aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/alac.c
blob: 538d1e5984e4e1537e06286b25cebf431462a4c2 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
/*
 * ALAC (Apple Lossless Audio Codec) decoder
 * Copyright (c) 2005 David Hammerton
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * ALAC (Apple Lossless Audio Codec) decoder
 * @author 2005 David Hammerton
 * @see http://crazney.net/programs/itunes/alac.html
 *
 * Note: This decoder expects a 36-byte QuickTime atom to be
 * passed through the extradata[_size] fields. This atom is tacked onto
 * the end of an 'alac' stsd atom and has the following format:
 *
 * 32 bits  atom size
 * 32 bits  tag                  ("alac")
 * 32 bits  tag version          (0)
 * 32 bits  samples per frame    (used when not set explicitly in the frames)
 *  8 bits  compatible version   (0)
 *  8 bits  sample size
 *  8 bits  history mult         (40)
 *  8 bits  initial history      (10)
 *  8 bits  rice param limit     (14)
 *  8 bits  channels
 * 16 bits  maxRun               (255)
 * 32 bits  max coded frame size (0 means unknown)
 * 32 bits  average bitrate      (0 means unknown)
 * 32 bits  samplerate
 */

#include <inttypes.h>

#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "get_bits.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "thread.h"
#include "unary.h"
#include "mathops.h"
#include "alac_data.h"
#include "alacdsp.h"

#define ALAC_EXTRADATA_SIZE 36

typedef struct ALACContext {
    AVClass *class;
    AVCodecContext *avctx;
    GetBitContext gb;
    int channels;

    int32_t *predict_error_buffer[2];
    int32_t *output_samples_buffer[2];
    int32_t *extra_bits_buffer[2];

    uint32_t max_samples_per_frame;
    uint8_t  sample_size;
    uint8_t  rice_history_mult;
    uint8_t  rice_initial_history;
    uint8_t  rice_limit;
    int      sample_rate;

    int extra_bits;     /**< number of extra bits beyond 16-bit */
    int nb_samples;     /**< number of samples in the current frame */

    int direct_output;
    int extra_bit_bug;

    ALACDSPContext dsp;
} ALACContext;

static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
{
    unsigned int x = get_unary_0_9(gb);

    if (x > 8) { /* RICE THRESHOLD */
        /* use alternative encoding */
        x = get_bits_long(gb, bps);
    } else if (k != 1) {
        int extrabits = show_bits(gb, k);

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

        if (extrabits > 1) {
            x += extrabits - 1;
            skip_bits(gb, k);
        } else
            skip_bits(gb, k - 1);
    }
    return x;
}

static int rice_decompress(ALACContext *alac, int32_t *output_buffer,
                            int nb_samples, int bps, int rice_history_mult)
{
    GetBitContext *gb = &alac->gb;
    int i;
    unsigned int history = alac->rice_initial_history;
    int sign_modifier = 0;

    for (i = 0; i < nb_samples; i++) {
        int k;
        unsigned int x;

        if (get_bits_left(gb) <= 0)
            return AVERROR_INVALIDDATA;

        /* calculate rice param and decode next value */
        k = av_log2((history >> 9) + 3);
        k = FFMIN(k, alac->rice_limit);
        x = decode_scalar(gb, k, bps);
        x += sign_modifier;
        sign_modifier = 0;
        output_buffer[i] = (x >> 1) ^ -(x & 1);

        /* update the history */
        if (x > 0xffff)
            history = 0xffff;
        else
            history +=         x * rice_history_mult -
                       ((history * rice_history_mult) >> 9);

        /* special case: there may be compressed blocks of 0 */
        if ((history < 128) && (i + 1 < nb_samples)) {
            int block_size;

            /* calculate rice param and decode block size */
            k = 7 - av_log2(history) + ((history + 16) >> 6);
            k = FFMIN(k, alac->rice_limit);
            block_size = decode_scalar(gb, k, 16);

            if (block_size > 0) {
                if (block_size >= nb_samples - i) {
                    av_log(alac->avctx, AV_LOG_ERROR,
                           "invalid zero block size of %d %d %d\n", block_size,
                           nb_samples, i);
                    block_size = nb_samples - i - 1;
                }
                memset(&output_buffer[i + 1], 0,
                       block_size * sizeof(*output_buffer));
                i += block_size;
            }
            if (block_size <= 0xffff)
                sign_modifier = 1;
            history = 0;
        }
    }
    return 0;
}

static inline int sign_only(int v)
{
    return FFDIFFSIGN(v, 0);
}

static void lpc_prediction(int32_t *error_buffer, uint32_t *buffer_out,
                           int nb_samples, int bps, int16_t *lpc_coefs,
                           int lpc_order, int lpc_quant)
{
    int i;
    uint32_t *pred = buffer_out;

    /* first sample always copies */
    *buffer_out = *error_buffer;

    if (nb_samples <= 1)
        return;

    if (!lpc_order) {
        memcpy(&buffer_out[1], &error_buffer[1],
               (nb_samples - 1) * sizeof(*buffer_out));
        return;
    }

    if (lpc_order == 31) {
        /* simple 1st-order prediction */
        for (i = 1; i < nb_samples; i++) {
            buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
                                        bps);
        }
        return;
    }

    /* read warm-up samples */
    for (i = 1; i <= lpc_order && i < nb_samples; i++)
        buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);

    /* NOTE: 4 and 8 are very common cases that could be optimized. */

    for (; i < nb_samples; i++) {
        int j;
        int val = 0;
        unsigned error_val = error_buffer[i];
        int error_sign;
        int d = *pred++;

        /* LPC prediction */
        for (j = 0; j < lpc_order; j++)
            val += (pred[j] - d) * lpc_coefs[j];
        val = (val + (1LL << (lpc_quant - 1))) >> lpc_quant;
        val += d + error_val;
        buffer_out[i] = sign_extend(val, bps);

        /* adapt LPC coefficients */
        error_sign = sign_only(error_val);
        if (error_sign) {
            for (j = 0; j < lpc_order && (int)(error_val * error_sign) > 0; j++) {
                int sign;
                val  = d - pred[j];
                sign = sign_only(val) * error_sign;
                lpc_coefs[j] -= sign;
                val *= (unsigned)sign;
                error_val -= (val >> lpc_quant) * (j + 1U);
            }
        }
    }
}

static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
                          int channels)
{
    ALACContext *alac = avctx->priv_data;
    int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
    GetBitContext *gb = &alac->gb;
    uint32_t output_samples;
    int i, ch;

    skip_bits(gb, 4);  /* element instance tag */
    skip_bits(gb, 12); /* unused header bits */

    /* the number of output samples is stored in the frame */
    has_size = get_bits1(gb);

    alac->extra_bits = get_bits(gb, 2) << 3;
    bps = alac->sample_size - alac->extra_bits + channels - 1;
    if (bps > 32) {
        avpriv_report_missing_feature(avctx, "bps %d", bps);
        return AVERROR_PATCHWELCOME;
    }
    if (bps < 1)
        return AVERROR_INVALIDDATA;

    /* whether the frame is compressed */
    is_compressed = !get_bits1(gb);

    if (has_size)
        output_samples = get_bits_long(gb, 32);
    else
        output_samples = alac->max_samples_per_frame;
    if (!output_samples || output_samples > alac->max_samples_per_frame) {
        av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %"PRIu32"\n",
               output_samples);
        return AVERROR_INVALIDDATA;
    }
    if (!alac->nb_samples) {
        /* get output buffer */
        frame->nb_samples = output_samples;
        if ((ret = ff_thread_get_buffer(avctx, frame, 0)) < 0)
            return ret;
    } else if (output_samples != alac->nb_samples) {
        av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %"PRIu32" != %d\n",
               output_samples, alac->nb_samples);
        return AVERROR_INVALIDDATA;
    }
    alac->nb_samples = output_samples;
    if (alac->direct_output) {
        for (ch = 0; ch < channels; ch++)
            alac->output_samples_buffer[ch] = (int32_t *)frame->extended_data[ch_index + ch];
    }

    if (is_compressed) {
        int16_t lpc_coefs[2][32];
        int lpc_order[2];
        int prediction_type[2];
        int lpc_quant[2];
        int rice_history_mult[2];

        if (!alac->rice_limit) {
            avpriv_request_sample(alac->avctx,
                                  "Compression with rice limit 0");
            return AVERROR(ENOSYS);
        }

        decorr_shift       = get_bits(gb, 8);
        decorr_left_weight = get_bits(gb, 8);

        if (channels == 2 && decorr_left_weight && decorr_shift > 31)
            return AVERROR_INVALIDDATA;

        for (ch = 0; ch < channels; ch++) {
            prediction_type[ch]   = get_bits(gb, 4);
            lpc_quant[ch]         = get_bits(gb, 4);
            rice_history_mult[ch] = get_bits(gb, 3);
            lpc_order[ch]         = get_bits(gb, 5);

            if (lpc_order[ch] >= alac->max_samples_per_frame || !lpc_quant[ch])
                return AVERROR_INVALIDDATA;

            /* read the predictor table */
            for (i = lpc_order[ch] - 1; i >= 0; i--)
                lpc_coefs[ch][i] = get_sbits(gb, 16);
        }

        if (alac->extra_bits) {
            const int extra_bits = alac->extra_bits;
            if (get_bits_left(gb) < (int64_t)alac->nb_samples * channels * extra_bits)
                return AVERROR_INVALIDDATA;
            for (i = 0; i < alac->nb_samples; i++) {
                for (ch = 0; ch < channels; ch++)
                    alac->extra_bits_buffer[ch][i] = get_bits(gb, extra_bits);
            }
        }
        for (ch = 0; ch < channels; ch++) {
            int ret = rice_decompress(alac, alac->predict_error_buffer[ch],
                            alac->nb_samples, bps,
                            rice_history_mult[ch] * alac->rice_history_mult / 4);
            if (ret < 0)
                return ret;

            /* adaptive FIR filter */
            if (prediction_type[ch] == 15) {
                /* Prediction type 15 runs the adaptive FIR twice.
                 * The first pass uses the special-case coef_num = 31, while
                 * the second pass uses the coefs from the bitstream.
                 *
                 * However, this prediction type is not currently used by the
                 * reference encoder.
                 */
                lpc_prediction(alac->predict_error_buffer[ch],
                               alac->predict_error_buffer[ch],
                               alac->nb_samples, bps, NULL, 31, 0);
            } else if (prediction_type[ch] > 0) {
                av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
                       prediction_type[ch]);
            }
            lpc_prediction(alac->predict_error_buffer[ch],
                           alac->output_samples_buffer[ch], alac->nb_samples,
                           bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
        }
    } else {
        const int sample_size = alac->sample_size;
        /* not compressed, easy case */
        if (get_bits_left(gb) < (int64_t)alac->nb_samples * channels * sample_size)
            return AVERROR_INVALIDDATA;
        for (i = 0; i < alac->nb_samples; i++) {
            for (ch = 0; ch < channels; ch++) {
                alac->output_samples_buffer[ch][i] =
                         get_sbits_long(gb, sample_size);
            }
        }
        alac->extra_bits   = 0;
        decorr_shift       = 0;
        decorr_left_weight = 0;
    }

    if (channels == 2) {
        if (alac->extra_bits && alac->extra_bit_bug) {
            alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
                                           alac->extra_bits, channels, alac->nb_samples);
        }

        if (decorr_left_weight) {
            alac->dsp.decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
                                         decorr_shift, decorr_left_weight);
        }

        if (alac->extra_bits && !alac->extra_bit_bug) {
            alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
                                           alac->extra_bits, channels, alac->nb_samples);
        }
    } else if (alac->extra_bits) {
        alac->dsp.append_extra_bits[0](alac->output_samples_buffer, alac->extra_bits_buffer,
                                       alac->extra_bits, channels, alac->nb_samples);
    }

    switch(alac->sample_size) {
    case 16: {
        for (ch = 0; ch < channels; ch++) {
            int16_t *outbuffer = (int16_t *)frame->extended_data[ch_index + ch];
            for (i = 0; i < alac->nb_samples; i++)
                *outbuffer++ = alac->output_samples_buffer[ch][i];
        }}
        break;
    case 20: {
        for (ch = 0; ch < channels; ch++) {
            for (i = 0; i < alac->nb_samples; i++)
                alac->output_samples_buffer[ch][i] *= 1U << 12;
        }}
        break;
    case 24: {
        for (ch = 0; ch < channels; ch++) {
            for (i = 0; i < alac->nb_samples; i++)
                alac->output_samples_buffer[ch][i] *= 1U << 8;
        }}
        break;
    }

    return 0;
}

static int alac_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    ALACContext *alac = avctx->priv_data;
    enum AlacRawDataBlockType element;
    int channels;
    int ch, ret, got_end;

    if ((ret = init_get_bits8(&alac->gb, avpkt->data, avpkt->size)) < 0)
        return ret;

    got_end = 0;
    alac->nb_samples = 0;
    ch = 0;
    while (get_bits_left(&alac->gb) >= 3) {
        element = get_bits(&alac->gb, 3);
        if (element == TYPE_END) {
            got_end = 1;
            break;
        }
        if (element > TYPE_CPE && element != TYPE_LFE) {
            avpriv_report_missing_feature(avctx, "Syntax element %d", element);
            return AVERROR_PATCHWELCOME;
        }

        channels = (element == TYPE_CPE) ? 2 : 1;
        if (ch + channels > alac->channels ||
            ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels > alac->channels) {
            av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
            return AVERROR_INVALIDDATA;
        }

        ret = decode_element(avctx, frame,
                             ff_alac_channel_layout_offsets[alac->channels - 1][ch],
                             channels);
        if (ret < 0 && get_bits_left(&alac->gb))
            return ret;

        ch += channels;
    }
    if (!got_end) {
        av_log(avctx, AV_LOG_ERROR, "no end tag found. incomplete packet.\n");
        return AVERROR_INVALIDDATA;
    }

    if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
        av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
               avpkt->size * 8 - get_bits_count(&alac->gb));
    }

    if (alac->channels == ch && alac->nb_samples)
        *got_frame_ptr = 1;
    else
        av_log(avctx, AV_LOG_WARNING, "Failed to decode all channels\n");

    return avpkt->size;
}

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

    int ch;
    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
        av_freep(&alac->predict_error_buffer[ch]);
        if (!alac->direct_output)
            av_freep(&alac->output_samples_buffer[ch]);
        av_freep(&alac->extra_bits_buffer[ch]);
    }

    return 0;
}

static int allocate_buffers(ALACContext *alac)
{
    int ch;
    unsigned buf_size = alac->max_samples_per_frame * sizeof(int32_t);
    unsigned extra_buf_size = buf_size + AV_INPUT_BUFFER_PADDING_SIZE;

    for (ch = 0; ch < 2; ch++) {
        alac->predict_error_buffer[ch]  = NULL;
        alac->output_samples_buffer[ch] = NULL;
        alac->extra_bits_buffer[ch]     = NULL;
    }

    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
        if (!(alac->predict_error_buffer[ch] = av_malloc(buf_size)))
            return AVERROR(ENOMEM);

        alac->direct_output = alac->sample_size > 16;
        if (!alac->direct_output) {
            if (!(alac->output_samples_buffer[ch] = av_malloc(extra_buf_size)))
                return AVERROR(ENOMEM);
        }

        if (!(alac->extra_bits_buffer[ch] = av_malloc(extra_buf_size)))
            return AVERROR(ENOMEM);
    }
    return 0;
}

static int alac_set_info(ALACContext *alac)
{
    GetByteContext gb;

    bytestream2_init(&gb, alac->avctx->extradata,
                     alac->avctx->extradata_size);

    bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4

    alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
    if (!alac->max_samples_per_frame ||
        alac->max_samples_per_frame > 4096 * 4096) {
        av_log(alac->avctx, AV_LOG_ERROR,
               "max samples per frame invalid: %"PRIu32"\n",
               alac->max_samples_per_frame);
        return AVERROR_INVALIDDATA;
    }
    bytestream2_skipu(&gb, 1);  // compatible version
    alac->sample_size          = bytestream2_get_byteu(&gb);
    alac->rice_history_mult    = bytestream2_get_byteu(&gb);
    alac->rice_initial_history = bytestream2_get_byteu(&gb);
    alac->rice_limit           = bytestream2_get_byteu(&gb);
    alac->channels             = bytestream2_get_byteu(&gb);
    bytestream2_get_be16u(&gb); // maxRun
    bytestream2_get_be32u(&gb); // max coded frame size
    bytestream2_get_be32u(&gb); // average bitrate
    alac->sample_rate          = bytestream2_get_be32u(&gb);

    return 0;
}

static av_cold int alac_decode_init(AVCodecContext * avctx)
{
    int ret;
    ALACContext *alac = avctx->priv_data;
    alac->avctx = avctx;

    /* initialize from the extradata */
    if (alac->avctx->extradata_size < ALAC_EXTRADATA_SIZE) {
        av_log(avctx, AV_LOG_ERROR, "extradata is too small\n");
        return AVERROR_INVALIDDATA;
    }
    if ((ret = alac_set_info(alac)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "set_info failed\n");
        return ret;
    }

    switch (alac->sample_size) {
    case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
             break;
    case 20:
    case 24:
    case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
             break;
    default: avpriv_request_sample(avctx, "Sample depth %d", alac->sample_size);
             return AVERROR_PATCHWELCOME;
    }
    avctx->bits_per_raw_sample = alac->sample_size;
    avctx->sample_rate         = alac->sample_rate;

    if (alac->channels < 1) {
        av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
        if (avctx->ch_layout.nb_channels < 1)
            return AVERROR(EINVAL);
        alac->channels = avctx->ch_layout.nb_channels;
    }
    if (alac->channels > ALAC_MAX_CHANNELS) {
        avpriv_report_missing_feature(avctx, "Channel count %d",
                                      alac->channels);
        return AVERROR_PATCHWELCOME;
    }
    av_channel_layout_uninit(&avctx->ch_layout);
    avctx->ch_layout = ff_alac_ch_layouts[alac->channels - 1];

    if ((ret = allocate_buffers(alac)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");
        return ret;
    }

    ff_alacdsp_init(&alac->dsp);

    return 0;
}

static const AVOption options[] = {
    { "extra_bits_bug", "Force non-standard decoding process",
      offsetof(ALACContext, extra_bit_bug), AV_OPT_TYPE_BOOL, { .i64 = 0 },
      0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM },
    { NULL },
};

static const AVClass alac_class = {
    .class_name = "alac",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

const FFCodec ff_alac_decoder = {
    .p.name         = "alac",
    CODEC_LONG_NAME("ALAC (Apple Lossless Audio Codec)"),
    .p.type         = AVMEDIA_TYPE_AUDIO,
    .p.id           = AV_CODEC_ID_ALAC,
    .priv_data_size = sizeof(ALACContext),
    .init           = alac_decode_init,
    .close          = alac_decode_close,
    FF_CODEC_DECODE_CB(alac_decode_frame),
    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS | AV_CODEC_CAP_CHANNEL_CONF,
    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
    .p.priv_class   = &alac_class
};