summaryrefslogtreecommitdiffstats
path: root/apps/codecs/libm4a/m4a.c
blob: 92e619db35b6657fe149bb961e8fbd738ba610f6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2005 Dave Chapman
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/

#include <codecs.h>
#include <inttypes.h>
#include "m4a.h"

/* Implementation of the stream.h functions used by libalac */

#define _Swap32(v) do { \
                   v = (((v) & 0x000000FF) << 0x18) | \
                       (((v) & 0x0000FF00) << 0x08) | \
                       (((v) & 0x00FF0000) >> 0x08) | \
                       (((v) & 0xFF000000) >> 0x18); } while(0)

#define _Swap16(v) do { \
                   v = (((v) & 0x00FF) << 0x08) | \
                       (((v) & 0xFF00) >> 0x08); } while (0)

/* A normal read without any byte-swapping */
void stream_read(stream_t *stream, size_t size, void *buf)
{
    stream->ci->read_filebuf(buf,size);
    if (stream->ci->curpos >= stream->ci->filesize) { stream->eof=1; }
}

int32_t stream_read_int32(stream_t *stream)
{
    int32_t v;
    stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
    _Swap32(v);
#endif
    return v;
}

int32_t stream_tell(stream_t *stream)
{
    return stream->ci->curpos;
}

uint32_t stream_read_uint32(stream_t *stream)
{
    uint32_t v;
    stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
    _Swap32(v);
#endif
    return v;
}

int16_t stream_read_int16(stream_t *stream)
{
    int16_t v;
    stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
    _Swap16(v);
#endif
    return v;
}

uint16_t stream_read_uint16(stream_t *stream)
{
    uint16_t v;
    stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
    _Swap16(v);
#endif
    return v;
}

int8_t stream_read_int8(stream_t *stream)
{
    int8_t v;
    stream_read(stream, 1, &v);
    return v;
}

uint8_t stream_read_uint8(stream_t *stream)
{
    uint8_t v;
    stream_read(stream, 1, &v);
    return v;
}

void stream_skip(stream_t *stream, size_t skip)
{
  stream->ci->advance_buffer(skip);
}

int stream_eof(stream_t *stream)
{
    return stream->eof;
}

void stream_create(stream_t *stream,struct codec_api* ci)
{
    stream->ci=ci;
    stream->eof=0;
}

/* This function was part of the original alac decoder implementation */

int get_sample_info(demux_res_t *demux_res, uint32_t samplenum,
                           uint32_t *sample_duration,
                           uint32_t *sample_byte_size)
{
    unsigned int duration_index_accum = 0;
    unsigned int duration_cur_index = 0;

    if (samplenum >= demux_res->num_sample_byte_sizes) { 
        return 0;
    }

    if (!demux_res->num_time_to_samples) {
        return 0;
    }

    while ((demux_res->time_to_sample[duration_cur_index].sample_count
            + duration_index_accum) <= samplenum) {
        duration_index_accum +=
        demux_res->time_to_sample[duration_cur_index].sample_count;

        duration_cur_index++;
        if (duration_cur_index >= demux_res->num_time_to_samples) {
            return 0;
        }
    }

    *sample_duration =
     demux_res->time_to_sample[duration_cur_index].sample_duration;
    *sample_byte_size = demux_res->sample_byte_size[samplenum];

    return 1;
}

unsigned int get_sample_offset(demux_res_t *demux_res, uint32_t sample)
{
    uint32_t chunk = 1;
    uint32_t range_samples = 0;
    uint32_t total_samples = 0;
    uint32_t chunk_sample;
    uint32_t prev_chunk;
    uint32_t prev_chunk_samples;
    uint32_t file_offset;
    uint32_t i;
    
    /* First check we have the appropriate metadata - we should always
     * have it.
     */
       
    if (sample >= demux_res->num_sample_byte_sizes ||
        !demux_res->num_sample_to_chunks ||
        !demux_res->num_chunk_offsets) 
    {
        return 0;
    }

    /* Locate the chunk containing the sample */
    
    prev_chunk = demux_res->sample_to_chunk[0].first_chunk;
    prev_chunk_samples = demux_res->sample_to_chunk[0].num_samples;

    for (i = 1; i < demux_res->num_sample_to_chunks; i++) 
    {
        chunk = demux_res->sample_to_chunk[i].first_chunk;
        range_samples = (chunk - prev_chunk) * prev_chunk_samples;

        if (sample < total_samples + range_samples)
        {
            break;
        }

        total_samples += range_samples;
        prev_chunk = demux_res->sample_to_chunk[i].first_chunk;
        prev_chunk_samples = demux_res->sample_to_chunk[i].num_samples;
    }

    if (prev_chunk_samples > 0 &&
        sample >= demux_res->sample_to_chunk[0].num_samples)
    {
        chunk = prev_chunk + (sample - total_samples) / prev_chunk_samples;
    }
    else
    {
        chunk = 1;
    }
    
    /* Get sample of the first sample in the chunk */
    
    chunk_sample = total_samples + (chunk - prev_chunk) * prev_chunk_samples;
    
    /* Get offset in file */
    
    if (chunk > demux_res->num_chunk_offsets)
    {
        file_offset = demux_res->chunk_offset[demux_res->num_chunk_offsets - 1];
    }
    else
    {
        file_offset = demux_res->chunk_offset[chunk - 1];
    }
    
    if (chunk_sample > sample) 
    {
        return 0;
    }
 
    for (i = chunk_sample; i < sample; i++)
    {
        file_offset += demux_res->sample_byte_size[i];
    }
    
    if (file_offset > demux_res->mdat_offset + demux_res->mdat_len)
    {
        return 0;
    }
    
    return file_offset;
}

/* Seek to the sample containing sound_sample_loc. Return 1 on success 
 * (and modify sound_samples_done and current_sample), 0 if failed.
 *
 * Seeking uses the following arrays:
 *
 * 1) the time_to_sample array contains the duration (in sound samples) 
 *    of each sample of data.
 *
 * 2) the sample_byte_size array contains the length in bytes of each
 *    sample.
 *
 * 3) the sample_to_chunk array contains information about which chunk
 *    of samples each sample belongs to.
 *
 * 4) the chunk_offset array contains the file offset of each chunk.
 *
 * So find the sample number we are going to seek to (using time_to_sample)
 * and then find the offset in the file (using sample_to_chunk, 
 * chunk_offset sample_byte_size, in that order.).
 *
 */
unsigned int alac_seek(demux_res_t* demux_res, stream_t* stream, 
    uint32_t sound_sample_loc, uint32_t* sound_samples_done, 
    int* current_sample)
{
    uint32_t i;
    uint32_t j;
    uint32_t new_sample;
    uint32_t new_sound_sample;
    uint32_t new_pos;

    /* First check we have the appropriate metadata - we should always
     * have it.
     */
       
    if ((demux_res->num_time_to_samples==0) ||
       (demux_res->num_sample_byte_sizes==0))
    { 
        return 0; 
    }

    /* Find the destination block from time_to_sample array */
    
    i = 0;
    new_sample = 0;
    new_sound_sample = 0;

    while ((i < demux_res->num_time_to_samples) &&
        (new_sound_sample < sound_sample_loc)) 
    {
        j = (sound_sample_loc - new_sound_sample) /
            demux_res->time_to_sample[i].sample_duration;
    
        if (j <= demux_res->time_to_sample[i].sample_count)
        {
            new_sample += j;
            new_sound_sample += j * 
                demux_res->time_to_sample[i].sample_duration;
            break;
        } 
        else 
        {
            new_sound_sample += (demux_res->time_to_sample[i].sample_duration
                * demux_res->time_to_sample[i].sample_count);
            new_sample += demux_res->time_to_sample[i].sample_count;
            i++;
        }
    }

    /* We know the new block, now calculate the file position. */
  
    new_pos = get_sample_offset(demux_res, new_sample);

    /* We know the new file position, so let's try to seek to it */
  
    if (stream->ci->seek_buffer(new_pos)) 
    {
        *sound_samples_done = new_sound_sample;
        *current_sample = new_sample;
        return 1;
    }
    
    return 0;
}

/* Seek to the sample containing file_loc. Return 1 on success (and modify
 * sound_samples_done and current_sample), 0 if failed.
 *
 * Seeking uses the following arrays:
 *
 * 1) the chunk_offset array contains the file offset of each chunk.
 *
 * 2) the sample_to_chunk array contains information about which chunk
 *    of samples each sample belongs to.
 *
 * 3) the sample_byte_size array contains the length in bytes of each
 *    sample.
 *
 * 4) the time_to_sample array contains the duration (in sound samples) 
 *    of each sample of data.
 *
 * Locate the chunk containing location (using chunk_offset), find the 
 * sample of that chunk (using sample_to_chunk) and finally the location
 * of that sample (using sample_byte_size). Then use time_to_sample to
 * calculate the sound_samples_done value.
 */
unsigned int alac_seek_raw(demux_res_t* demux_res, stream_t* stream,
    uint32_t file_loc, uint32_t* sound_samples_done, 
    int* current_sample)
{
    uint32_t chunk_sample = 0;
    uint32_t total_samples = 0;
    uint32_t new_sound_sample = 0;
    uint32_t new_pos;
    uint32_t chunk;
    uint32_t i;

    if (!demux_res->num_chunk_offsets ||
        !demux_res->num_sample_to_chunks) 
    {
        return 0;
    }

    /* Locate the chunk containing file_loc. */

    for (i = 0; i < demux_res->num_chunk_offsets && 
        file_loc < demux_res->chunk_offset[i]; i++)
    {
    }
    
    chunk = i + 1;
    new_pos = demux_res->chunk_offset[chunk - 1];

    /* Get the first sample of the chunk. */
    
    for (i = 1; i < demux_res->num_sample_to_chunks &&
        chunk < demux_res->sample_to_chunk[i - 1].first_chunk; i++) 
    {
        chunk_sample += demux_res->sample_to_chunk[i - 1].num_samples *
            (demux_res->sample_to_chunk[i].first_chunk - 
                demux_res->sample_to_chunk[i - 1].first_chunk);
    }
    
    chunk_sample += (chunk - demux_res->sample_to_chunk[i - 1].first_chunk) *
        demux_res->sample_to_chunk[i - 1].num_samples;

    /* Get the position within the chunk. */
    
    for (; chunk_sample < demux_res->num_sample_byte_sizes; chunk_sample++)
    {
        if (file_loc < new_pos + demux_res->sample_byte_size[chunk_sample])
        {
            break;
        }
        
        new_pos += demux_res->sample_byte_size[chunk_sample];
    }
    
    /* Get sound sample offset. */

    for (i = 0; i < demux_res->num_time_to_samples; i++)
    {
        if (chunk_sample < 
            total_samples + demux_res->time_to_sample[i].sample_count)
        {
            break;
        }
        
        total_samples += demux_res->time_to_sample[i].sample_count;
        new_sound_sample += demux_res->time_to_sample[i].sample_count 
            * demux_res->time_to_sample[i].sample_duration;
    }
    
    new_sound_sample += (chunk_sample - total_samples) 
        * demux_res->time_to_sample[i].sample_duration;

    /* Go to the new file position. */
    
    if (stream->ci->seek_buffer(new_pos)) 
    {
        *sound_samples_done = new_sound_sample;
        *current_sample = chunk_sample;
        return 1;
    } 

    return 0;
}