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1
/*
2
 * FLAC (Free Lossless Audio Codec) decoder
3
 * Copyright (c) 2003 Alex Beregszaszi
4
 *
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 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
 * Lesser General Public License for more details.
14
 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
19

    
20
/**
21
 * @file flac.c
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 * FLAC (Free Lossless Audio Codec) decoder
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 * @author Alex Beregszaszi
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 *
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 * For more information on the FLAC format, visit:
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 *  http://flac.sourceforge.net/
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 *
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 * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
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 * through, starting from the initial 'fLaC' signature; or by passing the
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 * 34-byte streaminfo structure through avctx->extradata[_size] followed
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 * by data starting with the 0xFFF8 marker.
32
 */
33

    
34
#include <limits.h>
35

    
36
#define ALT_BITSTREAM_READER
37
#include "avcodec.h"
38
#include "bitstream.h"
39
#include "golomb.h"
40
#include "crc.h"
41

    
42
#undef NDEBUG
43
#include <assert.h>
44

    
45
#define MAX_CHANNELS 8
46
#define MAX_BLOCKSIZE 65535
47
#define FLAC_STREAMINFO_SIZE 34
48

    
49
enum decorrelation_type {
50
    INDEPENDENT,
51
    LEFT_SIDE,
52
    RIGHT_SIDE,
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    MID_SIDE,
54
};
55

    
56
typedef struct FLACContext {
57
    AVCodecContext *avctx;
58
    GetBitContext gb;
59

    
60
    int min_blocksize, max_blocksize;
61
    int min_framesize, max_framesize;
62
    int samplerate, channels;
63
    int blocksize/*, last_blocksize*/;
64
    int bps, curr_bps;
65
    enum decorrelation_type decorrelation;
66

    
67
    int32_t *decoded[MAX_CHANNELS];
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    uint8_t *bitstream;
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    int bitstream_size;
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    int bitstream_index;
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    unsigned int allocated_bitstream_size;
72
} FLACContext;
73

    
74
#define METADATA_TYPE_STREAMINFO 0
75

    
76
static int sample_rate_table[] =
77
{ 0, 0, 0, 0,
78
  8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
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  0, 0, 0, 0 };
80

    
81
static int sample_size_table[] =
82
{ 0, 8, 12, 0, 16, 20, 24, 0 };
83

    
84
static int blocksize_table[] = {
85
     0,    192, 576<<0, 576<<1, 576<<2, 576<<3,      0,      0,
86
256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
87
};
88

    
89
static int64_t get_utf8(GetBitContext *gb){
90
    int64_t val;
91
    GET_UTF8(val, get_bits(gb, 8), return -1;)
92
    return val;
93
}
94

    
95
static void metadata_streaminfo(FLACContext *s);
96
static void dump_headers(FLACContext *s);
97

    
98
static int flac_decode_init(AVCodecContext * avctx)
99
{
100
    FLACContext *s = avctx->priv_data;
101
    s->avctx = avctx;
102

    
103
    /* initialize based on the demuxer-supplied streamdata header */
104
    if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
105
        init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
106
        metadata_streaminfo(s);
107
        dump_headers(s);
108
    }
109

    
110
    return 0;
111
}
112

    
113
static void dump_headers(FLACContext *s)
114
{
115
    av_log(s->avctx, AV_LOG_DEBUG, "  Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
116
    av_log(s->avctx, AV_LOG_DEBUG, "  Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
117
    av_log(s->avctx, AV_LOG_DEBUG, "  Samplerate: %d\n", s->samplerate);
118
    av_log(s->avctx, AV_LOG_DEBUG, "  Channels: %d\n", s->channels);
119
    av_log(s->avctx, AV_LOG_DEBUG, "  Bits: %d\n", s->bps);
120
}
121

    
122
static void allocate_buffers(FLACContext *s){
123
    int i;
124

    
125
    assert(s->max_blocksize);
126

    
127
    if(s->max_framesize == 0 && s->max_blocksize){
128
        s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
129
    }
130

    
131
    for (i = 0; i < s->channels; i++)
132
    {
133
        s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
134
    }
135

    
136
    s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
137
}
138

    
139
static void metadata_streaminfo(FLACContext *s)
140
{
141
    /* mandatory streaminfo */
142
    s->min_blocksize = get_bits(&s->gb, 16);
143
    s->max_blocksize = get_bits(&s->gb, 16);
144

    
145
    s->min_framesize = get_bits_long(&s->gb, 24);
146
    s->max_framesize = get_bits_long(&s->gb, 24);
147

    
148
    s->samplerate = get_bits_long(&s->gb, 20);
149
    s->channels = get_bits(&s->gb, 3) + 1;
150
    s->bps = get_bits(&s->gb, 5) + 1;
151

    
152
    s->avctx->channels = s->channels;
153
    s->avctx->sample_rate = s->samplerate;
154

    
155
    skip_bits(&s->gb, 36); /* total num of samples */
156

    
157
    skip_bits(&s->gb, 64); /* md5 sum */
158
    skip_bits(&s->gb, 64); /* md5 sum */
159

    
160
    allocate_buffers(s);
161
}
162

    
163
static int decode_residuals(FLACContext *s, int channel, int pred_order)
164
{
165
    int i, tmp, partition, method_type, rice_order;
166
    int sample = 0, samples;
167

    
168
    method_type = get_bits(&s->gb, 2);
169
    if (method_type != 0){
170
        av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
171
        return -1;
172
    }
173

    
174
    rice_order = get_bits(&s->gb, 4);
175

    
176
    samples= s->blocksize >> rice_order;
177

    
178
    sample=
179
    i= pred_order;
180
    for (partition = 0; partition < (1 << rice_order); partition++)
181
    {
182
        tmp = get_bits(&s->gb, 4);
183
        if (tmp == 15)
184
        {
185
            av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
186
            tmp = get_bits(&s->gb, 5);
187
            for (; i < samples; i++, sample++)
188
                s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
189
        }
190
        else
191
        {
192
//            av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
193
            for (; i < samples; i++, sample++){
194
                s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
195
            }
196
        }
197
        i= 0;
198
    }
199

    
200
//    av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
201

    
202
    return 0;
203
}
204

    
205
static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
206
{
207
    int i;
208

    
209
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME FIXED\n");
210

    
211
    /* warm up samples */
212
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
213

    
214
    for (i = 0; i < pred_order; i++)
215
    {
216
        s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
217
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
218
    }
219

    
220
    if (decode_residuals(s, channel, pred_order) < 0)
221
        return -1;
222

    
223
    switch(pred_order)
224
    {
225
        case 0:
226
            break;
227
        case 1:
228
            for (i = pred_order; i < s->blocksize; i++)
229
                s->decoded[channel][i] +=   s->decoded[channel][i-1];
230
            break;
231
        case 2:
232
            for (i = pred_order; i < s->blocksize; i++)
233
                s->decoded[channel][i] += 2*s->decoded[channel][i-1]
234
                                          - s->decoded[channel][i-2];
235
            break;
236
        case 3:
237
            for (i = pred_order; i < s->blocksize; i++)
238
                s->decoded[channel][i] += 3*s->decoded[channel][i-1]
239
                                        - 3*s->decoded[channel][i-2]
240
                                        +   s->decoded[channel][i-3];
241
            break;
242
        case 4:
243
            for (i = pred_order; i < s->blocksize; i++)
244
                s->decoded[channel][i] += 4*s->decoded[channel][i-1]
245
                                        - 6*s->decoded[channel][i-2]
246
                                        + 4*s->decoded[channel][i-3]
247
                                        -   s->decoded[channel][i-4];
248
            break;
249
        default:
250
            av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
251
            return -1;
252
    }
253

    
254
    return 0;
255
}
256

    
257
static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
258
{
259
    int i, j;
260
    int coeff_prec, qlevel;
261
    int coeffs[pred_order];
262

    
263
//    av_log(s->avctx, AV_LOG_DEBUG, "  SUBFRAME LPC\n");
264

    
265
    /* warm up samples */
266
//    av_log(s->avctx, AV_LOG_DEBUG, "   warm up samples: %d\n", pred_order);
267

    
268
    for (i = 0; i < pred_order; i++)
269
    {
270
        s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
271
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, s->decoded[channel][i]);
272
    }
273

    
274
    coeff_prec = get_bits(&s->gb, 4) + 1;
275
    if (coeff_prec == 16)
276
    {
277
        av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
278
        return -1;
279
    }
280
//    av_log(s->avctx, AV_LOG_DEBUG, "   qlp coeff prec: %d\n", coeff_prec);
281
    qlevel = get_sbits(&s->gb, 5);
282
//    av_log(s->avctx, AV_LOG_DEBUG, "   quant level: %d\n", qlevel);
283
    if(qlevel < 0){
284
        av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
285
        return -1;
286
    }
287

    
288
    for (i = 0; i < pred_order; i++)
289
    {
290
        coeffs[i] = get_sbits(&s->gb, coeff_prec);
291
//        av_log(s->avctx, AV_LOG_DEBUG, "    %d: %d\n", i, coeffs[i]);
292
    }
293

    
294
    if (decode_residuals(s, channel, pred_order) < 0)
295
        return -1;
296

    
297
    if (s->bps > 16) {
298
        int64_t sum;
299
        for (i = pred_order; i < s->blocksize; i++)
300
        {
301
            sum = 0;
302
            for (j = 0; j < pred_order; j++)
303
                sum += (int64_t)coeffs[j] * s->decoded[channel][i-j-1];
304
            s->decoded[channel][i] += sum >> qlevel;
305
        }
306
    } else {
307
        int sum;
308
        for (i = pred_order; i < s->blocksize; i++)
309
        {
310
            sum = 0;
311
            for (j = 0; j < pred_order; j++)
312
                sum += coeffs[j] * s->decoded[channel][i-j-1];
313
            s->decoded[channel][i] += sum >> qlevel;
314
        }
315
    }
316

    
317
    return 0;
318
}
319

    
320
static inline int decode_subframe(FLACContext *s, int channel)
321
{
322
    int type, wasted = 0;
323
    int i, tmp;
324

    
325
    s->curr_bps = s->bps;
326
    if(channel == 0){
327
        if(s->decorrelation == RIGHT_SIDE)
328
            s->curr_bps++;
329
    }else{
330
        if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
331
            s->curr_bps++;
332
    }
333

    
334
    if (get_bits1(&s->gb))
335
    {
336
        av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
337
        return -1;
338
    }
339
    type = get_bits(&s->gb, 6);
340
//    wasted = get_bits1(&s->gb);
341

    
342
//    if (wasted)
343
//    {
344
//        while (!get_bits1(&s->gb))
345
//            wasted++;
346
//        if (wasted)
347
//            wasted++;
348
//        s->curr_bps -= wasted;
349
//    }
350
#if 0
351
    wasted= 16 - av_log2(show_bits(&s->gb, 17));
352
    skip_bits(&s->gb, wasted+1);
353
    s->curr_bps -= wasted;
354
#else
355
    if (get_bits1(&s->gb))
356
    {
357
        wasted = 1;
358
        while (!get_bits1(&s->gb))
359
            wasted++;
360
        s->curr_bps -= wasted;
361
        av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
362
    }
363
#endif
364
//FIXME use av_log2 for types
365
    if (type == 0)
366
    {
367
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
368
        tmp = get_sbits(&s->gb, s->curr_bps);
369
        for (i = 0; i < s->blocksize; i++)
370
            s->decoded[channel][i] = tmp;
371
    }
372
    else if (type == 1)
373
    {
374
        av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
375
        for (i = 0; i < s->blocksize; i++)
376
            s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
377
    }
378
    else if ((type >= 8) && (type <= 12))
379
    {
380
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
381
        if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
382
            return -1;
383
    }
384
    else if (type >= 32)
385
    {
386
//        av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
387
        if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
388
            return -1;
389
    }
390
    else
391
    {
392
        av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
393
        return -1;
394
    }
395

    
396
    if (wasted)
397
    {
398
        int i;
399
        for (i = 0; i < s->blocksize; i++)
400
            s->decoded[channel][i] <<= wasted;
401
    }
402

    
403
    return 0;
404
}
405

    
406
static int decode_frame(FLACContext *s)
407
{
408
    int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
409
    int decorrelation, bps, blocksize, samplerate;
410

    
411
    blocksize_code = get_bits(&s->gb, 4);
412

    
413
    sample_rate_code = get_bits(&s->gb, 4);
414

    
415
    assignment = get_bits(&s->gb, 4); /* channel assignment */
416
    if (assignment < 8 && s->channels == assignment+1)
417
        decorrelation = INDEPENDENT;
418
    else if (assignment >=8 && assignment < 11 && s->channels == 2)
419
        decorrelation = LEFT_SIDE + assignment - 8;
420
    else
421
    {
422
        av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
423
        return -1;
424
    }
425

    
426
    sample_size_code = get_bits(&s->gb, 3);
427
    if(sample_size_code == 0)
428
        bps= s->bps;
429
    else if((sample_size_code != 3) && (sample_size_code != 7))
430
        bps = sample_size_table[sample_size_code];
431
    else
432
    {
433
        av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
434
        return -1;
435
    }
436

    
437
    if (get_bits1(&s->gb))
438
    {
439
        av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
440
        return -1;
441
    }
442

    
443
    if(get_utf8(&s->gb) < 0){
444
        av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
445
        return -1;
446
    }
447
#if 0
448
    if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
449
        (s->min_blocksize != s->max_blocksize)){
450
    }else{
451
    }
452
#endif
453

    
454
    if (blocksize_code == 0)
455
        blocksize = s->min_blocksize;
456
    else if (blocksize_code == 6)
457
        blocksize = get_bits(&s->gb, 8)+1;
458
    else if (blocksize_code == 7)
459
        blocksize = get_bits(&s->gb, 16)+1;
460
    else
461
        blocksize = blocksize_table[blocksize_code];
462

    
463
    if(blocksize > s->max_blocksize){
464
        av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
465
        return -1;
466
    }
467

    
468
    if (sample_rate_code == 0){
469
        samplerate= s->samplerate;
470
    }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
471
        samplerate = sample_rate_table[sample_rate_code];
472
    else if (sample_rate_code == 12)
473
        samplerate = get_bits(&s->gb, 8) * 1000;
474
    else if (sample_rate_code == 13)
475
        samplerate = get_bits(&s->gb, 16);
476
    else if (sample_rate_code == 14)
477
        samplerate = get_bits(&s->gb, 16) * 10;
478
    else{
479
        av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
480
        return -1;
481
    }
482

    
483
    skip_bits(&s->gb, 8);
484
    crc8= av_crc(av_crc07, 0, s->gb.buffer, get_bits_count(&s->gb)/8);
485
    if(crc8){
486
        av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
487
        return -1;
488
    }
489

    
490
    s->blocksize    = blocksize;
491
    s->samplerate   = samplerate;
492
    s->bps          = bps;
493
    s->decorrelation= decorrelation;
494

    
495
//    dump_headers(s);
496

    
497
    /* subframes */
498
    for (i = 0; i < s->channels; i++)
499
    {
500
//        av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
501
        if (decode_subframe(s, i) < 0)
502
            return -1;
503
    }
504

    
505
    align_get_bits(&s->gb);
506

    
507
    /* frame footer */
508
    skip_bits(&s->gb, 16); /* data crc */
509

    
510
    return 0;
511
}
512

    
513
static inline int16_t shift_to_16_bits(int32_t data, int bps)
514
{
515
    if (bps == 24) {
516
        return (data >> 8);
517
    } else if (bps == 20) {
518
        return (data >> 4);
519
    } else {
520
        return data;
521
    }
522
}
523

    
524
static int flac_decode_frame(AVCodecContext *avctx,
525
                            void *data, int *data_size,
526
                            uint8_t *buf, int buf_size)
527
{
528
    FLACContext *s = avctx->priv_data;
529
    int metadata_last, metadata_type, metadata_size;
530
    int tmp = 0, i, j = 0, input_buf_size = 0;
531
    int16_t *samples = data;
532

    
533
    if(s->max_framesize == 0){
534
        s->max_framesize= 65536; // should hopefully be enough for the first header
535
        s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
536
    }
537

    
538
    if(1 && s->max_framesize){//FIXME truncated
539
            buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
540
            input_buf_size= buf_size;
541

    
542
            if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
543
//                printf("memmove\n");
544
                memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
545
                s->bitstream_index=0;
546
            }
547
            memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
548
            buf= &s->bitstream[s->bitstream_index];
549
            buf_size += s->bitstream_size;
550
            s->bitstream_size= buf_size;
551

    
552
            if(buf_size < s->max_framesize){
553
//                printf("wanna more data ...\n");
554
                return input_buf_size;
555
            }
556
    }
557

    
558
    init_get_bits(&s->gb, buf, buf_size*8);
559

    
560
    /* fLaC signature (be) */
561
    if (show_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
562
    {
563
        skip_bits(&s->gb, 32);
564

    
565
        av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
566
        do {
567
            metadata_last = get_bits(&s->gb, 1);
568
            metadata_type = get_bits(&s->gb, 7);
569
            metadata_size = get_bits_long(&s->gb, 24);
570

    
571
            av_log(s->avctx, AV_LOG_DEBUG, " metadata block: flag = %d, type = %d, size = %d\n",
572
                metadata_last, metadata_type,
573
                metadata_size);
574
            if(metadata_size){
575
                switch(metadata_type)
576
                {
577
                case METADATA_TYPE_STREAMINFO:{
578
                    metadata_streaminfo(s);
579

    
580
                    /* Buffer might have been reallocated, reinit bitreader */
581
                    if(buf != &s->bitstream[s->bitstream_index])
582
                    {
583
                        int bits_count = get_bits_count(&s->gb);
584
                        buf= &s->bitstream[s->bitstream_index];
585
                        init_get_bits(&s->gb, buf, buf_size*8);
586
                        skip_bits(&s->gb, bits_count);
587
                    }
588

    
589
                    dump_headers(s);
590
                    break;}
591
                default:
592
                    for(i=0; i<metadata_size; i++)
593
                        skip_bits(&s->gb, 8);
594
                }
595
            }
596
        } while(!metadata_last);
597
    }
598
    else
599
    {
600

    
601
        tmp = show_bits(&s->gb, 16);
602
        if(tmp != 0xFFF8){
603
            av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
604
            while(get_bits_count(&s->gb)/8+2 < buf_size && show_bits(&s->gb, 16) != 0xFFF8)
605
                skip_bits(&s->gb, 8);
606
            goto end; // we may not have enough bits left to decode a frame, so try next time
607
        }
608
        skip_bits(&s->gb, 16);
609
        if (decode_frame(s) < 0){
610
            av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
611
            s->bitstream_size=0;
612
            s->bitstream_index=0;
613
            return -1;
614
        }
615
    }
616

    
617

    
618
#if 0
619
    /* fix the channel order here */
620
    if (s->order == MID_SIDE)
621
    {
622
        short *left = samples;
623
        short *right = samples + s->blocksize;
624
        for (i = 0; i < s->blocksize; i += 2)
625
        {
626
            uint32_t x = s->decoded[0][i];
627
            uint32_t y = s->decoded[0][i+1];
628

629
            right[i] = x - (y / 2);
630
            left[i] = right[i] + y;
631
        }
632
        *data_size = 2 * s->blocksize;
633
    }
634
    else
635
    {
636
    for (i = 0; i < s->channels; i++)
637
    {
638
        switch(s->order)
639
        {
640
            case INDEPENDENT:
641
                for (j = 0; j < s->blocksize; j++)
642
                    samples[(s->blocksize*i)+j] = s->decoded[i][j];
643
                break;
644
            case LEFT_SIDE:
645
            case RIGHT_SIDE:
646
                if (i == 0)
647
                    for (j = 0; j < s->blocksize; j++)
648
                        samples[(s->blocksize*i)+j] = s->decoded[0][j];
649
                else
650
                    for (j = 0; j < s->blocksize; j++)
651
                        samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
652
                break;
653
//            case MID_SIDE:
654
//                av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
655
        }
656
        *data_size += s->blocksize;
657
    }
658
    }
659
#else
660
#define DECORRELATE(left, right)\
661
            assert(s->channels == 2);\
662
            for (i = 0; i < s->blocksize; i++)\
663
            {\
664
                int a= s->decoded[0][i];\
665
                int b= s->decoded[1][i];\
666
                *(samples++) = (left ) >> (16 - s->bps);\
667
                *(samples++) = (right) >> (16 - s->bps);\
668
            }\
669
            break;
670

    
671
    switch(s->decorrelation)
672
    {
673
        case INDEPENDENT:
674
            for (j = 0; j < s->blocksize; j++)
675
            {
676
                for (i = 0; i < s->channels; i++)
677
                    *(samples++) = shift_to_16_bits(s->decoded[i][j], s->bps);
678
            }
679
            break;
680
        case LEFT_SIDE:
681
            DECORRELATE(a,a-b)
682
        case RIGHT_SIDE:
683
            DECORRELATE(a+b,b)
684
        case MID_SIDE:
685
            DECORRELATE( (a-=b>>1) + b, a)
686
    }
687
#endif
688

    
689
    *data_size = (int8_t *)samples - (int8_t *)data;
690
//    av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
691

    
692
//    s->last_blocksize = s->blocksize;
693
end:
694
    i= (get_bits_count(&s->gb)+7)/8;;
695
    if(i > buf_size){
696
        av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
697
        s->bitstream_size=0;
698
        s->bitstream_index=0;
699
        return -1;
700
    }
701

    
702
    if(s->bitstream_size){
703
        s->bitstream_index += i;
704
        s->bitstream_size  -= i;
705
        return input_buf_size;
706
    }else
707
        return i;
708
}
709

    
710
static int flac_decode_close(AVCodecContext *avctx)
711
{
712
    FLACContext *s = avctx->priv_data;
713
    int i;
714

    
715
    for (i = 0; i < s->channels; i++)
716
    {
717
        av_freep(&s->decoded[i]);
718
    }
719
    av_freep(&s->bitstream);
720

    
721
    return 0;
722
}
723

    
724
static void flac_flush(AVCodecContext *avctx){
725
    FLACContext *s = avctx->priv_data;
726

    
727
    s->bitstream_size=
728
    s->bitstream_index= 0;
729
}
730

    
731
AVCodec flac_decoder = {
732
    "flac",
733
    CODEC_TYPE_AUDIO,
734
    CODEC_ID_FLAC,
735
    sizeof(FLACContext),
736
    flac_decode_init,
737
    NULL,
738
    flac_decode_close,
739
    flac_decode_frame,
740
    .flush= flac_flush,
741
};