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1
/*
2
 * ALAC (Apple Lossless Audio Codec) decoder
3
 * Copyright (c) 2005 David Hammerton
4
 *
5
 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * 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
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; 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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 */
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22
/**
23
 * @file libavcodec/alac.c
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 * ALAC (Apple Lossless Audio Codec) decoder
25
 * @author 2005 David Hammerton
26
 *
27
 * For more information on the ALAC format, visit:
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 *  http://crazney.net/programs/itunes/alac.html
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 *
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 * Note: This decoder expects a 36- (0x24-)byte QuickTime atom to be
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 * passed through the extradata[_size] fields. This atom is tacked onto
32
 * the end of an 'alac' stsd atom and has the following format:
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 *  bytes 0-3   atom size (0x24), big-endian
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 *  bytes 4-7   atom type ('alac', not the 'alac' tag from start of stsd)
35
 *  bytes 8-35  data bytes needed by decoder
36
 *
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 * Extradata:
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 * 32bit  size
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 * 32bit  tag (=alac)
40
 * 32bit  zero?
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 * 32bit  max sample per frame
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 *  8bit  ?? (zero?)
43
 *  8bit  sample size
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 *  8bit  history mult
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 *  8bit  initial history
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 *  8bit  kmodifier
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 *  8bit  channels?
48
 * 16bit  ??
49
 * 32bit  max coded frame size
50
 * 32bit  bitrate?
51
 * 32bit  samplerate
52
 */
53

    
54

    
55
#include "avcodec.h"
56
#include "get_bits.h"
57
#include "bytestream.h"
58
#include "unary.h"
59
#include "mathops.h"
60

    
61
#define ALAC_EXTRADATA_SIZE 36
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#define MAX_CHANNELS 2
63

    
64
typedef struct {
65

    
66
    AVCodecContext *avctx;
67
    GetBitContext gb;
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    /* init to 0; first frame decode should initialize from extradata and
69
     * set this to 1 */
70
    int context_initialized;
71

    
72
    int numchannels;
73
    int bytespersample;
74

    
75
    /* buffers */
76
    int32_t *predicterror_buffer[MAX_CHANNELS];
77

    
78
    int32_t *outputsamples_buffer[MAX_CHANNELS];
79

    
80
    int32_t *wasted_bits_buffer[MAX_CHANNELS];
81

    
82
    /* stuff from setinfo */
83
    uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */    /* max samples per frame? */
84
    uint8_t setinfo_sample_size; /* 0x10 */
85
    uint8_t setinfo_rice_historymult; /* 0x28 */
86
    uint8_t setinfo_rice_initialhistory; /* 0x0a */
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    uint8_t setinfo_rice_kmodifier; /* 0x0e */
88
    /* end setinfo stuff */
89

    
90
    int wasted_bits;
91
} ALACContext;
92

    
93
static void allocate_buffers(ALACContext *alac)
94
{
95
    int chan;
96
    for (chan = 0; chan < MAX_CHANNELS; chan++) {
97
        alac->predicterror_buffer[chan] =
98
            av_malloc(alac->setinfo_max_samples_per_frame * 4);
99

    
100
        alac->outputsamples_buffer[chan] =
101
            av_malloc(alac->setinfo_max_samples_per_frame * 4);
102

    
103
        alac->wasted_bits_buffer[chan] = av_malloc(alac->setinfo_max_samples_per_frame * 4);
104
    }
105
}
106

    
107
static int alac_set_info(ALACContext *alac)
108
{
109
    const unsigned char *ptr = alac->avctx->extradata;
110

    
111
    ptr += 4; /* size */
112
    ptr += 4; /* alac */
113
    ptr += 4; /* 0 ? */
114

    
115
    if(AV_RB32(ptr) >= UINT_MAX/4){
116
        av_log(alac->avctx, AV_LOG_ERROR, "setinfo_max_samples_per_frame too large\n");
117
        return -1;
118
    }
119

    
120
    /* buffer size / 2 ? */
121
    alac->setinfo_max_samples_per_frame = bytestream_get_be32(&ptr);
122
    ptr++;                          /* ??? */
123
    alac->setinfo_sample_size           = *ptr++;
124
    if (alac->setinfo_sample_size > 32) {
125
        av_log(alac->avctx, AV_LOG_ERROR, "setinfo_sample_size too large\n");
126
        return -1;
127
    }
128
    alac->setinfo_rice_historymult      = *ptr++;
129
    alac->setinfo_rice_initialhistory   = *ptr++;
130
    alac->setinfo_rice_kmodifier        = *ptr++;
131
    ptr++;                         /* channels? */
132
    bytestream_get_be16(&ptr);      /* ??? */
133
    bytestream_get_be32(&ptr);      /* max coded frame size */
134
    bytestream_get_be32(&ptr);      /* bitrate ? */
135
    bytestream_get_be32(&ptr);      /* samplerate */
136

    
137
    allocate_buffers(alac);
138

    
139
    return 0;
140
}
141

    
142
static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsamplesize){
143
    /* read x - number of 1s before 0 represent the rice */
144
    int x = get_unary_0_9(gb);
145

    
146
    if (x > 8) { /* RICE THRESHOLD */
147
        /* use alternative encoding */
148
        x = get_bits(gb, readsamplesize);
149
    } else {
150
        if (k >= limit)
151
            k = limit;
152

    
153
        if (k != 1) {
154
            int extrabits = show_bits(gb, k);
155

    
156
            /* multiply x by 2^k - 1, as part of their strange algorithm */
157
            x = (x << k) - x;
158

    
159
            if (extrabits > 1) {
160
                x += extrabits - 1;
161
                skip_bits(gb, k);
162
            } else
163
                skip_bits(gb, k - 1);
164
        }
165
    }
166
    return x;
167
}
168

    
169
static void bastardized_rice_decompress(ALACContext *alac,
170
                                 int32_t *output_buffer,
171
                                 int output_size,
172
                                 int readsamplesize, /* arg_10 */
173
                                 int rice_initialhistory, /* arg424->b */
174
                                 int rice_kmodifier, /* arg424->d */
175
                                 int rice_historymult, /* arg424->c */
176
                                 int rice_kmodifier_mask /* arg424->e */
177
        )
178
{
179
    int output_count;
180
    unsigned int history = rice_initialhistory;
181
    int sign_modifier = 0;
182

    
183
    for (output_count = 0; output_count < output_size; output_count++) {
184
        int32_t x;
185
        int32_t x_modified;
186
        int32_t final_val;
187

    
188
        /* standard rice encoding */
189
        int k; /* size of extra bits */
190

    
191
        /* read k, that is bits as is */
192
        k = av_log2((history >> 9) + 3);
193
        x= decode_scalar(&alac->gb, k, rice_kmodifier, readsamplesize);
194

    
195
        x_modified = sign_modifier + x;
196
        final_val = (x_modified + 1) / 2;
197
        if (x_modified & 1) final_val *= -1;
198

    
199
        output_buffer[output_count] = final_val;
200

    
201
        sign_modifier = 0;
202

    
203
        /* now update the history */
204
        history += x_modified * rice_historymult
205
                   - ((history * rice_historymult) >> 9);
206

    
207
        if (x_modified > 0xffff)
208
            history = 0xffff;
209

    
210
        /* special case: there may be compressed blocks of 0 */
211
        if ((history < 128) && (output_count+1 < output_size)) {
212
            int k;
213
            unsigned int block_size;
214

    
215
            sign_modifier = 1;
216

    
217
            k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
218

    
219
            block_size= decode_scalar(&alac->gb, k, rice_kmodifier, 16);
220

    
221
            if (block_size > 0) {
222
                if(block_size >= output_size - output_count){
223
                    av_log(alac->avctx, AV_LOG_ERROR, "invalid zero block size of %d %d %d\n", block_size, output_size, output_count);
224
                    block_size= output_size - output_count - 1;
225
                }
226
                memset(&output_buffer[output_count+1], 0, block_size * 4);
227
                output_count += block_size;
228
            }
229

    
230
            if (block_size > 0xffff)
231
                sign_modifier = 0;
232

    
233
            history = 0;
234
        }
235
    }
236
}
237

    
238
static inline int sign_only(int v)
239
{
240
    return v ? FFSIGN(v) : 0;
241
}
242

    
243
static void predictor_decompress_fir_adapt(int32_t *error_buffer,
244
                                           int32_t *buffer_out,
245
                                           int output_size,
246
                                           int readsamplesize,
247
                                           int16_t *predictor_coef_table,
248
                                           int predictor_coef_num,
249
                                           int predictor_quantitization)
250
{
251
    int i;
252

    
253
    /* first sample always copies */
254
    *buffer_out = *error_buffer;
255

    
256
    if (!predictor_coef_num) {
257
        if (output_size <= 1)
258
            return;
259

    
260
        memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
261
        return;
262
    }
263

    
264
    if (predictor_coef_num == 0x1f) { /* 11111 - max value of predictor_coef_num */
265
      /* second-best case scenario for fir decompression,
266
       * error describes a small difference from the previous sample only
267
       */
268
        if (output_size <= 1)
269
            return;
270
        for (i = 0; i < output_size - 1; i++) {
271
            int32_t prev_value;
272
            int32_t error_value;
273

    
274
            prev_value = buffer_out[i];
275
            error_value = error_buffer[i+1];
276
            buffer_out[i+1] =
277
                sign_extend((prev_value + error_value), readsamplesize);
278
        }
279
        return;
280
    }
281

    
282
    /* read warm-up samples */
283
    if (predictor_coef_num > 0)
284
        for (i = 0; i < predictor_coef_num; i++) {
285
            int32_t val;
286

    
287
            val = buffer_out[i] + error_buffer[i+1];
288
            val = sign_extend(val, readsamplesize);
289
            buffer_out[i+1] = val;
290
        }
291

    
292
#if 0
293
    /* 4 and 8 are very common cases (the only ones i've seen). these
294
     * should be unrolled and optimized
295
     */
296
    if (predictor_coef_num == 4) {
297
        /* FIXME: optimized general case */
298
        return;
299
    }
300

301
    if (predictor_coef_table == 8) {
302
        /* FIXME: optimized general case */
303
        return;
304
    }
305
#endif
306

    
307
    /* general case */
308
    if (predictor_coef_num > 0) {
309
        for (i = predictor_coef_num + 1; i < output_size; i++) {
310
            int j;
311
            int sum = 0;
312
            int outval;
313
            int error_val = error_buffer[i];
314

    
315
            for (j = 0; j < predictor_coef_num; j++) {
316
                sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
317
                       predictor_coef_table[j];
318
            }
319

    
320
            outval = (1 << (predictor_quantitization-1)) + sum;
321
            outval = outval >> predictor_quantitization;
322
            outval = outval + buffer_out[0] + error_val;
323
            outval = sign_extend(outval, readsamplesize);
324

    
325
            buffer_out[predictor_coef_num+1] = outval;
326

    
327
            if (error_val > 0) {
328
                int predictor_num = predictor_coef_num - 1;
329

    
330
                while (predictor_num >= 0 && error_val > 0) {
331
                    int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
332
                    int sign = sign_only(val);
333

    
334
                    predictor_coef_table[predictor_num] -= sign;
335

    
336
                    val *= sign; /* absolute value */
337

    
338
                    error_val -= ((val >> predictor_quantitization) *
339
                                  (predictor_coef_num - predictor_num));
340

    
341
                    predictor_num--;
342
                }
343
            } else if (error_val < 0) {
344
                int predictor_num = predictor_coef_num - 1;
345

    
346
                while (predictor_num >= 0 && error_val < 0) {
347
                    int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
348
                    int sign = - sign_only(val);
349

    
350
                    predictor_coef_table[predictor_num] -= sign;
351

    
352
                    val *= sign; /* neg value */
353

    
354
                    error_val -= ((val >> predictor_quantitization) *
355
                                  (predictor_coef_num - predictor_num));
356

    
357
                    predictor_num--;
358
                }
359
            }
360

    
361
            buffer_out++;
362
        }
363
    }
364
}
365

    
366
static void reconstruct_stereo_16(int32_t *buffer[MAX_CHANNELS],
367
                                  int16_t *buffer_out,
368
                                  int numchannels, int numsamples,
369
                                  uint8_t interlacing_shift,
370
                                  uint8_t interlacing_leftweight)
371
{
372
    int i;
373
    if (numsamples <= 0)
374
        return;
375

    
376
    /* weighted interlacing */
377
    if (interlacing_leftweight) {
378
        for (i = 0; i < numsamples; i++) {
379
            int32_t a, b;
380

    
381
            a = buffer[0][i];
382
            b = buffer[1][i];
383

    
384
            a -= (b * interlacing_leftweight) >> interlacing_shift;
385
            b += a;
386

    
387
            buffer_out[i*numchannels] = b;
388
            buffer_out[i*numchannels + 1] = a;
389
        }
390

    
391
        return;
392
    }
393

    
394
    /* otherwise basic interlacing took place */
395
    for (i = 0; i < numsamples; i++) {
396
        int16_t left, right;
397

    
398
        left = buffer[0][i];
399
        right = buffer[1][i];
400

    
401
        buffer_out[i*numchannels] = left;
402
        buffer_out[i*numchannels + 1] = right;
403
    }
404
}
405

    
406
static void decorrelate_stereo_24(int32_t *buffer[MAX_CHANNELS],
407
                                  int32_t *buffer_out,
408
                                  int32_t *wasted_bits_buffer[MAX_CHANNELS],
409
                                  int wasted_bits,
410
                                  int numchannels, int numsamples,
411
                                  uint8_t interlacing_shift,
412
                                  uint8_t interlacing_leftweight)
413
{
414
    int i;
415

    
416
    if (numsamples <= 0)
417
        return;
418

    
419
    /* weighted interlacing */
420
    if (interlacing_leftweight) {
421
        for (i = 0; i < numsamples; i++) {
422
            int32_t a, b;
423

    
424
            a = buffer[0][i];
425
            b = buffer[1][i];
426

    
427
            a -= (b * interlacing_leftweight) >> interlacing_shift;
428
            b += a;
429

    
430
            if (wasted_bits) {
431
                b  = (b  << wasted_bits) | wasted_bits_buffer[0][i];
432
                a  = (a  << wasted_bits) | wasted_bits_buffer[1][i];
433
            }
434

    
435
            buffer_out[i * numchannels]     = b << 8;
436
            buffer_out[i * numchannels + 1] = a << 8;
437
        }
438
    } else {
439
        for (i = 0; i < numsamples; i++) {
440
            int32_t left, right;
441

    
442
            left  = buffer[0][i];
443
            right = buffer[1][i];
444

    
445
            if (wasted_bits) {
446
                left   = (left   << wasted_bits) | wasted_bits_buffer[0][i];
447
                right  = (right  << wasted_bits) | wasted_bits_buffer[1][i];
448
            }
449

    
450
            buffer_out[i * numchannels]     = left  << 8;
451
            buffer_out[i * numchannels + 1] = right << 8;
452
        }
453
    }
454
}
455

    
456
static int alac_decode_frame(AVCodecContext *avctx,
457
                             void *outbuffer, int *outputsize,
458
                             AVPacket *avpkt)
459
{
460
    const uint8_t *inbuffer = avpkt->data;
461
    int input_buffer_size = avpkt->size;
462
    ALACContext *alac = avctx->priv_data;
463

    
464
    int channels;
465
    unsigned int outputsamples;
466
    int hassize;
467
    unsigned int readsamplesize;
468
    int isnotcompressed;
469
    uint8_t interlacing_shift;
470
    uint8_t interlacing_leftweight;
471

    
472
    /* short-circuit null buffers */
473
    if (!inbuffer || !input_buffer_size)
474
        return input_buffer_size;
475

    
476
    /* initialize from the extradata */
477
    if (!alac->context_initialized) {
478
        if (alac->avctx->extradata_size != ALAC_EXTRADATA_SIZE) {
479
            av_log(avctx, AV_LOG_ERROR, "alac: expected %d extradata bytes\n",
480
                ALAC_EXTRADATA_SIZE);
481
            return input_buffer_size;
482
        }
483
        if (alac_set_info(alac)) {
484
            av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
485
            return input_buffer_size;
486
        }
487
        alac->context_initialized = 1;
488
    }
489

    
490
    init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
491

    
492
    channels = get_bits(&alac->gb, 3) + 1;
493
    if (channels > MAX_CHANNELS) {
494
        av_log(avctx, AV_LOG_ERROR, "channels > %d not supported\n",
495
               MAX_CHANNELS);
496
        return input_buffer_size;
497
    }
498

    
499
    /* 2^result = something to do with output waiting.
500
     * perhaps matters if we read > 1 frame in a pass?
501
     */
502
    skip_bits(&alac->gb, 4);
503

    
504
    skip_bits(&alac->gb, 12); /* unknown, skip 12 bits */
505

    
506
    /* the output sample size is stored soon */
507
    hassize = get_bits1(&alac->gb);
508

    
509
    alac->wasted_bits = get_bits(&alac->gb, 2) << 3;
510

    
511
    /* whether the frame is compressed */
512
    isnotcompressed = get_bits1(&alac->gb);
513

    
514
    if (hassize) {
515
        /* now read the number of samples as a 32bit integer */
516
        outputsamples = get_bits_long(&alac->gb, 32);
517
        if(outputsamples > alac->setinfo_max_samples_per_frame){
518
            av_log(avctx, AV_LOG_ERROR, "outputsamples %d > %d\n", outputsamples, alac->setinfo_max_samples_per_frame);
519
            return -1;
520
        }
521
    } else
522
        outputsamples = alac->setinfo_max_samples_per_frame;
523

    
524
    switch (alac->setinfo_sample_size) {
525
    case 16: avctx->sample_fmt    = SAMPLE_FMT_S16;
526
             alac->bytespersample = channels << 1;
527
             break;
528
    case 24: avctx->sample_fmt    = SAMPLE_FMT_S32;
529
             alac->bytespersample = channels << 2;
530
             break;
531
    default: av_log(avctx, AV_LOG_ERROR, "Sample depth %d is not supported.\n",
532
                    alac->setinfo_sample_size);
533
             return -1;
534
    }
535

    
536
    if(outputsamples > *outputsize / alac->bytespersample){
537
        av_log(avctx, AV_LOG_ERROR, "sample buffer too small\n");
538
        return -1;
539
    }
540

    
541
    *outputsize = outputsamples * alac->bytespersample;
542
    readsamplesize = alac->setinfo_sample_size - (alac->wasted_bits) + channels - 1;
543
    if (readsamplesize > MIN_CACHE_BITS) {
544
        av_log(avctx, AV_LOG_ERROR, "readsamplesize too big (%d)\n", readsamplesize);
545
        return -1;
546
    }
547

    
548
    if (!isnotcompressed) {
549
        /* so it is compressed */
550
        int16_t predictor_coef_table[channels][32];
551
        int predictor_coef_num[channels];
552
        int prediction_type[channels];
553
        int prediction_quantitization[channels];
554
        int ricemodifier[channels];
555
        int i, chan;
556

    
557
        interlacing_shift = get_bits(&alac->gb, 8);
558
        interlacing_leftweight = get_bits(&alac->gb, 8);
559

    
560
        for (chan = 0; chan < channels; chan++) {
561
            prediction_type[chan] = get_bits(&alac->gb, 4);
562
            prediction_quantitization[chan] = get_bits(&alac->gb, 4);
563

    
564
            ricemodifier[chan] = get_bits(&alac->gb, 3);
565
            predictor_coef_num[chan] = get_bits(&alac->gb, 5);
566

    
567
            /* read the predictor table */
568
            for (i = 0; i < predictor_coef_num[chan]; i++)
569
                predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
570
        }
571

    
572
        if (alac->wasted_bits) {
573
            int i, ch;
574
            for (i = 0; i < outputsamples; i++) {
575
                for (ch = 0; ch < channels; ch++)
576
                    alac->wasted_bits_buffer[ch][i] = get_bits(&alac->gb, alac->wasted_bits);
577
            }
578
        }
579
        for (chan = 0; chan < channels; chan++) {
580
            bastardized_rice_decompress(alac,
581
                                        alac->predicterror_buffer[chan],
582
                                        outputsamples,
583
                                        readsamplesize,
584
                                        alac->setinfo_rice_initialhistory,
585
                                        alac->setinfo_rice_kmodifier,
586
                                        ricemodifier[chan] * alac->setinfo_rice_historymult / 4,
587
                                        (1 << alac->setinfo_rice_kmodifier) - 1);
588

    
589
            if (prediction_type[chan] == 0) {
590
                /* adaptive fir */
591
                predictor_decompress_fir_adapt(alac->predicterror_buffer[chan],
592
                                               alac->outputsamples_buffer[chan],
593
                                               outputsamples,
594
                                               readsamplesize,
595
                                               predictor_coef_table[chan],
596
                                               predictor_coef_num[chan],
597
                                               prediction_quantitization[chan]);
598
            } else {
599
                av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[chan]);
600
                /* I think the only other prediction type (or perhaps this is
601
                 * just a boolean?) runs adaptive fir twice.. like:
602
                 * predictor_decompress_fir_adapt(predictor_error, tempout, ...)
603
                 * predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
604
                 * little strange..
605
                 */
606
            }
607
        }
608
    } else {
609
        /* not compressed, easy case */
610
        int i, chan;
611
        if (alac->setinfo_sample_size <= 16) {
612
        for (i = 0; i < outputsamples; i++)
613
            for (chan = 0; chan < channels; chan++) {
614
                int32_t audiobits;
615

    
616
                audiobits = get_sbits_long(&alac->gb, alac->setinfo_sample_size);
617

    
618
                alac->outputsamples_buffer[chan][i] = audiobits;
619
            }
620
        } else {
621
            for (i = 0; i < outputsamples; i++) {
622
                for (chan = 0; chan < channels; chan++) {
623
                    alac->outputsamples_buffer[chan][i] = get_bits(&alac->gb,
624
                                                          alac->setinfo_sample_size);
625
                    alac->outputsamples_buffer[chan][i] = sign_extend(alac->outputsamples_buffer[chan][i],
626
                                                                      alac->setinfo_sample_size);
627
                }
628
            }
629
        }
630
        alac->wasted_bits = 0;
631
        interlacing_shift = 0;
632
        interlacing_leftweight = 0;
633
    }
634
    if (get_bits(&alac->gb, 3) != 7)
635
        av_log(avctx, AV_LOG_ERROR, "Error : Wrong End Of Frame\n");
636

    
637
    switch(alac->setinfo_sample_size) {
638
    case 16:
639
        if (channels == 2) {
640
            reconstruct_stereo_16(alac->outputsamples_buffer,
641
                                  (int16_t*)outbuffer,
642
                                  alac->numchannels,
643
                                  outputsamples,
644
                                  interlacing_shift,
645
                                  interlacing_leftweight);
646
        } else {
647
            int i;
648
            for (i = 0; i < outputsamples; i++) {
649
                ((int16_t*)outbuffer)[i] = alac->outputsamples_buffer[0][i];
650
            }
651
        }
652
        break;
653
    case 24:
654
        if (channels == 2) {
655
            decorrelate_stereo_24(alac->outputsamples_buffer,
656
                                  outbuffer,
657
                                  alac->wasted_bits_buffer,
658
                                  alac->wasted_bits,
659
                                  alac->numchannels,
660
                                  outputsamples,
661
                                  interlacing_shift,
662
                                  interlacing_leftweight);
663
        } else {
664
            int i;
665
            for (i = 0; i < outputsamples; i++)
666
                ((int32_t *)outbuffer)[i] = alac->outputsamples_buffer[0][i] << 8;
667
        }
668
        break;
669
    }
670

    
671
    if (input_buffer_size * 8 - get_bits_count(&alac->gb) > 8)
672
        av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n", input_buffer_size * 8 - get_bits_count(&alac->gb));
673

    
674
    return input_buffer_size;
675
}
676

    
677
static av_cold int alac_decode_init(AVCodecContext * avctx)
678
{
679
    ALACContext *alac = avctx->priv_data;
680
    alac->avctx = avctx;
681
    alac->context_initialized = 0;
682

    
683
    alac->numchannels = alac->avctx->channels;
684

    
685
    return 0;
686
}
687

    
688
static av_cold int alac_decode_close(AVCodecContext *avctx)
689
{
690
    ALACContext *alac = avctx->priv_data;
691

    
692
    int chan;
693
    for (chan = 0; chan < MAX_CHANNELS; chan++) {
694
        av_freep(&alac->predicterror_buffer[chan]);
695
        av_freep(&alac->outputsamples_buffer[chan]);
696
        av_freep(&alac->wasted_bits_buffer[chan]);
697
    }
698

    
699
    return 0;
700
}
701

    
702
AVCodec alac_decoder = {
703
    "alac",
704
    CODEC_TYPE_AUDIO,
705
    CODEC_ID_ALAC,
706
    sizeof(ALACContext),
707
    alac_decode_init,
708
    NULL,
709
    alac_decode_close,
710
    alac_decode_frame,
711
    .long_name = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
712
};