitContext gb;
  78
  79     int min_framesize, max_framesize;
  80     int channels;
  81
  82     int32_t *decoded[MAX_CHANNELS];
  83     int32_t *offset[MAX_CHANNELS];
  84     uint8_t *bitstream;
  85     int bitstream_size;
  86     int bitstream_index;
  87     int allocated_bitstream_size;
  88     int header_size;
  89     uint8_t header[OUT_BUFFER_SIZE];
  90     int version;
  91     int cur_chan;
  92     int bitshift;
  93     int nmean;
  94     int internal_ftype;
  95     int nwrap;
  96     int blocksize;
  97     int bitindex;
  98     int32_t lpcqoffset;
  99 } ShortenContext;
 100
 101 static int shorten_decode_init(AVCodecContext * avctx)
 102 {
 103     ShortenContext *s = avctx->priv_data;
 104     s->avctx = avctx;
 105
 106     return 0;
 107 }
 108
 109 static void allocate_buffers(ShortenContext *s)
 110 {
 111     int i, chan;
 112     for (chan=0; chan<s->channels; chan++) {
 113         s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
 114
 115         s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
 116         for (i=0; i<s->nwrap; i++)
 117             s->decoded[chan][i] = 0;
 118         s->decoded[chan] += s->nwrap;
 119
 120     }
 121 }
 122
 123
 124 static inline unsigned int get_uint(ShortenContext *s, int k)
 125 {
 126     if (s->version != 0)
 127         k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
 128     return get_ur_golomb_shorten(&s->gb, k);
 129 }
 130
 131
 132 static void fix_bitshift(ShortenContext *s, int32_t *buffer)
 133 {
 134     int i;
 135
 136     if (s->bitshift != 0)
 137         for (i = 0; i < s->blocksize; i++)
 138             buffer[s->nwrap + i] <<= s->bitshift;
 139 }
 140
 141
 142 static void init_offset(ShortenContext *s)
 143 {
 144     int32_t mean = 0;
 145     int  chan, i;
 146     int nblock = FFMAX(1, s->nmean);
 147     /* initialise offset */
 148     switch (s->internal_ftype)
 149     {
 150         case TYPE_S16HL:
 151         case TYPE_S16LH:
 152             mean = 0;
 153             break;
 154         default:
 155             av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
 156             abort();
 157     }
 158
 159     for (chan = 0; chan < s->channels; chan++)
 160         for (i = 0; i < nblock; i++)
 161             s->offset[chan][i] = mean;
 162 }
 163
 164 static int inline get_le32(GetBitContext *gb)
 165 {
 166     return bswap_32(get_bits_long(gb, 32));
 167 }
 168
 169 static short inline get_le16(GetBitContext *gb)
 170 {
 171     return bswap_16(get_bits_long(gb, 16));
 172 }
 173
 174 static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
 175 {
 176     GetBitContext hb;
 177     int len;
 178     int chunk_size;
 179     short wave_format;
 180
 181     init_get_bits(&hb, header, header_size*8);
 182     if (get_le32(&hb) != MKTAG('R','I','F','F')) {
 183         av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
 184         return -1;
 185     }
 186
 187     chunk_size = get_le32(&hb);
 188
 189     if (get_le32(&hb) != MKTAG('W','A','V','E')) {
 190         av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
 191         return -1;
 192     }
 193
 194     while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
 195         len = get_le32(&hb);
 196         skip_bits(&hb, 8*len);
 197     }
 198     len = get_le32(&hb);
 199
 200     if (len < 16) {
 201         av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
 202         return -1;
 203     }
 204
 205     wave_format = get_le16(&hb);
 206
 207     switch (wave_format) {
 208         case WAVE_FORMAT_PCM:
 209             break;
 210         default:
 211             av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
 212             return -1;
 213     }
 214
 215     avctx->channels = get_le16(&hb);
 216     avctx->sample_rate = get_le32(&hb);
 217     avctx->bit_rate = get_le32(&hb) * 8;
 218     avctx->block_align = get_le16(&hb);
 219     avctx->bits_per_sample = get_le16(&hb);
 220
 221     if (avctx->bits_per_sample != 16) {
 222         av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
 223         return -1;
 224     }
 225
 226     len -= 16;
 227     if (len > 0)
 228         av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
 229
 230     return 0;
 231 }
 232
 233 static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
 234     int i, chan;
 235     for (i=0; i<blocksize; i++)
 236         for (chan=0; chan < nchan; chan++)
 237             *samples++ = FFMIN(buffer[chan][i], 32768);
 238     return samples;
 239 }
 240
 241 static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
 242 {
 243     int sum, i, j;
 244     int coeffs[pred_order];
 245
 246     for (i=0; i<pred_order; i++)
 247         coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
 248
 249     for (i=0; i < s->blocksize; i++) {
 250         sum = s->lpcqoffset;
 251         for (j=0; j<pred_order; j++)
 252             sum += coeffs[j] * s->decoded[channel][i-j-1];
 253         s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
 254     }
 255 }
 256
 257
 258 static int shorten_decode_frame(AVCodecContext *avctx,
 259         void *data, int *data_size,
 260         uint8_t *buf, int buf_size)
 261 {
 262     ShortenContext *s = avctx->priv_data;
 263     int i, input_buf_size = 0;
 264     int16_t *samples = data;
 265     if(s->max_framesize == 0){
 266         s->max_framesize= 1024; // should hopefully be enough for the first header
 267         s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
 268     }
 269
 270     if(1 && s->max_framesize){//FIXME truncated
 271         buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
 272         input_buf_size= buf_size;
 273
 274         if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
 275             //                printf("memmove\n");
 276             memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
 277             s->bitstream_index=0;
 278         }
 279         memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
 280         buf= &s->bitstream[s->bitstream_index];
 281         buf_size += s->bitstream_size;
 282         s->bitstream_size= buf_size;
 283
 284         if(buf_size < s->max_framesize){
 285             //dprintf("wanna more data ... %d\n", buf_size);
 286             return input_buf_size;
 287         }
 288     }
 289     init_get_bits(&s->gb, buf, buf_size*8);
 290     get_bits(&s->gb, s->bitindex);
 291     if (!s->blocksize)
 292     {
 293         int maxnlpc = 0;
 294         /* shorten signature */
 295         if (get_bits_long(&s->gb, 32) != bswap_32(ff_get_fourcc("ajkg"))) {
 296             av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
 297             return -1;
 298         }
 299
 300         s->lpcqoffset = 0;
 301         s->blocksize = DEFAULT_BLOCK_SIZE;
 302         s->channels = 1;
 303         s->nmean = -1;
 304         s->version = get_bits(&s->gb, 8);
 305         s->internal_ftype = get_uint(s, TYPESIZE);
 306
 307         s->channels = get_uint(s, CHANSIZE);
 308         if (s->channels > MAX_CHANNELS) {
 309             av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
 310             return -1;
 311         }
 312
 313         /* get blocksize if version > 0 */
 314         if (s->version > 0) {
 315             int skip_bytes;
 316             s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
 317             maxnlpc = get_uint(s, LPCQSIZE);
 318             s->nmean = get_uint(s, 0);
 319
 320             skip_bytes = get_uint(s, NSKIPSIZE);
 321             for (i=0; i<skip_bytes; i++) {
 322                 skip_bits(&s->gb, 8);
 323             }
 324         }
 325         s->nwrap = FFMAX(NWRAP, maxnlpc);
 326
 327         allocate_buffers(s);
 328
 329         init_offset(s);
 330
 331         if (s->version > 1)
 332             s->lpcqoffset = V2LPCQOFFSET;
 333
 334         if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
 335             av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at begining of stream\n");
 336             return -1;
 337         }
 338
 339         s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 340         if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
 341             av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
 342             return -1;
 343         }
 344
 345         for (i=0; i<s->header_size; i++)
 346             s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 347
 348         if (decode_wave_header(avctx, s->header, s->header_size) < 0)
 349             return -1;
 350
 351         s->cur_chan = 0;
 352         s->bitshift = 0;
 353     }
 354     else
 355     {
 356         int cmd;
 357         int len;
 358         cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
 359         switch (cmd) {
 360             case FN_ZERO:
 361             case FN_DIFF0:
 362             case FN_DIFF1:
 363             case FN_DIFF2:
 364             case FN_DIFF3:
 365             case FN_QLPC:
 366                 {
 367                     int residual_size = 0;
 368                     int channel = s->cur_chan;
 369                     int32_t coffset;
 370                     if (cmd != FN_ZERO) {
 371                         residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
 372                         /* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
 373                         if (s->version == 0)
 374                             residual_size--;
 375                     }
 376
 377                     if (s->nmean == 0)
 378                         coffset = s->offset[channel][0];
 379                     else {
 380                         int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
 381                         for (i=0; i<s->nmean; i++)
 382                             sum += s->offset[channel][i];
 383                         coffset = sum / s->nmean;
 384                         if (s->version >= 2)
 385                             coffset >>= FFMIN(1, s->bitshift);
 386                     }
 387                     switch (cmd) {
 388                         case FN_ZERO:
 389                             for (i=0; i<s->blocksize; i++)
 390                                 s->decoded[channel][i] = 0;
 391                             break;
 392                         case FN_DIFF0:
 393                             for (i=0; i<s->blocksize; i++)
 394                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
 395                             break;
 396                         case FN_DIFF1:
 397                             for (i=0; i<s->blocksize; i++)
 398                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
 399                             break;
 400                         case FN_DIFF2:
 401                             for (i=0; i<s->blocksize; i++)
 402                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
 403                                                                                                       -   s->decoded[channel][i-2];
 404                             break;
 405                         case FN_DIFF3:
 406                             for (i=0; i<s->blocksize; i++)
 407                                 s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
 408                                                                                                       - 3*s->decoded[channel][i-2]
 409                                                                                                       +   s->decoded[channel][i-3];
 410                             break;
 411                         case FN_QLPC:
 412                             {
 413                                 int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
 414                                 for (i=0; i<pred_order; i++)
 415                                     s->decoded[channel][i - pred_order] -= coffset;
 416                                 decode_subframe_lpc(s, channel, residual_size, pred_order);
 417                                 if (coffset != 0)
 418                                     for (i=0; i < s->blocksize; i++)
 419                                         s->decoded[channel][i] += coffset;
 420                             }
 421                     }
 422                     if (s->nmean > 0) {
 423                         int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
 424                         for (i=0; i<s->blocksize; i++)
 425                             sum += s->decoded[channel][i];
 426
 427                         for (i=1; i<s->nmean; i++)
 428                             s->offset[channel][i-1] = s->offset[channel][i];
 429
 430                         if (s->version < 2)
 431                             s->offset[channel][s->nmean - 1] = sum / s->blocksize;
 432                         else
 433                             s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
 434                     }
 435                     for (i=-s->nwrap; i<0; i++)
 436                         s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
 437
 438                     fix_bitshift(s, s->decoded[channel]);
 439
 440                     s->cur_chan++;
 441                     if (s->cur_chan == s->channels) {
 442                         samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
 443                         s->cur_chan = 0;
 444                         goto frame_done;
 445                     }
 446                     break;
 447                 }
 448                 break;
 449             case FN_VERBATIM:
 450                 len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
 451                 while (len--) {
 452                     get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
 453                 }
 454                 break;
 455             case FN_BITSHIFT:
 456                 s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
 457                 break;
 458             case FN_BLOCKSIZE:
 459                 s->blocksize = get_uint(s, av_log2(s->blocksize));
 460                 break;
 461             case FN_QUIT:
 462                 return buf_size;
 463                 break;
 464             default:
 465                 av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
 466                 return -1;
 467                 break;
 468         }
 469     }
 470 frame_done:
 471     *data_size = (int8_t *)samples - (int8_t *)data;
 472
 473     //    s->last_blocksize = s->blocksize;
 474     s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
 475     i= (get_bits_count(&s->gb))/8;
 476     if (i > buf_size) {
 477         av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
 478         s->bitstream_size=0;
 479         s->bitstream_index=0;
 480         return -1;
 481     }
 482     if (s->bitstream_size) {
 483         s->bitstream_index += i;
 484         s->bitstream_size  -= i;
 485         return input_buf_size;
 486     } else
 487         return i;
 488 }
 489
 490 static int shorten_decode_close(AVCodecContext *avctx)
 491 {
 492     ShortenContext *s = avctx->priv_data;
 493     int i;
 494
 495     for (i = 0; i < s->channels; i++) {
 496         s->decoded[i] -= s->nwrap;
 497         av_freep(&s->decoded[i]);
 498         av_freep(&s->offset[i]);
 499     }
 500     av_freep(&s->bitstream);
 501     return 0;
 502 }
 503
 504 static void shorten_flush(AVCodecContext *avctx){
 505     ShortenContext *s = avctx->priv_data;
 506
 507     s->bitstream_size=
 508         s->bitstream_index= 0;
 509 }
 510
 511 AVCodec shorten_decoder = {
 512     "shorten",
 513     CODEC_TYPE_AUDIO,
 514     CODEC_ID_SHORTEN,
 515     sizeof(ShortenContext),
 516     shorten_decode_init,
 517     NULL,
 518     shorten_decode_close,
 519     shorten_decode_frame,
 520     .flush= shorten_flush,
 521 };