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.
36 #define ALT_BITSTREAM_READER
38 #include "bitstream.h"
45 #define MAX_CHANNELS 8
46 #define MAX_BLOCKSIZE 65535
47 #define FLAC_STREAMINFO_SIZE 34
49 enum decorrelation_type {
56 typedef struct FLACContext {
57 AVCodecContext *avctx;
60 int min_blocksize, max_blocksize;
61 int min_framesize, max_framesize;
62 int samplerate, channels;
63 int blocksize/*, last_blocksize*/;
65 enum decorrelation_type decorrelation;
67 int32_t *decoded[MAX_CHANNELS];
71 unsigned int allocated_bitstream_size;
74 #define METADATA_TYPE_STREAMINFO 0
76 static int sample_rate_table[] =
78 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
81 static int sample_size_table[] =
82 { 0, 8, 12, 0, 16, 20, 24, 0 };
84 static int blocksize_table[] = {
85 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0,
86 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
89 static int64_t get_utf8(GetBitContext *gb){
91 GET_UTF8(val, get_bits(gb, 8), return -1;)
95 static void metadata_streaminfo(FLACContext *s);
96 static void dump_headers(FLACContext *s);
98 static int flac_decode_init(AVCodecContext * avctx)
100 FLACContext *s = avctx->priv_data;
103 /* initialize based on the demuxer-supplied streamdata header */
104 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
105 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
106 metadata_streaminfo(s);
113 static void dump_headers(FLACContext *s)
115 av_log(s->avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
116 av_log(s->avctx, AV_LOG_DEBUG, " Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
117 av_log(s->avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
118 av_log(s->avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
119 av_log(s->avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
122 static void allocate_buffers(FLACContext *s){
125 assert(s->max_blocksize);
127 if(s->max_framesize == 0 && s->max_blocksize){
128 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
131 for (i = 0; i < s->channels; i++)
133 s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
136 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
139 static void metadata_streaminfo(FLACContext *s)
141 /* mandatory streaminfo */
142 s->min_blocksize = get_bits(&s->gb, 16);
143 s->max_blocksize = get_bits(&s->gb, 16);
145 s->min_framesize = get_bits_long(&s->gb, 24);
146 s->max_framesize = get_bits_long(&s->gb, 24);
148 s->samplerate = get_bits_long(&s->gb, 20);
149 s->channels = get_bits(&s->gb, 3) + 1;
150 s->bps = get_bits(&s->gb, 5) + 1;
152 s->avctx->channels = s->channels;
153 s->avctx->sample_rate = s->samplerate;
155 skip_bits(&s->gb, 36); /* total num of samples */
157 skip_bits(&s->gb, 64); /* md5 sum */
158 skip_bits(&s->gb, 64); /* md5 sum */
163 static int decode_residuals(FLACContext *s, int channel, int pred_order)
165 int i, tmp, partition, method_type, rice_order;
166 int sample = 0, samples;
168 method_type = get_bits(&s->gb, 2);
169 if (method_type != 0){
170 av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
174 rice_order = get_bits(&s->gb, 4);
176 samples= s->blocksize >> rice_order;
180 for (partition = 0; partition < (1 << rice_order); partition++)
182 tmp = get_bits(&s->gb, 4);
185 av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
186 tmp = get_bits(&s->gb, 5);
187 for (; i < samples; i++, sample++)
188 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
192 // av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
193 for (; i < samples; i++, sample++){
194 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
200 // av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
205 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
209 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME FIXED\n");
211 /* warm up samples */
212 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
214 for (i = 0; i < pred_order; i++)
216 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
217 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
220 if (decode_residuals(s, channel, pred_order) < 0)
228 for (i = pred_order; i < s->blocksize; i++)
229 s->decoded[channel][i] += s->decoded[channel][i-1];
232 for (i = pred_order; i < s->blocksize; i++)
233 s->decoded[channel][i] += 2*s->decoded[channel][i-1]
234 - s->decoded[channel][i-2];
237 for (i = pred_order; i < s->blocksize; i++)
238 s->decoded[channel][i] += 3*s->decoded[channel][i-1]
239 - 3*s->decoded[channel][i-2]
240 + s->decoded[channel][i-3];
243 for (i = pred_order; i < s->blocksize; i++)
244 s->decoded[channel][i] += 4*s->decoded[channel][i-1]
245 - 6*s->decoded[channel][i-2]
246 + 4*s->decoded[channel][i-3]
247 - s->decoded[channel][i-4];
250 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
257 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
260 int coeff_prec, qlevel;
261 int coeffs[pred_order];
263 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME LPC\n");
265 /* warm up samples */
266 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
268 for (i = 0; i < pred_order; i++)
270 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
271 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
274 coeff_prec = get_bits(&s->gb, 4) + 1;
275 if (coeff_prec == 16)
277 av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
280 // av_log(s->avctx, AV_LOG_DEBUG, " qlp coeff prec: %d\n", coeff_prec);
281 qlevel = get_sbits(&s->gb, 5);
282 // av_log(s->avctx, AV_LOG_DEBUG, " quant level: %d\n", qlevel);
284 av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
288 for (i = 0; i < pred_order; i++)
290 coeffs[i] = get_sbits(&s->gb, coeff_prec);
291 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, coeffs[i]);
294 if (decode_residuals(s, channel, pred_order) < 0)
299 for (i = pred_order; i < s->blocksize; i++)
302 for (j = 0; j < pred_order; j++)
303 sum += (int64_t)coeffs[j] * s->decoded[channel][i-j-1];
304 s->decoded[channel][i] += sum >> qlevel;
308 for (i = pred_order; i < s->blocksize; i++)
311 for (j = 0; j < pred_order; j++)
312 sum += coeffs[j] * s->decoded[channel][i-j-1];
313 s->decoded[channel][i] += sum >> qlevel;
320 static inline int decode_subframe(FLACContext *s, int channel)
322 int type, wasted = 0;
325 s->curr_bps = s->bps;
327 if(s->decorrelation == RIGHT_SIDE)
330 if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
334 if (get_bits1(&s->gb))
336 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
339 type = get_bits(&s->gb, 6);
340 // wasted = get_bits1(&s->gb);
344 // while (!get_bits1(&s->gb))
348 // s->curr_bps -= wasted;
351 wasted= 16 - av_log2(show_bits(&s->gb, 17));
352 skip_bits(&s->gb, wasted+1);
353 s->curr_bps -= wasted;
355 if (get_bits1(&s->gb))
358 while (!get_bits1(&s->gb))
360 s->curr_bps -= wasted;
361 av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
364 //FIXME use av_log2 for types
367 av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
368 tmp = get_sbits(&s->gb, s->curr_bps);
369 for (i = 0; i < s->blocksize; i++)
370 s->decoded[channel][i] = tmp;
374 av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
375 for (i = 0; i < s->blocksize; i++)
376 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
378 else if ((type >= 8) && (type <= 12))
380 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
381 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
386 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
387 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
392 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
399 for (i = 0; i < s->blocksize; i++)
400 s->decoded[channel][i] <<= wasted;
406 static int decode_frame(FLACContext *s)
408 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
409 int decorrelation, bps, blocksize, samplerate;
411 blocksize_code = get_bits(&s->gb, 4);
413 sample_rate_code = get_bits(&s->gb, 4);
415 assignment = get_bits(&s->gb, 4); /* channel assignment */
416 if (assignment < 8 && s->channels == assignment+1)
417 decorrelation = INDEPENDENT;
418 else if (assignment >=8 && assignment < 11 && s->channels == 2)
419 decorrelation = LEFT_SIDE + assignment - 8;
422 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
426 sample_size_code = get_bits(&s->gb, 3);
427 if(sample_size_code == 0)
429 else if((sample_size_code != 3) && (sample_size_code != 7))
430 bps = sample_size_table[sample_size_code];
433 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
437 if (get_bits1(&s->gb))
439 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
443 if(get_utf8(&s->gb) < 0){
444 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
448 if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
449 (s->min_blocksize != s->max_blocksize)){
454 if (blocksize_code == 0)
455 blocksize = s->min_blocksize;
456 else if (blocksize_code == 6)
457 blocksize = get_bits(&s->gb, 8)+1;
458 else if (blocksize_code == 7)
459 blocksize = get_bits(&s->gb, 16)+1;
461 blocksize = blocksize_table[blocksize_code];
463 if(blocksize > s->max_blocksize){
464 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
468 if (sample_rate_code == 0){
469 samplerate= s->samplerate;
470 }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
471 samplerate = sample_rate_table[sample_rate_code];
472 else if (sample_rate_code == 12)
473 samplerate = get_bits(&s->gb, 8) * 1000;
474 else if (sample_rate_code == 13)
475 samplerate = get_bits(&s->gb, 16);
476 else if (sample_rate_code == 14)
477 samplerate = get_bits(&s->gb, 16) * 10;
479 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
483 skip_bits(&s->gb, 8);
484 crc8= av_crc(av_crc07, 0, s->gb.buffer, get_bits_count(&s->gb)/8);
486 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
490 s->blocksize = blocksize;
491 s->samplerate = samplerate;
493 s->decorrelation= decorrelation;
498 for (i = 0; i < s->channels; i++)
500 // av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
501 if (decode_subframe(s, i) < 0)
505 align_get_bits(&s->gb);
508 skip_bits(&s->gb, 16); /* data crc */
513 static inline int16_t shift_to_16_bits(int32_t data, int bps)
517 } else if (bps == 20) {
524 static int flac_decode_frame(AVCodecContext *avctx,
525 void *data, int *data_size,
526 uint8_t *buf, int buf_size)
528 FLACContext *s = avctx->priv_data;
529 int metadata_last, metadata_type, metadata_size;
530 int tmp = 0, i, j = 0, input_buf_size = 0;
531 int16_t *samples = data;
533 if(s->max_framesize == 0){
534 s->max_framesize= 65536; // should hopefully be enough for the first header
535 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
538 if(1 && s->max_framesize){//FIXME truncated
539 buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
540 input_buf_size= buf_size;
542 if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
543 // printf("memmove\n");
544 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
545 s->bitstream_index=0;
547 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
548 buf= &s->bitstream[s->bitstream_index];
549 buf_size += s->bitstream_size;
550 s->bitstream_size= buf_size;
552 if(buf_size < s->max_framesize){
553 // printf("wanna more data ...\n");
554 return input_buf_size;
558 init_get_bits(&s->gb, buf, buf_size*8);
560 /* fLaC signature (be) */
561 if (show_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
563 skip_bits(&s->gb, 32);
565 av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
567 metadata_last = get_bits(&s->gb, 1);
568 metadata_type = get_bits(&s->gb, 7);
569 metadata_size = get_bits_long(&s->gb, 24);
571 av_log(s->avctx, AV_LOG_DEBUG, " metadata block: flag = %d, type = %d, size = %d\n",
572 metadata_last, metadata_type,
575 switch(metadata_type)
577 case METADATA_TYPE_STREAMINFO:{
578 metadata_streaminfo(s);
580 /* Buffer might have been reallocated, reinit bitreader */
581 if(buf != &s->bitstream[s->bitstream_index])
583 int bits_count = get_bits_count(&s->gb);
584 buf= &s->bitstream[s->bitstream_index];
585 init_get_bits(&s->gb, buf, buf_size*8);
586 skip_bits(&s->gb, bits_count);
592 for(i=0; i<metadata_size; i++)
593 skip_bits(&s->gb, 8);
596 } while(!metadata_last);
601 tmp = show_bits(&s->gb, 16);
603 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
604 while(get_bits_count(&s->gb)/8+2 < buf_size && show_bits(&s->gb, 16) != 0xFFF8)
605 skip_bits(&s->gb, 8);
606 goto end; // we may not have enough bits left to decode a frame, so try next time
608 skip_bits(&s->gb, 16);
609 if (decode_frame(s) < 0){
610 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
612 s->bitstream_index=0;
619 /* fix the channel order here */
620 if (s->order == MID_SIDE)
622 short *left = samples;
623 short *right = samples + s->blocksize;
624 for (i = 0; i < s->blocksize; i += 2)
626 uint32_t x = s->decoded[0][i];
627 uint32_t y = s->decoded[0][i+1];
629 right[i] = x - (y / 2);
630 left[i] = right[i] + y;
632 *data_size = 2 * s->blocksize;
636 for (i = 0; i < s->channels; i++)
641 for (j = 0; j < s->blocksize; j++)
642 samples[(s->blocksize*i)+j] = s->decoded[i][j];
647 for (j = 0; j < s->blocksize; j++)
648 samples[(s->blocksize*i)+j] = s->decoded[0][j];
650 for (j = 0; j < s->blocksize; j++)
651 samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
654 // av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
656 *data_size += s->blocksize;
660 #define DECORRELATE(left, right)\
661 assert(s->channels == 2);\
662 for (i = 0; i < s->blocksize; i++)\
664 int a= s->decoded[0][i];\
665 int b= s->decoded[1][i];\
666 *(samples++) = (left ) >> (16 - s->bps);\
667 *(samples++) = (right) >> (16 - s->bps);\
671 switch(s->decorrelation)
674 for (j = 0; j < s->blocksize; j++)
676 for (i = 0; i < s->channels; i++)
677 *(samples++) = shift_to_16_bits(s->decoded[i][j], s->bps);
685 DECORRELATE( (a-=b>>1) + b, a)
689 *data_size = (int8_t *)samples - (int8_t *)data;
690 // av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
692 // s->last_blocksize = s->blocksize;
694 i= (get_bits_count(&s->gb)+7)/8;;
696 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
698 s->bitstream_index=0;
702 if(s->bitstream_size){
703 s->bitstream_index += i;
704 s->bitstream_size -= i;
705 return input_buf_size;
710 static int flac_decode_close(AVCodecContext *avctx)
712 FLACContext *s = avctx->priv_data;
715 for (i = 0; i < s->channels; i++)
717 av_freep(&s->decoded[i]);
719 av_freep(&s->bitstream);
724 static void flac_flush(AVCodecContext *avctx){
725 FLACContext *s = avctx->priv_data;
728 s->bitstream_index= 0;
731 AVCodec flac_decoder = {