2 * FLAC (Free Lossless Audio Codec) decoder
3 * Copyright (c) 2003 Alex Beregszaszi
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 * FLAC (Free Lossless Audio Codec) decoder
23 * @author Alex Beregszaszi
25 * For more information on the FLAC format, visit:
26 * http://flac.sourceforge.net/
28 * This decoder can be used in 1 of 2 ways: Either raw FLAC data can be fed
29 * through, starting from the initial 'fLaC' signature; or by passing the
30 * 34-byte streaminfo structure through avctx->extradata[_size] followed
31 * by data starting with the 0xFFF8 marker.
37 #include "bitstream.h"
44 #define MAX_CHANNELS 8
45 #define MAX_BLOCKSIZE 65535
46 #define FLAC_STREAMINFO_SIZE 34
48 enum decorrelation_type {
55 typedef struct FLACContext {
56 AVCodecContext *avctx;
59 int min_blocksize, max_blocksize;
60 int min_framesize, max_framesize;
61 int samplerate, channels;
62 int blocksize/*, last_blocksize*/;
64 enum decorrelation_type decorrelation;
66 int32_t *decoded[MAX_CHANNELS];
70 unsigned int allocated_bitstream_size;
73 #define METADATA_TYPE_STREAMINFO 0
75 static int sample_rate_table[] =
77 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
80 static int sample_size_table[] =
81 { 0, 8, 12, 0, 16, 20, 24, 0 };
83 static int blocksize_table[] = {
84 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0,
85 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
88 static int64_t get_utf8(GetBitContext *gb){
90 GET_UTF8(val, get_bits(gb, 8), return -1;)
94 static void metadata_streaminfo(FLACContext *s);
95 static void dump_headers(FLACContext *s);
97 static int flac_decode_init(AVCodecContext * avctx)
99 FLACContext *s = avctx->priv_data;
102 /* initialize based on the demuxer-supplied streamdata header */
103 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
104 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
105 metadata_streaminfo(s);
112 static void dump_headers(FLACContext *s)
114 av_log(s->avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
115 av_log(s->avctx, AV_LOG_DEBUG, " Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
116 av_log(s->avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
117 av_log(s->avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
118 av_log(s->avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
121 static void allocate_buffers(FLACContext *s){
124 assert(s->max_blocksize);
126 if(s->max_framesize == 0 && s->max_blocksize){
127 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
130 for (i = 0; i < s->channels; i++)
132 s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
135 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
138 static void metadata_streaminfo(FLACContext *s)
140 /* mandatory streaminfo */
141 s->min_blocksize = get_bits(&s->gb, 16);
142 s->max_blocksize = get_bits(&s->gb, 16);
144 s->min_framesize = get_bits_long(&s->gb, 24);
145 s->max_framesize = get_bits_long(&s->gb, 24);
147 s->samplerate = get_bits_long(&s->gb, 20);
148 s->channels = get_bits(&s->gb, 3) + 1;
149 s->bps = get_bits(&s->gb, 5) + 1;
151 s->avctx->channels = s->channels;
152 s->avctx->sample_rate = s->samplerate;
154 skip_bits(&s->gb, 36); /* total num of samples */
156 skip_bits(&s->gb, 64); /* md5 sum */
157 skip_bits(&s->gb, 64); /* md5 sum */
162 static int decode_residuals(FLACContext *s, int channel, int pred_order)
164 int i, tmp, partition, method_type, rice_order;
165 int sample = 0, samples;
167 method_type = get_bits(&s->gb, 2);
168 if (method_type != 0){
169 av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
173 rice_order = get_bits(&s->gb, 4);
175 samples= s->blocksize >> rice_order;
179 for (partition = 0; partition < (1 << rice_order); partition++)
181 tmp = get_bits(&s->gb, 4);
184 av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
185 tmp = get_bits(&s->gb, 5);
186 for (; i < samples; i++, sample++)
187 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
191 // av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
192 for (; i < samples; i++, sample++){
193 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
199 // av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
204 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
208 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME FIXED\n");
210 /* warm up samples */
211 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
213 for (i = 0; i < pred_order; i++)
215 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
216 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
219 if (decode_residuals(s, channel, pred_order) < 0)
227 for (i = pred_order; i < s->blocksize; i++)
228 s->decoded[channel][i] += s->decoded[channel][i-1];
231 for (i = pred_order; i < s->blocksize; i++)
232 s->decoded[channel][i] += 2*s->decoded[channel][i-1]
233 - s->decoded[channel][i-2];
236 for (i = pred_order; i < s->blocksize; i++)
237 s->decoded[channel][i] += 3*s->decoded[channel][i-1]
238 - 3*s->decoded[channel][i-2]
239 + s->decoded[channel][i-3];
242 for (i = pred_order; i < s->blocksize; i++)
243 s->decoded[channel][i] += 4*s->decoded[channel][i-1]
244 - 6*s->decoded[channel][i-2]
245 + 4*s->decoded[channel][i-3]
246 - s->decoded[channel][i-4];
249 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
256 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
259 int coeff_prec, qlevel;
260 int coeffs[pred_order];
262 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME LPC\n");
264 /* warm up samples */
265 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
267 for (i = 0; i < pred_order; i++)
269 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
270 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
273 coeff_prec = get_bits(&s->gb, 4) + 1;
274 if (coeff_prec == 16)
276 av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
279 // av_log(s->avctx, AV_LOG_DEBUG, " qlp coeff prec: %d\n", coeff_prec);
280 qlevel = get_sbits(&s->gb, 5);
281 // av_log(s->avctx, AV_LOG_DEBUG, " quant level: %d\n", qlevel);
283 av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
287 for (i = 0; i < pred_order; i++)
289 coeffs[i] = get_sbits(&s->gb, coeff_prec);
290 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, coeffs[i]);
293 if (decode_residuals(s, channel, pred_order) < 0)
298 for (i = pred_order; i < s->blocksize; i++)
301 for (j = 0; j < pred_order; j++)
302 sum += (int64_t)coeffs[j] * s->decoded[channel][i-j-1];
303 s->decoded[channel][i] += sum >> qlevel;
307 for (i = pred_order; i < s->blocksize; i++)
310 for (j = 0; j < pred_order; j++)
311 sum += coeffs[j] * s->decoded[channel][i-j-1];
312 s->decoded[channel][i] += sum >> qlevel;
319 static inline int decode_subframe(FLACContext *s, int channel)
321 int type, wasted = 0;
324 s->curr_bps = s->bps;
326 if(s->decorrelation == RIGHT_SIDE)
329 if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
333 if (get_bits1(&s->gb))
335 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
338 type = get_bits(&s->gb, 6);
339 // wasted = get_bits1(&s->gb);
343 // while (!get_bits1(&s->gb))
347 // s->curr_bps -= wasted;
350 wasted= 16 - av_log2(show_bits(&s->gb, 17));
351 skip_bits(&s->gb, wasted+1);
352 s->curr_bps -= wasted;
354 if (get_bits1(&s->gb))
357 while (!get_bits1(&s->gb))
359 s->curr_bps -= wasted;
360 av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
363 //FIXME use av_log2 for types
366 av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
367 tmp = get_sbits(&s->gb, s->curr_bps);
368 for (i = 0; i < s->blocksize; i++)
369 s->decoded[channel][i] = tmp;
373 av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
374 for (i = 0; i < s->blocksize; i++)
375 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
377 else if ((type >= 8) && (type <= 12))
379 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
380 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
385 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
386 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
391 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
398 for (i = 0; i < s->blocksize; i++)
399 s->decoded[channel][i] <<= wasted;
405 static int decode_frame(FLACContext *s)
407 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
408 int decorrelation, bps, blocksize, samplerate;
410 blocksize_code = get_bits(&s->gb, 4);
412 sample_rate_code = get_bits(&s->gb, 4);
414 assignment = get_bits(&s->gb, 4); /* channel assignment */
415 if (assignment < 8 && s->channels == assignment+1)
416 decorrelation = INDEPENDENT;
417 else if (assignment >=8 && assignment < 11 && s->channels == 2)
418 decorrelation = LEFT_SIDE + assignment - 8;
421 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
425 sample_size_code = get_bits(&s->gb, 3);
426 if(sample_size_code == 0)
428 else if((sample_size_code != 3) && (sample_size_code != 7))
429 bps = sample_size_table[sample_size_code];
432 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
436 if (get_bits1(&s->gb))
438 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
442 if(get_utf8(&s->gb) < 0){
443 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
447 if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
448 (s->min_blocksize != s->max_blocksize)){
453 if (blocksize_code == 0)
454 blocksize = s->min_blocksize;
455 else if (blocksize_code == 6)
456 blocksize = get_bits(&s->gb, 8)+1;
457 else if (blocksize_code == 7)
458 blocksize = get_bits(&s->gb, 16)+1;
460 blocksize = blocksize_table[blocksize_code];
462 if(blocksize > s->max_blocksize){
463 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
467 if (sample_rate_code == 0){
468 samplerate= s->samplerate;
469 }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
470 samplerate = sample_rate_table[sample_rate_code];
471 else if (sample_rate_code == 12)
472 samplerate = get_bits(&s->gb, 8) * 1000;
473 else if (sample_rate_code == 13)
474 samplerate = get_bits(&s->gb, 16);
475 else if (sample_rate_code == 14)
476 samplerate = get_bits(&s->gb, 16) * 10;
478 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
482 skip_bits(&s->gb, 8);
483 crc8= av_crc(av_crc07, 0, s->gb.buffer, get_bits_count(&s->gb)/8);
485 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
489 s->blocksize = blocksize;
490 s->samplerate = samplerate;
492 s->decorrelation= decorrelation;
497 for (i = 0; i < s->channels; i++)
499 // av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
500 if (decode_subframe(s, i) < 0)
504 align_get_bits(&s->gb);
507 skip_bits(&s->gb, 16); /* data crc */
512 static inline int16_t shift_to_16_bits(int32_t data, int bps)
516 } else if (bps == 20) {
523 static int flac_decode_frame(AVCodecContext *avctx,
524 void *data, int *data_size,
525 uint8_t *buf, int buf_size)
527 FLACContext *s = avctx->priv_data;
528 int metadata_last, metadata_type, metadata_size;
529 int tmp = 0, i, j = 0, input_buf_size = 0;
530 int16_t *samples = data;
532 if(s->max_framesize == 0){
533 s->max_framesize= 65536; // should hopefully be enough for the first header
534 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
537 if(1 && s->max_framesize){//FIXME truncated
538 buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
539 input_buf_size= buf_size;
541 if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
542 // printf("memmove\n");
543 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
544 s->bitstream_index=0;
546 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
547 buf= &s->bitstream[s->bitstream_index];
548 buf_size += s->bitstream_size;
549 s->bitstream_size= buf_size;
551 if(buf_size < s->max_framesize){
552 // printf("wanna more data ...\n");
553 return input_buf_size;
557 init_get_bits(&s->gb, buf, buf_size*8);
559 /* fLaC signature (be) */
560 if (show_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
562 skip_bits(&s->gb, 32);
564 av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
566 metadata_last = get_bits(&s->gb, 1);
567 metadata_type = get_bits(&s->gb, 7);
568 metadata_size = get_bits_long(&s->gb, 24);
570 av_log(s->avctx, AV_LOG_DEBUG, " metadata block: flag = %d, type = %d, size = %d\n",
571 metadata_last, metadata_type,
574 switch(metadata_type)
576 case METADATA_TYPE_STREAMINFO:{
577 metadata_streaminfo(s);
579 /* Buffer might have been reallocated, reinit bitreader */
580 if(buf != &s->bitstream[s->bitstream_index])
582 int bits_count = get_bits_count(&s->gb);
583 buf= &s->bitstream[s->bitstream_index];
584 init_get_bits(&s->gb, buf, buf_size*8);
585 skip_bits(&s->gb, bits_count);
591 for(i=0; i<metadata_size; i++)
592 skip_bits(&s->gb, 8);
595 } while(!metadata_last);
600 tmp = show_bits(&s->gb, 16);
602 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
603 while(get_bits_count(&s->gb)/8+2 < buf_size && show_bits(&s->gb, 16) != 0xFFF8)
604 skip_bits(&s->gb, 8);
605 goto end; // we may not have enough bits left to decode a frame, so try next time
607 skip_bits(&s->gb, 16);
608 if (decode_frame(s) < 0){
609 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
611 s->bitstream_index=0;
618 /* fix the channel order here */
619 if (s->order == MID_SIDE)
621 short *left = samples;
622 short *right = samples + s->blocksize;
623 for (i = 0; i < s->blocksize; i += 2)
625 uint32_t x = s->decoded[0][i];
626 uint32_t y = s->decoded[0][i+1];
628 right[i] = x - (y / 2);
629 left[i] = right[i] + y;
631 *data_size = 2 * s->blocksize;
635 for (i = 0; i < s->channels; i++)
640 for (j = 0; j < s->blocksize; j++)
641 samples[(s->blocksize*i)+j] = s->decoded[i][j];
646 for (j = 0; j < s->blocksize; j++)
647 samples[(s->blocksize*i)+j] = s->decoded[0][j];
649 for (j = 0; j < s->blocksize; j++)
650 samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
653 // av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
655 *data_size += s->blocksize;
659 #define DECORRELATE(left, right)\
660 assert(s->channels == 2);\
661 for (i = 0; i < s->blocksize; i++)\
663 int a= s->decoded[0][i];\
664 int b= s->decoded[1][i];\
665 *(samples++) = (left ) >> (16 - s->bps);\
666 *(samples++) = (right) >> (16 - s->bps);\
670 switch(s->decorrelation)
673 for (j = 0; j < s->blocksize; j++)
675 for (i = 0; i < s->channels; i++)
676 *(samples++) = shift_to_16_bits(s->decoded[i][j], s->bps);
684 DECORRELATE( (a-=b>>1) + b, a)
688 *data_size = (int8_t *)samples - (int8_t *)data;
689 // av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
691 // s->last_blocksize = s->blocksize;
693 i= (get_bits_count(&s->gb)+7)/8;;
695 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
697 s->bitstream_index=0;
701 if(s->bitstream_size){
702 s->bitstream_index += i;
703 s->bitstream_size -= i;
704 return input_buf_size;
709 static int flac_decode_close(AVCodecContext *avctx)
711 FLACContext *s = avctx->priv_data;
714 for (i = 0; i < s->channels; i++)
716 av_freep(&s->decoded[i]);
718 av_freep(&s->bitstream);
723 static void flac_flush(AVCodecContext *avctx){
724 FLACContext *s = avctx->priv_data;
727 s->bitstream_index= 0;
730 AVCodec flac_decoder = {