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
51 enum decorrelation_type {
58 typedef struct FLACContext {
61 AVCodecContext *avctx;
64 int blocksize/*, last_blocksize*/;
66 enum decorrelation_type decorrelation;
68 int32_t *decoded[MAX_CHANNELS];
70 unsigned int bitstream_size;
71 unsigned int bitstream_index;
72 unsigned int allocated_bitstream_size;
75 static const int sample_rate_table[] =
77 88200, 176400, 192000,
78 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
81 static const int sample_size_table[] =
82 { 0, 8, 12, 0, 16, 20, 24, 0 };
84 static const 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)
92 GET_UTF8(val, get_bits(gb, 8), return -1;)
96 static void allocate_buffers(FLACContext *s);
97 static int metadata_parse(FLACContext *s);
99 static av_cold int flac_decode_init(AVCodecContext *avctx)
101 FLACContext *s = avctx->priv_data;
104 if (avctx->extradata_size > 4) {
105 /* initialize based on the demuxer-supplied streamdata header */
106 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
107 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s,
111 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
116 avctx->sample_fmt = SAMPLE_FMT_S16;
120 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
122 av_log(avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d\n", s->min_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)
134 assert(s->max_blocksize);
136 if (s->max_framesize == 0 && s->max_blocksize) {
137 // FIXME header overhead
138 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8;
141 for (i = 0; i < s->channels; i++) {
142 s->decoded[i] = av_realloc(s->decoded[i],
143 sizeof(int32_t)*s->max_blocksize);
146 if (s->allocated_bitstream_size < s->max_framesize)
147 s->bitstream= av_fast_realloc(s->bitstream,
148 &s->allocated_bitstream_size,
152 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
153 const uint8_t *buffer)
156 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
158 /* mandatory streaminfo */
159 s->min_blocksize = get_bits(&gb, 16);
160 s->max_blocksize = get_bits(&gb, 16);
162 skip_bits(&gb, 24); /* skip min frame size */
163 s->max_framesize = get_bits_long(&gb, 24);
165 s->samplerate = get_bits_long(&gb, 20);
166 s->channels = get_bits(&gb, 3) + 1;
167 s->bps = get_bits(&gb, 5) + 1;
169 avctx->channels = s->channels;
170 avctx->sample_rate = s->samplerate;
172 skip_bits(&gb, 36); /* total num of samples */
174 skip_bits(&gb, 64); /* md5 sum */
175 skip_bits(&gb, 64); /* md5 sum */
177 dump_headers(avctx, s);
181 * Parse a list of metadata blocks. This list of blocks must begin with
183 * @param s the flac decoding context containing the gb bit reader used to
185 * @return 1 if some metadata was read, 0 if no fLaC marker was found
187 static int metadata_parse(FLACContext *s)
189 int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
190 int initial_pos= get_bits_count(&s->gb);
192 if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
193 skip_bits(&s->gb, 32);
196 metadata_last = get_bits1(&s->gb);
197 metadata_type = get_bits(&s->gb, 7);
198 metadata_size = get_bits_long(&s->gb, 24);
200 if (get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits) {
201 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
206 switch (metadata_type) {
207 case FLAC_METADATA_TYPE_STREAMINFO:
208 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s,
209 s->gb.buffer+get_bits_count(&s->gb)/8);
210 streaminfo_updated = 1;
213 for (i = 0; i < metadata_size; i++)
214 skip_bits(&s->gb, 8);
217 } while (!metadata_last);
219 if (streaminfo_updated)
226 static int decode_residuals(FLACContext *s, int channel, int pred_order)
228 int i, tmp, partition, method_type, rice_order;
229 int sample = 0, samples;
231 method_type = get_bits(&s->gb, 2);
232 if (method_type > 1) {
233 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n",
238 rice_order = get_bits(&s->gb, 4);
240 samples= s->blocksize >> rice_order;
241 if (pred_order > samples) {
242 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n",
243 pred_order, samples);
249 for (partition = 0; partition < (1 << rice_order); partition++) {
250 tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
251 if (tmp == (method_type == 0 ? 15 : 31)) {
252 tmp = get_bits(&s->gb, 5);
253 for (; i < samples; i++, sample++)
254 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
256 for (; i < samples; i++, sample++) {
257 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
266 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
268 const int blocksize = s->blocksize;
269 int32_t *decoded = s->decoded[channel];
272 /* warm up samples */
273 for (i = 0; i < pred_order; i++) {
274 decoded[i] = get_sbits(&s->gb, s->curr_bps);
277 if (decode_residuals(s, channel, pred_order) < 0)
281 a = decoded[pred_order-1];
283 b = a - decoded[pred_order-2];
285 c = b - decoded[pred_order-2] + decoded[pred_order-3];
287 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
289 switch (pred_order) {
293 for (i = pred_order; i < blocksize; i++)
294 decoded[i] = a += decoded[i];
297 for (i = pred_order; i < blocksize; i++)
298 decoded[i] = a += b += decoded[i];
301 for (i = pred_order; i < blocksize; i++)
302 decoded[i] = a += b += c += decoded[i];
305 for (i = pred_order; i < blocksize; i++)
306 decoded[i] = a += b += c += d += decoded[i];
309 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
316 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
319 int coeff_prec, qlevel;
320 int coeffs[pred_order];
321 int32_t *decoded = s->decoded[channel];
323 /* warm up samples */
324 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) {
330 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
333 qlevel = get_sbits(&s->gb, 5);
335 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n",
340 for (i = 0; i < pred_order; i++) {
341 coeffs[i] = get_sbits(&s->gb, coeff_prec);
344 if (decode_residuals(s, channel, pred_order) < 0)
349 for (i = pred_order; i < s->blocksize; i++) {
351 for (j = 0; j < pred_order; j++)
352 sum += (int64_t)coeffs[j] * decoded[i-j-1];
353 decoded[i] += sum >> qlevel;
356 for (i = pred_order; i < s->blocksize-1; i += 2) {
358 int d = decoded[i-pred_order];
360 for (j = pred_order-1; j > 0; j--) {
368 d = decoded[i] += s0 >> qlevel;
370 decoded[i+1] += s1 >> qlevel;
372 if (i < s->blocksize) {
374 for (j = 0; j < pred_order; j++)
375 sum += coeffs[j] * decoded[i-j-1];
376 decoded[i] += sum >> qlevel;
383 static inline int decode_subframe(FLACContext *s, int channel)
385 int type, wasted = 0;
388 s->curr_bps = s->bps;
390 if (s->decorrelation == RIGHT_SIDE)
393 if (s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
397 if (get_bits1(&s->gb)) {
398 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
401 type = get_bits(&s->gb, 6);
403 if (get_bits1(&s->gb)) {
405 while (!get_bits1(&s->gb))
407 s->curr_bps -= wasted;
410 //FIXME use av_log2 for types
412 tmp = get_sbits(&s->gb, s->curr_bps);
413 for (i = 0; i < s->blocksize; i++)
414 s->decoded[channel][i] = tmp;
415 } else if (type == 1) {
416 for (i = 0; i < s->blocksize; i++)
417 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
418 } else if ((type >= 8) && (type <= 12)) {
419 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
421 } else if (type >= 32) {
422 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
425 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
431 for (i = 0; i < s->blocksize; i++)
432 s->decoded[channel][i] <<= wasted;
438 static int decode_frame(FLACContext *s, int alloc_data_size)
440 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
441 int decorrelation, bps, blocksize, samplerate;
443 blocksize_code = get_bits(&s->gb, 4);
445 sample_rate_code = get_bits(&s->gb, 4);
447 assignment = get_bits(&s->gb, 4); /* channel assignment */
448 if (assignment < 8 && s->channels == assignment+1)
449 decorrelation = INDEPENDENT;
450 else if (assignment >=8 && assignment < 11 && s->channels == 2)
451 decorrelation = LEFT_SIDE + assignment - 8;
453 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n",
454 assignment, s->channels);
458 sample_size_code = get_bits(&s->gb, 3);
459 if (sample_size_code == 0)
461 else if ((sample_size_code != 3) && (sample_size_code != 7))
462 bps = sample_size_table[sample_size_code];
464 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
469 if (get_bits1(&s->gb)) {
470 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
474 if (get_utf8(&s->gb) < 0) {
475 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
479 if (blocksize_code == 0)
480 blocksize = s->min_blocksize;
481 else if (blocksize_code == 6)
482 blocksize = get_bits(&s->gb, 8)+1;
483 else if (blocksize_code == 7)
484 blocksize = get_bits(&s->gb, 16)+1;
486 blocksize = blocksize_table[blocksize_code];
488 if (blocksize > s->max_blocksize) {
489 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize,
494 if (blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
497 if (sample_rate_code == 0)
498 samplerate= s->samplerate;
499 else if (sample_rate_code < 12)
500 samplerate = sample_rate_table[sample_rate_code];
501 else if (sample_rate_code == 12)
502 samplerate = get_bits(&s->gb, 8) * 1000;
503 else if (sample_rate_code == 13)
504 samplerate = get_bits(&s->gb, 16);
505 else if (sample_rate_code == 14)
506 samplerate = get_bits(&s->gb, 16) * 10;
508 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
513 skip_bits(&s->gb, 8);
514 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
515 s->gb.buffer, get_bits_count(&s->gb)/8);
517 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
521 s->blocksize = blocksize;
522 s->samplerate = samplerate;
524 s->decorrelation= decorrelation;
526 // dump_headers(s->avctx, (FLACStreaminfo *)s);
529 for (i = 0; i < s->channels; i++) {
530 if (decode_subframe(s, i) < 0)
534 align_get_bits(&s->gb);
537 skip_bits(&s->gb, 16); /* data crc */
542 static int flac_decode_frame(AVCodecContext *avctx,
543 void *data, int *data_size,
544 const uint8_t *buf, int buf_size)
546 FLACContext *s = avctx->priv_data;
547 int tmp = 0, i, j = 0, input_buf_size = 0;
548 int16_t *samples = data;
549 int alloc_data_size= *data_size;
553 if (s->max_framesize == 0) {
554 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
555 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
558 if (1 && s->max_framesize) { //FIXME truncated
559 if (s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
560 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
561 input_buf_size= buf_size;
563 if (s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
566 if (s->allocated_bitstream_size < s->bitstream_size + buf_size)
567 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
569 if (s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size) {
570 memmove(s->bitstream, &s->bitstream[s->bitstream_index],
572 s->bitstream_index=0;
574 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size],
576 buf= &s->bitstream[s->bitstream_index];
577 buf_size += s->bitstream_size;
578 s->bitstream_size= buf_size;
580 if (buf_size < s->max_framesize && input_buf_size) {
581 return input_buf_size;
585 init_get_bits(&s->gb, buf, buf_size*8);
587 if (metadata_parse(s))
590 tmp = show_bits(&s->gb, 16);
591 if ((tmp & 0xFFFE) != 0xFFF8) {
592 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
593 while (get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
594 skip_bits(&s->gb, 8);
595 goto end; // we may not have enough bits left to decode a frame, so try next time
597 skip_bits(&s->gb, 16);
598 if (decode_frame(s, alloc_data_size) < 0) {
599 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
601 s->bitstream_index=0;
605 #define DECORRELATE(left, right)\
606 assert(s->channels == 2);\
607 for (i = 0; i < s->blocksize; i++) {\
608 int a= s->decoded[0][i];\
609 int b= s->decoded[1][i];\
610 *samples++ = ((left) << (24 - s->bps)) >> 8;\
611 *samples++ = ((right) << (24 - s->bps)) >> 8;\
615 switch (s->decorrelation) {
617 for (j = 0; j < s->blocksize; j++) {
618 for (i = 0; i < s->channels; i++)
619 *samples++ = (s->decoded[i][j] << (24 - s->bps)) >> 8;
627 DECORRELATE( (a-=b>>1) + b, a)
630 *data_size = (int8_t *)samples - (int8_t *)data;
633 i= (get_bits_count(&s->gb)+7)/8;
635 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
637 s->bitstream_index=0;
641 if (s->bitstream_size) {
642 s->bitstream_index += i;
643 s->bitstream_size -= i;
644 return input_buf_size;
649 static av_cold int flac_decode_close(AVCodecContext *avctx)
651 FLACContext *s = avctx->priv_data;
654 for (i = 0; i < s->channels; i++) {
655 av_freep(&s->decoded[i]);
657 av_freep(&s->bitstream);
662 static void flac_flush(AVCodecContext *avctx)
664 FLACContext *s = avctx->priv_data;
667 s->bitstream_index= 0;
670 AVCodec flac_decoder = {
681 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),