4ed15c9e0b843cd6c6df19054dd2a6eb19051309
[libav.git] / libavcodec / flacdec.c
1 /*
2 * FLAC (Free Lossless Audio Codec) decoder
3 * Copyright (c) 2003 Alex Beregszaszi
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 libavcodec/flacdec.c
24 * FLAC (Free Lossless Audio Codec) decoder
25 * @author Alex Beregszaszi
26 *
27 * For more information on the FLAC format, visit:
28 * http://flac.sourceforge.net/
29 *
30 * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
31 * through, starting from the initial 'fLaC' signature; or by passing the
32 * 34-byte streaminfo structure through avctx->extradata[_size] followed
33 * by data starting with the 0xFFF8 marker.
34 */
35
36 #include <limits.h>
37
38 #include "libavutil/crc.h"
39 #include "avcodec.h"
40 #include "internal.h"
41 #include "bitstream.h"
42 #include "bytestream.h"
43 #include "golomb.h"
44 #include "flac.h"
45
46 #undef NDEBUG
47 #include <assert.h>
48
49 #define MAX_CHANNELS 8
50 #define MAX_BLOCKSIZE 65535
51
52 enum decorrelation_type {
53 INDEPENDENT,
54 LEFT_SIDE,
55 RIGHT_SIDE,
56 MID_SIDE,
57 };
58
59 typedef struct FLACContext {
60 FLACSTREAMINFO
61
62 AVCodecContext *avctx; ///< parent AVCodecContext
63 GetBitContext gb; ///< GetBitContext initialized to start at the current frame
64
65 int blocksize; ///< number of samples in the current frame
66 int curr_bps; ///< bps for current subframe, adjusted for channel correlation and wasted bits
67 int sample_shift; ///< shift required to make output samples 16-bit or 32-bit
68 int is32; ///< flag to indicate if output should be 32-bit instead of 16-bit
69 enum decorrelation_type decorrelation; ///< channel decorrelation type in the current frame
70 int got_streaminfo; ///< indicates if the STREAMINFO has been read
71
72 int32_t *decoded[MAX_CHANNELS]; ///< decoded samples
73 uint8_t *bitstream;
74 unsigned int bitstream_size;
75 unsigned int bitstream_index;
76 unsigned int allocated_bitstream_size;
77 } FLACContext;
78
79 static const int sample_rate_table[] =
80 { 0,
81 88200, 176400, 192000,
82 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
83 0, 0, 0, 0 };
84
85 static const int sample_size_table[] =
86 { 0, 8, 12, 0, 16, 20, 24, 0 };
87
88 static const int blocksize_table[] = {
89 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0,
90 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
91 };
92
93 static int64_t get_utf8(GetBitContext *gb)
94 {
95 int64_t val;
96 GET_UTF8(val, get_bits(gb, 8), return -1;)
97 return val;
98 }
99
100 static void allocate_buffers(FLACContext *s);
101
102 int ff_flac_is_extradata_valid(AVCodecContext *avctx,
103 enum FLACExtradataFormat *format,
104 uint8_t **streaminfo_start)
105 {
106 if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
107 av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
108 return 0;
109 }
110 if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
111 /* extradata contains STREAMINFO only */
112 if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
113 av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
114 FLAC_STREAMINFO_SIZE-avctx->extradata_size);
115 }
116 *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
117 *streaminfo_start = avctx->extradata;
118 } else {
119 if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
120 av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
121 return 0;
122 }
123 *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
124 *streaminfo_start = &avctx->extradata[8];
125 }
126 return 1;
127 }
128
129 static av_cold int flac_decode_init(AVCodecContext *avctx)
130 {
131 enum FLACExtradataFormat format;
132 uint8_t *streaminfo;
133 FLACContext *s = avctx->priv_data;
134 s->avctx = avctx;
135
136 avctx->sample_fmt = SAMPLE_FMT_S16;
137
138 /* for now, the raw FLAC header is allowed to be passed to the decoder as
139 frame data instead of extradata. */
140 if (!avctx->extradata)
141 return 0;
142
143 if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo))
144 return -1;
145
146 /* initialize based on the demuxer-supplied streamdata header */
147 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, streaminfo);
148 allocate_buffers(s);
149 s->got_streaminfo = 1;
150
151 return 0;
152 }
153
154 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
155 {
156 av_log(avctx, AV_LOG_DEBUG, " Max Blocksize: %d\n", s->max_blocksize);
157 av_log(avctx, AV_LOG_DEBUG, " Max Framesize: %d\n", s->max_framesize);
158 av_log(avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
159 av_log(avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
160 av_log(avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
161 }
162
163 static void allocate_buffers(FLACContext *s)
164 {
165 int i;
166
167 assert(s->max_blocksize);
168
169 if (s->max_framesize == 0 && s->max_blocksize) {
170 // FIXME header overhead
171 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8;
172 }
173
174 for (i = 0; i < s->channels; i++) {
175 s->decoded[i] = av_realloc(s->decoded[i],
176 sizeof(int32_t)*s->max_blocksize);
177 }
178
179 if (s->allocated_bitstream_size < s->max_framesize)
180 s->bitstream= av_fast_realloc(s->bitstream,
181 &s->allocated_bitstream_size,
182 s->max_framesize);
183 }
184
185 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
186 const uint8_t *buffer)
187 {
188 GetBitContext gb;
189 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
190
191 skip_bits(&gb, 16); /* skip min blocksize */
192 s->max_blocksize = get_bits(&gb, 16);
193 if (s->max_blocksize < 16) {
194 av_log(avctx, AV_LOG_WARNING, "invalid max blocksize: %d\n",
195 s->max_blocksize);
196 s->max_blocksize = 16;
197 }
198
199 skip_bits(&gb, 24); /* skip min frame size */
200 s->max_framesize = get_bits_long(&gb, 24);
201
202 s->samplerate = get_bits_long(&gb, 20);
203 s->channels = get_bits(&gb, 3) + 1;
204 s->bps = get_bits(&gb, 5) + 1;
205
206 avctx->channels = s->channels;
207 avctx->sample_rate = s->samplerate;
208 avctx->bits_per_raw_sample = s->bps;
209 if (s->bps > 16)
210 avctx->sample_fmt = SAMPLE_FMT_S32;
211 else
212 avctx->sample_fmt = SAMPLE_FMT_S16;
213
214 s->samples = get_bits_long(&gb, 32) << 4;
215 s->samples |= get_bits(&gb, 4);
216
217 skip_bits_long(&gb, 64); /* md5 sum */
218 skip_bits_long(&gb, 64); /* md5 sum */
219
220 dump_headers(avctx, s);
221 }
222
223 /**
224 * Parse the STREAMINFO from an inline header.
225 * @param s the flac decoding context
226 * @param buf input buffer, starting with the "fLaC" marker
227 * @param buf_size buffer size
228 * @return non-zero if metadata is invalid
229 */
230 static int parse_streaminfo(FLACContext *s, const uint8_t *buf, int buf_size)
231 {
232 int metadata_type, metadata_size;
233
234 if (buf_size < FLAC_STREAMINFO_SIZE+8) {
235 /* need more data */
236 return 0;
237 }
238 buf += 4;
239 metadata_type = bytestream_get_byte(&buf) & 0x7F;
240 metadata_size = bytestream_get_be24(&buf);
241 if (metadata_type != FLAC_METADATA_TYPE_STREAMINFO ||
242 metadata_size != FLAC_STREAMINFO_SIZE) {
243 return AVERROR_INVALIDDATA;
244 }
245 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, buf);
246 allocate_buffers(s);
247 s->got_streaminfo = 1;
248
249 return 0;
250 }
251
252 /**
253 * Determine the size of an inline header.
254 * @param buf input buffer, starting with the "fLaC" marker
255 * @param buf_size buffer size
256 * @return number of bytes in the header, or 0 if more data is needed
257 */
258 static int get_metadata_size(const uint8_t *buf, int buf_size)
259 {
260 int metadata_last, metadata_size;
261 const uint8_t *buf_end = buf + buf_size;
262
263 buf += 4;
264 do {
265 metadata_last = bytestream_get_byte(&buf) & 0x80;
266 metadata_size = bytestream_get_be24(&buf);
267 if (buf + metadata_size > buf_end) {
268 /* need more data in order to read the complete header */
269 return 0;
270 }
271 buf += metadata_size;
272 } while (!metadata_last);
273
274 return buf_size - (buf_end - buf);
275 }
276
277 static int decode_residuals(FLACContext *s, int channel, int pred_order)
278 {
279 int i, tmp, partition, method_type, rice_order;
280 int sample = 0, samples;
281
282 method_type = get_bits(&s->gb, 2);
283 if (method_type > 1) {
284 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n",
285 method_type);
286 return -1;
287 }
288
289 rice_order = get_bits(&s->gb, 4);
290
291 samples= s->blocksize >> rice_order;
292 if (pred_order > samples) {
293 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n",
294 pred_order, samples);
295 return -1;
296 }
297
298 sample=
299 i= pred_order;
300 for (partition = 0; partition < (1 << rice_order); partition++) {
301 tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
302 if (tmp == (method_type == 0 ? 15 : 31)) {
303 tmp = get_bits(&s->gb, 5);
304 for (; i < samples; i++, sample++)
305 s->decoded[channel][sample] = get_sbits_long(&s->gb, tmp);
306 } else {
307 for (; i < samples; i++, sample++) {
308 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
309 }
310 }
311 i= 0;
312 }
313
314 return 0;
315 }
316
317 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
318 {
319 const int blocksize = s->blocksize;
320 int32_t *decoded = s->decoded[channel];
321 int av_uninit(a), av_uninit(b), av_uninit(c), av_uninit(d), i;
322
323 /* warm up samples */
324 for (i = 0; i < pred_order; i++) {
325 decoded[i] = get_sbits_long(&s->gb, s->curr_bps);
326 }
327
328 if (decode_residuals(s, channel, pred_order) < 0)
329 return -1;
330
331 if (pred_order > 0)
332 a = decoded[pred_order-1];
333 if (pred_order > 1)
334 b = a - decoded[pred_order-2];
335 if (pred_order > 2)
336 c = b - decoded[pred_order-2] + decoded[pred_order-3];
337 if (pred_order > 3)
338 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
339
340 switch (pred_order) {
341 case 0:
342 break;
343 case 1:
344 for (i = pred_order; i < blocksize; i++)
345 decoded[i] = a += decoded[i];
346 break;
347 case 2:
348 for (i = pred_order; i < blocksize; i++)
349 decoded[i] = a += b += decoded[i];
350 break;
351 case 3:
352 for (i = pred_order; i < blocksize; i++)
353 decoded[i] = a += b += c += decoded[i];
354 break;
355 case 4:
356 for (i = pred_order; i < blocksize; i++)
357 decoded[i] = a += b += c += d += decoded[i];
358 break;
359 default:
360 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
361 return -1;
362 }
363
364 return 0;
365 }
366
367 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
368 {
369 int i, j;
370 int coeff_prec, qlevel;
371 int coeffs[pred_order];
372 int32_t *decoded = s->decoded[channel];
373
374 /* warm up samples */
375 for (i = 0; i < pred_order; i++) {
376 decoded[i] = get_sbits_long(&s->gb, s->curr_bps);
377 }
378
379 coeff_prec = get_bits(&s->gb, 4) + 1;
380 if (coeff_prec == 16) {
381 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
382 return -1;
383 }
384 qlevel = get_sbits(&s->gb, 5);
385 if (qlevel < 0) {
386 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n",
387 qlevel);
388 return -1;
389 }
390
391 for (i = 0; i < pred_order; i++) {
392 coeffs[i] = get_sbits(&s->gb, coeff_prec);
393 }
394
395 if (decode_residuals(s, channel, pred_order) < 0)
396 return -1;
397
398 if (s->bps > 16) {
399 int64_t sum;
400 for (i = pred_order; i < s->blocksize; i++) {
401 sum = 0;
402 for (j = 0; j < pred_order; j++)
403 sum += (int64_t)coeffs[j] * decoded[i-j-1];
404 decoded[i] += sum >> qlevel;
405 }
406 } else {
407 for (i = pred_order; i < s->blocksize-1; i += 2) {
408 int c;
409 int d = decoded[i-pred_order];
410 int s0 = 0, s1 = 0;
411 for (j = pred_order-1; j > 0; j--) {
412 c = coeffs[j];
413 s0 += c*d;
414 d = decoded[i-j];
415 s1 += c*d;
416 }
417 c = coeffs[0];
418 s0 += c*d;
419 d = decoded[i] += s0 >> qlevel;
420 s1 += c*d;
421 decoded[i+1] += s1 >> qlevel;
422 }
423 if (i < s->blocksize) {
424 int sum = 0;
425 for (j = 0; j < pred_order; j++)
426 sum += coeffs[j] * decoded[i-j-1];
427 decoded[i] += sum >> qlevel;
428 }
429 }
430
431 return 0;
432 }
433
434 static inline int decode_subframe(FLACContext *s, int channel)
435 {
436 int type, wasted = 0;
437 int i, tmp;
438
439 s->curr_bps = s->bps;
440 if (channel == 0) {
441 if (s->decorrelation == RIGHT_SIDE)
442 s->curr_bps++;
443 } else {
444 if (s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
445 s->curr_bps++;
446 }
447
448 if (get_bits1(&s->gb)) {
449 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
450 return -1;
451 }
452 type = get_bits(&s->gb, 6);
453
454 if (get_bits1(&s->gb)) {
455 wasted = 1;
456 while (!get_bits1(&s->gb))
457 wasted++;
458 s->curr_bps -= wasted;
459 }
460 if (s->curr_bps > 32) {
461 ff_log_missing_feature(s->avctx, "decorrelated bit depth > 32", 0);
462 return -1;
463 }
464
465 //FIXME use av_log2 for types
466 if (type == 0) {
467 tmp = get_sbits_long(&s->gb, s->curr_bps);
468 for (i = 0; i < s->blocksize; i++)
469 s->decoded[channel][i] = tmp;
470 } else if (type == 1) {
471 for (i = 0; i < s->blocksize; i++)
472 s->decoded[channel][i] = get_sbits_long(&s->gb, s->curr_bps);
473 } else if ((type >= 8) && (type <= 12)) {
474 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
475 return -1;
476 } else if (type >= 32) {
477 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
478 return -1;
479 } else {
480 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
481 return -1;
482 }
483
484 if (wasted) {
485 int i;
486 for (i = 0; i < s->blocksize; i++)
487 s->decoded[channel][i] <<= wasted;
488 }
489
490 return 0;
491 }
492
493 static int decode_frame(FLACContext *s, int alloc_data_size)
494 {
495 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
496 int decorrelation, bps, blocksize, samplerate;
497
498 blocksize_code = get_bits(&s->gb, 4);
499
500 sample_rate_code = get_bits(&s->gb, 4);
501
502 assignment = get_bits(&s->gb, 4); /* channel assignment */
503 if (assignment < 8 && s->channels == assignment+1)
504 decorrelation = INDEPENDENT;
505 else if (assignment >=8 && assignment < 11 && s->channels == 2)
506 decorrelation = LEFT_SIDE + assignment - 8;
507 else {
508 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n",
509 assignment, s->channels);
510 return -1;
511 }
512
513 sample_size_code = get_bits(&s->gb, 3);
514 if (sample_size_code == 0)
515 bps= s->bps;
516 else if ((sample_size_code != 3) && (sample_size_code != 7))
517 bps = sample_size_table[sample_size_code];
518 else {
519 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
520 sample_size_code);
521 return -1;
522 }
523 if (bps > 16) {
524 s->avctx->sample_fmt = SAMPLE_FMT_S32;
525 s->sample_shift = 32 - bps;
526 s->is32 = 1;
527 } else {
528 s->avctx->sample_fmt = SAMPLE_FMT_S16;
529 s->sample_shift = 16 - bps;
530 s->is32 = 0;
531 }
532 s->bps = s->avctx->bits_per_raw_sample = bps;
533
534 if (get_bits1(&s->gb)) {
535 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
536 return -1;
537 }
538
539 if (get_utf8(&s->gb) < 0) {
540 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
541 return -1;
542 }
543
544 if (blocksize_code == 0) {
545 av_log(s->avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
546 return -1;
547 } else if (blocksize_code == 6)
548 blocksize = get_bits(&s->gb, 8)+1;
549 else if (blocksize_code == 7)
550 blocksize = get_bits(&s->gb, 16)+1;
551 else
552 blocksize = blocksize_table[blocksize_code];
553
554 if (blocksize > s->max_blocksize) {
555 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize,
556 s->max_blocksize);
557 return -1;
558 }
559
560 if (blocksize * s->channels * (s->is32 ? 4 : 2) > alloc_data_size)
561 return -1;
562
563 if (sample_rate_code == 0)
564 samplerate= s->samplerate;
565 else if (sample_rate_code < 12)
566 samplerate = sample_rate_table[sample_rate_code];
567 else if (sample_rate_code == 12)
568 samplerate = get_bits(&s->gb, 8) * 1000;
569 else if (sample_rate_code == 13)
570 samplerate = get_bits(&s->gb, 16);
571 else if (sample_rate_code == 14)
572 samplerate = get_bits(&s->gb, 16) * 10;
573 else {
574 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
575 sample_rate_code);
576 return -1;
577 }
578
579 skip_bits(&s->gb, 8);
580 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
581 s->gb.buffer, get_bits_count(&s->gb)/8);
582 if (crc8) {
583 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
584 return -1;
585 }
586
587 s->blocksize = blocksize;
588 s->samplerate = samplerate;
589 s->bps = bps;
590 s->decorrelation= decorrelation;
591
592 // dump_headers(s->avctx, (FLACStreaminfo *)s);
593
594 /* subframes */
595 for (i = 0; i < s->channels; i++) {
596 if (decode_subframe(s, i) < 0)
597 return -1;
598 }
599
600 align_get_bits(&s->gb);
601
602 /* frame footer */
603 skip_bits(&s->gb, 16); /* data crc */
604
605 return 0;
606 }
607
608 static int flac_decode_frame(AVCodecContext *avctx,
609 void *data, int *data_size,
610 const uint8_t *buf, int buf_size)
611 {
612 FLACContext *s = avctx->priv_data;
613 int i, j = 0, input_buf_size = 0, bytes_read = 0;
614 int16_t *samples_16 = data;
615 int32_t *samples_32 = data;
616 int alloc_data_size= *data_size;
617
618 *data_size=0;
619
620 if (s->max_framesize == 0) {
621 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
622 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
623 }
624
625 if (1 && s->max_framesize) { //FIXME truncated
626 if (s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
627 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
628 input_buf_size= buf_size;
629
630 if (s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
631 return -1;
632
633 if (s->allocated_bitstream_size < s->bitstream_size + buf_size)
634 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
635
636 if (s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size) {
637 memmove(s->bitstream, &s->bitstream[s->bitstream_index],
638 s->bitstream_size);
639 s->bitstream_index=0;
640 }
641 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size],
642 buf, buf_size);
643 buf= &s->bitstream[s->bitstream_index];
644 buf_size += s->bitstream_size;
645 s->bitstream_size= buf_size;
646
647 if (buf_size < s->max_framesize && input_buf_size) {
648 return input_buf_size;
649 }
650 }
651
652 /* check that there is at least the smallest decodable amount of data.
653 this amount corresponds to the smallest valid FLAC frame possible. */
654 if (buf_size < 11)
655 goto end;
656
657 /* check for inline header */
658 if (AV_RB32(buf) == MKBETAG('f','L','a','C')) {
659 if (!s->got_streaminfo && parse_streaminfo(s, buf, buf_size)) {
660 av_log(s->avctx, AV_LOG_ERROR, "invalid header\n");
661 return -1;
662 }
663 bytes_read = get_metadata_size(buf, buf_size);
664 goto end;
665 }
666
667 /* check for frame sync code and resync stream if necessary */
668 if ((AV_RB16(buf) & 0xFFFE) != 0xFFF8) {
669 const uint8_t *buf_end = buf + buf_size;
670 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
671 while (buf+2 < buf_end && (AV_RB16(buf) & 0xFFFE) != 0xFFF8)
672 buf++;
673 bytes_read = buf_size - (buf_end - buf);
674 goto end; // we may not have enough bits left to decode a frame, so try next time
675 }
676
677 /* decode frame */
678 init_get_bits(&s->gb, buf, buf_size*8);
679 skip_bits(&s->gb, 16);
680 if (decode_frame(s, alloc_data_size) < 0) {
681 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
682 s->bitstream_size=0;
683 s->bitstream_index=0;
684 return -1;
685 }
686 *data_size = s->blocksize * s->channels * (s->is32 ? 4 : 2);
687 bytes_read = (get_bits_count(&s->gb)+7)/8;
688
689 #define DECORRELATE(left, right)\
690 assert(s->channels == 2);\
691 for (i = 0; i < s->blocksize; i++) {\
692 int a= s->decoded[0][i];\
693 int b= s->decoded[1][i];\
694 if (s->is32) {\
695 *samples_32++ = (left) << s->sample_shift;\
696 *samples_32++ = (right) << s->sample_shift;\
697 } else {\
698 *samples_16++ = (left) << s->sample_shift;\
699 *samples_16++ = (right) << s->sample_shift;\
700 }\
701 }\
702 break;
703
704 switch (s->decorrelation) {
705 case INDEPENDENT:
706 for (j = 0; j < s->blocksize; j++) {
707 for (i = 0; i < s->channels; i++) {
708 if (s->is32)
709 *samples_32++ = s->decoded[i][j] << s->sample_shift;
710 else
711 *samples_16++ = s->decoded[i][j] << s->sample_shift;
712 }
713 }
714 break;
715 case LEFT_SIDE:
716 DECORRELATE(a,a-b)
717 case RIGHT_SIDE:
718 DECORRELATE(a+b,b)
719 case MID_SIDE:
720 DECORRELATE( (a-=b>>1) + b, a)
721 }
722
723 end:
724 if (bytes_read > buf_size) {
725 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", bytes_read - buf_size);
726 s->bitstream_size=0;
727 s->bitstream_index=0;
728 return -1;
729 }
730
731 if (s->bitstream_size) {
732 s->bitstream_index += bytes_read;
733 s->bitstream_size -= bytes_read;
734 return input_buf_size;
735 } else
736 return bytes_read;
737 }
738
739 static av_cold int flac_decode_close(AVCodecContext *avctx)
740 {
741 FLACContext *s = avctx->priv_data;
742 int i;
743
744 for (i = 0; i < s->channels; i++) {
745 av_freep(&s->decoded[i]);
746 }
747 av_freep(&s->bitstream);
748
749 return 0;
750 }
751
752 static void flac_flush(AVCodecContext *avctx)
753 {
754 FLACContext *s = avctx->priv_data;
755
756 s->bitstream_size=
757 s->bitstream_index= 0;
758 }
759
760 AVCodec flac_decoder = {
761 "flac",
762 CODEC_TYPE_AUDIO,
763 CODEC_ID_FLAC,
764 sizeof(FLACContext),
765 flac_decode_init,
766 NULL,
767 flac_decode_close,
768 flac_decode_frame,
769 CODEC_CAP_DELAY,
770 .flush= flac_flush,
771 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
772 };