Cosmetics: alignment
[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 *
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5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
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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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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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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
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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
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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
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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
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102 alac->outputsamples_buffer[chan] =
103 av_malloc(alac->setinfo_max_samples_per_frame * 4);
104 }
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105}
106
3a1a7e32 107static int alac_set_info(ALACContext *alac)
6d6d7970 108{
6d021b00 109 unsigned char *ptr = alac->avctx->extradata;
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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
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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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136
137 allocate_buffers(alac);
3a1a7e32
MN
138
139 return 0;
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140}
141
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142/* hideously inefficient. could use a bitmask search,
143 * alternatively bsr on x86,
144 */
145static int count_leading_zeros(int32_t input)
146{
147 int i = 0;
148 while (!(0x80000000 & input) && i < 32) {
149 i++;
150 input = input << 1;
151 }
152 return i;
153}
154
1b47fafd 155static void bastardized_rice_decompress(ALACContext *alac,
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156 int32_t *output_buffer,
157 int output_size,
158 int readsamplesize, /* arg_10 */
159 int rice_initialhistory, /* arg424->b */
160 int rice_kmodifier, /* arg424->d */
161 int rice_historymult, /* arg424->c */
162 int rice_kmodifier_mask /* arg424->e */
163 )
164{
165 int output_count;
166 unsigned int history = rice_initialhistory;
167 int sign_modifier = 0;
168
169 for (output_count = 0; output_count < output_size; output_count++) {
170 int32_t x = 0;
171 int32_t x_modified;
172 int32_t final_val;
173
174 /* read x - number of 1s before 0 represent the rice */
6d021b00 175 while (x <= 8 && get_bits1(&alac->gb)) {
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176 x++;
177 }
178
179
180 if (x > 8) { /* RICE THRESHOLD */
181 /* use alternative encoding */
182 int32_t value;
183
6d021b00 184 value = get_bits(&alac->gb, readsamplesize);
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185
186 /* mask value to readsamplesize size */
187 if (readsamplesize != 32)
188 value &= (0xffffffff >> (32 - readsamplesize));
189
190 x = value;
191 } else {
192 /* standard rice encoding */
193 int extrabits;
194 int k; /* size of extra bits */
195
196 /* read k, that is bits as is */
197 k = 31 - rice_kmodifier - count_leading_zeros((history >> 9) + 3);
198
115329f1 199 if (k < 0)
6d6d7970 200 k += rice_kmodifier;
115329f1 201 else
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202 k = rice_kmodifier;
203
204 if (k != 1) {
6d021b00 205 extrabits = show_bits(&alac->gb, k);
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206
207 /* multiply x by 2^k - 1, as part of their strange algorithm */
208 x = (x << k) - x;
209
210 if (extrabits > 1) {
211 x += extrabits - 1;
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212 get_bits(&alac->gb, k);
213 } else {
214 get_bits(&alac->gb, k - 1);
215 }
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216 }
217 }
218
219 x_modified = sign_modifier + x;
220 final_val = (x_modified + 1) / 2;
221 if (x_modified & 1) final_val *= -1;
222
223 output_buffer[output_count] = final_val;
224
225 sign_modifier = 0;
226
227 /* now update the history */
228 history += (x_modified * rice_historymult)
229 - ((history * rice_historymult) >> 9);
230
231 if (x_modified > 0xffff)
232 history = 0xffff;
233
234 /* special case: there may be compressed blocks of 0 */
235 if ((history < 128) && (output_count+1 < output_size)) {
236 int block_size;
237
238 sign_modifier = 1;
239
240 x = 0;
6d021b00 241 while (x <= 8 && get_bits1(&alac->gb)) {
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242 x++;
243 }
244
245 if (x > 8) {
6d021b00 246 block_size = get_bits(&alac->gb, 16);
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247 block_size &= 0xffff;
248 } else {
249 int k;
250 int extrabits;
251
252 k = count_leading_zeros(history) + ((history + 16) >> 6 /* / 64 */) - 24;
253
6d021b00 254 extrabits = show_bits(&alac->gb, k);
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255
256 block_size = (((1 << k) - 1) & rice_kmodifier_mask) * x
257 + extrabits - 1;
258
259 if (extrabits < 2) {
260 x = 1 - extrabits;
261 block_size += x;
6d021b00
MM
262 get_bits(&alac->gb, k - 1);
263 } else {
264 get_bits(&alac->gb, k);
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265 }
266 }
267
268 if (block_size > 0) {
269 memset(&output_buffer[output_count+1], 0, block_size * 4);
270 output_count += block_size;
271
272 }
273
274 if (block_size > 0xffff)
275 sign_modifier = 0;
276
277 history = 0;
278 }
279 }
280}
281
282#define SIGN_EXTENDED32(val, bits) ((val << (32 - bits)) >> (32 - bits))
283
284#define SIGN_ONLY(v) \
285 ((v < 0) ? (-1) : \
286 ((v > 0) ? (1) : \
287 (0)))
288
289static void predictor_decompress_fir_adapt(int32_t *error_buffer,
290 int32_t *buffer_out,
291 int output_size,
292 int readsamplesize,
293 int16_t *predictor_coef_table,
294 int predictor_coef_num,
295 int predictor_quantitization)
296{
297 int i;
298
299 /* first sample always copies */
300 *buffer_out = *error_buffer;
301
302 if (!predictor_coef_num) {
303 if (output_size <= 1) return;
304 memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
305 return;
306 }
307
308 if (predictor_coef_num == 0x1f) { /* 11111 - max value of predictor_coef_num */
309 /* second-best case scenario for fir decompression,
310 * error describes a small difference from the previous sample only
311 */
312 if (output_size <= 1) return;
313 for (i = 0; i < output_size - 1; i++) {
314 int32_t prev_value;
315 int32_t error_value;
316
317 prev_value = buffer_out[i];
318 error_value = error_buffer[i+1];
319 buffer_out[i+1] = SIGN_EXTENDED32((prev_value + error_value), readsamplesize);
320 }
321 return;
322 }
323
324 /* read warm-up samples */
325 if (predictor_coef_num > 0) {
326 int i;
327 for (i = 0; i < predictor_coef_num; i++) {
328 int32_t val;
329
330 val = buffer_out[i] + error_buffer[i+1];
331
332 val = SIGN_EXTENDED32(val, readsamplesize);
333
334 buffer_out[i+1] = val;
335 }
336 }
337
338#if 0
339 /* 4 and 8 are very common cases (the only ones i've seen). these
340 * should be unrolled and optimised
341 */
342 if (predictor_coef_num == 4) {
343 /* FIXME: optimised general case */
344 return;
345 }
346
347 if (predictor_coef_table == 8) {
348 /* FIXME: optimised general case */
349 return;
350 }
351#endif
352
353
354 /* general case */
355 if (predictor_coef_num > 0) {
356 for (i = predictor_coef_num + 1;
357 i < output_size;
358 i++) {
359 int j;
360 int sum = 0;
361 int outval;
362 int error_val = error_buffer[i];
363
364 for (j = 0; j < predictor_coef_num; j++) {
365 sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
366 predictor_coef_table[j];
367 }
368
369 outval = (1 << (predictor_quantitization-1)) + sum;
370 outval = outval >> predictor_quantitization;
371 outval = outval + buffer_out[0] + error_val;
372 outval = SIGN_EXTENDED32(outval, readsamplesize);
373
374 buffer_out[predictor_coef_num+1] = outval;
375
376 if (error_val > 0) {
377 int predictor_num = predictor_coef_num - 1;
378
379 while (predictor_num >= 0 && error_val > 0) {
380 int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
381 int sign = SIGN_ONLY(val);
382
383 predictor_coef_table[predictor_num] -= sign;
384
385 val *= sign; /* absolute value */
386
387 error_val -= ((val >> predictor_quantitization) *
388 (predictor_coef_num - predictor_num));
389
390 predictor_num--;
391 }
392 } else if (error_val < 0) {
393 int predictor_num = predictor_coef_num - 1;
394
395 while (predictor_num >= 0 && error_val < 0) {
396 int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
397 int sign = - SIGN_ONLY(val);
398
399 predictor_coef_table[predictor_num] -= sign;
400
401 val *= sign; /* neg value */
402
403 error_val -= ((val >> predictor_quantitization) *
404 (predictor_coef_num - predictor_num));
405
406 predictor_num--;
407 }
408 }
409
410 buffer_out++;
411 }
412 }
413}
414
7b49ce2e 415static void deinterlace_16(int32_t *buffer_a, int32_t *buffer_b,
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416 int16_t *buffer_out,
417 int numchannels, int numsamples,
418 uint8_t interlacing_shift,
7ff85a81
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419 uint8_t interlacing_leftweight)
420{
6d6d7970
MM
421 int i;
422 if (numsamples <= 0) return;
423
424 /* weighted interlacing */
425 if (interlacing_leftweight) {
426 for (i = 0; i < numsamples; i++) {
427 int32_t difference, midright;
428 int16_t left;
429 int16_t right;
430
431 midright = buffer_a[i];
432 difference = buffer_b[i];
433
434
435 right = midright - ((difference * interlacing_leftweight) >> interlacing_shift);
436 left = (midright - ((difference * interlacing_leftweight) >> interlacing_shift))
437 + difference;
438
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MM
439 buffer_out[i*numchannels] = left;
440 buffer_out[i*numchannels + 1] = right;
441 }
442
443 return;
444 }
445
446 /* otherwise basic interlacing took place */
447 for (i = 0; i < numsamples; i++) {
448 int16_t left, right;
449
450 left = buffer_a[i];
451 right = buffer_b[i];
452
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453 buffer_out[i*numchannels] = left;
454 buffer_out[i*numchannels + 1] = right;
455 }
456}
457
f770ee03
MM
458static int alac_decode_frame(AVCodecContext *avctx,
459 void *outbuffer, int *outputsize,
460 uint8_t *inbuffer, int input_buffer_size)
7ff85a81 461{
6d021b00 462 ALACContext *alac = avctx->priv_data;
f770ee03 463
6d6d7970 464 int channels;
7ff85a81 465 int32_t outputsamples;
a562e2e6
VS
466 int hassize;
467 int readsamplesize;
468 int wasted_bytes;
469 int isnotcompressed;
d562ba23
VS
470 uint8_t interlacing_shift;
471 uint8_t interlacing_leftweight;
6d6d7970 472
f770ee03
MM
473 /* short-circuit null buffers */
474 if (!inbuffer || !input_buffer_size)
475 return input_buffer_size;
476
6d6d7970 477 /* initialize from the extradata */
6d021b00
MM
478 if (!alac->context_initialized) {
479 if (alac->avctx->extradata_size != ALAC_EXTRADATA_SIZE) {
a1db1fc4 480 av_log(avctx, AV_LOG_ERROR, "alac: expected %d extradata bytes\n",
6d6d7970
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481 ALAC_EXTRADATA_SIZE);
482 return input_buffer_size;
483 }
1e25a7e7
MH
484 if (alac_set_info(alac)) {
485 av_log(avctx, AV_LOG_ERROR, "alac: set_info failed\n");
486 return input_buffer_size;
487 }
6d021b00 488 alac->context_initialized = 1;
6d6d7970 489 }
7ff85a81 490
6d021b00 491 init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
6d6d7970 492
e3be5693 493 channels = get_bits(&alac->gb, 3) + 1;
6d6d7970 494
6d6d7970
MM
495 /* 2^result = something to do with output waiting.
496 * perhaps matters if we read > 1 frame in a pass?
497 */
6d021b00 498 get_bits(&alac->gb, 4);
6d6d7970 499
6d021b00 500 get_bits(&alac->gb, 12); /* unknown, skip 12 bits */
6d6d7970 501
6d021b00 502 hassize = get_bits(&alac->gb, 1); /* the output sample size is stored soon */
6d6d7970 503
6d021b00 504 wasted_bytes = get_bits(&alac->gb, 2); /* unknown ? */
6d6d7970 505
6d021b00 506 isnotcompressed = get_bits(&alac->gb, 1); /* whether the frame is compressed */
6d6d7970
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507
508 if (hassize) {
509 /* now read the number of samples,
510 * as a 32bit integer */
6d021b00 511 outputsamples = get_bits(&alac->gb, 32);
a562e2e6
VS
512 } else
513 outputsamples = alac->setinfo_max_samples_per_frame;
6d6d7970 514
a562e2e6 515 *outputsize = outputsamples * alac->bytespersample;
e3be5693 516 readsamplesize = alac->setinfo_sample_size - (wasted_bytes * 8) + channels - 1;
a562e2e6 517
6d6d7970
MM
518 if (!isnotcompressed) {
519 /* so it is compressed */
7f268016
VS
520 int16_t predictor_coef_table[channels][32];
521 int predictor_coef_num[channels];
522 int prediction_type[channels];
523 int prediction_quantitization[channels];
524 int ricemodifier[channels];
6d6d7970 525
7f268016 526 int i, chan;
6d6d7970 527
6d021b00
MM
528 interlacing_shift = get_bits(&alac->gb, 8);
529 interlacing_leftweight = get_bits(&alac->gb, 8);
6d6d7970 530
7f268016
VS
531 for (chan = 0; chan < channels; chan++) {
532 prediction_type[chan] = get_bits(&alac->gb, 4);
533 prediction_quantitization[chan] = get_bits(&alac->gb, 4);
6d6d7970 534
7f268016
VS
535 ricemodifier[chan] = get_bits(&alac->gb, 3);
536 predictor_coef_num[chan] = get_bits(&alac->gb, 5);
6d6d7970
MM
537
538 /* read the predictor table */
7f268016
VS
539 for (i = 0; i < predictor_coef_num[chan]; i++) {
540 predictor_coef_table[chan][i] = (int16_t)get_bits(&alac->gb, 16);
6d6d7970 541 }
7f268016 542 }
6d6d7970 543
6d6d7970 544 if (wasted_bytes) {
a1db1fc4 545 av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented, unhandling of wasted_bytes\n");
6d6d7970
MM
546 }
547
7f268016 548 for (chan = 0; chan < channels; chan++) {
6d6d7970 549 bastardized_rice_decompress(alac,
7f268016 550 alac->predicterror_buffer[chan],
6d6d7970
MM
551 outputsamples,
552 readsamplesize,
553 alac->setinfo_rice_initialhistory,
554 alac->setinfo_rice_kmodifier,
7f268016 555 ricemodifier[chan] * alac->setinfo_rice_historymult / 4,
6d6d7970
MM
556 (1 << alac->setinfo_rice_kmodifier) - 1);
557
7f268016 558 if (prediction_type[chan] == 0) {
6d6d7970 559 /* adaptive fir */
7f268016
VS
560 predictor_decompress_fir_adapt(alac->predicterror_buffer[chan],
561 alac->outputsamples_buffer[chan],
6d6d7970
MM
562 outputsamples,
563 readsamplesize,
7f268016
VS
564 predictor_coef_table[chan],
565 predictor_coef_num[chan],
566 prediction_quantitization[chan]);
6d6d7970 567 } else {
7f268016 568 av_log(avctx, AV_LOG_ERROR, "FIXME: unhandled prediction type: %i\n", prediction_type[chan]);
10fb5763
VS
569 /* i think the only other prediction type (or perhaps this is just a
570 * boolean?) runs adaptive fir twice.. like:
571 * predictor_decompress_fir_adapt(predictor_error, tempout, ...)
572 * predictor_decompress_fir_adapt(predictor_error, outputsamples ...)
573 * little strange..
574 */
6d6d7970 575 }
7f268016 576 }
115329f1 577 } else {
6d6d7970
MM
578 /* not compressed, easy case */
579 if (alac->setinfo_sample_size <= 16) {
7f268016
VS
580 int i, chan;
581 for (chan = 0; chan < channels; chan++) {
6d6d7970 582 for (i = 0; i < outputsamples; i++) {
7f268016 583 int32_t audiobits;
6d6d7970 584
7f268016 585 audiobits = get_bits(&alac->gb, alac->setinfo_sample_size);
10fb5763
VS
586 audiobits = SIGN_EXTENDED32(audiobits, readsamplesize);
587
7f268016 588 alac->outputsamples_buffer[chan][i] = audiobits;
6d6d7970 589 }
7f268016 590 }
6d6d7970 591 } else {
7f268016
VS
592 int i, chan;
593 for (chan = 0; chan < channels; chan++) {
6d6d7970 594 for (i = 0; i < outputsamples; i++) {
7f268016 595 int32_t audiobits;
6d6d7970 596
7f268016 597 audiobits = get_bits(&alac->gb, 16);
10fb5763
VS
598 /* special case of sign extension..
599 * as we'll be ORing the low 16bits into this */
7f268016
VS
600 audiobits = audiobits << 16;
601 audiobits = audiobits >> (32 - alac->setinfo_sample_size);
602 audiobits |= get_bits(&alac->gb, alac->setinfo_sample_size - 16);
6d6d7970 603
7f268016 604 alac->outputsamples_buffer[chan][i] = audiobits;
6d6d7970 605 }
7f268016 606 }
6d6d7970
MM
607 }
608 /* wasted_bytes = 0; */
609 interlacing_shift = 0;
610 interlacing_leftweight = 0;
611 }
612
613 switch(alac->setinfo_sample_size) {
614 case 16: {
10fb5763 615 if (channels == 2) {
153696a6
VS
616 deinterlace_16(alac->outputsamples_buffer[0],
617 alac->outputsamples_buffer[1],
6d6d7970
MM
618 (int16_t*)outbuffer,
619 alac->numchannels,
620 outputsamples,
621 interlacing_shift,
622 interlacing_leftweight);
10fb5763
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623 } else {
624 int i;
625 for (i = 0; i < outputsamples; i++) {
626 int16_t sample = alac->outputsamples_buffer[0][i];
627 ((int16_t*)outbuffer)[i * alac->numchannels] = sample;
628 }
629 }
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630 break;
631 }
632 case 20:
633 case 24:
634 case 32:
a1db1fc4 635 av_log(avctx, AV_LOG_ERROR, "FIXME: unimplemented sample size %i\n", alac->setinfo_sample_size);
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636 break;
637 default:
638 break;
639 }
640
6d6d7970 641
f770ee03 642 return input_buffer_size;
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643}
644
645static int alac_decode_init(AVCodecContext * avctx)
646{
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647 ALACContext *alac = avctx->priv_data;
648 alac->avctx = avctx;
649 alac->context_initialized = 0;
6d6d7970 650
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651 alac->samplesize = alac->avctx->bits_per_sample;
652 alac->numchannels = alac->avctx->channels;
653 alac->bytespersample = (alac->samplesize / 8) * alac->numchannels;
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654
655 return 0;
656}
657
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658static int alac_decode_close(AVCodecContext *avctx)
659{
6d021b00 660 ALACContext *alac = avctx->priv_data;
6d6d7970 661
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662 int chan;
663 for (chan = 0; chan < MAX_CHANNELS; chan++) {
664 av_free(alac->predicterror_buffer[chan]);
665 av_free(alac->outputsamples_buffer[chan]);
666 }
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667
668 return 0;
669}
670
671AVCodec alac_decoder = {
672 "alac",
673 CODEC_TYPE_AUDIO,
674 CODEC_ID_ALAC,
675 sizeof(ALACContext),
676 alac_decode_init,
677 NULL,
678 alac_decode_close,
679 alac_decode_frame,
680};