Statistics
| Branch: | Revision:

ffmpeg / libavcodec / flac.c @ 7a886063

History | View | Annotate | Download (21.5 KB)

1
/*
2
 * FLAC (Free Lossless Audio Codec) decoder
3
 * Copyright (c) 2003 Alex Beregszaszi
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 flac.c
24
 * FLAC (Free Lossless Audio Codec) decoder
25
 * @author Alex Beregszaszi
26
 *
27
 * For more information on the FLAC format, visit:
28
 *  http://flac.sourceforge.net/
29
 *
30
 * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
31
 * through, starting from the initial 'fLaC' signature; or by passing the
32
 * 34-byte streaminfo structure through avctx->extradata[_size] followed
33
 * by data starting with the 0xFFF8 marker.
34
 */
35

    
36
#include <limits.h>
37

    
38
#define ALT_BITSTREAM_READER
39
#include "avcodec.h"
40
#include "bitstream.h"
41
#include "golomb.h"
42
#include "crc.h"
43

    
44
#undef NDEBUG
45
#include <assert.h>
46

    
47
#define MAX_CHANNELS 8
48
#define MAX_BLOCKSIZE 65535
49
#define FLAC_STREAMINFO_SIZE 34
50

    
51
enum decorrelation_type {
52
    INDEPENDENT,
53
    LEFT_SIDE,
54
    RIGHT_SIDE,
55
    MID_SIDE,
56
};
57

    
58
typedef struct FLACContext {
59
    AVCodecContext *avctx;
60
    GetBitContext gb;
61

    
62
    int min_blocksize, max_blocksize;
63
    int min_framesize, max_framesize;
64
    int samplerate, channels;
65
    int blocksize/*, last_blocksize*/;
66
    int bps, curr_bps;
67
    enum decorrelation_type decorrelation;
68

    
69
    int32_t *decoded[MAX_CHANNELS];
70
    uint8_t *bitstream;
71
    int bitstream_size;
72
    int bitstream_index;
73
    unsigned int allocated_bitstream_size;
74
} FLACContext;
75

    
76
#define METADATA_TYPE_STREAMINFO 0
77

    
78
static int sample_rate_table[] =
79
{ 0, 0, 0, 0,
80
  8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
81
  0, 0, 0, 0 };
82

    
83
static int sample_size_table[] =
84
{ 0, 8, 12, 0, 16, 20, 24, 0 };
85

    
86
static int blocksize_table[] = {
87
     0,    192, 576<<0, 576<<1, 576<<2, 576<<3,      0,      0,
88
256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
89
};
90

    
91
static int64_t get_utf8(GetBitContext *gb){
92
    int64_t val;
93
    GET_UTF8(val, get_bits(gb, 8), return -1;)
94
    return val;
95
}
96

    
97
static void metadata_streaminfo(FLACContext *s);
98
static void allocate_buffers(FLACContext *s);
99
static int metadata_parse(FLACContext *s);
100

    
101
static int flac_decode_init(AVCodecContext * avctx)
102
{
103
    FLACContext *s = avctx->priv_data;
104
    s->avctx = avctx;
105

    
106
    if (avctx->extradata_size > 4) {
107
        /* initialize based on the demuxer-supplied streamdata header */
108
        init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
109
        if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
110
            metadata_streaminfo(s);
111
            allocate_buffers(s);
112
        } else {
113
            metadata_parse(s);
114
        }
115
    }
116

    
117
    return 0;
118
}
119

    
120
static void dump_headers(FLACContext *s)
121
{
122
    av_log(s->avctx, AV_LOG_DEBUG, "  Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
123
    av_log(s->avctx, AV_LOG_DEBUG, "  Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
124
    av_log(s->avctx, AV_LOG_DEBUG, "  Samplerate: %d\n", s->samplerate);
125
    av_log(s->avctx, AV_LOG_DEBUG, "  Channels: %d\n", s->channels);
126
    av_log(s->avctx, AV_LOG_DEBUG, "  Bits: %d\n", s->bps);
127
}
128

    
129
static void allocate_buffers(FLACContext *s){
130
    int i;
131

    
132
    assert(s->max_blocksize);
133

    
134
    if(s->max_framesize == 0 && s->max_blocksize){
135
        s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
136
    }
137

    
138
    for (i = 0; i < s->channels; i++)
139
    {
140
        s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
141
    }
142

    
143
    s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
144
}
145

    
146
static void metadata_streaminfo(FLACContext *s)
147
{
148
    /* mandatory streaminfo */
149
    s->min_blocksize = get_bits(&s->gb, 16);
150
    s->max_blocksize = get_bits(&s->gb, 16);
151

    
152
    s->min_framesize = get_bits_long(&s->gb, 24);
153
    s->max_framesize = get_bits_long(&s->gb, 24);
154

    
155
    s->samplerate = get_bits_long(&s->gb, 20);
156
    s->channels = get_bits(&s->gb, 3) + 1;
157
    s->bps = get_bits(&s->gb, 5) + 1;
158

    
159
    s->avctx->channels = s->channels;
160
    s->avctx->sample_rate = s->samplerate;
161

    
162
    skip_bits(&s->gb, 36); /* total num of samples */
163

    
164
    skip_bits(&s->gb, 64); /* md5 sum */
165
    skip_bits(&s->gb, 64); /* md5 sum */
166

    
167
    dump_headers(s);
168
}
169

    
170
/**
171
 * Parse a list of metadata blocks. This list of blocks must begin with
172
 * the fLaC marker.
173
 * @param s the flac decoding context containing the gb bit reader used to
174
 *          parse metadata
175
 * @return 1 if some metadata was read, 0 if no fLaC marker was found
176
 */
177
static int metadata_parse(FLACContext *s)
178
{
179
    int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
180

    
181
    if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
182
        skip_bits(&s->gb, 32);
183

    
184
        av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
185
        do {
186
            metadata_last = get_bits(&s->gb, 1);
187
            metadata_type = get_bits(&s->gb, 7);
188
            metadata_size = get_bits_long(&s->gb, 24);
189

    
190
            av_log(s->avctx, AV_LOG_DEBUG,
191
                   " metadata block: flag = %d, type = %d, size = %d\n",
192
                   metadata_last, metadata_type, metadata_size);
193
            if (metadata_size) {
194
                switch (metadata_type) {
195
                case METADATA_TYPE_STREAMINFO:
196
                    metadata_streaminfo(s);
197
                    streaminfo_updated = 1;
198
                    break;
199

    
200
                default:
201
                    for (i=0; i<metadata_size; i++)
202
                        skip_bits(&s->gb, 8);
203
                }
204
            }
205
        } while (!metadata_last);
206

    
207
        if (streaminfo_updated)
208
            allocate_buffers(s);
209
        return 1;
210
    }
211
    return 0;
212
}
213

    
214
static int decode_residuals(FLACContext *s, int channel, int pred_order)
215
{
216
    int i, tmp, partition, method_type, rice_order;
217
    int sample = 0, samples;
218

    
219
    method_type = get_bits(&s->gb, 2);
220
    if (method_type != 0){
221
        av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
222
        return -1;
223
    }
224

    
225
    rice_order = get_bits(&s->gb, 4);
226

    
227
    samples= s->blocksize >> rice_order;
228

    
229
    sample=
230
    i= pred_order;
231
    for (partition = 0; partition < (1 << rice_order); partition++)
232
    {
233
        tmp = get_bits(&s->gb, 4);
234
        if (tmp == 15)
235
        {
236
            av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
237
            tmp = get_bits(&s->gb, 5);
238
            for (; i < samples; i++, sample++)
239
                s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
240
        }
241
        else
242
        {
243
//            av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
244
            for (; i < samples; i++, sample++){
245
                s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
246
            }
247
        }
248
        i= 0;
249
    }
250

    
251
//    av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
252

    
253
    return 0;
254
}
255

    
256
static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
257
{
258
    int i;
259

    
260
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME FIXED\n");
261

    
262
    /* warm up samples */
263
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
264

    
265
    for (i = 0; i < pred_order; i++)
266
    {
267
        s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
268
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
269
    }
270

    
271
    if (decode_residuals(s, channel, pred_order) < 0)
272
        return -1;
273

    
274
    switch(pred_order)
275
    {
276
        case 0:
277
            break;
278
        case 1:
279
            for (i = pred_order; i < s->blocksize; i++)
280
                s->decoded[channel][i] +=   s->decoded[channel][i-1];
281
            break;
282
        case 2:
283
            for (i = pred_order; i < s->blocksize; i++)
284
                s->decoded[channel][i] += 2*s->decoded[channel][i-1]
285
                                          - s->decoded[channel][i-2];
286
            break;
287
        case 3:
288
            for (i = pred_order; i < s->blocksize; i++)
289
                s->decoded[channel][i] += 3*s->decoded[channel][i-1]
290
                                        - 3*s->decoded[channel][i-2]
291
                                        +   s->decoded[channel][i-3];
292
            break;
293
        case 4:
294
            for (i = pred_order; i < s->blocksize; i++)
295
                s->decoded[channel][i] += 4*s->decoded[channel][i-1]
296
                                        - 6*s->decoded[channel][i-2]
297
                                        + 4*s->decoded[channel][i-3]
298
                                        -   s->decoded[channel][i-4];
299
            break;
300
        default:
301
            av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
302
            return -1;
303
    }
304

    
305
    return 0;
306
}
307

    
308
static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
309
{
310
    int i, j;
311
    int coeff_prec, qlevel;
312
    int coeffs[pred_order];
313

    
314
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME LPC\n");
315

    
316
    /* warm up samples */
317
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
318

    
319
    for (i = 0; i < pred_order; i++)
320
    {
321
        s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
322
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
323
    }
324

    
325
    coeff_prec = get_bits(&s->gb, 4) + 1;
326
    if (coeff_prec == 16)
327
    {
328
        av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
329
        return -1;
330
    }
331
//    av_log(s->avctx, AV_LOG_DEBUG, "   qlp coeff prec: %d\n", coeff_prec);
332
    qlevel = get_sbits(&s->gb, 5);
333
//    av_log(s->avctx, AV_LOG_DEBUG, "   quant level: %d\n", qlevel);
334
    if(qlevel < 0){
335
        av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
336
        return -1;
337
    }
338

    
339
    for (i = 0; i < pred_order; i++)
340
    {
341
        coeffs[i] = get_sbits(&s->gb, coeff_prec);
342
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, coeffs[i]);
343
    }
344

    
345
    if (decode_residuals(s, channel, pred_order) < 0)
346
        return -1;
347

    
348
    if (s->bps > 16) {
349
        int64_t sum;
350
        for (i = pred_order; i < s->blocksize; i++)
351
        {
352
            sum = 0;
353
            for (j = 0; j < pred_order; j++)
354
                sum += (int64_t)coeffs[j] * s->decoded[channel][i-j-1];
355
            s->decoded[channel][i] += sum >> qlevel;
356
        }
357
    } else {
358
        int sum;
359
        for (i = pred_order; i < s->blocksize; i++)
360
        {
361
            sum = 0;
362
            for (j = 0; j < pred_order; j++)
363
                sum += coeffs[j] * s->decoded[channel][i-j-1];
364
            s->decoded[channel][i] += sum >> qlevel;
365
        }
366
    }
367

    
368
    return 0;
369
}
370

    
371
static inline int decode_subframe(FLACContext *s, int channel)
372
{
373
    int type, wasted = 0;
374
    int i, tmp;
375

    
376
    s->curr_bps = s->bps;
377
    if(channel == 0){
378
        if(s->decorrelation == RIGHT_SIDE)
379
            s->curr_bps++;
380
    }else{
381
        if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
382
            s->curr_bps++;
383
    }
384

    
385
    if (get_bits1(&s->gb))
386
    {
387
        av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
388
        return -1;
389
    }
390
    type = get_bits(&s->gb, 6);
391
//    wasted = get_bits1(&s->gb);
392

    
393
//    if (wasted)
394
//    {
395
//        while (!get_bits1(&s->gb))
396
//            wasted++;
397
//        if (wasted)
398
//            wasted++;
399
//        s->curr_bps -= wasted;
400
//    }
401
#if 0
402
    wasted= 16 - av_log2(show_bits(&s->gb, 17));
403
    skip_bits(&s->gb, wasted+1);
404
    s->curr_bps -= wasted;
405
#else
406
    if (get_bits1(&s->gb))
407
    {
408
        wasted = 1;
409
        while (!get_bits1(&s->gb))
410
            wasted++;
411
        s->curr_bps -= wasted;
412
        av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
413
    }
414
#endif
415
//FIXME use av_log2 for types
416
    if (type == 0)
417
    {
418
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
419
        tmp = get_sbits(&s->gb, s->curr_bps);
420
        for (i = 0; i < s->blocksize; i++)
421
            s->decoded[channel][i] = tmp;
422
    }
423
    else if (type == 1)
424
    {
425
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
426
        for (i = 0; i < s->blocksize; i++)
427
            s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
428
    }
429
    else if ((type >= 8) && (type <= 12))
430
    {
431
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
432
        if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
433
            return -1;
434
    }
435
    else if (type >= 32)
436
    {
437
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
438
        if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
439
            return -1;
440
    }
441
    else
442
    {
443
        av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
444
        return -1;
445
    }
446

    
447
    if (wasted)
448
    {
449
        int i;
450
        for (i = 0; i < s->blocksize; i++)
451
            s->decoded[channel][i] <<= wasted;
452
    }
453

    
454
    return 0;
455
}
456

    
457
static int decode_frame(FLACContext *s)
458
{
459
    int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
460
    int decorrelation, bps, blocksize, samplerate;
461

    
462
    blocksize_code = get_bits(&s->gb, 4);
463

    
464
    sample_rate_code = get_bits(&s->gb, 4);
465

    
466
    assignment = get_bits(&s->gb, 4); /* channel assignment */
467
    if (assignment < 8 && s->channels == assignment+1)
468
        decorrelation = INDEPENDENT;
469
    else if (assignment >=8 && assignment < 11 && s->channels == 2)
470
        decorrelation = LEFT_SIDE + assignment - 8;
471
    else
472
    {
473
        av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
474
        return -1;
475
    }
476

    
477
    sample_size_code = get_bits(&s->gb, 3);
478
    if(sample_size_code == 0)
479
        bps= s->bps;
480
    else if((sample_size_code != 3) && (sample_size_code != 7))
481
        bps = sample_size_table[sample_size_code];
482
    else
483
    {
484
        av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
485
        return -1;
486
    }
487

    
488
    if (get_bits1(&s->gb))
489
    {
490
        av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
491
        return -1;
492
    }
493

    
494
    if(get_utf8(&s->gb) < 0){
495
        av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
496
        return -1;
497
    }
498
#if 0
499
    if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
500
        (s->min_blocksize != s->max_blocksize)){
501
    }else{
502
    }
503
#endif
504

    
505
    if (blocksize_code == 0)
506
        blocksize = s->min_blocksize;
507
    else if (blocksize_code == 6)
508
        blocksize = get_bits(&s->gb, 8)+1;
509
    else if (blocksize_code == 7)
510
        blocksize = get_bits(&s->gb, 16)+1;
511
    else
512
        blocksize = blocksize_table[blocksize_code];
513

    
514
    if(blocksize > s->max_blocksize){
515
        av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
516
        return -1;
517
    }
518

    
519
    if (sample_rate_code == 0){
520
        samplerate= s->samplerate;
521
    }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
522
        samplerate = sample_rate_table[sample_rate_code];
523
    else if (sample_rate_code == 12)
524
        samplerate = get_bits(&s->gb, 8) * 1000;
525
    else if (sample_rate_code == 13)
526
        samplerate = get_bits(&s->gb, 16);
527
    else if (sample_rate_code == 14)
528
        samplerate = get_bits(&s->gb, 16) * 10;
529
    else{
530
        av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
531
        return -1;
532
    }
533

    
534
    skip_bits(&s->gb, 8);
535
    crc8= av_crc(av_crc07, 0, s->gb.buffer, get_bits_count(&s->gb)/8);
536
    if(crc8){
537
        av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
538
        return -1;
539
    }
540

    
541
    s->blocksize    = blocksize;
542
    s->samplerate   = samplerate;
543
    s->bps          = bps;
544
    s->decorrelation= decorrelation;
545

    
546
//    dump_headers(s);
547

    
548
    /* subframes */
549
    for (i = 0; i < s->channels; i++)
550
    {
551
//        av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
552
        if (decode_subframe(s, i) < 0)
553
            return -1;
554
    }
555

    
556
    align_get_bits(&s->gb);
557

    
558
    /* frame footer */
559
    skip_bits(&s->gb, 16); /* data crc */
560

    
561
    return 0;
562
}
563

    
564
static inline int16_t shift_to_16_bits(int32_t data, int bps)
565
{
566
    if (bps == 24) {
567
        return (data >> 8);
568
    } else if (bps == 20) {
569
        return (data >> 4);
570
    } else {
571
        return data;
572
    }
573
}
574

    
575
static int flac_decode_frame(AVCodecContext *avctx,
576
                            void *data, int *data_size,
577
                            uint8_t *buf, int buf_size)
578
{
579
    FLACContext *s = avctx->priv_data;
580
    int tmp = 0, i, j = 0, input_buf_size = 0;
581
    int16_t *samples = data;
582

    
583
    if(s->max_framesize == 0){
584
        s->max_framesize= 65536; // should hopefully be enough for the first header
585
        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
586
    }
587

    
588
    if(1 && s->max_framesize){//FIXME truncated
589
            buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
590
            input_buf_size= buf_size;
591

    
592
            if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
593
//                printf("memmove\n");
594
                memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
595
                s->bitstream_index=0;
596
            }
597
            memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
598
            buf= &s->bitstream[s->bitstream_index];
599
            buf_size += s->bitstream_size;
600
            s->bitstream_size= buf_size;
601

    
602
            if(buf_size < s->max_framesize){
603
//                printf("wanna more data ...\n");
604
                return input_buf_size;
605
            }
606
    }
607

    
608
    init_get_bits(&s->gb, buf, buf_size*8);
609

    
610
    if (!metadata_parse(s))
611
    {
612
        tmp = show_bits(&s->gb, 16);
613
        if(tmp != 0xFFF8){
614
            av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
615
            while(get_bits_count(&s->gb)/8+2 < buf_size && show_bits(&s->gb, 16) != 0xFFF8)
616
                skip_bits(&s->gb, 8);
617
            goto end; // we may not have enough bits left to decode a frame, so try next time
618
        }
619
        skip_bits(&s->gb, 16);
620
        if (decode_frame(s) < 0){
621
            av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
622
            s->bitstream_size=0;
623
            s->bitstream_index=0;
624
            return -1;
625
        }
626
    }
627

    
628

    
629
#if 0
630
    /* fix the channel order here */
631
    if (s->order == MID_SIDE)
632
    {
633
        short *left = samples;
634
        short *right = samples + s->blocksize;
635
        for (i = 0; i < s->blocksize; i += 2)
636
        {
637
            uint32_t x = s->decoded[0][i];
638
            uint32_t y = s->decoded[0][i+1];
639

640
            right[i] = x - (y / 2);
641
            left[i] = right[i] + y;
642
        }
643
        *data_size = 2 * s->blocksize;
644
    }
645
    else
646
    {
647
    for (i = 0; i < s->channels; i++)
648
    {
649
        switch(s->order)
650
        {
651
            case INDEPENDENT:
652
                for (j = 0; j < s->blocksize; j++)
653
                    samples[(s->blocksize*i)+j] = s->decoded[i][j];
654
                break;
655
            case LEFT_SIDE:
656
            case RIGHT_SIDE:
657
                if (i == 0)
658
                    for (j = 0; j < s->blocksize; j++)
659
                        samples[(s->blocksize*i)+j] = s->decoded[0][j];
660
                else
661
                    for (j = 0; j < s->blocksize; j++)
662
                        samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
663
                break;
664
//            case MID_SIDE:
665
//                av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
666
        }
667
        *data_size += s->blocksize;
668
    }
669
    }
670
#else
671
#define DECORRELATE(left, right)\
672
            assert(s->channels == 2);\
673
            for (i = 0; i < s->blocksize; i++)\
674
            {\
675
                int a= s->decoded[0][i];\
676
                int b= s->decoded[1][i];\
677
                *(samples++) = (left ) >> (16 - s->bps);\
678
                *(samples++) = (right) >> (16 - s->bps);\
679
            }\
680
            break;
681

    
682
    switch(s->decorrelation)
683
    {
684
        case INDEPENDENT:
685
            for (j = 0; j < s->blocksize; j++)
686
            {
687
                for (i = 0; i < s->channels; i++)
688
                    *(samples++) = shift_to_16_bits(s->decoded[i][j], s->bps);
689
            }
690
            break;
691
        case LEFT_SIDE:
692
            DECORRELATE(a,a-b)
693
        case RIGHT_SIDE:
694
            DECORRELATE(a+b,b)
695
        case MID_SIDE:
696
            DECORRELATE( (a-=b>>1) + b, a)
697
    }
698
#endif
699

    
700
    *data_size = (int8_t *)samples - (int8_t *)data;
701
//    av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
702

    
703
//    s->last_blocksize = s->blocksize;
704
end:
705
    i= (get_bits_count(&s->gb)+7)/8;;
706
    if(i > buf_size){
707
        av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
708
        s->bitstream_size=0;
709
        s->bitstream_index=0;
710
        return -1;
711
    }
712

    
713
    if(s->bitstream_size){
714
        s->bitstream_index += i;
715
        s->bitstream_size  -= i;
716
        return input_buf_size;
717
    }else
718
        return i;
719
}
720

    
721
static int flac_decode_close(AVCodecContext *avctx)
722
{
723
    FLACContext *s = avctx->priv_data;
724
    int i;
725

    
726
    for (i = 0; i < s->channels; i++)
727
    {
728
        av_freep(&s->decoded[i]);
729
    }
730
    av_freep(&s->bitstream);
731

    
732
    return 0;
733
}
734

    
735
static void flac_flush(AVCodecContext *avctx){
736
    FLACContext *s = avctx->priv_data;
737

    
738
    s->bitstream_size=
739
    s->bitstream_index= 0;
740
}
741

    
742
AVCodec flac_decoder = {
743
    "flac",
744
    CODEC_TYPE_AUDIO,
745
    CODEC_ID_FLAC,
746
    sizeof(FLACContext),
747
    flac_decode_init,
748
    NULL,
749
    flac_decode_close,
750
    flac_decode_frame,
751
    .flush= flac_flush,
752
};