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
40 #include "bitstream.h"
47 #define MAX_CHANNELS 8
48 #define MAX_BLOCKSIZE 65535
49 #define FLAC_STREAMINFO_SIZE 34
51 enum decorrelation_type {
58 typedef struct FLACContext {
59 AVCodecContext *avctx;
62 int min_blocksize, max_blocksize;
63 int min_framesize, max_framesize;
64 int samplerate, channels;
65 int blocksize/*, last_blocksize*/;
67 enum decorrelation_type decorrelation;
69 int32_t *decoded[MAX_CHANNELS];
73 unsigned int allocated_bitstream_size;
76 #define METADATA_TYPE_STREAMINFO 0
78 static int sample_rate_table[] =
80 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
83 static int sample_size_table[] =
84 { 0, 8, 12, 0, 16, 20, 24, 0 };
86 static int blocksize_table[] = {
87 0, 192, 576<<0, 576<<1, 576<<2, 576<<3, 0, 0,
88 256<<0, 256<<1, 256<<2, 256<<3, 256<<4, 256<<5, 256<<6, 256<<7
91 static int64_t get_utf8(GetBitContext *gb){
93 GET_UTF8(val, get_bits(gb, 8), return -1;)
97 static void metadata_streaminfo(FLACContext *s);
98 static void dump_headers(FLACContext *s);
100 static int flac_decode_init(AVCodecContext * avctx)
102 FLACContext *s = avctx->priv_data;
105 /* initialize based on the demuxer-supplied streamdata header */
106 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
107 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
108 metadata_streaminfo(s);
115 static void dump_headers(FLACContext *s)
117 av_log(s->avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
118 av_log(s->avctx, AV_LOG_DEBUG, " Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
119 av_log(s->avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
120 av_log(s->avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
121 av_log(s->avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
124 static void allocate_buffers(FLACContext *s){
127 assert(s->max_blocksize);
129 if(s->max_framesize == 0 && s->max_blocksize){
130 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8; //FIXME header overhead
133 for (i = 0; i < s->channels; i++)
135 s->decoded[i] = av_realloc(s->decoded[i], sizeof(int32_t)*s->max_blocksize);
138 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
141 static void metadata_streaminfo(FLACContext *s)
143 /* mandatory streaminfo */
144 s->min_blocksize = get_bits(&s->gb, 16);
145 s->max_blocksize = get_bits(&s->gb, 16);
147 s->min_framesize = get_bits_long(&s->gb, 24);
148 s->max_framesize = get_bits_long(&s->gb, 24);
150 s->samplerate = get_bits_long(&s->gb, 20);
151 s->channels = get_bits(&s->gb, 3) + 1;
152 s->bps = get_bits(&s->gb, 5) + 1;
154 s->avctx->channels = s->channels;
155 s->avctx->sample_rate = s->samplerate;
157 skip_bits(&s->gb, 36); /* total num of samples */
159 skip_bits(&s->gb, 64); /* md5 sum */
160 skip_bits(&s->gb, 64); /* md5 sum */
165 static int decode_residuals(FLACContext *s, int channel, int pred_order)
167 int i, tmp, partition, method_type, rice_order;
168 int sample = 0, samples;
170 method_type = get_bits(&s->gb, 2);
171 if (method_type != 0){
172 av_log(s->avctx, AV_LOG_DEBUG, "illegal residual coding method %d\n", method_type);
176 rice_order = get_bits(&s->gb, 4);
178 samples= s->blocksize >> rice_order;
182 for (partition = 0; partition < (1 << rice_order); partition++)
184 tmp = get_bits(&s->gb, 4);
187 av_log(s->avctx, AV_LOG_DEBUG, "fixed len partition\n");
188 tmp = get_bits(&s->gb, 5);
189 for (; i < samples; i++, sample++)
190 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
194 // av_log(s->avctx, AV_LOG_DEBUG, "rice coded partition k=%d\n", tmp);
195 for (; i < samples; i++, sample++){
196 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
202 // av_log(s->avctx, AV_LOG_DEBUG, "partitions: %d, samples: %d\n", 1 << rice_order, sample);
207 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
211 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME FIXED\n");
213 /* warm up samples */
214 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
216 for (i = 0; i < pred_order; i++)
218 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
219 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
222 if (decode_residuals(s, channel, pred_order) < 0)
230 for (i = pred_order; i < s->blocksize; i++)
231 s->decoded[channel][i] += s->decoded[channel][i-1];
234 for (i = pred_order; i < s->blocksize; i++)
235 s->decoded[channel][i] += 2*s->decoded[channel][i-1]
236 - s->decoded[channel][i-2];
239 for (i = pred_order; i < s->blocksize; i++)
240 s->decoded[channel][i] += 3*s->decoded[channel][i-1]
241 - 3*s->decoded[channel][i-2]
242 + s->decoded[channel][i-3];
245 for (i = pred_order; i < s->blocksize; i++)
246 s->decoded[channel][i] += 4*s->decoded[channel][i-1]
247 - 6*s->decoded[channel][i-2]
248 + 4*s->decoded[channel][i-3]
249 - s->decoded[channel][i-4];
252 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
259 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
262 int coeff_prec, qlevel;
263 int coeffs[pred_order];
265 // av_log(s->avctx, AV_LOG_DEBUG, " SUBFRAME LPC\n");
267 /* warm up samples */
268 // av_log(s->avctx, AV_LOG_DEBUG, " warm up samples: %d\n", pred_order);
270 for (i = 0; i < pred_order; i++)
272 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
273 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, s->decoded[channel][i]);
276 coeff_prec = get_bits(&s->gb, 4) + 1;
277 if (coeff_prec == 16)
279 av_log(s->avctx, AV_LOG_DEBUG, "invalid coeff precision\n");
282 // av_log(s->avctx, AV_LOG_DEBUG, " qlp coeff prec: %d\n", coeff_prec);
283 qlevel = get_sbits(&s->gb, 5);
284 // av_log(s->avctx, AV_LOG_DEBUG, " quant level: %d\n", qlevel);
286 av_log(s->avctx, AV_LOG_DEBUG, "qlevel %d not supported, maybe buggy stream\n", qlevel);
290 for (i = 0; i < pred_order; i++)
292 coeffs[i] = get_sbits(&s->gb, coeff_prec);
293 // av_log(s->avctx, AV_LOG_DEBUG, " %d: %d\n", i, coeffs[i]);
296 if (decode_residuals(s, channel, pred_order) < 0)
301 for (i = pred_order; i < s->blocksize; i++)
304 for (j = 0; j < pred_order; j++)
305 sum += (int64_t)coeffs[j] * s->decoded[channel][i-j-1];
306 s->decoded[channel][i] += sum >> qlevel;
310 for (i = pred_order; i < s->blocksize; i++)
313 for (j = 0; j < pred_order; j++)
314 sum += coeffs[j] * s->decoded[channel][i-j-1];
315 s->decoded[channel][i] += sum >> qlevel;
322 static inline int decode_subframe(FLACContext *s, int channel)
324 int type, wasted = 0;
327 s->curr_bps = s->bps;
329 if(s->decorrelation == RIGHT_SIDE)
332 if(s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
336 if (get_bits1(&s->gb))
338 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
341 type = get_bits(&s->gb, 6);
342 // wasted = get_bits1(&s->gb);
346 // while (!get_bits1(&s->gb))
350 // s->curr_bps -= wasted;
353 wasted= 16 - av_log2(show_bits(&s->gb, 17));
354 skip_bits(&s->gb, wasted+1);
355 s->curr_bps -= wasted;
357 if (get_bits1(&s->gb))
360 while (!get_bits1(&s->gb))
362 s->curr_bps -= wasted;
363 av_log(s->avctx, AV_LOG_DEBUG, "%d wasted bits\n", wasted);
366 //FIXME use av_log2 for types
369 av_log(s->avctx, AV_LOG_DEBUG, "coding type: constant\n");
370 tmp = get_sbits(&s->gb, s->curr_bps);
371 for (i = 0; i < s->blocksize; i++)
372 s->decoded[channel][i] = tmp;
376 av_log(s->avctx, AV_LOG_DEBUG, "coding type: verbatim\n");
377 for (i = 0; i < s->blocksize; i++)
378 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
380 else if ((type >= 8) && (type <= 12))
382 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: fixed\n");
383 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
388 // av_log(s->avctx, AV_LOG_DEBUG, "coding type: lpc\n");
389 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
394 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
401 for (i = 0; i < s->blocksize; i++)
402 s->decoded[channel][i] <<= wasted;
408 static int decode_frame(FLACContext *s)
410 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
411 int decorrelation, bps, blocksize, samplerate;
413 blocksize_code = get_bits(&s->gb, 4);
415 sample_rate_code = get_bits(&s->gb, 4);
417 assignment = get_bits(&s->gb, 4); /* channel assignment */
418 if (assignment < 8 && s->channels == assignment+1)
419 decorrelation = INDEPENDENT;
420 else if (assignment >=8 && assignment < 11 && s->channels == 2)
421 decorrelation = LEFT_SIDE + assignment - 8;
424 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n", assignment, s->channels);
428 sample_size_code = get_bits(&s->gb, 3);
429 if(sample_size_code == 0)
431 else if((sample_size_code != 3) && (sample_size_code != 7))
432 bps = sample_size_table[sample_size_code];
435 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n", sample_size_code);
439 if (get_bits1(&s->gb))
441 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
445 if(get_utf8(&s->gb) < 0){
446 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
450 if (/*((blocksize_code == 6) || (blocksize_code == 7)) &&*/
451 (s->min_blocksize != s->max_blocksize)){
456 if (blocksize_code == 0)
457 blocksize = s->min_blocksize;
458 else if (blocksize_code == 6)
459 blocksize = get_bits(&s->gb, 8)+1;
460 else if (blocksize_code == 7)
461 blocksize = get_bits(&s->gb, 16)+1;
463 blocksize = blocksize_table[blocksize_code];
465 if(blocksize > s->max_blocksize){
466 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize, s->max_blocksize);
470 if (sample_rate_code == 0){
471 samplerate= s->samplerate;
472 }else if ((sample_rate_code > 3) && (sample_rate_code < 12))
473 samplerate = sample_rate_table[sample_rate_code];
474 else if (sample_rate_code == 12)
475 samplerate = get_bits(&s->gb, 8) * 1000;
476 else if (sample_rate_code == 13)
477 samplerate = get_bits(&s->gb, 16);
478 else if (sample_rate_code == 14)
479 samplerate = get_bits(&s->gb, 16) * 10;
481 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n", sample_rate_code);
485 skip_bits(&s->gb, 8);
486 crc8= av_crc(av_crc07, 0, s->gb.buffer, get_bits_count(&s->gb)/8);
488 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
492 s->blocksize = blocksize;
493 s->samplerate = samplerate;
495 s->decorrelation= decorrelation;
500 for (i = 0; i < s->channels; i++)
502 // av_log(s->avctx, AV_LOG_DEBUG, "decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
503 if (decode_subframe(s, i) < 0)
507 align_get_bits(&s->gb);
510 skip_bits(&s->gb, 16); /* data crc */
515 static inline int16_t shift_to_16_bits(int32_t data, int bps)
519 } else if (bps == 20) {
526 static int flac_decode_frame(AVCodecContext *avctx,
527 void *data, int *data_size,
528 uint8_t *buf, int buf_size)
530 FLACContext *s = avctx->priv_data;
531 int metadata_last, metadata_type, metadata_size;
532 int tmp = 0, i, j = 0, input_buf_size = 0;
533 int16_t *samples = data;
535 if(s->max_framesize == 0){
536 s->max_framesize= 65536; // should hopefully be enough for the first header
537 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
540 if(1 && s->max_framesize){//FIXME truncated
541 buf_size= FFMAX(FFMIN(buf_size, s->max_framesize - s->bitstream_size), 0);
542 input_buf_size= buf_size;
544 if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
545 // printf("memmove\n");
546 memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
547 s->bitstream_index=0;
549 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
550 buf= &s->bitstream[s->bitstream_index];
551 buf_size += s->bitstream_size;
552 s->bitstream_size= buf_size;
554 if(buf_size < s->max_framesize){
555 // printf("wanna more data ...\n");
556 return input_buf_size;
560 init_get_bits(&s->gb, buf, buf_size*8);
562 /* fLaC signature (be) */
563 if (show_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
565 skip_bits(&s->gb, 32);
567 av_log(s->avctx, AV_LOG_DEBUG, "STREAM HEADER\n");
569 metadata_last = get_bits(&s->gb, 1);
570 metadata_type = get_bits(&s->gb, 7);
571 metadata_size = get_bits_long(&s->gb, 24);
573 av_log(s->avctx, AV_LOG_DEBUG, " metadata block: flag = %d, type = %d, size = %d\n",
574 metadata_last, metadata_type,
577 switch(metadata_type)
579 case METADATA_TYPE_STREAMINFO:{
580 metadata_streaminfo(s);
582 /* Buffer might have been reallocated, reinit bitreader */
583 if(buf != &s->bitstream[s->bitstream_index])
585 int bits_count = get_bits_count(&s->gb);
586 buf= &s->bitstream[s->bitstream_index];
587 init_get_bits(&s->gb, buf, buf_size*8);
588 skip_bits(&s->gb, bits_count);
594 for(i=0; i<metadata_size; i++)
595 skip_bits(&s->gb, 8);
598 } while(!metadata_last);
603 tmp = show_bits(&s->gb, 16);
605 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
606 while(get_bits_count(&s->gb)/8+2 < buf_size && show_bits(&s->gb, 16) != 0xFFF8)
607 skip_bits(&s->gb, 8);
608 goto end; // we may not have enough bits left to decode a frame, so try next time
610 skip_bits(&s->gb, 16);
611 if (decode_frame(s) < 0){
612 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
614 s->bitstream_index=0;
621 /* fix the channel order here */
622 if (s->order == MID_SIDE)
624 short *left = samples;
625 short *right = samples + s->blocksize;
626 for (i = 0; i < s->blocksize; i += 2)
628 uint32_t x = s->decoded[0][i];
629 uint32_t y = s->decoded[0][i+1];
631 right[i] = x - (y / 2);
632 left[i] = right[i] + y;
634 *data_size = 2 * s->blocksize;
638 for (i = 0; i < s->channels; i++)
643 for (j = 0; j < s->blocksize; j++)
644 samples[(s->blocksize*i)+j] = s->decoded[i][j];
649 for (j = 0; j < s->blocksize; j++)
650 samples[(s->blocksize*i)+j] = s->decoded[0][j];
652 for (j = 0; j < s->blocksize; j++)
653 samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
656 // av_log(s->avctx, AV_LOG_DEBUG, "mid-side unsupported\n");
658 *data_size += s->blocksize;
662 #define DECORRELATE(left, right)\
663 assert(s->channels == 2);\
664 for (i = 0; i < s->blocksize; i++)\
666 int a= s->decoded[0][i];\
667 int b= s->decoded[1][i];\
668 *(samples++) = (left ) >> (16 - s->bps);\
669 *(samples++) = (right) >> (16 - s->bps);\
673 switch(s->decorrelation)
676 for (j = 0; j < s->blocksize; j++)
678 for (i = 0; i < s->channels; i++)
679 *(samples++) = shift_to_16_bits(s->decoded[i][j], s->bps);
687 DECORRELATE( (a-=b>>1) + b, a)
691 *data_size = (int8_t *)samples - (int8_t *)data;
692 // av_log(s->avctx, AV_LOG_DEBUG, "data size: %d\n", *data_size);
694 // s->last_blocksize = s->blocksize;
696 i= (get_bits_count(&s->gb)+7)/8;;
698 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
700 s->bitstream_index=0;
704 if(s->bitstream_size){
705 s->bitstream_index += i;
706 s->bitstream_size -= i;
707 return input_buf_size;
712 static int flac_decode_close(AVCodecContext *avctx)
714 FLACContext *s = avctx->priv_data;
717 for (i = 0; i < s->channels; i++)
719 av_freep(&s->decoded[i]);
721 av_freep(&s->bitstream);
726 static void flac_flush(AVCodecContext *avctx){
727 FLACContext *s = avctx->priv_data;
730 s->bitstream_index= 0;
733 AVCodec flac_decoder = {