Statistics
| Branch: | Revision:

ffmpeg / libavcodec / flac.c @ b88e6576

History | View | Annotate | Download (22 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 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 av_cold 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, "  Max Framesize: %d\n", 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
    skip_bits(&s->gb, 24); /* skip min frame size */
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_bits1(&s->gb);
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 > 1){
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
    if (pred_order > samples) {
229
        av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n", pred_order, samples);
230
        return -1;
231
    }
232

    
233
    sample=
234
    i= pred_order;
235
    for (partition = 0; partition < (1 << rice_order); partition++)
236
    {
237
        tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
238
        if (tmp == (method_type == 0 ? 15 : 31))
239
        {
240
            av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
241
            tmp = get_bits(&s->gb, 5);
242
            for (; i < samples; i++, sample++)
243
                s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
244
        }
245
        else
246
        {
247
//            av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
248
            for (; i < samples; i++, sample++){
249
                s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
250
            }
251
        }
252
        i= 0;
253
    }
254

    
255
//    av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
256

    
257
    return 0;
258
}
259

    
260
static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
261
{
262
    const int blocksize = s->blocksize;
263
    int32_t *decoded = s->decoded[channel];
264
    int a, b, c, d, i;
265

    
266
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME FIXED\n");
267

    
268
    /* warm up samples */
269
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
270

    
271
    for (i = 0; i < pred_order; i++)
272
    {
273
        decoded[i] = get_sbits(&s->gb, s->curr_bps);
274
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
275
    }
276

    
277
    if (decode_residuals(s, channel, pred_order) < 0)
278
        return -1;
279

    
280
    a = decoded[pred_order-1];
281
    b = a - decoded[pred_order-2];
282
    c = b - decoded[pred_order-2] + decoded[pred_order-3];
283
    d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
284

    
285
    switch(pred_order)
286
    {
287
        case 0:
288
            break;
289
        case 1:
290
            for (i = pred_order; i < blocksize; i++)
291
                decoded[i] = a += decoded[i];
292
            break;
293
        case 2:
294
            for (i = pred_order; i < blocksize; i++)
295
                decoded[i] = a += b += decoded[i];
296
            break;
297
        case 3:
298
            for (i = pred_order; i < blocksize; i++)
299
                decoded[i] = a += b += c += decoded[i];
300
            break;
301
        case 4:
302
            for (i = pred_order; i < blocksize; i++)
303
                decoded[i] = a += b += c += d += decoded[i];
304
            break;
305
        default:
306
            av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
307
            return -1;
308
    }
309

    
310
    return 0;
311
}
312

    
313
static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
314
{
315
    int i, j;
316
    int coeff_prec, qlevel;
317
    int coeffs[pred_order];
318
    int32_t *decoded = s->decoded[channel];
319

    
320
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME LPC\n");
321

    
322
    /* warm up samples */
323
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
324

    
325
    for (i = 0; i < pred_order; i++)
326
    {
327
        decoded[i] = get_sbits(&s->gb, s->curr_bps);
328
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, decoded[i]);
329
    }
330

    
331
    coeff_prec = get_bits(&s->gb, 4) + 1;
332
    if (coeff_prec == 16)
333
    {
334
        av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
335
        return -1;
336
    }
337
//    av_log(s->avctx, AV_LOG_DEBUG, "   qlp coeff prec: %d\n", coeff_prec);
338
    qlevel = get_sbits(&s->gb, 5);
339
//    av_log(s->avctx, AV_LOG_DEBUG, "   quant level: %d\n", qlevel);
340
    if(qlevel < 0){
341
        av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
342
        return -1;
343
    }
344

    
345
    for (i = 0; i < pred_order; i++)
346
    {
347
        coeffs[i] = get_sbits(&s->gb, coeff_prec);
348
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, coeffs[i]);
349
    }
350

    
351
    if (decode_residuals(s, channel, pred_order) < 0)
352
        return -1;
353

    
354
    if (s->bps > 16) {
355
        int64_t sum;
356
        for (i = pred_order; i < s->blocksize; i++)
357
        {
358
            sum = 0;
359
            for (j = 0; j < pred_order; j++)
360
                sum += (int64_t)coeffs[j] * decoded[i-j-1];
361
            decoded[i] += sum >> qlevel;
362
        }
363
    } else {
364
        for (i = pred_order; i < s->blocksize-1; i += 2)
365
        {
366
            int c;
367
            int d = decoded[i-pred_order];
368
            int s0 = 0, s1 = 0;
369
            for (j = pred_order-1; j > 0; j--)
370
            {
371
                c = coeffs[j];
372
                s0 += c*d;
373
                d = decoded[i-j];
374
                s1 += c*d;
375
            }
376
            c = coeffs[0];
377
            s0 += c*d;
378
            d = decoded[i] += s0 >> qlevel;
379
            s1 += c*d;
380
            decoded[i+1] += s1 >> qlevel;
381
        }
382
        if (i < s->blocksize)
383
        {
384
            int sum = 0;
385
            for (j = 0; j < pred_order; j++)
386
                sum += coeffs[j] * decoded[i-j-1];
387
            decoded[i] += sum >> qlevel;
388
        }
389
    }
390

    
391
    return 0;
392
}
393

    
394
static inline int decode_subframe(FLACContext *s, int channel)
395
{
396
    int type, wasted = 0;
397
    int i, tmp;
398

    
399
    s->curr_bps = s->bps;
400
    if(channel == 0){
401
        if(s->decorrelation == RIGHT_SIDE)
402
            s->curr_bps++;
403
    }else{
404
        if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
405
            s->curr_bps++;
406
    }
407

    
408
    if (get_bits1(&s->gb))
409
    {
410
        av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
411
        return -1;
412
    }
413
    type = get_bits(&s->gb, 6);
414
//    wasted = get_bits1(&s->gb);
415

    
416
//    if (wasted)
417
//    {
418
//        while (!get_bits1(&s->gb))
419
//            wasted++;
420
//        if (wasted)
421
//            wasted++;
422
//        s->curr_bps -= wasted;
423
//    }
424
#if 0
425
    wasted= 16 - av_log2(show_bits(&s->gb, 17));
426
    skip_bits(&s->gb, wasted+1);
427
    s->curr_bps -= wasted;
428
#else
429
    if (get_bits1(&s->gb))
430
    {
431
        wasted = 1;
432
        while (!get_bits1(&s->gb))
433
            wasted++;
434
        s->curr_bps -= wasted;
435
        av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
436
    }
437
#endif
438
//FIXME use av_log2 for types
439
    if (type == 0)
440
    {
441
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
442
        tmp = get_sbits(&s->gb, s->curr_bps);
443
        for (i = 0; i < s->blocksize; i++)
444
            s->decoded[channel][i] = tmp;
445
    }
446
    else if (type == 1)
447
    {
448
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
449
        for (i = 0; i < s->blocksize; i++)
450
            s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
451
    }
452
    else if ((type >= 8) && (type <= 12))
453
    {
454
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
455
        if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
456
            return -1;
457
    }
458
    else if (type >= 32)
459
    {
460
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
461
        if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
462
            return -1;
463
    }
464
    else
465
    {
466
        av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
467
        return -1;
468
    }
469

    
470
    if (wasted)
471
    {
472
        int i;
473
        for (i = 0; i < s->blocksize; i++)
474
            s->decoded[channel][i] <<= wasted;
475
    }
476

    
477
    return 0;
478
}
479

    
480
static int decode_frame(FLACContext *s, int alloc_data_size)
481
{
482
    int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
483
    int decorrelation, bps, blocksize, samplerate;
484

    
485
    blocksize_code = get_bits(&s->gb, 4);
486

    
487
    sample_rate_code = get_bits(&s->gb, 4);
488

    
489
    assignment = get_bits(&s->gb, 4); /* channel assignment */
490
    if (assignment < 8 && s->channels == assignment+1)
491
        decorrelation = INDEPENDENT;
492
    else if (assignment >=8 && assignment < 11 && s->channels == 2)
493
        decorrelation = LEFT_SIDE + assignment - 8;
494
    else
495
    {
496
        av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
497
        return -1;
498
    }
499

    
500
    sample_size_code = get_bits(&s->gb, 3);
501
    if(sample_size_code == 0)
502
        bps= s->bps;
503
    else if((sample_size_code != 3) && (sample_size_code != 7))
504
        bps = sample_size_table[sample_size_code];
505
    else
506
    {
507
        av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
508
        return -1;
509
    }
510

    
511
    if (get_bits1(&s->gb))
512
    {
513
        av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
514
        return -1;
515
    }
516

    
517
    if(get_utf8(&s->gb) < 0){
518
        av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
519
        return -1;
520
    }
521
#if 0
522
    if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
523
        (s->min_blocksize != s->max_blocksize)){
524
    }else{
525
    }
526
#endif
527

    
528
    if (blocksize_code == 0)
529
        blocksize = s->min_blocksize;
530
    else if (blocksize_code == 6)
531
        blocksize = get_bits(&s->gb, 8)+1;
532
    else if (blocksize_code == 7)
533
        blocksize = get_bits(&s->gb, 16)+1;
534
    else
535
        blocksize = blocksize_table[blocksize_code];
536

    
537
    if(blocksize > s->max_blocksize){
538
        av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
539
        return -1;
540
    }
541

    
542
    if(blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
543
        return -1;
544

    
545
    if (sample_rate_code == 0){
546
        samplerate= s->samplerate;
547
    }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
548
        samplerate = sample_rate_table[sample_rate_code];
549
    else if (sample_rate_code == 12)
550
        samplerate = get_bits(&s->gb, 8) * 1000;
551
    else if (sample_rate_code == 13)
552
        samplerate = get_bits(&s->gb, 16);
553
    else if (sample_rate_code == 14)
554
        samplerate = get_bits(&s->gb, 16) * 10;
555
    else{
556
        av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
557
        return -1;
558
    }
559

    
560
    skip_bits(&s->gb, 8);
561
    crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
562
                  s->gb.buffer, get_bits_count(&s->gb)/8);
563
    if(crc8){
564
        av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
565
        return -1;
566
    }
567

    
568
    s->blocksize    = blocksize;
569
    s->samplerate   = samplerate;
570
    s->bps          = bps;
571
    s->decorrelation= decorrelation;
572

    
573
//    dump_headers(s);
574

    
575
    /* subframes */
576
    for (i = 0; i < s->channels; i++)
577
    {
578
//        av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
579
        if (decode_subframe(s, i) < 0)
580
            return -1;
581
    }
582

    
583
    align_get_bits(&s->gb);
584

    
585
    /* frame footer */
586
    skip_bits(&s->gb, 16); /* data crc */
587

    
588
    return 0;
589
}
590

    
591
static int flac_decode_frame(AVCodecContext *avctx,
592
                            void *data, int *data_size,
593
                            const uint8_t *buf, int buf_size)
594
{
595
    FLACContext *s = avctx->priv_data;
596
    int tmp = 0, i, j = 0, input_buf_size = 0;
597
    int16_t *samples = data;
598
    int alloc_data_size= *data_size;
599

    
600
    *data_size=0;
601

    
602
    if(s->max_framesize == 0){
603
        s->max_framesize= 65536; // should hopefully be enough for the first header
604
        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
605
    }
606

    
607
    if(1 && s->max_framesize){//FIXME truncated
608
            buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
609
            input_buf_size= buf_size;
610

    
611
            if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
612
//                printf("memmove\n");
613
                memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
614
                s->bitstream_index=0;
615
            }
616
            memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
617
            buf= &s->bitstream[s->bitstream_index];
618
            buf_size += s->bitstream_size;
619
            s->bitstream_size= buf_size;
620

    
621
            if(buf_size < s->max_framesize){
622
//                printf("wanna more data ...\n");
623
                return input_buf_size;
624
            }
625
    }
626

    
627
    init_get_bits(&s->gb, buf, buf_size*8);
628

    
629
    if (!metadata_parse(s))
630
    {
631
        tmp = show_bits(&s->gb, 16);
632
        if((tmp & 0xFFFE) != 0xFFF8){
633
            av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
634
            while(get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
635
                skip_bits(&s->gb, 8);
636
            goto end; // we may not have enough bits left to decode a frame, so try next time
637
        }
638
        skip_bits(&s->gb, 16);
639
        if (decode_frame(s, alloc_data_size) < 0){
640
            av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
641
            s->bitstream_size=0;
642
            s->bitstream_index=0;
643
            return -1;
644
        }
645
    }
646

    
647

    
648
#if 0
649
    /* fix the channel order here */
650
    if (s->order == MID_SIDE)
651
    {
652
        short *left = samples;
653
        short *right = samples + s->blocksize;
654
        for (i = 0; i < s->blocksize; i += 2)
655
        {
656
            uint32_t x = s->decoded[0][i];
657
            uint32_t y = s->decoded[0][i+1];
658

659
            right[i] = x - (y / 2);
660
            left[i] = right[i] + y;
661
        }
662
        *data_size = 2 * s->blocksize;
663
    }
664
    else
665
    {
666
    for (i = 0; i < s->channels; i++)
667
    {
668
        switch(s->order)
669
        {
670
            case INDEPENDENT:
671
                for (j = 0; j < s->blocksize; j++)
672
                    samples[(s->blocksize*i)+j] = s->decoded[i][j];
673
                break;
674
            case LEFT_SIDE:
675
            case RIGHT_SIDE:
676
                if (i == 0)
677
                    for (j = 0; j < s->blocksize; j++)
678
                        samples[(s->blocksize*i)+j] = s->decoded[0][j];
679
                else
680
                    for (j = 0; j < s->blocksize; j++)
681
                        samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
682
                break;
683
//            case MID_SIDE:
684
//                av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
685
        }
686
        *data_size += s->blocksize;
687
    }
688
    }
689
#else
690
#define DECORRELATE(left, right)\
691
            assert(s->channels == 2);\
692
            for (i = 0; i < s->blocksize; i++)\
693
            {\
694
                int a= s->decoded[0][i];\
695
                int b= s->decoded[1][i];\
696
                *samples++ = ((left)  << (24 - s->bps)) >> 8;\
697
                *samples++ = ((right) << (24 - s->bps)) >> 8;\
698
            }\
699
            break;
700

    
701
    switch(s->decorrelation)
702
    {
703
        case INDEPENDENT:
704
            for (j = 0; j < s->blocksize; j++)
705
            {
706
                for (i = 0; i < s->channels; i++)
707
                    *samples++ = (s->decoded[i][j] << (24 - s->bps)) >> 8;
708
            }
709
            break;
710
        case LEFT_SIDE:
711
            DECORRELATE(a,a-b)
712
        case RIGHT_SIDE:
713
            DECORRELATE(a+b,b)
714
        case MID_SIDE:
715
            DECORRELATE( (a-=b>>1) + b, a)
716
    }
717
#endif
718

    
719
    *data_size = (int8_t *)samples - (int8_t *)data;
720
//    av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
721

    
722
//    s->last_blocksize = s->blocksize;
723
end:
724
    i= (get_bits_count(&s->gb)+7)/8;
725
    if(i > buf_size){
726
        av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
727
        s->bitstream_size=0;
728
        s->bitstream_index=0;
729
        return -1;
730
    }
731

    
732
    if(s->bitstream_size){
733
        s->bitstream_index += i;
734
        s->bitstream_size  -= i;
735
        return input_buf_size;
736
    }else
737
        return i;
738
}
739

    
740
static av_cold int flac_decode_close(AVCodecContext *avctx)
741
{
742
    FLACContext *s = avctx->priv_data;
743
    int i;
744

    
745
    for (i = 0; i < s->channels; i++)
746
    {
747
        av_freep(&s->decoded[i]);
748
    }
749
    av_freep(&s->bitstream);
750

    
751
    return 0;
752
}
753

    
754
static void flac_flush(AVCodecContext *avctx){
755
    FLACContext *s = avctx->priv_data;
756

    
757
    s->bitstream_size=
758
    s->bitstream_index= 0;
759
}
760

    
761
AVCodec flac_decoder = {
762
    "flac",
763
    CODEC_TYPE_AUDIO,
764
    CODEC_ID_FLAC,
765
    sizeof(FLACContext),
766
    flac_decode_init,
767
    NULL,
768
    flac_decode_close,
769
    flac_decode_frame,
770
    .flush= flac_flush,
771
    .long_name= "FLAC (Free Lossless Audio Codec)"
772
};