Remove reimplementation of av_log2
[libav.git] / libavcodec / alac.c
CommitLineData
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1/*
2 * ALAC (Apple Lossless Audio Codec) decoder
3 * Copyright (c) 2005 David Hammerton
6d6d7970 4 *
b78e7197
DB
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
6d6d7970
MM
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
b78e7197 10 * version 2.1 of the License, or (at your option) any later version.
6d6d7970 11 *
b78e7197 12 * FFmpeg is distributed in the hope that it will be useful,
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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
b78e7197 18 * License along with FFmpeg; if not, write to the Free Software
5509bffa 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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MM
20 */
21
22/**
23 * @file alac.c
24 * ALAC (Apple Lossless Audio Codec) decoder
25 * @author 2005 David Hammerton
26 *
27 * For more information on the ALAC format, visit:
28 * http://crazney.net/programs/itunes/alac.html
29 *
30 * Note: This decoder expects a 36- (0x24-)byte QuickTime atom to be
31 * passed through the extradata[_size] fields. This atom is tacked onto
32 * the end of an 'alac' stsd atom and has the following format:
33 * bytes 0-3 atom size (0x24), big-endian
34 * bytes 4-7 atom type ('alac', not the 'alac' tag from start of stsd)
35 * bytes 8-35 data bytes needed by decoder
a1db1fc4
AB
36 *
37 * Extradata:
38 * 32bit size
39 * 32bit tag (=alac)
40 * 32bit zero?
41 * 32bit max sample per frame
42 * 8bit ?? (zero?)
43 * 8bit sample size
44 * 8bit history mult
45 * 8bit initial history
46 * 8bit kmodifier
47 * 8bit channels?
48 * 16bit ??
49 * 32bit max coded frame size
50 * 32bit bitrate?
51 * 32bit samplerate
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MM
52 */
53
54
55#include "avcodec.h"
6d021b00 56#include "bitstream.h"
f79488d4 57#include "bytestream.h"
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58
59#define ALAC_EXTRADATA_SIZE 36
153696a6 60#define MAX_CHANNELS 2
6d6d7970 61
6d021b00
MM
62typedef struct {
63
64 AVCodecContext *avctx;
65 GetBitContext gb;
66 /* init to 0; first frame decode should initialize from extradata and
67 * set this to 1 */
68 int context_initialized;
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69
70 int samplesize;
71 int numchannels;
72 int bytespersample;
73
6d6d7970 74 /* buffers */
153696a6 75 int32_t *predicterror_buffer[MAX_CHANNELS];
6d6d7970 76
153696a6 77 int32_t *outputsamples_buffer[MAX_CHANNELS];
6d6d7970 78
6d6d7970
MM
79 /* stuff from setinfo */
80 uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */ /* max samples per frame? */
81 uint8_t setinfo_7a; /* 0x00 */
82 uint8_t setinfo_sample_size; /* 0x10 */
83 uint8_t setinfo_rice_historymult; /* 0x28 */
84 uint8_t setinfo_rice_initialhistory; /* 0x0a */
85 uint8_t setinfo_rice_kmodifier; /* 0x0e */
86 uint8_t setinfo_7f; /* 0x02 */
87 uint16_t setinfo_80; /* 0x00ff */
5b154bd5
VS
88 uint32_t setinfo_82; /* 0x000020e7 */ /* max sample size?? */
89 uint32_t setinfo_86; /* 0x00069fe4 */ /* bit rate (average)?? */
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90 uint32_t setinfo_8a_rate; /* 0x0000ac44 */
91 /* end setinfo stuff */
6d6d7970 92
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93} ALACContext;
94
6d021b00 95static void allocate_buffers(ALACContext *alac)
6d6d7970 96{
153696a6
VS
97 int chan;
98 for (chan = 0; chan < MAX_CHANNELS; chan++) {
99 alac->predicterror_buffer[chan] =
100 av_malloc(alac->setinfo_max_samples_per_frame * 4);
6d6d7970 101
153696a6
VS
102 alac->outputsamples_buffer[chan] =
103 av_malloc(alac->setinfo_max_samples_per_frame * 4);
104 }
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MM
105}
106
3a1a7e32 107static int alac_set_info(ALACContext *alac)
6d6d7970 108{
6d021b00 109 unsigned char *ptr = alac->avctx->extradata;
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MM
110
111 ptr += 4; /* size */
112 ptr += 4; /* alac */
113 ptr += 4; /* 0 ? */
114
fead30d4 115 if(AV_RB32(ptr) >= UINT_MAX/4){
3a1a7e32
MN
116 av_log(alac->avctx, AV_LOG_ERROR, "setinfo_max_samples_per_frame too large\n");
117 return -1;
118 }
f79488d4
VS
119
120 /* buffer size / 2 ? */
121 alac->setinfo_max_samples_per_frame = bytestream_get_be32(&ptr);
a1301f29
VS
122 alac->setinfo_7a = *ptr++;
123 alac->setinfo_sample_size = *ptr++;
124 alac->setinfo_rice_historymult = *ptr++;
125 alac->setinfo_rice_initialhistory = *ptr++;
126 alac->setinfo_rice_kmodifier = *ptr++;
127 /* channels? */
128 alac->setinfo_7f = *ptr++;
f79488d4
VS
129 alac->setinfo_80 = bytestream_get_be16(&ptr);
130 /* max coded frame size */
131 alac->setinfo_82 = bytestream_get_be32(&ptr);
132 /* bitrate ? */
133 alac->setinfo_86 = bytestream_get_be32(&ptr);
134 /* samplerate */
135 alac->setinfo_8a_rate = bytestream_get_be32(&ptr);
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MM
136
137 allocate_buffers(alac);
3a1a7e32
MN
138
139 return 0;
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140}
141
d0da8020 142static inline int count_leading_zeros(int32_t input)
6d6d7970 143{
d0da8020 144 return 31-av_log2(input);
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MM
145}
146
1b47fafd 147static void bastardized_rice_decompress(ALACContext *alac,
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148 int32_t *output_buffer,
149 int output_size,
150 int readsamplesize, /* arg_10 */
151 int rice_initialhistory, /* arg424->b */
152 int rice_kmodifier, /* arg424->d */
153 int rice_historymult, /* arg424->c */
154 int rice_kmodifier_mask /* arg424->e */
155 )
156{
157 int output_count;
158 unsigned int history = rice_initialhistory;
159 int sign_modifier = 0;
160
161 for (output_count = 0; output_count < output_size; output_count++) {
162 int32_t x = 0;
163 int32_t x_modified;
164 int32_t final_val;
165
166 /* read x - number of 1s before 0 represent the rice */
6d021b00 167 while (x <= 8 && get_bits1(&alac->gb)) {
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MM
168 x++;
169 }
170
171
172 if (x > 8) { /* RICE THRESHOLD */
173 /* use alternative encoding */
174 int32_t value;
175
6d021b00 176 value = get_bits(&alac->gb, readsamplesize);
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MM
177
178 /* mask value to readsamplesize size */
179 if (readsamplesize != 32)
180 value &= (0xffffffff >> (32 - readsamplesize));
181
182 x = value;
183 } else {
184 /* standard rice encoding */
185 int extrabits;
186 int k; /* size of extra bits */
187
188 /* read k, that is bits as is */
189 k = 31 - rice_kmodifier - count_leading_zeros((history >> 9) + 3);
190
115329f1 191 if (k < 0)
6d6d7970 192 k += rice_kmodifier;
115329f1 193 else
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MM
194 k = rice_kmodifier;
195
196 if (k != 1) {
6d021b00 197 extrabits = show_bits(&alac->gb, k);
6d6d7970
MM
198
199 /* multiply x by 2^k - 1, as part of their strange algorithm */
200 x = (x << k) - x;
201
202 if (extrabits > 1) {
203 x += extrabits - 1;
6d021b00
MM
204 get_bits(&alac->gb, k);
205 } else {
206 get_bits(&alac->gb, k - 1);
207 }
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MM
208 }
209 }
210
211 x_modified = sign_modifier + x;
212 final_val = (x_modified + 1) / 2;
213 if (x_modified & 1) final_val *= -1;
214
215 output_buffer[output_count] = final_val;
216
217 sign_modifier = 0;
218
219 /* now update the history */
220 history += (x_modified * rice_historymult)
221 - ((history * rice_historymult) >> 9);
222
223 if (x_modified > 0xffff)
224 history = 0xffff;
225
226 /* special case: there may be compressed blocks of 0 */
227 if ((history < 128) && (output_count+1 < output_size)) {
228 int block_size;
229
230 sign_modifier = 1;
231
232 x = 0;
6d021b00 233 while (x <= 8 && get_bits1(&alac->gb)) {
6d6d7970
MM
234 x++;
235 }
236
237 if (x > 8) {
6d021b00 238 block_size = get_bits(&alac->gb, 16);
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239 block_size &= 0xffff;
240 } else {
241 int k;
242 int extrabits;
243
244 k = count_leading_zeros(history) + ((history + 16) >> 6 /* / 64 */) - 24;
245
6d021b00 246 extrabits = show_bits(&alac->gb, k);
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MM
247
248 block_size = (((1 << k) - 1) & rice_kmodifier_mask) * x
249 + extrabits - 1;
250
251 if (extrabits < 2) {
252 x = 1 - extrabits;
253 block_size += x;
6d021b00
MM
254 get_bits(&alac->gb, k - 1);
255 } else {
256 get_bits(&alac->gb, k);
6d6d7970
MM
257 }
258 }
259
260 if (block_size > 0) {
261 memset(&output_buffer[output_count+1], 0, block_size * 4);
262 output_count += block_size;
263
264 }
265
266 if (block_size > 0xffff)
267 sign_modifier = 0;
268
269 history = 0;
270 }
271 }
272}
273
274#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
275
276#define SIGN_ONLY(v) \
277 ((v < 0) ? (-1) : \
278 ((v > 0) ? (1) : \
279 (0)))
280
281static void predictor_decompress_fir_adapt(int32_t *error_buffer,
282 int32_t *buffer_out,
283 int output_size,
284 int readsamplesize,
285 int16_t *predictor_coef_table,
286 int predictor_coef_num,
287 int predictor_quantitization)
288{
289 int i;
290
291 /* first sample always copies */
292 *buffer_out = *error_buffer;
293
294 if (!predictor_coef_num) {
295 if (output_size <= 1) return;
296 memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
297 return;
298 }
299
300 if (predictor_coef_num == 0x1f) { /* 11111 - max value of predictor_coef_num */
301 /* second-best case scenario for fir decompression,
302 * error describes a small difference from the previous sample only
303 */
304 if (output_size <= 1) return;
305 for (i = 0; i < output_size - 1; i++) {
306 int32_t prev_value;
307 int32_t error_value;
308
309 prev_value = buffer_out[i];
310 error_value = error_buffer[i+1];
311 buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
312 }
313 return;
314 }
315
316 /* read warm-up samples */
317 if (predictor_coef_num > 0) {
318 int i;
319 for (i = 0; i < predictor_coef_num; i++) {
320 int32_t val;
321
322 val = buffer_out[i] + error_buffer[i+1];
323
324 val = SIGN_EXTENDED32(val, readsamplesize);
325
326 buffer_out[i+1] = val;
327 }
328 }
329
330#if 0
331 /* 4 and 8 are very common cases (the only ones i've seen). these
332 * should be unrolled and optimised
333 */
334 if (predictor_coef_num == 4) {
335 /* FIXME: optimised general case */
336 return;
337 }
338
339 if (predictor_coef_table == 8) {
340 /* FIXME: optimised general case */
341 return;
342 }
343#endif
344
345
346 /* general case */
347 if (predictor_coef_num > 0) {
348 for (i = predictor_coef_num + 1;
349 i < output_size;
350 i++) {
351 int j;
352 int sum = 0;
353 int outval;
354 int error_val = error_buffer[i];
355
356 for (j = 0; j < predictor_coef_num; j++) {
357 sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
358 predictor_coef_table[j];
359 }
360
361 outval = (1 << (predictor_quantitization-1)) + sum;
362 outval = outval >> predictor_quantitization;
363 outval = outval + buffer_out[0] + error_val;
364 outval = SIGN_EXTENDED32(outval, readsamplesize);
365
366 buffer_out[predictor_coef_num+1] = outval;
367
368 if (error_val > 0) {
369 int predictor_num = predictor_coef_num - 1;
370
371 while (predictor_num >= 0 && error_val > 0) {
372 int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
373 int sign = SIGN_ONLY(val);
374
375 predictor_coef_table[predictor_num] -= sign;
376
377 val *= sign; /* absolute value */
378
379 error_val -= ((val >> predictor_quantitization) *
380 (predictor_coef_num - predictor_num));
381
382 predictor_num--;
383 }
384 } else if (error_val < 0) {
385 int predictor_num = predictor_coef_num - 1;
386
387 while (predictor_num >= 0 && error_val < 0) {
388 int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
389 int sign = - SIGN_ONLY(val);
390
391 predictor_coef_table[predictor_num] -= sign;
392
393 val *= sign; /* neg value */
394
395 error_val -= ((val >> predictor_quantitization) *
396 (predictor_coef_num - predictor_num));
397
398 predictor_num--;
399 }
400 }
401
402 buffer_out++;
403 }
404 }
405}
406
7b49ce2e 407static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
6d6d7970
MM
408 int16_t *buffer_out,
409 int numchannels, int numsamples,
410 uint8_t interlacing_shift,
7ff85a81
MM
411 uint8_t interlacing_leftweight)
412{
6d6d7970
MM
413 int i;
414 if (numsamples <= 0) return;
415
416 /* weighted interlacing */
417 if (interlacing_leftweight) {
418 for (i = 0; i < numsamples; i++) {
419 int32_t difference, midright;
420 int16_t left;
421 int16_t right;
422
423 midright = buffer_a[i];
424 difference = buffer_b[i];
425
426
427 right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
428 left = (midright - ((difference * interlacing_leftweight) >> interlacing_shift))
429 + difference;
430
6d6d7970
MM
431 buffer_out[i*numchannels] = left;
432 buffer_out[i*numchannels + 1] = right;
433 }
434
435 return;
436 }
437
438 /* otherwise basic interlacing took place */
439 for (i = 0; i < numsamples; i++) {
440 int16_t left, right;
441
442 left = buffer_a[i];
443 right = buffer_b[i];
444
6d6d7970
MM
445 buffer_out[i*numchannels] = left;
446 buffer_out[i*numchannels + 1] = right;
447 }
448}
449
f770ee03
MM
450static int alac_decode_frame(AVCodecContext *avctx,
451 void *outbuffer, int *outputsize,
452 uint8_t *inbuffer, int input_buffer_size)
7ff85a81 453{
6d021b00 454 ALACContext *alac = avctx->priv_data;
f770ee03 455
6d6d7970 456 int channels;
7ff85a81 457 int32_t outputsamples;
a562e2e6
VS
458 int hassize;
459 int readsamplesize;
460 int wasted_bytes;
461 int isnotcompressed;
d562ba23
VS
462 uint8_t interlacing_shift;
463 uint8_t interlacing_leftweight;
6d6d7970 464
f770ee03
MM
465 /* short-circuit null buffers */
466 if (!inbuffer || !input_buffer_size)
467 return input_buffer_size;
468
6d6d7970 469 /* initialize from the extradata */
6d021b00
MM
470 if (!alac->context_initialized) {
471 if (alac->avctx->extradata_size != ALAC_EXTRADATA_SIZE) {
a1db1fc4 472 av_log(avctx, AV_LOG_ERROR, "alac: expected %d extradata bytes\n",
6d6d7970
MM
473 ALAC_EXTRADATA_SIZE);
474 return input_buffer_size;
475 }
1e25a7e7
MH
476 if (alac_set_info(alac)) {
477 av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
478 return input_buffer_size;
479 }
6d021b00 480 alac->context_initialized = 1;
6d6d7970 481 }
7ff85a81 482
6d021b00 483 init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
6d6d7970 484
e3be5693 485 channels = get_bits(&alac->gb, 3) + 1;
f1752010
VS
486 if (channels > MAX_CHANNELS) {
487 av_log(avctx, AV_LOG_ERROR, "channels > %d not supported\n",
488 MAX_CHANNELS);
489 return input_buffer_size;
490 }
6d6d7970 491
586e5bd9
VS
492 /* 2^result = something to do with output waiting.
493 * perhaps matters if we read > 1 frame in a pass?
494 */
495 get_bits(&alac->gb, 4);
6d6d7970 496
586e5bd9 497 get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
6d6d7970 498
586e5bd9
VS
499 /* the output sample size is stored soon */
500 hassize = get_bits(&alac->gb, 1);
6d6d7970 501
586e5bd9 502 wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
6d6d7970 503
586e5bd9
VS
504 /* whether the frame is compressed */
505 isnotcompressed = get_bits(&alac->gb, 1);
6d6d7970 506
586e5bd9
VS
507 if (hassize) {
508 /* now read the number of samples as a 32bit integer */
509 outputsamples = get_bits(&alac->gb, 32);
510 } else
511 outputsamples = alac->setinfo_max_samples_per_frame;
a562e2e6 512
586e5bd9
VS
513 *outputsize = outputsamples * alac->bytespersample;
514 readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1;
6d6d7970 515
586e5bd9
VS
516 if (!isnotcompressed) {
517 /* so it is compressed */
518 int16_t predictor_coef_table[channels][32];
519 int predictor_coef_num[channels];
520 int prediction_type[channels];
521 int prediction_quantitization[channels];
522 int ricemodifier[channels];
523 int i, chan;
6d6d7970 524
586e5bd9
VS
525 interlacing_shift = get_bits(&alac->gb, 8);
526 interlacing_leftweight = get_bits(&alac->gb, 8);
6d6d7970 527
586e5bd9 528 for (chan = 0; chan < channels; chan++) {
7f268016
VS
529 prediction_type[chan] = get_bits(&alac->gb, 4);
530 prediction_quantitization[chan] = get_bits(&alac->gb, 4);
6d6d7970 531
7f268016
VS
532 ricemodifier[chan] = get_bits(&alac->gb, 3);
533 predictor_coef_num[chan] = get_bits(&alac->gb, 5);
6d6d7970
MM
534
535 /* read the predictor table */
7f268016
VS
536 for (i = 0; i < predictor_coef_num[chan]; i++) {
537 predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
6d6d7970 538 }
586e5bd9 539 }
6d6d7970 540
586e5bd9
VS
541 if (wasted_bytes) {
542 av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
543 }
6d6d7970 544
586e5bd9 545 for (chan = 0; chan < channels; chan++) {
6d6d7970 546 bastardized_rice_decompress(alac,
7f268016 547 alac->predicterror_buffer[chan],
6d6d7970
MM
548 outputsamples,
549 readsamplesize,
550 alac->setinfo_rice_initialhistory,
551 alac->setinfo_rice_kmodifier,
7f268016 552 ricemodifier[chan] * alac->setinfo_rice_historymult / 4,
6d6d7970
MM
553 (1 << alac->setinfo_rice_kmodifier) - 1);
554
7f268016 555 if (prediction_type[chan] == 0) {
586e5bd9 556 /* adaptive fir */
7f268016
VS
557 predictor_decompress_fir_adapt(alac->predicterror_buffer[chan],
558 alac->outputsamples_buffer[chan],
6d6d7970
MM
559 outputsamples,
560 readsamplesize,
7f268016
VS
561 predictor_coef_table[chan],
562 predictor_coef_num[chan],
563 prediction_quantitization[chan]);
6d6d7970 564 } else {
7f268016 565 av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[chan]);
10fb5763
VS
566 /* i think the only other prediction type (or perhaps this is just a
567 * boolean?) runs adaptive fir twice.. like:
568 * predictor_decompress_fir_adapt(predictor_error, tempout, ...)
569 * predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
570 * little strange..
571 */
6d6d7970 572 }
586e5bd9
VS
573 }
574 } else {
575 /* not compressed, easy case */
576 if (alac->setinfo_sample_size <= 16) {
577 int i, chan;
578 for (chan = 0; chan < channels; chan++) {
6d6d7970 579 for (i = 0; i < outputsamples; i++) {
7f268016 580 int32_t audiobits;
6d6d7970 581
7f268016 582 audiobits = get_bits(&alac->gb, alac->setinfo_sample_size);
10fb5763
VS
583 audiobits = SIGN_EXTENDED32(audiobits, readsamplesize);
584
7f268016 585 alac->outputsamples_buffer[chan][i] = audiobits;
6d6d7970 586 }
586e5bd9
VS
587 }
588 } else {
589 int i, chan;
590 for (chan = 0; chan < channels; chan++) {
6d6d7970 591 for (i = 0; i < outputsamples; i++) {
7f268016 592 int32_t audiobits;
6d6d7970 593
7f268016 594 audiobits = get_bits(&alac->gb, 16);
10fb5763
VS
595 /* special case of sign extension..
596 * as we'll be ORing the low 16bits into this */
7f268016
VS
597 audiobits = audiobits << 16;
598 audiobits = audiobits >> (32 - alac->setinfo_sample_size);
599 audiobits |= get_bits(&alac->gb, alac->setinfo_sample_size - 16);
6d6d7970 600
7f268016 601 alac->outputsamples_buffer[chan][i] = audiobits;
6d6d7970
MM
602 }
603 }
6d6d7970 604 }
586e5bd9
VS
605 /* wasted_bytes = 0; */
606 interlacing_shift = 0;
607 interlacing_leftweight = 0;
608 }
6d6d7970 609
586e5bd9
VS
610 switch(alac->setinfo_sample_size) {
611 case 16: {
612 if (channels == 2) {
153696a6
VS
613 deinterlace_16(alac->outputsamples_buffer[0],
614 alac->outputsamples_buffer[1],
6d6d7970
MM
615 (int16_t*)outbuffer,
616 alac->numchannels,
617 outputsamples,
618 interlacing_shift,
619 interlacing_leftweight);
586e5bd9
VS
620 } else {
621 int i;
622 for (i = 0; i < outputsamples; i++) {
623 int16_t sample = alac->outputsamples_buffer[0][i];
624 ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
625 }
6d6d7970 626 }
586e5bd9
VS
627 break;
628 }
629 case 20:
630 case 24:
631 case 32:
632 av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
633 break;
634 default:
635 break;
636 }
6d6d7970 637
f770ee03 638 return input_buffer_size;
6d6d7970
MM
639}
640
641static int alac_decode_init(AVCodecContext * avctx)
642{
6d021b00
MM
643 ALACContext *alac = avctx->priv_data;
644 alac->avctx = avctx;
645 alac->context_initialized = 0;
6d6d7970 646
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MM
647 alac->samplesize = alac->avctx->bits_per_sample;
648 alac->numchannels = alac->avctx->channels;
649 alac->bytespersample = (alac->samplesize / 8) * alac->numchannels;
6d6d7970
MM
650
651 return 0;
652}
653
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654static int alac_decode_close(AVCodecContext *avctx)
655{
6d021b00 656 ALACContext *alac = avctx->priv_data;
6d6d7970 657
153696a6
VS
658 int chan;
659 for (chan = 0; chan < MAX_CHANNELS; chan++) {
660 av_free(alac->predicterror_buffer[chan]);
661 av_free(alac->outputsamples_buffer[chan]);
662 }
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MM
663
664 return 0;
665}
666
667AVCodec alac_decoder = {
668 "alac",
669 CODEC_TYPE_AUDIO,
670 CODEC_ID_ALAC,
671 sizeof(ALACContext),
672 alac_decode_init,
673 NULL,
674 alac_decode_close,
675 alac_decode_frame,
676};