apps/codecs/libm4a/m4a.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2005 Dave Chapman
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 #include <codecs.h>
  23 #include <inttypes.h>
  24 #include "m4a.h"
  25
  26 /* Implementation of the stream.h functions used by libalac */
  27
  28 #define _Swap32(v) do { \
  29                    v = (((v) & 0x000000FF) << 0x18) | \
  30                        (((v) & 0x0000FF00) << 0x08) | \
  31                        (((v) & 0x00FF0000) >> 0x08) | \
  32                        (((v) & 0xFF000000) >> 0x18); } while(0)
  33
  34 #define _Swap16(v) do { \
  35                    v = (((v) & 0x00FF) << 0x08) | \
  36                        (((v) & 0xFF00) >> 0x08); } while (0)
  37
  38 /* A normal read without any byte-swapping */
  39 void stream_read(stream_t *stream, size_t size, void *buf)
  40 {
  41     stream->ci->read_filebuf(buf,size);
  42     if (stream->ci->curpos >= stream->ci->filesize) { stream->eof=1; }
  43 }
  44
  45 int32_t stream_read_int32(stream_t *stream)
  46 {
  47     int32_t v;
  48     stream_read(stream, 4, &v);
  49 #ifdef ROCKBOX_LITTLE_ENDIAN
  50     _Swap32(v);
  51 #endif
  52     return v;
  53 }
  54
  55 int32_t stream_tell(stream_t *stream)
  56 {
  57     return stream->ci->curpos;
  58 }
  59
  60 uint32_t stream_read_uint32(stream_t *stream)
  61 {
  62     uint32_t v;
  63     stream_read(stream, 4, &v);
  64 #ifdef ROCKBOX_LITTLE_ENDIAN
  65     _Swap32(v);
  66 #endif
  67     return v;
  68 }
  69
  70 int16_t stream_read_int16(stream_t *stream)
  71 {
  72     int16_t v;
  73     stream_read(stream, 2, &v);
  74 #ifdef ROCKBOX_LITTLE_ENDIAN
  75     _Swap16(v);
  76 #endif
  77     return v;
  78 }
  79
  80 uint16_t stream_read_uint16(stream_t *stream)
  81 {
  82     uint16_t v;
  83     stream_read(stream, 2, &v);
  84 #ifdef ROCKBOX_LITTLE_ENDIAN
  85     _Swap16(v);
  86 #endif
  87     return v;
  88 }
  89
  90 int8_t stream_read_int8(stream_t *stream)
  91 {
  92     int8_t v;
  93     stream_read(stream, 1, &v);
  94     return v;
  95 }
  96
  97 uint8_t stream_read_uint8(stream_t *stream)
  98 {
  99     uint8_t v;
 100     stream_read(stream, 1, &v);
 101     return v;
 102 }
 103
 104 void stream_skip(stream_t *stream, size_t skip)
 105 {
 106   stream->ci->advance_buffer(skip);
 107 }
 108
 109 int stream_eof(stream_t *stream)
 110 {
 111     return stream->eof;
 112 }
 113
 114 void stream_create(stream_t *stream,struct codec_api* ci)
 115 {
 116     stream->ci=ci;
 117     stream->eof=0;
 118 }
 119
 120 /* This function was part of the original alac decoder implementation */
 121
 122 int get_sample_info(demux_res_t *demux_res, uint32_t samplenum,
 123                            uint32_t *sample_duration,
 124                            uint32_t *sample_byte_size)
 125 {
 126     unsigned int duration_index_accum = 0;
 127     unsigned int duration_cur_index = 0;
 128
 129     if (samplenum >= demux_res->num_sample_byte_sizes) {
 130         return 0;
 131     }
 132
 133     if (!demux_res->num_time_to_samples) {
 134         return 0;
 135     }
 136
 137     while ((demux_res->time_to_sample[duration_cur_index].sample_count
 138             + duration_index_accum) <= samplenum) {
 139         duration_index_accum +=
 140         demux_res->time_to_sample[duration_cur_index].sample_count;
 141
 142         duration_cur_index++;
 143         if (duration_cur_index >= demux_res->num_time_to_samples) {
 144             return 0;
 145         }
 146     }
 147
 148     *sample_duration =
 149      demux_res->time_to_sample[duration_cur_index].sample_duration;
 150     *sample_byte_size = demux_res->sample_byte_size[samplenum];
 151
 152     return 1;
 153 }
 154
 155 unsigned int get_sample_offset(demux_res_t *demux_res, uint32_t sample)
 156 {
 157     uint32_t chunk = 1;
 158     uint32_t range_samples = 0;
 159     uint32_t total_samples = 0;
 160     uint32_t chunk_sample;
 161     uint32_t prev_chunk;
 162     uint32_t prev_chunk_samples;
 163     uint32_t file_offset;
 164     uint32_t i;
 165
 166     /* First check we have the appropriate metadata - we should always
 167      * have it.
 168      */
 169
 170     if (sample >= demux_res->num_sample_byte_sizes ||
 171         !demux_res->num_sample_to_chunks ||
 172         !demux_res->num_chunk_offsets)
 173     {
 174         return 0;
 175     }
 176
 177     /* Locate the chunk containing the sample */
 178
 179     prev_chunk = demux_res->sample_to_chunk[0].first_chunk;
 180     prev_chunk_samples = demux_res->sample_to_chunk[0].num_samples;
 181
 182     for (i = 1; i < demux_res->num_sample_to_chunks; i++)
 183     {
 184         chunk = demux_res->sample_to_chunk[i].first_chunk;
 185         range_samples = (chunk - prev_chunk) * prev_chunk_samples;
 186
 187         if (sample < total_samples + range_samples)
 188         {
 189             break;
 190         }
 191
 192         total_samples += range_samples;
 193         prev_chunk = demux_res->sample_to_chunk[i].first_chunk;
 194         prev_chunk_samples = demux_res->sample_to_chunk[i].num_samples;
 195     }
 196
 197     if (sample >= demux_res->sample_to_chunk[0].num_samples)
 198     {
 199         chunk = prev_chunk + (sample - total_samples) / prev_chunk_samples;
 200     }
 201     else
 202     {
 203         chunk = 1;
 204     }
 205
 206     /* Get sample of the first sample in the chunk */
 207
 208     chunk_sample = total_samples + (chunk - prev_chunk) * prev_chunk_samples;
 209
 210     /* Get offset in file */
 211
 212     if (chunk > demux_res->num_chunk_offsets)
 213     {
 214         file_offset = demux_res->chunk_offset[demux_res->num_chunk_offsets - 1];
 215     }
 216     else
 217     {
 218         file_offset = demux_res->chunk_offset[chunk - 1];
 219     }
 220
 221     if (chunk_sample > sample)
 222     {
 223         return 0;
 224     }
 225
 226     for (i = chunk_sample; i < sample; i++)
 227     {
 228         file_offset += demux_res->sample_byte_size[i];
 229     }
 230
 231     if (file_offset > demux_res->mdat_offset + demux_res->mdat_len)
 232     {
 233         return 0;
 234     }
 235
 236     return file_offset;
 237 }
 238
 239 /* Seek to the sample containing sound_sample_loc. Return 1 on success
 240  * (and modify sound_samples_done and current_sample), 0 if failed.
 241  *
 242  * Seeking uses the following arrays:
 243  *
 244  * 1) the time_to_sample array contains the duration (in sound samples)
 245  *    of each sample of data.
 246  *
 247  * 2) the sample_byte_size array contains the length in bytes of each
 248  *    sample.
 249  *
 250  * 3) the sample_to_chunk array contains information about which chunk
 251  *    of samples each sample belongs to.
 252  *
 253  * 4) the chunk_offset array contains the file offset of each chunk.
 254  *
 255  * So find the sample number we are going to seek to (using time_to_sample)
 256  * and then find the offset in the file (using sample_to_chunk,
 257  * chunk_offset sample_byte_size, in that order.).
 258  *
 259  */
 260 unsigned int alac_seek(demux_res_t* demux_res, stream_t* stream,
 261     uint32_t sound_sample_loc, uint32_t* sound_samples_done,
 262     int* current_sample)
 263 {
 264     uint32_t i;
 265     uint32_t j;
 266     uint32_t new_sample;
 267     uint32_t new_sound_sample;
 268     uint32_t new_pos;
 269
 270     /* First check we have the appropriate metadata - we should always
 271      * have it.
 272      */
 273
 274     if ((demux_res->num_time_to_samples==0) ||
 275        (demux_res->num_sample_byte_sizes==0))
 276     {
 277         return 0;
 278     }
 279
 280     /* Find the destination block from time_to_sample array */
 281
 282     i = 0;
 283     new_sample = 0;
 284     new_sound_sample = 0;
 285
 286     while ((i < demux_res->num_time_to_samples) &&
 287         (new_sound_sample < sound_sample_loc))
 288     {
 289         j = (sound_sample_loc - new_sound_sample) /
 290             demux_res->time_to_sample[i].sample_duration;
 291
 292         if (j <= demux_res->time_to_sample[i].sample_count)
 293         {
 294             new_sample += j;
 295             new_sound_sample += j *
 296                 demux_res->time_to_sample[i].sample_duration;
 297             break;
 298         }
 299         else
 300         {
 301             new_sound_sample += (demux_res->time_to_sample[i].sample_duration
 302                 * demux_res->time_to_sample[i].sample_count);
 303             new_sample += demux_res->time_to_sample[i].sample_count;
 304             i++;
 305         }
 306     }
 307
 308     /* We know the new block, now calculate the file position. */
 309
 310     new_pos = get_sample_offset(demux_res, new_sample);
 311
 312     /* We know the new file position, so let's try to seek to it */
 313
 314     if (stream->ci->seek_buffer(new_pos))
 315     {
 316         *sound_samples_done = new_sound_sample;
 317         *current_sample = new_sample;
 318         return 1;
 319     }
 320
 321     return 0;
 322 }
 323
 324 /* Seek to the sample containing file_loc. Return 1 on success (and modify
 325  * sound_samples_done and current_sample), 0 if failed.
 326  *
 327  * Seeking uses the following arrays:
 328  *
 329  * 1) the chunk_offset array contains the file offset of each chunk.
 330  *
 331  * 2) the sample_to_chunk array contains information about which chunk
 332  *    of samples each sample belongs to.
 333  *
 334  * 3) the sample_byte_size array contains the length in bytes of each
 335  *    sample.
 336  *
 337  * 4) the time_to_sample array contains the duration (in sound samples)
 338  *    of each sample of data.
 339  *
 340  * Locate the chunk containing location (using chunk_offset), find the
 341  * sample of that chunk (using sample_to_chunk) and finally the location
 342  * of that sample (using sample_byte_size). Then use time_to_sample to
 343  * calculate the sound_samples_done value.
 344  */
 345 unsigned int alac_seek_raw(demux_res_t* demux_res, stream_t* stream,
 346     uint32_t file_loc, uint32_t* sound_samples_done,
 347     int* current_sample)
 348 {
 349     uint32_t chunk_sample = 0;
 350     uint32_t total_samples = 0;
 351     uint32_t new_sound_sample = 0;
 352     uint32_t new_pos;
 353     uint32_t chunk;
 354     uint32_t i;
 355
 356     if (!demux_res->num_chunk_offsets ||
 357         !demux_res->num_sample_to_chunks)
 358     {
 359         return 0;
 360     }
 361
 362     /* Locate the chunk containing file_loc. */
 363
 364     for (i = 0; i < demux_res->num_chunk_offsets &&
 365         file_loc < demux_res->chunk_offset[i]; i++)
 366     {
 367     }
 368
 369     chunk = i + 1;
 370     new_pos = demux_res->chunk_offset[chunk - 1];
 371
 372     /* Get the first sample of the chunk. */
 373
 374     for (i = 1; i < demux_res->num_sample_to_chunks &&
 375         chunk < demux_res->sample_to_chunk[i - 1].first_chunk; i++)
 376     {
 377         chunk_sample += demux_res->sample_to_chunk[i - 1].num_samples *
 378             (demux_res->sample_to_chunk[i].first_chunk -
 379                 demux_res->sample_to_chunk[i - 1].first_chunk);
 380     }
 381
 382     chunk_sample += (chunk - demux_res->sample_to_chunk[i - 1].first_chunk) *
 383         demux_res->sample_to_chunk[i - 1].num_samples;
 384
 385     /* Get the position within the chunk. */
 386
 387     for (; chunk_sample < demux_res->num_sample_byte_sizes; chunk_sample++)
 388     {
 389         if (file_loc < new_pos + demux_res->sample_byte_size[chunk_sample])
 390         {
 391             break;
 392         }
 393
 394         new_pos += demux_res->sample_byte_size[chunk_sample];
 395     }
 396
 397     /* Get sound sample offset. */
 398
 399     for (i = 0; i < demux_res->num_time_to_samples; i++)
 400     {
 401         if (chunk_sample <
 402             total_samples + demux_res->time_to_sample[i].sample_count)
 403         {
 404             break;
 405         }
 406
 407         total_samples += demux_res->time_to_sample[i].sample_count;
 408         new_sound_sample += demux_res->time_to_sample[i].sample_count
 409             * demux_res->time_to_sample[i].sample_duration;
 410     }
 411
 412     new_sound_sample += (chunk_sample - total_samples)
 413         * demux_res->time_to_sample[i].sample_duration;
 414
 415     /* Go to the new file position. */
 416
 417     if (stream->ci->seek_buffer(new_pos))
 418     {
 419         *sound_samples_done = new_sound_sample;
 420         *current_sample = chunk_sample;
 421         return 1;
 422     }
 423
 424     return 0;
 425 }