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
23 * @file libavcodec/flacdec.c
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; ///< parent AVCodecContext
62 GetBitContext gb; ///< GetBitContext initialized to start at the current frame
64 int blocksize; ///< number of samples in the current frame
65 int curr_bps; ///< bps for current subframe, adjusted for channel correlation and wasted bits
66 int sample_shift; ///< shift required to make output samples 16-bit or 32-bit
67 int is32; ///< flag to indicate if output should be 32-bit instead of 16-bit
68 enum decorrelation_type decorrelation; ///< channel decorrelation type in the current frame
70 int32_t *decoded[MAX_CHANNELS]; ///< decoded samples
72 unsigned int bitstream_size;
73 unsigned int bitstream_index;
74 unsigned int allocated_bitstream_size;
77 static const int sample_rate_table[] =
79 88200, 176400, 192000,
80 8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
83 static const int sample_size_table[] =
84 { 0, 8, 12, 0, 16, 20, 24, 0 };
86 static const 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)
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 avctx->sample_fmt = SAMPLE_FMT_S16;
108 if (avctx->extradata_size > 4) {
109 /* initialize based on the demuxer-supplied streamdata header */
110 if (avctx->extradata_size == FLAC_STREAMINFO_SIZE) {
111 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s,
115 init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
123 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
125 av_log(avctx, AV_LOG_DEBUG, " Blocksize: %d .. %d\n", s->min_blocksize,
127 av_log(avctx, AV_LOG_DEBUG, " Max Framesize: %d\n", s->max_framesize);
128 av_log(avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
129 av_log(avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
130 av_log(avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
133 static void allocate_buffers(FLACContext *s)
137 assert(s->max_blocksize);
139 if (s->max_framesize == 0 && s->max_blocksize) {
140 // FIXME header overhead
141 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8;
144 for (i = 0; i < s->channels; i++) {
145 s->decoded[i] = av_realloc(s->decoded[i],
146 sizeof(int32_t)*s->max_blocksize);
149 if (s->allocated_bitstream_size < s->max_framesize)
150 s->bitstream= av_fast_realloc(s->bitstream,
151 &s->allocated_bitstream_size,
155 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
156 const uint8_t *buffer)
159 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
161 /* mandatory streaminfo */
162 s->min_blocksize = get_bits(&gb, 16);
163 s->max_blocksize = get_bits(&gb, 16);
165 skip_bits(&gb, 24); /* skip min frame size */
166 s->max_framesize = get_bits_long(&gb, 24);
168 s->samplerate = get_bits_long(&gb, 20);
169 s->channels = get_bits(&gb, 3) + 1;
170 s->bps = get_bits(&gb, 5) + 1;
172 avctx->channels = s->channels;
173 avctx->sample_rate = s->samplerate;
174 avctx->bits_per_raw_sample = s->bps;
176 avctx->sample_fmt = SAMPLE_FMT_S32;
178 avctx->sample_fmt = SAMPLE_FMT_S16;
180 s->samples = get_bits_long(&gb, 32) << 4;
181 s->samples |= get_bits_long(&gb, 4);
183 skip_bits(&gb, 64); /* md5 sum */
184 skip_bits(&gb, 64); /* md5 sum */
186 dump_headers(avctx, s);
190 * Parse a list of metadata blocks. This list of blocks must begin with
192 * @param s the flac decoding context containing the gb bit reader used to
194 * @return 1 if some metadata was read, 0 if no fLaC marker was found
196 static int metadata_parse(FLACContext *s)
198 int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
199 int initial_pos= get_bits_count(&s->gb);
201 if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
202 skip_bits(&s->gb, 32);
205 metadata_last = get_bits1(&s->gb);
206 metadata_type = get_bits(&s->gb, 7);
207 metadata_size = get_bits_long(&s->gb, 24);
209 if (get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits) {
210 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
215 switch (metadata_type) {
216 case FLAC_METADATA_TYPE_STREAMINFO:
217 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s,
218 s->gb.buffer+get_bits_count(&s->gb)/8);
219 streaminfo_updated = 1;
222 for (i = 0; i < metadata_size; i++)
223 skip_bits(&s->gb, 8);
226 } while (!metadata_last);
228 if (streaminfo_updated)
235 static int decode_residuals(FLACContext *s, int channel, int pred_order)
237 int i, tmp, partition, method_type, rice_order;
238 int sample = 0, samples;
240 method_type = get_bits(&s->gb, 2);
241 if (method_type > 1) {
242 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n",
247 rice_order = get_bits(&s->gb, 4);
249 samples= s->blocksize >> rice_order;
250 if (pred_order > samples) {
251 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n",
252 pred_order, samples);
258 for (partition = 0; partition < (1 << rice_order); partition++) {
259 tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
260 if (tmp == (method_type == 0 ? 15 : 31)) {
261 tmp = get_bits(&s->gb, 5);
262 for (; i < samples; i++, sample++)
263 s->decoded[channel][sample] = get_sbits(&s->gb, tmp);
265 for (; i < samples; i++, sample++) {
266 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
275 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
277 const int blocksize = s->blocksize;
278 int32_t *decoded = s->decoded[channel];
279 int av_uninit(a), av_uninit(b), av_uninit(c), av_uninit(d), i;
281 /* warm up samples */
282 for (i = 0; i < pred_order; i++) {
283 decoded[i] = get_sbits(&s->gb, s->curr_bps);
286 if (decode_residuals(s, channel, pred_order) < 0)
290 a = decoded[pred_order-1];
292 b = a - decoded[pred_order-2];
294 c = b - decoded[pred_order-2] + decoded[pred_order-3];
296 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
298 switch (pred_order) {
302 for (i = pred_order; i < blocksize; i++)
303 decoded[i] = a += decoded[i];
306 for (i = pred_order; i < blocksize; i++)
307 decoded[i] = a += b += decoded[i];
310 for (i = pred_order; i < blocksize; i++)
311 decoded[i] = a += b += c += decoded[i];
314 for (i = pred_order; i < blocksize; i++)
315 decoded[i] = a += b += c += d += decoded[i];
318 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
325 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
328 int coeff_prec, qlevel;
329 int coeffs[pred_order];
330 int32_t *decoded = s->decoded[channel];
332 /* warm up samples */
333 for (i = 0; i < pred_order; i++) {
334 decoded[i] = get_sbits(&s->gb, s->curr_bps);
337 coeff_prec = get_bits(&s->gb, 4) + 1;
338 if (coeff_prec == 16) {
339 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
342 qlevel = get_sbits(&s->gb, 5);
344 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n",
349 for (i = 0; i < pred_order; i++) {
350 coeffs[i] = get_sbits(&s->gb, coeff_prec);
353 if (decode_residuals(s, channel, pred_order) < 0)
358 for (i = pred_order; i < s->blocksize; i++) {
360 for (j = 0; j < pred_order; j++)
361 sum += (int64_t)coeffs[j] * decoded[i-j-1];
362 decoded[i] += sum >> qlevel;
365 for (i = pred_order; i < s->blocksize-1; i += 2) {
367 int d = decoded[i-pred_order];
369 for (j = pred_order-1; j > 0; j--) {
377 d = decoded[i] += s0 >> qlevel;
379 decoded[i+1] += s1 >> qlevel;
381 if (i < s->blocksize) {
383 for (j = 0; j < pred_order; j++)
384 sum += coeffs[j] * decoded[i-j-1];
385 decoded[i] += sum >> qlevel;
392 static inline int decode_subframe(FLACContext *s, int channel)
394 int type, wasted = 0;
397 s->curr_bps = s->bps;
399 if (s->decorrelation == RIGHT_SIDE)
402 if (s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
406 if (get_bits1(&s->gb)) {
407 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
410 type = get_bits(&s->gb, 6);
412 if (get_bits1(&s->gb)) {
414 while (!get_bits1(&s->gb))
416 s->curr_bps -= wasted;
419 //FIXME use av_log2 for types
421 tmp = get_sbits(&s->gb, s->curr_bps);
422 for (i = 0; i < s->blocksize; i++)
423 s->decoded[channel][i] = tmp;
424 } else if (type == 1) {
425 for (i = 0; i < s->blocksize; i++)
426 s->decoded[channel][i] = get_sbits(&s->gb, s->curr_bps);
427 } else if ((type >= 8) && (type <= 12)) {
428 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
430 } else if (type >= 32) {
431 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
434 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
440 for (i = 0; i < s->blocksize; i++)
441 s->decoded[channel][i] <<= wasted;
447 static int decode_frame(FLACContext *s, int alloc_data_size)
449 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
450 int decorrelation, bps, blocksize, samplerate;
452 blocksize_code = get_bits(&s->gb, 4);
454 sample_rate_code = get_bits(&s->gb, 4);
456 assignment = get_bits(&s->gb, 4); /* channel assignment */
457 if (assignment < 8 && s->channels == assignment+1)
458 decorrelation = INDEPENDENT;
459 else if (assignment >=8 && assignment < 11 && s->channels == 2)
460 decorrelation = LEFT_SIDE + assignment - 8;
462 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n",
463 assignment, s->channels);
467 sample_size_code = get_bits(&s->gb, 3);
468 if (sample_size_code == 0)
470 else if ((sample_size_code != 3) && (sample_size_code != 7))
471 bps = sample_size_table[sample_size_code];
473 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
478 s->avctx->sample_fmt = SAMPLE_FMT_S32;
479 s->sample_shift = 32 - bps;
482 s->avctx->sample_fmt = SAMPLE_FMT_S16;
483 s->sample_shift = 16 - bps;
486 s->bps = s->avctx->bits_per_raw_sample = bps;
488 if (get_bits1(&s->gb)) {
489 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
493 if (get_utf8(&s->gb) < 0) {
494 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
498 if (blocksize_code == 0)
499 blocksize = s->min_blocksize;
500 else if (blocksize_code == 6)
501 blocksize = get_bits(&s->gb, 8)+1;
502 else if (blocksize_code == 7)
503 blocksize = get_bits(&s->gb, 16)+1;
505 blocksize = blocksize_table[blocksize_code];
507 if (blocksize > s->max_blocksize) {
508 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize,
513 if (blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
516 if (sample_rate_code == 0)
517 samplerate= s->samplerate;
518 else if (sample_rate_code < 12)
519 samplerate = sample_rate_table[sample_rate_code];
520 else if (sample_rate_code == 12)
521 samplerate = get_bits(&s->gb, 8) * 1000;
522 else if (sample_rate_code == 13)
523 samplerate = get_bits(&s->gb, 16);
524 else if (sample_rate_code == 14)
525 samplerate = get_bits(&s->gb, 16) * 10;
527 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
532 skip_bits(&s->gb, 8);
533 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
534 s->gb.buffer, get_bits_count(&s->gb)/8);
536 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
540 s->blocksize = blocksize;
541 s->samplerate = samplerate;
543 s->decorrelation= decorrelation;
545 // dump_headers(s->avctx, (FLACStreaminfo *)s);
548 for (i = 0; i < s->channels; i++) {
549 if (decode_subframe(s, i) < 0)
553 align_get_bits(&s->gb);
556 skip_bits(&s->gb, 16); /* data crc */
561 static int flac_decode_frame(AVCodecContext *avctx,
562 void *data, int *data_size,
563 const uint8_t *buf, int buf_size)
565 FLACContext *s = avctx->priv_data;
566 int tmp = 0, i, j = 0, input_buf_size = 0;
567 int16_t *samples_16 = data;
568 int32_t *samples_32 = data;
569 int alloc_data_size= *data_size;
573 if (s->max_framesize == 0) {
574 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
575 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
578 if (1 && s->max_framesize) { //FIXME truncated
579 if (s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
580 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
581 input_buf_size= buf_size;
583 if (s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
586 if (s->allocated_bitstream_size < s->bitstream_size + buf_size)
587 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
589 if (s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size) {
590 memmove(s->bitstream, &s->bitstream[s->bitstream_index],
592 s->bitstream_index=0;
594 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size],
596 buf= &s->bitstream[s->bitstream_index];
597 buf_size += s->bitstream_size;
598 s->bitstream_size= buf_size;
600 if (buf_size < s->max_framesize && input_buf_size) {
601 return input_buf_size;
605 init_get_bits(&s->gb, buf, buf_size*8);
607 if (metadata_parse(s))
610 tmp = show_bits(&s->gb, 16);
611 if ((tmp & 0xFFFE) != 0xFFF8) {
612 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
613 while (get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
614 skip_bits(&s->gb, 8);
615 goto end; // we may not have enough bits left to decode a frame, so try next time
617 skip_bits(&s->gb, 16);
618 if (decode_frame(s, alloc_data_size) < 0) {
619 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
621 s->bitstream_index=0;
625 #define DECORRELATE(left, right)\
626 assert(s->channels == 2);\
627 for (i = 0; i < s->blocksize; i++) {\
628 int a= s->decoded[0][i];\
629 int b= s->decoded[1][i];\
631 *samples_32++ = (left) << s->sample_shift;\
632 *samples_32++ = (right) << s->sample_shift;\
634 *samples_16++ = (left) << s->sample_shift;\
635 *samples_16++ = (right) << s->sample_shift;\
640 switch (s->decorrelation) {
642 for (j = 0; j < s->blocksize; j++) {
643 for (i = 0; i < s->channels; i++) {
645 *samples_32++ = s->decoded[i][j] << s->sample_shift;
647 *samples_16++ = s->decoded[i][j] << s->sample_shift;
656 DECORRELATE( (a-=b>>1) + b, a)
659 *data_size = s->blocksize * s->channels * (s->is32 ? 4 : 2);
662 i= (get_bits_count(&s->gb)+7)/8;
664 av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
666 s->bitstream_index=0;
670 if (s->bitstream_size) {
671 s->bitstream_index += i;
672 s->bitstream_size -= i;
673 return input_buf_size;
678 static av_cold int flac_decode_close(AVCodecContext *avctx)
680 FLACContext *s = avctx->priv_data;
683 for (i = 0; i < s->channels; i++) {
684 av_freep(&s->decoded[i]);
686 av_freep(&s->bitstream);
691 static void flac_flush(AVCodecContext *avctx)
693 FLACContext *s = avctx->priv_data;
696 s->bitstream_index= 0;
699 AVCodec flac_decoder = {
710 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),