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 void stream_seek(stream_t *stream, size_t offset)
 110 {
 111     stream->ci->seek_buffer(offset);
 112 }
 113
 114 int stream_eof(stream_t *stream)
 115 {
 116     return stream->eof;
 117 }
 118
 119 void stream_create(stream_t *stream,struct codec_api* ci)
 120 {
 121     stream->ci=ci;
 122     stream->eof=0;
 123 }
 124
 125 /* This function was part of the original alac decoder implementation */
 126
 127 int get_sample_info(demux_res_t *demux_res, uint32_t samplenum,
 128                            uint32_t *sample_duration,
 129                            uint32_t *sample_byte_size)
 130 {
 131     unsigned int duration_index_accum = 0;
 132     unsigned int duration_cur_index = 0;
 133
 134     if (samplenum >= demux_res->num_sample_byte_sizes) {
 135         return 0;
 136     }
 137
 138     if (!demux_res->num_time_to_samples) {
 139         return 0;
 140     }
 141
 142     while ((demux_res->time_to_sample[duration_cur_index].sample_count
 143             + duration_index_accum) <= samplenum) {
 144         duration_index_accum +=
 145         demux_res->time_to_sample[duration_cur_index].sample_count;
 146
 147         duration_cur_index++;
 148         if (duration_cur_index >= demux_res->num_time_to_samples) {
 149             return 0;
 150         }
 151     }
 152
 153     *sample_duration =
 154      demux_res->time_to_sample[duration_cur_index].sample_duration;
 155     *sample_byte_size = demux_res->sample_byte_size[samplenum];
 156
 157     return 1;
 158 }
 159
 160 unsigned int get_sample_offset(demux_res_t *demux_res, uint32_t sample)
 161 {
 162     uint32_t chunk = 1;
 163     uint32_t range_samples = 0;
 164     uint32_t total_samples = 0;
 165     uint32_t chunk_sample;
 166     uint32_t prev_chunk;
 167     uint32_t prev_chunk_samples;
 168     uint32_t file_offset;
 169     uint32_t i;
 170
 171     /* First check we have the appropriate metadata - we should always
 172      * have it.
 173      */
 174
 175     if (sample >= demux_res->num_sample_byte_sizes ||
 176         !demux_res->num_sample_to_chunks ||
 177         !demux_res->num_chunk_offsets)
 178     {
 179         return 0;
 180     }
 181
 182     /* Locate the chunk containing the sample */
 183
 184     prev_chunk = demux_res->sample_to_chunk[0].first_chunk;
 185     prev_chunk_samples = demux_res->sample_to_chunk[0].num_samples;
 186
 187     for (i = 1; i < demux_res->num_sample_to_chunks; i++)
 188     {
 189         chunk = demux_res->sample_to_chunk[i].first_chunk;
 190         range_samples = (chunk - prev_chunk) * prev_chunk_samples;
 191
 192         if (sample < total_samples + range_samples)
 193         {
 194             break;
 195         }
 196
 197         total_samples += range_samples;
 198         prev_chunk = demux_res->sample_to_chunk[i].first_chunk;
 199         prev_chunk_samples = demux_res->sample_to_chunk[i].num_samples;
 200     }
 201
 202     if (prev_chunk_samples > 0 &&
 203         sample >= demux_res->sample_to_chunk[0].num_samples)
 204     {
 205         chunk = prev_chunk + (sample - total_samples) / prev_chunk_samples;
 206     }
 207     else
 208     {
 209         chunk = 1;
 210     }
 211
 212     /* Get sample of the first sample in the chunk */
 213
 214     chunk_sample = total_samples + (chunk - prev_chunk) * prev_chunk_samples;
 215
 216     /* Get offset in file */
 217
 218     if (chunk > demux_res->num_chunk_offsets)
 219     {
 220         file_offset = demux_res->chunk_offset[demux_res->num_chunk_offsets - 1];
 221     }
 222     else
 223     {
 224         file_offset = demux_res->chunk_offset[chunk - 1];
 225     }
 226
 227     if (chunk_sample > sample)
 228     {
 229         return 0;
 230     }
 231
 232     for (i = chunk_sample; i < sample; i++)
 233     {
 234         file_offset += demux_res->sample_byte_size[i];
 235     }
 236
 237     if (file_offset > demux_res->mdat_offset + demux_res->mdat_len)
 238     {
 239         return 0;
 240     }
 241
 242     return file_offset;
 243 }
 244
 245 /* Seek to the sample containing sound_sample_loc. Return 1 on success
 246  * (and modify sound_samples_done and current_sample), 0 if failed.
 247  *
 248  * Seeking uses the following arrays:
 249  *
 250  * 1) the time_to_sample array contains the duration (in sound samples)
 251  *    of each sample of data.
 252  *
 253  * 2) the sample_byte_size array contains the length in bytes of each
 254  *    sample.
 255  *
 256  * 3) the sample_to_chunk array contains information about which chunk
 257  *    of samples each sample belongs to.
 258  *
 259  * 4) the chunk_offset array contains the file offset of each chunk.
 260  *
 261  * So find the sample number we are going to seek to (using time_to_sample)
 262  * and then find the offset in the file (using sample_to_chunk,
 263  * chunk_offset sample_byte_size, in that order.).
 264  *
 265  */
 266 unsigned int alac_seek(demux_res_t* demux_res, stream_t* stream,
 267     uint32_t sound_sample_loc, uint32_t* sound_samples_done,
 268     int* current_sample)
 269 {
 270     uint32_t i = 0;
 271     uint32_t tmp_var, tmp_cnt, tmp_dur;
 272     uint32_t new_sample = 0;       /* Holds the amount of chunks/frames. */
 273     uint32_t new_sound_sample = 0; /* Sums up total amount of samples. */
 274     uint32_t new_pos;              /* Holds the desired chunk/frame index. */
 275
 276     /* First check we have the appropriate metadata - we should always
 277      * have it.
 278      */
 279     if (!demux_res->num_time_to_samples || !demux_res->num_sample_byte_sizes)
 280     {
 281         return 0;
 282     }
 283
 284     /* Find the destination block from time_to_sample array */
 285     time_to_sample_t *tab = demux_res->time_to_sample;
 286     while (i < demux_res->num_time_to_samples)
 287     {
 288         tmp_cnt = tab[i].sample_count;
 289         tmp_dur = tab[i].sample_duration;
 290         tmp_var = tmp_cnt * tmp_dur;
 291         if (sound_sample_loc <= new_sound_sample + tmp_var)
 292         {
 293             tmp_var = (sound_sample_loc - new_sound_sample);
 294             new_sample       += tmp_var / tmp_dur;
 295             new_sound_sample += tmp_var;
 296             break;
 297         }
 298         new_sample       += tmp_cnt;
 299         new_sound_sample += tmp_var;
 300         ++i;
 301     }
 302
 303     /* We know the new block, now calculate the file position. */
 304     new_pos = get_sample_offset(demux_res, new_sample);
 305
 306     /* We know the new file position, so let's try to seek to it */
 307     if (stream->ci->seek_buffer(new_pos))
 308     {
 309         *sound_samples_done = new_sound_sample;
 310         *current_sample = new_sample;
 311         return 1;
 312     }
 313
 314     return 0;
 315 }
 316
 317 /* Seek to the sample containing file_loc. Return 1 on success (and modify
 318  * sound_samples_done and current_sample), 0 if failed.
 319  *
 320  * Seeking uses the following arrays:
 321  *
 322  * 1) the chunk_offset array contains the file offset of each chunk.
 323  *
 324  * 2) the sample_to_chunk array contains information about which chunk
 325  *    of samples each sample belongs to.
 326  *
 327  * 3) the sample_byte_size array contains the length in bytes of each
 328  *    sample.
 329  *
 330  * 4) the time_to_sample array contains the duration (in sound samples)
 331  *    of each sample of data.
 332  *
 333  * Locate the chunk containing location (using chunk_offset), find the
 334  * sample of that chunk (using sample_to_chunk) and finally the location
 335  * of that sample (using sample_byte_size). Then use time_to_sample to
 336  * calculate the sound_samples_done value.
 337  */
 338 unsigned int alac_seek_raw(demux_res_t* demux_res, stream_t* stream,
 339     uint32_t file_loc, uint32_t* sound_samples_done,
 340     int* current_sample)
 341 {
 342     uint32_t chunk_sample = 0;     /* Holds the chunk/frame index. */
 343     uint32_t total_samples = 0;    /* Sums up total amount of chunks/frames. */
 344     uint32_t new_sound_sample = 0; /* Sums up total amount of samples. */
 345     uint32_t new_pos;
 346     uint32_t chunk;
 347     uint32_t i, tmp_dur, tmp_cnt;
 348
 349     /* There is no metadata available to perform raw seek. */
 350     if (!demux_res->num_chunk_offsets || !demux_res->num_sample_to_chunks)
 351     {
 352         return 0;
 353     }
 354
 355     /* Locate the chunk containing file_loc. */
 356     chunk = 0;
 357     while (chunk < demux_res->num_chunk_offsets)
 358     {
 359         if (file_loc < demux_res->chunk_offset[chunk++])
 360         {
 361             break;
 362         }
 363     }
 364     new_pos = demux_res->chunk_offset[chunk-1];
 365
 366     /* Get the first sample of the chunk. */
 367     i = 1;
 368     sample_to_chunk_t *tab1 = demux_res->sample_to_chunk;
 369     while (i < demux_res->num_sample_to_chunks)
 370     {
 371         if (chunk <= tab1[i].first_chunk)
 372         {
 373             break;
 374         }
 375         chunk_sample += tab1[i-1].num_samples * (tab1[i].first_chunk - tab1[i-1].first_chunk);
 376         ++i;
 377     }
 378     chunk_sample += (chunk - tab1[i-1].first_chunk) * tab1[i-1].num_samples;
 379
 380     /* Get the position within the chunk. */
 381     while (chunk_sample < demux_res->num_sample_byte_sizes &&
 382            file_loc >= new_pos + demux_res->sample_byte_size[chunk_sample])
 383     {
 384         new_pos += demux_res->sample_byte_size[chunk_sample++];
 385     }
 386
 387     /* Get sound sample offset. */
 388     i = 0;
 389     time_to_sample_t *tab2 = demux_res->time_to_sample;
 390     while (i < demux_res->num_time_to_samples)
 391     {
 392         tmp_dur = tab2[i].sample_duration;
 393         tmp_cnt = tab2[i].sample_count;
 394         total_samples    += tmp_cnt;
 395         new_sound_sample += tmp_cnt * tmp_dur;
 396         if (chunk_sample <= total_samples)
 397         {
 398             new_sound_sample += (chunk_sample - total_samples) * tmp_dur;
 399             break;
 400         }
 401         ++i;
 402     }
 403
 404     /* Go to the new file position. */
 405     if (stream->ci->seek_buffer(new_pos))
 406     {
 407         *sound_samples_done = new_sound_sample;
 408         *current_sample = chunk_sample;
 409         return 1;
 410     }
 411
 412     return 0;
 413 }