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){
94 GET_UTF8(val, get_bits(gb, 8), return -1;)
98 static void allocate_buffers(FLACContext *s);
99 static int metadata_parse(FLACContext *s);
101 static av_cold int flac_decode_init(AVCodecContext * avctx)
103 FLACContext *s = avctx->priv_data;
106 if (avctx->extradata_size > 4) {
107 /* initialize based on the demuxer-supplied streamdata header */
108 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
109 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, avctx->extradata);
112 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
117 avctx->sample_fmt = SAMPLE_FMT_S16;
121 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
123 av_log(avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d\n", s->min_blocksize, s->max_blocksize);
124 av_log(avctx, AV_LOG_DEBUG, " Max Framesize: %d\n", s->max_framesize);
125 av_log(avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
126 av_log(avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
127 av_log(avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
130 static void allocate_buffers(FLACContext *s){
133 assert(s->max_blocksize);
135 if(s->max_framesize == 0 && s->max_blocksize){
136 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
139 for (i = 0; i < s->channels; i++)
141 s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
144 if(s->allocated_bitstream_size < s->max_framesize)
145 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
148 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
149 const uint8_t *buffer)
152 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
154 /* mandatory streaminfo */
155 s->min_blocksize = get_bits(&gb, 16);
156 s->max_blocksize = get_bits(&gb, 16);
158 skip_bits(&gb, 24); /* skip min frame size */
159 s->max_framesize = get_bits_long(&gb, 24);
161 s->samplerate = get_bits_long(&gb, 20);
162 s->channels = get_bits(&gb, 3) + 1;
163 s->bps = get_bits(&gb, 5) + 1;
165 avctx->channels = s->channels;
166 avctx->sample_rate = s->samplerate;
168 skip_bits(&gb, 36); /* total num of samples */
170 skip_bits(&gb, 64); /* md5 sum */
171 skip_bits(&gb, 64); /* md5 sum */
173 dump_headers(avctx, s);
177 * Parse a list of metadata blocks. This list of blocks must begin with
179 * @param s the flac decoding context containing the gb bit reader used to
181 * @return 1 if some metadata was read, 0 if no fLaC marker was found
183 static int metadata_parse(FLACContext *s)
185 int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
186 int initial_pos= get_bits_count(&s->gb);
188 if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
189 skip_bits(&s->gb, 32);
192 metadata_last = get_bits1(&s->gb);
193 metadata_type = get_bits(&s->gb, 7);
194 metadata_size = get_bits_long(&s->gb, 24);
196 if(get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits){
197 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
202 switch (metadata_type) {
203 case METADATA_TYPE_STREAMINFO:
204 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s, s->gb.buffer+get_bits_count(&s->gb)/8);
205 streaminfo_updated = 1;
208 for (i=0; i<metadata_size; i++)
209 skip_bits(&s->gb, 8);
212 } while (!metadata_last);
214 if (streaminfo_updated)
221 static int decode_residuals(FLACContext *s, int channel, int pred_order)
223 int i, tmp, partition, method_type, rice_order;
224 int sample = 0, samples;
226 method_type = get_bits(&s->gb, 2);
227 if (method_type > 1){
228 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n", method_type);
232 rice_order = get_bits(&s->gb, 4);
234 samples= s->blocksize >> rice_order;
235 if (pred_order > samples) {
236 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n", pred_order, samples);
242 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))
247 tmp = get_bits(&s->gb, 5);
248 for (; i < samples; i++, sample++)
249 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
253 for (; i < samples; i++, sample++){
254 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
263 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
265 const int blocksize = s->blocksize;
266 int32_t *decoded = s->decoded[channel];
269 /* warm up samples */
270 for (i = 0; i < pred_order; i++)
272 decoded[i] = get_sbits(&s->gb, s->curr_bps);
275 if (decode_residuals(s, channel, pred_order) < 0)
279 a = decoded[pred_order-1];
281 b = a - decoded[pred_order-2];
283 c = b - decoded[pred_order-2] + decoded[pred_order-3];
285 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
292 for (i = pred_order; i < blocksize; i++)
293 decoded[i] = a += decoded[i];
296 for (i = pred_order; i < blocksize; i++)
297 decoded[i] = a += b += decoded[i];
300 for (i = pred_order; i < blocksize; i++)
301 decoded[i] = a += b += c += decoded[i];
304 for (i = pred_order; i < blocksize; i++)
305 decoded[i] = a += b += c += d += decoded[i];
308 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
315 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
318 int coeff_prec, qlevel;
319 int coeffs[pred_order];
320 int32_t *decoded = s->decoded[channel];
322 /* warm up samples */
323 for (i = 0; i < pred_order; i++)
325 decoded[i] = get_sbits(&s->gb, s->curr_bps);
328 coeff_prec = get_bits(&s->gb, 4) + 1;
329 if (coeff_prec == 16)
331 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
334 qlevel = get_sbits(&s->gb, 5);
336 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n", qlevel);
340 for (i = 0; i < pred_order; i++)
342 coeffs[i] = get_sbits(&s->gb, coeff_prec);
345 if (decode_residuals(s, channel, pred_order) < 0)
350 for (i = pred_order; i < s->blocksize; i++)
353 for (j = 0; j < pred_order; j++)
354 sum += (int64_t)coeffs[j] * decoded[i-j-1];
355 decoded[i] += sum >> qlevel;
358 for (i = pred_order; i < s->blocksize-1; i += 2)
361 int d = decoded[i-pred_order];
363 for (j = pred_order-1; j > 0; j--)
372 d = decoded[i] += s0 >> qlevel;
374 decoded[i+1] += s1 >> qlevel;
376 if (i < s->blocksize)
379 for (j = 0; j < pred_order; j++)
380 sum += coeffs[j] * decoded[i-j-1];
381 decoded[i] += sum >> qlevel;
388 static inline int decode_subframe(FLACContext *s, int channel)
390 int type, wasted = 0;
393 s->curr_bps = s->bps;
395 if(s->decorrelation == RIGHT_SIDE)
398 if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
402 if (get_bits1(&s->gb))
404 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
407 type = get_bits(&s->gb, 6);
409 if (get_bits1(&s->gb))
412 while (!get_bits1(&s->gb))
414 s->curr_bps -= wasted;
417 //FIXME use av_log2 for types
420 tmp = get_sbits(&s->gb, s->curr_bps);
421 for (i = 0; i < s->blocksize; i++)
422 s->decoded[channel][i] = tmp;
426 for (i = 0; i < s->blocksize; i++)
427 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
429 else if ((type >= 8) && (type <= 12))
431 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
436 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
441 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
448 for (i = 0; i < s->blocksize; i++)
449 s->decoded[channel][i] <<= wasted;
455 static int decode_frame(FLACContext *s, int alloc_data_size)
457 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
458 int decorrelation, bps, blocksize, samplerate;
460 blocksize_code = get_bits(&s->gb, 4);
462 sample_rate_code = get_bits(&s->gb, 4);
464 assignment = get_bits(&s->gb, 4); /* channel assignment */
465 if (assignment < 8 && s->channels == assignment+1)
466 decorrelation = INDEPENDENT;
467 else if (assignment >=8 && assignment < 11 && s->channels == 2)
468 decorrelation = LEFT_SIDE + assignment - 8;
471 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
475 sample_size_code = get_bits(&s->gb, 3);
476 if(sample_size_code == 0)
478 else if((sample_size_code != 3) && (sample_size_code != 7))
479 bps = sample_size_table[sample_size_code];
482 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
486 if (get_bits1(&s->gb))
488 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
492 if(get_utf8(&s->gb) < 0){
493 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
497 if (blocksize_code == 0)
498 blocksize = s->min_blocksize;
499 else if (blocksize_code == 6)
500 blocksize = get_bits(&s->gb, 8)+1;
501 else if (blocksize_code == 7)
502 blocksize = get_bits(&s->gb, 16)+1;
504 blocksize = blocksize_table[blocksize_code];
506 if(blocksize > s->max_blocksize){
507 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
511 if(blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
514 if (sample_rate_code == 0){
515 samplerate= s->samplerate;
516 }else if (sample_rate_code < 12)
517 samplerate = sample_rate_table[sample_rate_code];
518 else if (sample_rate_code == 12)
519 samplerate = get_bits(&s->gb, 8) * 1000;
520 else if (sample_rate_code == 13)
521 samplerate = get_bits(&s->gb, 16);
522 else if (sample_rate_code == 14)
523 samplerate = get_bits(&s->gb, 16) * 10;
525 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
529 skip_bits(&s->gb, 8);
530 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
531 s->gb.buffer, get_bits_count(&s->gb)/8);
533 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
537 s->blocksize = blocksize;
538 s->samplerate = samplerate;
540 s->decorrelation= decorrelation;
542 // dump_headers(s->avctx, (FLACStreaminfo *)s);
545 for (i = 0; i < s->channels; i++)
547 if (decode_subframe(s, i) < 0)
551 align_get_bits(&s->gb);
554 skip_bits(&s->gb, 16); /* data crc */
559 static int flac_decode_frame(AVCodecContext *avctx,
560 void *data, int *data_size,
561 const uint8_t *buf, int buf_size)
563 FLACContext *s = avctx->priv_data;
564 int tmp = 0, i, j = 0, input_buf_size = 0;
565 int16_t *samples = data;
566 int alloc_data_size= *data_size;
570 if(s->max_framesize == 0){
571 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
572 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
575 if(1 && s->max_framesize){//FIXME truncated
576 if(s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
577 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
578 input_buf_size= buf_size;
580 if(s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
583 if(s->allocated_bitstream_size < s->bitstream_size + buf_size)
584 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
586 if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
587 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
588 s->bitstream_index=0;
590 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
591 buf= &s->bitstream[s->bitstream_index];
592 buf_size += s->bitstream_size;
593 s->bitstream_size= buf_size;
595 if(buf_size < s->max_framesize && input_buf_size){
596 return input_buf_size;
600 init_get_bits(&s->gb, buf, buf_size*8);
602 if(metadata_parse(s))
605 tmp = show_bits(&s->gb, 16);
606 if((tmp & 0xFFFE) != 0xFFF8){
607 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
608 while(get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
609 skip_bits(&s->gb, 8);
610 goto end; // we may not have enough bits left to decode a frame, so try next time
612 skip_bits(&s->gb, 16);
613 if (decode_frame(s, alloc_data_size) < 0){
614 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
616 s->bitstream_index=0;
620 #define DECORRELATE(left, right)\
621 assert(s->channels == 2);\
622 for (i = 0; i < s->blocksize; i++)\
624 int a= s->decoded[0][i];\
625 int b= s->decoded[1][i];\
626 *samples++ = ((left) << (24 - s->bps)) >> 8;\
627 *samples++ = ((right) << (24 - s->bps)) >> 8;\
631 switch(s->decorrelation)
634 for (j = 0; j < s->blocksize; j++)
636 for (i = 0; i < s->channels; i++)
637 *samples++ = (s->decoded[i][j] << (24 - s->bps)) >> 8;
645 DECORRELATE( (a-=b>>1) + b, a)
648 *data_size = (int8_t *)samples - (int8_t *)data;
651 i= (get_bits_count(&s->gb)+7)/8;
653 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
655 s->bitstream_index=0;
659 if(s->bitstream_size){
660 s->bitstream_index += i;
661 s->bitstream_size -= i;
662 return input_buf_size;
667 static av_cold int flac_decode_close(AVCodecContext *avctx)
669 FLACContext *s = avctx->priv_data;
672 for (i = 0; i < s->channels; i++)
674 av_freep(&s->decoded[i]);
676 av_freep(&s->bitstream);
681 static void flac_flush(AVCodecContext *avctx){
682 FLACContext *s = avctx->priv_data;
685 s->bitstream_index= 0;
688 AVCodec flac_decoder = {
699 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),