GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/alac.c Lines: 227 292 77.7 %
Date: 2020-07-11 02:49:52 Branches: 132 197 67.0 %

Line Branch Exec Source
1
/*
2
 * ALAC (Apple Lossless Audio Codec) decoder
3
 * Copyright (c) 2005 David Hammerton
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
24
 * ALAC (Apple Lossless Audio Codec) decoder
25
 * @author 2005 David Hammerton
26
 * @see http://crazney.net/programs/itunes/alac.html
27
 *
28
 * Note: This decoder expects a 36-byte QuickTime atom to be
29
 * passed through the extradata[_size] fields. This atom is tacked onto
30
 * the end of an 'alac' stsd atom and has the following format:
31
 *
32
 * 32 bits  atom size
33
 * 32 bits  tag                  ("alac")
34
 * 32 bits  tag version          (0)
35
 * 32 bits  samples per frame    (used when not set explicitly in the frames)
36
 *  8 bits  compatible version   (0)
37
 *  8 bits  sample size
38
 *  8 bits  history mult         (40)
39
 *  8 bits  initial history      (10)
40
 *  8 bits  rice param limit     (14)
41
 *  8 bits  channels
42
 * 16 bits  maxRun               (255)
43
 * 32 bits  max coded frame size (0 means unknown)
44
 * 32 bits  average bitrate      (0 means unknown)
45
 * 32 bits  samplerate
46
 */
47
48
#include <inttypes.h>
49
50
#include "libavutil/channel_layout.h"
51
#include "libavutil/opt.h"
52
#include "avcodec.h"
53
#include "get_bits.h"
54
#include "bytestream.h"
55
#include "internal.h"
56
#include "thread.h"
57
#include "unary.h"
58
#include "mathops.h"
59
#include "alac_data.h"
60
#include "alacdsp.h"
61
62
#define ALAC_EXTRADATA_SIZE 36
63
64
typedef struct ALACContext {
65
    AVClass *class;
66
    AVCodecContext *avctx;
67
    GetBitContext gb;
68
    int channels;
69
70
    int32_t *predict_error_buffer[2];
71
    int32_t *output_samples_buffer[2];
72
    int32_t *extra_bits_buffer[2];
73
74
    uint32_t max_samples_per_frame;
75
    uint8_t  sample_size;
76
    uint8_t  rice_history_mult;
77
    uint8_t  rice_initial_history;
78
    uint8_t  rice_limit;
79
    int      sample_rate;
80
81
    int extra_bits;     /**< number of extra bits beyond 16-bit */
82
    int nb_samples;     /**< number of samples in the current frame */
83
84
    int direct_output;
85
    int extra_bit_bug;
86
87
    ALACDSPContext dsp;
88
} ALACContext;
89
90
16507234
static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
91
{
92
16507234
    unsigned int x = get_unary_0_9(gb);
93
94
16507234
    if (x > 8) { /* RICE THRESHOLD */
95
        /* use alternative encoding */
96
27035
        x = get_bits_long(gb, bps);
97
16480199
    } else if (k != 1) {
98
16477495
        int extrabits = show_bits(gb, k);
99
100
        /* multiply x by 2^k - 1, as part of their strange algorithm */
101
16477495
        x = (x << k) - x;
102
103
16477495
        if (extrabits > 1) {
104
14896137
            x += extrabits - 1;
105
14896137
            skip_bits(gb, k);
106
        } else
107
1581358
            skip_bits(gb, k - 1);
108
    }
109
16507234
    return x;
110
}
111
112
4074
static int rice_decompress(ALACContext *alac, int32_t *output_buffer,
113
                            int nb_samples, int bps, int rice_history_mult)
114
{
115
    int i;
116
4074
    unsigned int history = alac->rice_initial_history;
117
4074
    int sign_modifier = 0;
118
119
16511147
    for (i = 0; i < nb_samples; i++) {
120
        int k;
121
        unsigned int x;
122
123
16507073
        if(get_bits_left(&alac->gb) <= 0)
124
            return AVERROR_INVALIDDATA;
125
126
        /* calculate rice param and decode next value */
127
16507073
        k = av_log2((history >> 9) + 3);
128
16507073
        k = FFMIN(k, alac->rice_limit);
129
16507073
        x = decode_scalar(&alac->gb, k, bps);
130
16507073
        x += sign_modifier;
131
16507073
        sign_modifier = 0;
132
16507073
        output_buffer[i] = (x >> 1) ^ -(x & 1);
133
134
        /* update the history */
135
16507073
        if (x > 0xffff)
136
11363
            history = 0xffff;
137
        else
138
16495710
            history +=         x * rice_history_mult -
139
16495710
                       ((history * rice_history_mult) >> 9);
140
141
        /* special case: there may be compressed blocks of 0 */
142

16507073
        if ((history < 128) && (i + 1 < nb_samples)) {
143
            int block_size;
144
145
            /* calculate rice param and decode block size */
146
161
            k = 7 - av_log2(history) + ((history + 16) >> 6);
147
161
            k = FFMIN(k, alac->rice_limit);
148
161
            block_size = decode_scalar(&alac->gb, k, 16);
149
150
161
            if (block_size > 0) {
151
65
                if (block_size >= nb_samples - i) {
152
                    av_log(alac->avctx, AV_LOG_ERROR,
153
                           "invalid zero block size of %d %d %d\n", block_size,
154
                           nb_samples, i);
155
                    block_size = nb_samples - i - 1;
156
                }
157
65
                memset(&output_buffer[i + 1], 0,
158
                       block_size * sizeof(*output_buffer));
159
65
                i += block_size;
160
            }
161
161
            if (block_size <= 0xffff)
162
161
                sign_modifier = 1;
163
161
            history = 0;
164
        }
165
    }
166
4074
    return 0;
167
}
168
169
86321215
static inline int sign_only(int v)
170
{
171

86321215
    return v ? FFSIGN(v) : 0;
172
}
173
174
4074
static void lpc_prediction(int32_t *error_buffer, uint32_t *buffer_out,
175
                           int nb_samples, int bps, int16_t *lpc_coefs,
176
                           int lpc_order, int lpc_quant)
177
{
178
    int i;
179
4074
    uint32_t *pred = buffer_out;
180
181
    /* first sample always copies */
182
4074
    *buffer_out = *error_buffer;
183
184
4074
    if (nb_samples <= 1)
185
        return;
186
187
4074
    if (!lpc_order) {
188
        memcpy(&buffer_out[1], &error_buffer[1],
189
               (nb_samples - 1) * sizeof(*buffer_out));
190
        return;
191
    }
192
193
4074
    if (lpc_order == 31) {
194
        /* simple 1st-order prediction */
195
        for (i = 1; i < nb_samples; i++) {
196
            buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
197
                                        bps);
198
        }
199
        return;
200
    }
201
202
    /* read warm-up samples */
203

37687
    for (i = 1; i <= lpc_order && i < nb_samples; i++)
204
33613
        buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);
205
206
    /* NOTE: 4 and 8 are very common cases that could be optimized. */
207
208
16626395
    for (; i < nb_samples; i++) {
209
        int j;
210
16622321
        int val = 0;
211
16622321
        unsigned error_val = error_buffer[i];
212
        int error_sign;
213
16622321
        int d = *pred++;
214
215
        /* LPC prediction */
216
153619021
        for (j = 0; j < lpc_order; j++)
217
136996700
            val += (pred[j] - d) * lpc_coefs[j];
218
16622321
        val = (val + (1LL << (lpc_quant - 1))) >> lpc_quant;
219
16622321
        val += d + error_val;
220
16622321
        buffer_out[i] = sign_extend(val, bps);
221
222
        /* adapt LPC coefficients */
223
16622321
        error_sign = sign_only(error_val);
224
16622321
        if (error_sign) {
225

85499474
            for (j = 0; j < lpc_order && (int)(error_val * error_sign) > 0; j++) {
226
                int sign;
227
69698894
                val  = d - pred[j];
228
69698894
                sign = sign_only(val) * error_sign;
229
69698894
                lpc_coefs[j] -= sign;
230
69698894
                val *= (unsigned)sign;
231
69698894
                error_val -= (val >> lpc_quant) * (j + 1U);
232
            }
233
        }
234
    }
235
}
236
237
2609
static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
238
                          int channels)
239
{
240
2609
    ALACContext *alac = avctx->priv_data;
241
    int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
242
    uint32_t output_samples;
243
    int i, ch;
244
245
2609
    skip_bits(&alac->gb, 4);  /* element instance tag */
246
2609
    skip_bits(&alac->gb, 12); /* unused header bits */
247
248
    /* the number of output samples is stored in the frame */
249
2609
    has_size = get_bits1(&alac->gb);
250
251
2609
    alac->extra_bits = get_bits(&alac->gb, 2) << 3;
252
2609
    bps = alac->sample_size - alac->extra_bits + channels - 1;
253
2609
    if (bps > 32) {
254
        avpriv_report_missing_feature(avctx, "bps %d", bps);
255
        return AVERROR_PATCHWELCOME;
256
    }
257
2609
    if (bps < 1)
258
        return AVERROR_INVALIDDATA;
259
260
    /* whether the frame is compressed */
261
2609
    is_compressed = !get_bits1(&alac->gb);
262
263
2609
    if (has_size)
264
11
        output_samples = get_bits_long(&alac->gb, 32);
265
    else
266
2598
        output_samples = alac->max_samples_per_frame;
267

2609
    if (!output_samples || output_samples > alac->max_samples_per_frame) {
268
        av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %"PRIu32"\n",
269
               output_samples);
270
        return AVERROR_INVALIDDATA;
271
    }
272
2609
    if (!alac->nb_samples) {
273
2609
        ThreadFrame tframe = { .f = frame };
274
        /* get output buffer */
275
2609
        frame->nb_samples = output_samples;
276
2609
        if ((ret = ff_thread_get_buffer(avctx, &tframe, 0)) < 0)
277
            return ret;
278
    } else if (output_samples != alac->nb_samples) {
279
        av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %"PRIu32" != %d\n",
280
               output_samples, alac->nb_samples);
281
        return AVERROR_INVALIDDATA;
282
    }
283
2609
    alac->nb_samples = output_samples;
284
2609
    if (alac->direct_output) {
285
5628
        for (ch = 0; ch < channels; ch++)
286
3752
            alac->output_samples_buffer[ch] = (int32_t *)frame->extended_data[ch_index + ch];
287
    }
288
289
2609
    if (is_compressed) {
290
        int16_t lpc_coefs[2][32];
291
        int lpc_order[2];
292
        int prediction_type[2];
293
        int lpc_quant[2];
294
        int rice_history_mult[2];
295
296
2037
        if (!alac->rice_limit) {
297
            avpriv_request_sample(alac->avctx,
298
                                  "Compression with rice limit 0");
299
            return AVERROR(ENOSYS);
300
        }
301
302
2037
        decorr_shift       = get_bits(&alac->gb, 8);
303
2037
        decorr_left_weight = get_bits(&alac->gb, 8);
304
305
6111
        for (ch = 0; ch < channels; ch++) {
306
4074
            prediction_type[ch]   = get_bits(&alac->gb, 4);
307
4074
            lpc_quant[ch]         = get_bits(&alac->gb, 4);
308
4074
            rice_history_mult[ch] = get_bits(&alac->gb, 3);
309
4074
            lpc_order[ch]         = get_bits(&alac->gb, 5);
310
311

4074
            if (lpc_order[ch] >= alac->max_samples_per_frame || !lpc_quant[ch])
312
                return AVERROR_INVALIDDATA;
313
314
            /* read the predictor table */
315
37687
            for (i = lpc_order[ch] - 1; i >= 0; i--)
316
33613
                lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);
317
        }
318
319
2037
        if (alac->extra_bits) {
320
5761407
            for (i = 0; i < alac->nb_samples; i++) {
321
5760000
                if(get_bits_left(&alac->gb) <= 0)
322
                    return AVERROR_INVALIDDATA;
323
17280000
                for (ch = 0; ch < channels; ch++)
324
11520000
                    alac->extra_bits_buffer[ch][i] = get_bits(&alac->gb, alac->extra_bits);
325
            }
326
        }
327
6111
        for (ch = 0; ch < channels; ch++) {
328
4074
            int ret=rice_decompress(alac, alac->predict_error_buffer[ch],
329
                            alac->nb_samples, bps,
330
4074
                            rice_history_mult[ch] * alac->rice_history_mult / 4);
331
4074
            if(ret<0)
332
                return ret;
333
334
            /* adaptive FIR filter */
335
4074
            if (prediction_type[ch] == 15) {
336
                /* Prediction type 15 runs the adaptive FIR twice.
337
                 * The first pass uses the special-case coef_num = 31, while
338
                 * the second pass uses the coefs from the bitstream.
339
                 *
340
                 * However, this prediction type is not currently used by the
341
                 * reference encoder.
342
                 */
343
                lpc_prediction(alac->predict_error_buffer[ch],
344
                               alac->predict_error_buffer[ch],
345
                               alac->nb_samples, bps, NULL, 31, 0);
346
4074
            } else if (prediction_type[ch] > 0) {
347
                av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
348
                       prediction_type[ch]);
349
            }
350
4074
            lpc_prediction(alac->predict_error_buffer[ch],
351
4074
                           alac->output_samples_buffer[ch], alac->nb_samples,
352
4074
                           bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
353
        }
354
    } else {
355
        /* not compressed, easy case */
356
2339522
        for (i = 0; i < alac->nb_samples; i++) {
357
2338950
            if(get_bits_left(&alac->gb) <= 0)
358
                return AVERROR_INVALIDDATA;
359
7016850
            for (ch = 0; ch < channels; ch++) {
360
4677900
                alac->output_samples_buffer[ch][i] =
361
4677900
                         get_sbits_long(&alac->gb, alac->sample_size);
362
            }
363
        }
364
572
        alac->extra_bits   = 0;
365
572
        decorr_shift       = 0;
366
572
        decorr_left_weight = 0;
367
    }
368
369
2609
    if (channels == 2) {
370

2609
        if (alac->extra_bits && alac->extra_bit_bug) {
371
            alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
372
                                           alac->extra_bits, channels, alac->nb_samples);
373
        }
374
375
2609
        if (decorr_left_weight) {
376
596
            alac->dsp.decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
377
                                         decorr_shift, decorr_left_weight);
378
        }
379
380

2609
        if (alac->extra_bits && !alac->extra_bit_bug) {
381
1407
            alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
382
                                           alac->extra_bits, channels, alac->nb_samples);
383
        }
384
    } else if (alac->extra_bits) {
385
        alac->dsp.append_extra_bits[0](alac->output_samples_buffer, alac->extra_bits_buffer,
386
                                       alac->extra_bits, channels, alac->nb_samples);
387
    }
388
389

2609
    switch(alac->sample_size) {
390
733
    case 16: {
391
2199
        for (ch = 0; ch < channels; ch++) {
392
1466
            int16_t *outbuffer = (int16_t *)frame->extended_data[ch_index + ch];
393
5979374
            for (i = 0; i < alac->nb_samples; i++)
394
5977908
                *outbuffer++ = alac->output_samples_buffer[ch][i];
395
        }}
396
733
        break;
397
    case 20: {
398
        for (ch = 0; ch < channels; ch++) {
399
            for (i = 0; i < alac->nb_samples; i++)
400
                alac->output_samples_buffer[ch][i] *= 1U << 12;
401
        }}
402
        break;
403
1876
    case 24: {
404
5628
        for (ch = 0; ch < channels; ch++) {
405
15363752
            for (i = 0; i < alac->nb_samples; i++)
406
15360000
                alac->output_samples_buffer[ch][i] *= 1U << 8;
407
        }}
408
1876
        break;
409
    }
410
411
2609
    return 0;
412
}
413
414
2609
static int alac_decode_frame(AVCodecContext *avctx, void *data,
415
                             int *got_frame_ptr, AVPacket *avpkt)
416
{
417
2609
    ALACContext *alac = avctx->priv_data;
418
2609
    AVFrame *frame    = data;
419
    enum AlacRawDataBlockType element;
420
    int channels;
421
    int ch, ret, got_end;
422
423
2609
    if ((ret = init_get_bits8(&alac->gb, avpkt->data, avpkt->size)) < 0)
424
        return ret;
425
426
2609
    got_end = 0;
427
2609
    alac->nb_samples = 0;
428
2609
    ch = 0;
429
5218
    while (get_bits_left(&alac->gb) >= 3) {
430
5218
        element = get_bits(&alac->gb, 3);
431
5218
        if (element == TYPE_END) {
432
2609
            got_end = 1;
433
2609
            break;
434
        }
435

2609
        if (element > TYPE_CPE && element != TYPE_LFE) {
436
            avpriv_report_missing_feature(avctx, "Syntax element %d", element);
437
            return AVERROR_PATCHWELCOME;
438
        }
439
440
2609
        channels = (element == TYPE_CPE) ? 2 : 1;
441
2609
        if (ch + channels > alac->channels ||
442
2609
            ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels > alac->channels) {
443
            av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
444
            return AVERROR_INVALIDDATA;
445
        }
446
447
2609
        ret = decode_element(avctx, frame,
448
2609
                             ff_alac_channel_layout_offsets[alac->channels - 1][ch],
449
                             channels);
450

2609
        if (ret < 0 && get_bits_left(&alac->gb))
451
            return ret;
452
453
2609
        ch += channels;
454
    }
455
2609
    if (!got_end) {
456
        av_log(avctx, AV_LOG_ERROR, "no end tag found. incomplete packet.\n");
457
        return AVERROR_INVALIDDATA;
458
    }
459
460
2609
    if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
461
        av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
462
               avpkt->size * 8 - get_bits_count(&alac->gb));
463
    }
464
465

2609
    if (alac->channels == ch && alac->nb_samples)
466
2609
        *got_frame_ptr = 1;
467
    else
468
        av_log(avctx, AV_LOG_WARNING, "Failed to decode all channels\n");
469
470
2609
    return avpkt->size;
471
}
472
473
25
static av_cold int alac_decode_close(AVCodecContext *avctx)
474
{
475
25
    ALACContext *alac = avctx->priv_data;
476
477
    int ch;
478
75
    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
479
50
        av_freep(&alac->predict_error_buffer[ch]);
480
50
        if (!alac->direct_output)
481
34
            av_freep(&alac->output_samples_buffer[ch]);
482
50
        av_freep(&alac->extra_bits_buffer[ch]);
483
    }
484
485
25
    return 0;
486
}
487
488
25
static int allocate_buffers(ALACContext *alac)
489
{
490
    int ch;
491
25
    unsigned buf_size = alac->max_samples_per_frame * sizeof(int32_t);
492
25
    unsigned extra_buf_size = buf_size + AV_INPUT_BUFFER_PADDING_SIZE;
493
494
75
    for (ch = 0; ch < 2; ch++) {
495
50
        alac->predict_error_buffer[ch]  = NULL;
496
50
        alac->output_samples_buffer[ch] = NULL;
497
50
        alac->extra_bits_buffer[ch]     = NULL;
498
    }
499
500
75
    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
501
50
        if (!(alac->predict_error_buffer[ch] = av_malloc(buf_size)))
502
            return AVERROR(ENOMEM);
503
504
50
        alac->direct_output = alac->sample_size > 16;
505
50
        if (!alac->direct_output) {
506
34
            if (!(alac->output_samples_buffer[ch] = av_malloc(extra_buf_size)))
507
                return AVERROR(ENOMEM);
508
        }
509
510
50
        if (!(alac->extra_bits_buffer[ch] = av_malloc(extra_buf_size)))
511
            return AVERROR(ENOMEM);
512
    }
513
25
    return 0;
514
}
515
516
25
static int alac_set_info(ALACContext *alac)
517
{
518
    GetByteContext gb;
519
520
25
    bytestream2_init(&gb, alac->avctx->extradata,
521
25
                     alac->avctx->extradata_size);
522
523
25
    bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
524
525
25
    alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
526
25
    if (!alac->max_samples_per_frame ||
527
25
        alac->max_samples_per_frame > 4096 * 4096) {
528
        av_log(alac->avctx, AV_LOG_ERROR,
529
               "max samples per frame invalid: %"PRIu32"\n",
530
               alac->max_samples_per_frame);
531
        return AVERROR_INVALIDDATA;
532
    }
533
25
    bytestream2_skipu(&gb, 1);  // compatible version
534
25
    alac->sample_size          = bytestream2_get_byteu(&gb);
535
25
    alac->rice_history_mult    = bytestream2_get_byteu(&gb);
536
25
    alac->rice_initial_history = bytestream2_get_byteu(&gb);
537
25
    alac->rice_limit           = bytestream2_get_byteu(&gb);
538
25
    alac->channels             = bytestream2_get_byteu(&gb);
539
25
    bytestream2_get_be16u(&gb); // maxRun
540
25
    bytestream2_get_be32u(&gb); // max coded frame size
541
25
    bytestream2_get_be32u(&gb); // average bitrate
542
25
    alac->sample_rate          = bytestream2_get_be32u(&gb);
543
544
25
    return 0;
545
}
546
547
25
static av_cold int alac_decode_init(AVCodecContext * avctx)
548
{
549
    int ret;
550
25
    ALACContext *alac = avctx->priv_data;
551
25
    alac->avctx = avctx;
552
553
    /* initialize from the extradata */
554
25
    if (alac->avctx->extradata_size < ALAC_EXTRADATA_SIZE) {
555
        av_log(avctx, AV_LOG_ERROR, "extradata is too small\n");
556
        return AVERROR_INVALIDDATA;
557
    }
558
25
    if ((ret = alac_set_info(alac)) < 0) {
559
        av_log(avctx, AV_LOG_ERROR, "set_info failed\n");
560
        return ret;
561
    }
562
563
25
    switch (alac->sample_size) {
564
17
    case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
565
17
             break;
566
8
    case 20:
567
    case 24:
568
8
    case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
569
8
             break;
570
    default: avpriv_request_sample(avctx, "Sample depth %d", alac->sample_size);
571
             return AVERROR_PATCHWELCOME;
572
    }
573
25
    avctx->bits_per_raw_sample = alac->sample_size;
574
25
    avctx->sample_rate         = alac->sample_rate;
575
576
25
    if (alac->channels < 1) {
577
        av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
578
        alac->channels = avctx->channels;
579
    } else {
580
25
        if (alac->channels > ALAC_MAX_CHANNELS)
581
            alac->channels = avctx->channels;
582
        else
583
25
            avctx->channels = alac->channels;
584
    }
585

25
    if (avctx->channels > ALAC_MAX_CHANNELS || avctx->channels <= 0 ) {
586
        avpriv_report_missing_feature(avctx, "Channel count %d",
587
                                      avctx->channels);
588
        return AVERROR_PATCHWELCOME;
589
    }
590
25
    avctx->channel_layout = ff_alac_channel_layouts[alac->channels - 1];
591
592
25
    if ((ret = allocate_buffers(alac)) < 0) {
593
        av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");
594
        return ret;
595
    }
596
597
25
    ff_alacdsp_init(&alac->dsp);
598
599
25
    return 0;
600
}
601
602
static const AVOption options[] = {
603
    { "extra_bits_bug", "Force non-standard decoding process",
604
      offsetof(ALACContext, extra_bit_bug), AV_OPT_TYPE_BOOL, { .i64 = 0 },
605
      0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM },
606
    { NULL },
607
};
608
609
static const AVClass alac_class = {
610
    .class_name = "alac",
611
    .item_name  = av_default_item_name,
612
    .option     = options,
613
    .version    = LIBAVUTIL_VERSION_INT,
614
};
615
616
AVCodec ff_alac_decoder = {
617
    .name           = "alac",
618
    .long_name      = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
619
    .type           = AVMEDIA_TYPE_AUDIO,
620
    .id             = AV_CODEC_ID_ALAC,
621
    .priv_data_size = sizeof(ALACContext),
622
    .init           = alac_decode_init,
623
    .close          = alac_decode_close,
624
    .decode         = alac_decode_frame,
625
    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
626
    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
627
    .priv_class     = &alac_class
628
};