2 * FLAC (Free Lossless Audio Codec) decoder
3 * Copyright (c) 2003 Alex Beregszaszi
5 * This file is part of FFmpeg.
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.
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.
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
24 * FLAC (Free Lossless Audio Codec) decoder
25 * @author Alex Beregszaszi
27 * For more information on the FLAC format, visit:
28 * http://flac.sourceforge.net/
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.
38 #define ALT_BITSTREAM_READER
39 #include "libavutil/crc.h"
41 #include "bitstream.h"
48 #define MAX_CHANNELS 8
49 #define MAX_BLOCKSIZE 65535
50 #define FLAC_STREAMINFO_SIZE 34
52 enum decorrelation_type {
59 typedef struct FLACContext {
62 AVCodecContext *avctx;
65 int blocksize/*, last_blocksize*/;
67 enum decorrelation_type decorrelation;
69 int32_t *decoded[MAX_CHANNELS];
71 unsigned int bitstream_size;
72 unsigned int bitstream_index;
73 unsigned int allocated_bitstream_size;
76 #define METADATA_TYPE_STREAMINFO 0
78 static const int sample_rate_table[] =
80 88200, 176400, 192000,
81 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
84 static const int sample_size_table[] =
85 { 0, 8, 12, 0, 16, 20, 24, 0 };
87 static const int blocksize_table[] = {
88 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0,
89 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
92 static int64_t get_utf8(GetBitContext *gb)
95 GET_UTF8(val, get_bits(gb, 8), return -1;)
99 static void allocate_buffers(FLACContext *s);
100 static int metadata_parse(FLACContext *s);
102 static av_cold int flac_decode_init(AVCodecContext *avctx)
104 FLACContext *s = avctx->priv_data;
107 if (avctx->extradata_size > 4) {
108 /* initialize based on the demuxer-supplied streamdata header */
109 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
110 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, avctx->extradata);
113 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
118 avctx->sample_fmt = SAMPLE_FMT_S16;
122 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
124 av_log(avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d\n", s->min_blocksize, s->max_blocksize);
125 av_log(avctx, AV_LOG_DEBUG, " Max Framesize: %d\n", s->max_framesize);
126 av_log(avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
127 av_log(avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
128 av_log(avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
131 static void allocate_buffers(FLACContext *s)
135 assert(s->max_blocksize);
137 if (s->max_framesize == 0 && s->max_blocksize) {
138 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
141 for (i = 0; i < s->channels; i++) {
142 s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
145 if (s->allocated_bitstream_size < s->max_framesize)
146 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
149 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
150 const uint8_t *buffer)
153 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
155 /* mandatory streaminfo */
156 s->min_blocksize = get_bits(&gb, 16);
157 s->max_blocksize = get_bits(&gb, 16);
159 skip_bits(&gb, 24); /* skip min frame size */
160 s->max_framesize = get_bits_long(&gb, 24);
162 s->samplerate = get_bits_long(&gb, 20);
163 s->channels = get_bits(&gb, 3) + 1;
164 s->bps = get_bits(&gb, 5) + 1;
166 avctx->channels = s->channels;
167 avctx->sample_rate = s->samplerate;
169 skip_bits(&gb, 36); /* total num of samples */
171 skip_bits(&gb, 64); /* md5 sum */
172 skip_bits(&gb, 64); /* md5 sum */
174 dump_headers(avctx, s);
178 * Parse a list of metadata blocks. This list of blocks must begin with
180 * @param s the flac decoding context containing the gb bit reader used to
182 * @return 1 if some metadata was read, 0 if no fLaC marker was found
184 static int metadata_parse(FLACContext *s)
186 int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
187 int initial_pos= get_bits_count(&s->gb);
189 if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
190 skip_bits(&s->gb, 32);
193 metadata_last = get_bits1(&s->gb);
194 metadata_type = get_bits(&s->gb, 7);
195 metadata_size = get_bits_long(&s->gb, 24);
197 if (get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits) {
198 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
203 switch (metadata_type) {
204 case METADATA_TYPE_STREAMINFO:
205 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, s->gb.buffer+get_bits_count(&s->gb)/8);
206 streaminfo_updated = 1;
209 for (i = 0; i < metadata_size; i++)
210 skip_bits(&s->gb, 8);
213 } while (!metadata_last);
215 if (streaminfo_updated)
222 static int decode_residuals(FLACContext *s, int channel, int pred_order)
224 int i, tmp, partition, method_type, rice_order;
225 int sample = 0, samples;
227 method_type = get_bits(&s->gb, 2);
228 if (method_type > 1) {
229 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n", method_type);
233 rice_order = get_bits(&s->gb, 4);
235 samples= s->blocksize >> rice_order;
236 if (pred_order > samples) {
237 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n", pred_order, samples);
243 for (partition = 0; partition < (1 << rice_order); partition++) {
244 tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
245 if (tmp == (method_type == 0 ? 15 : 31)) {
246 tmp = get_bits(&s->gb, 5);
247 for (; i < samples; i++, sample++)
248 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
250 for (; i < samples; i++, sample++) {
251 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
260 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
262 const int blocksize = s->blocksize;
263 int32_t *decoded = s->decoded[channel];
266 /* warm up samples */
267 for (i = 0; i < pred_order; i++) {
268 decoded[i] = get_sbits(&s->gb, s->curr_bps);
271 if (decode_residuals(s, channel, pred_order) < 0)
275 a = decoded[pred_order-1];
277 b = a - decoded[pred_order-2];
279 c = b - decoded[pred_order-2] + decoded[pred_order-3];
281 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
283 switch (pred_order) {
287 for (i = pred_order; i < blocksize; i++)
288 decoded[i] = a += decoded[i];
291 for (i = pred_order; i < blocksize; i++)
292 decoded[i] = a += b += decoded[i];
295 for (i = pred_order; i < blocksize; i++)
296 decoded[i] = a += b += c += decoded[i];
299 for (i = pred_order; i < blocksize; i++)
300 decoded[i] = a += b += c += d += decoded[i];
303 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
310 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
313 int coeff_prec, qlevel;
314 int coeffs[pred_order];
315 int32_t *decoded = s->decoded[channel];
317 /* warm up samples */
318 for (i = 0; i < pred_order; i++) {
319 decoded[i] = get_sbits(&s->gb, s->curr_bps);
322 coeff_prec = get_bits(&s->gb, 4) + 1;
323 if (coeff_prec == 16) {
324 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
327 qlevel = get_sbits(&s->gb, 5);
329 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n", qlevel);
333 for (i = 0; i < pred_order; i++) {
334 coeffs[i] = get_sbits(&s->gb, coeff_prec);
337 if (decode_residuals(s, channel, pred_order) < 0)
342 for (i = pred_order; i < s->blocksize; i++) {
344 for (j = 0; j < pred_order; j++)
345 sum += (int64_t)coeffs[j] * decoded[i-j-1];
346 decoded[i] += sum >> qlevel;
349 for (i = pred_order; i < s->blocksize-1; i += 2) {
351 int d = decoded[i-pred_order];
353 for (j = pred_order-1; j > 0; j--) {
361 d = decoded[i] += s0 >> qlevel;
363 decoded[i+1] += s1 >> qlevel;
365 if (i < s->blocksize) {
367 for (j = 0; j < pred_order; j++)
368 sum += coeffs[j] * decoded[i-j-1];
369 decoded[i] += sum >> qlevel;
376 static inline int decode_subframe(FLACContext *s, int channel)
378 int type, wasted = 0;
381 s->curr_bps = s->bps;
383 if (s->decorrelation == RIGHT_SIDE)
386 if (s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
390 if (get_bits1(&s->gb)) {
391 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
394 type = get_bits(&s->gb, 6);
396 if (get_bits1(&s->gb)) {
398 while (!get_bits1(&s->gb))
400 s->curr_bps -= wasted;
403 //FIXME use av_log2 for types
405 tmp = get_sbits(&s->gb, s->curr_bps);
406 for (i = 0; i < s->blocksize; i++)
407 s->decoded[channel][i] = tmp;
408 } else if (type == 1) {
409 for (i = 0; i < s->blocksize; i++)
410 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
411 } else if ((type >= 8) && (type <= 12)) {
412 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
414 } else if (type >= 32) {
415 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
418 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
424 for (i = 0; i < s->blocksize; i++)
425 s->decoded[channel][i] <<= wasted;
431 static int decode_frame(FLACContext *s, int alloc_data_size)
433 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
434 int decorrelation, bps, blocksize, samplerate;
436 blocksize_code = get_bits(&s->gb, 4);
438 sample_rate_code = get_bits(&s->gb, 4);
440 assignment = get_bits(&s->gb, 4); /* channel assignment */
441 if (assignment < 8 && s->channels == assignment+1)
442 decorrelation = INDEPENDENT;
443 else if (assignment >=8 && assignment < 11 && s->channels == 2)
444 decorrelation = LEFT_SIDE + assignment - 8;
446 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
450 sample_size_code = get_bits(&s->gb, 3);
451 if (sample_size_code == 0)
453 else if ((sample_size_code != 3) && (sample_size_code != 7))
454 bps = sample_size_table[sample_size_code];
456 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
460 if (get_bits1(&s->gb)) {
461 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
465 if (get_utf8(&s->gb) < 0) {
466 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
470 if (blocksize_code == 0)
471 blocksize = s->min_blocksize;
472 else if (blocksize_code == 6)
473 blocksize = get_bits(&s->gb, 8)+1;
474 else if (blocksize_code == 7)
475 blocksize = get_bits(&s->gb, 16)+1;
477 blocksize = blocksize_table[blocksize_code];
479 if (blocksize > s->max_blocksize) {
480 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
484 if (blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
487 if (sample_rate_code == 0)
488 samplerate= s->samplerate;
489 else if (sample_rate_code < 12)
490 samplerate = sample_rate_table[sample_rate_code];
491 else if (sample_rate_code == 12)
492 samplerate = get_bits(&s->gb, 8) * 1000;
493 else if (sample_rate_code == 13)
494 samplerate = get_bits(&s->gb, 16);
495 else if (sample_rate_code == 14)
496 samplerate = get_bits(&s->gb, 16) * 10;
498 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
502 skip_bits(&s->gb, 8);
503 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
504 s->gb.buffer, get_bits_count(&s->gb)/8);
506 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
510 s->blocksize = blocksize;
511 s->samplerate = samplerate;
513 s->decorrelation= decorrelation;
515 // dump_headers(s->avctx, (FLACStreaminfo *)s);
518 for (i = 0; i < s->channels; i++) {
519 if (decode_subframe(s, i) < 0)
523 align_get_bits(&s->gb);
526 skip_bits(&s->gb, 16); /* data crc */
531 static int flac_decode_frame(AVCodecContext *avctx,
532 void *data, int *data_size,
533 const uint8_t *buf, int buf_size)
535 FLACContext *s = avctx->priv_data;
536 int tmp = 0, i, j = 0, input_buf_size = 0;
537 int16_t *samples = data;
538 int alloc_data_size= *data_size;
542 if (s->max_framesize == 0) {
543 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
544 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
547 if (1 && s->max_framesize) { //FIXME truncated
548 if (s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
549 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
550 input_buf_size= buf_size;
552 if (s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
555 if (s->allocated_bitstream_size < s->bitstream_size + buf_size)
556 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
558 if (s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size) {
559 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
560 s->bitstream_index=0;
562 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
563 buf= &s->bitstream[s->bitstream_index];
564 buf_size += s->bitstream_size;
565 s->bitstream_size= buf_size;
567 if (buf_size < s->max_framesize && input_buf_size) {
568 return input_buf_size;
572 init_get_bits(&s->gb, buf, buf_size*8);
574 if (metadata_parse(s))
577 tmp = show_bits(&s->gb, 16);
578 if ((tmp & 0xFFFE) != 0xFFF8) {
579 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
580 while (get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
581 skip_bits(&s->gb, 8);
582 goto end; // we may not have enough bits left to decode a frame, so try next time
584 skip_bits(&s->gb, 16);
585 if (decode_frame(s, alloc_data_size) < 0) {
586 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
588 s->bitstream_index=0;
592 #define DECORRELATE(left, right)\
593 assert(s->channels == 2);\
594 for (i = 0; i < s->blocksize; i++) {\
595 int a= s->decoded[0][i];\
596 int b= s->decoded[1][i];\
597 *samples++ = ((left) << (24 - s->bps)) >> 8;\
598 *samples++ = ((right) << (24 - s->bps)) >> 8;\
602 switch (s->decorrelation) {
604 for (j = 0; j < s->blocksize; j++) {
605 for (i = 0; i < s->channels; i++)
606 *samples++ = (s->decoded[i][j] << (24 - s->bps)) >> 8;
614 DECORRELATE( (a-=b>>1) + b, a)
617 *data_size = (int8_t *)samples - (int8_t *)data;
620 i= (get_bits_count(&s->gb)+7)/8;
622 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
624 s->bitstream_index=0;
628 if (s->bitstream_size) {
629 s->bitstream_index += i;
630 s->bitstream_size -= i;
631 return input_buf_size;
636 static av_cold int flac_decode_close(AVCodecContext *avctx)
638 FLACContext *s = avctx->priv_data;
641 for (i = 0; i < s->channels; i++) {
642 av_freep(&s->decoded[i]);
644 av_freep(&s->bitstream);
649 static void flac_flush(AVCodecContext *avctx)
651 FLACContext *s = avctx->priv_data;
654 s->bitstream_index= 0;
657 AVCodec flac_decoder = {
668 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),