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 #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);
100 int ff_flac_is_extradata_valid(AVCodecContext *avctx,
101 enum FLACExtradataFormat *format,
102 uint8_t **streaminfo_start)
104 if (!avctx->extradata || avctx->extradata_size < FLAC_STREAMINFO_SIZE) {
105 av_log(avctx, AV_LOG_ERROR, "extradata NULL or too small.\n");
108 if (AV_RL32(avctx->extradata) != MKTAG('f','L','a','C')) {
109 /* extradata contains STREAMINFO only */
110 if (avctx->extradata_size != FLAC_STREAMINFO_SIZE) {
111 av_log(avctx, AV_LOG_WARNING, "extradata contains %d bytes too many.\n",
112 FLAC_STREAMINFO_SIZE-avctx->extradata_size);
114 *format = FLAC_EXTRADATA_FORMAT_STREAMINFO;
115 *streaminfo_start = avctx->extradata;
117 if (avctx->extradata_size < 8+FLAC_STREAMINFO_SIZE) {
118 av_log(avctx, AV_LOG_ERROR, "extradata too small.\n");
121 *format = FLAC_EXTRADATA_FORMAT_FULL_HEADER;
122 *streaminfo_start = &avctx->extradata[8];
127 static av_cold int flac_decode_init(AVCodecContext *avctx)
129 enum FLACExtradataFormat format;
131 FLACContext *s = avctx->priv_data;
134 avctx->sample_fmt = SAMPLE_FMT_S16;
136 /* for now, the raw FLAC header is allowed to be passed to the decoder as
137 frame data instead of extradata. */
138 if (!avctx->extradata)
141 if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo))
144 /* initialize based on the demuxer-supplied streamdata header */
145 ff_flac_parse_streaminfo(avctx, (FLACStreaminfo *)s, streaminfo);
151 static void dump_headers(AVCodecContext *avctx, FLACStreaminfo *s)
153 av_log(avctx, AV_LOG_DEBUG, " Max Blocksize: %d\n", s->max_blocksize);
154 av_log(avctx, AV_LOG_DEBUG, " Max Framesize: %d\n", s->max_framesize);
155 av_log(avctx, AV_LOG_DEBUG, " Samplerate: %d\n", s->samplerate);
156 av_log(avctx, AV_LOG_DEBUG, " Channels: %d\n", s->channels);
157 av_log(avctx, AV_LOG_DEBUG, " Bits: %d\n", s->bps);
160 static void allocate_buffers(FLACContext *s)
164 assert(s->max_blocksize);
166 if (s->max_framesize == 0 && s->max_blocksize) {
167 // FIXME header overhead
168 s->max_framesize= (s->channels * s->bps * s->max_blocksize + 7)/ 8;
171 for (i = 0; i < s->channels; i++) {
172 s->decoded[i] = av_realloc(s->decoded[i],
173 sizeof(int32_t)*s->max_blocksize);
176 if (s->allocated_bitstream_size < s->max_framesize)
177 s->bitstream= av_fast_realloc(s->bitstream,
178 &s->allocated_bitstream_size,
182 void ff_flac_parse_streaminfo(AVCodecContext *avctx, struct FLACStreaminfo *s,
183 const uint8_t *buffer)
186 init_get_bits(&gb, buffer, FLAC_STREAMINFO_SIZE*8);
188 /* mandatory streaminfo */
189 skip_bits(&gb, 16); /* skip min blocksize */
190 s->max_blocksize = get_bits(&gb, 16);
192 skip_bits(&gb, 24); /* skip min frame size */
193 s->max_framesize = get_bits_long(&gb, 24);
195 s->samplerate = get_bits_long(&gb, 20);
196 s->channels = get_bits(&gb, 3) + 1;
197 s->bps = get_bits(&gb, 5) + 1;
199 avctx->channels = s->channels;
200 avctx->sample_rate = s->samplerate;
201 avctx->bits_per_raw_sample = s->bps;
203 avctx->sample_fmt = SAMPLE_FMT_S32;
205 avctx->sample_fmt = SAMPLE_FMT_S16;
207 s->samples = get_bits_long(&gb, 32) << 4;
208 s->samples |= get_bits(&gb, 4);
210 skip_bits_long(&gb, 64); /* md5 sum */
211 skip_bits_long(&gb, 64); /* md5 sum */
213 dump_headers(avctx, s);
217 * Parse a list of metadata blocks. This list of blocks must begin with
219 * @param s the flac decoding context containing the gb bit reader used to
221 * @return 1 if some metadata was read, 0 if no fLaC marker was found
223 static int metadata_parse(FLACContext *s)
225 int i, metadata_last, metadata_type, metadata_size, streaminfo_updated=0;
226 int initial_pos= get_bits_count(&s->gb);
228 if (show_bits_long(&s->gb, 32) == MKBETAG('f','L','a','C')) {
229 skip_bits_long(&s->gb, 32);
232 metadata_last = get_bits1(&s->gb);
233 metadata_type = get_bits(&s->gb, 7);
234 metadata_size = get_bits_long(&s->gb, 24);
236 if (get_bits_count(&s->gb) + 8*metadata_size > s->gb.size_in_bits) {
237 skip_bits_long(&s->gb, initial_pos - get_bits_count(&s->gb));
242 switch (metadata_type) {
243 case FLAC_METADATA_TYPE_STREAMINFO:
244 ff_flac_parse_streaminfo(s->avctx, (FLACStreaminfo *)s,
245 s->gb.buffer+get_bits_count(&s->gb)/8);
246 streaminfo_updated = 1;
249 for (i = 0; i < metadata_size; i++)
250 skip_bits(&s->gb, 8);
253 } while (!metadata_last);
255 if (streaminfo_updated)
262 static int decode_residuals(FLACContext *s, int channel, int pred_order)
264 int i, tmp, partition, method_type, rice_order;
265 int sample = 0, samples;
267 method_type = get_bits(&s->gb, 2);
268 if (method_type > 1) {
269 av_log(s->avctx, AV_LOG_ERROR, "illegal residual coding method %d\n",
274 rice_order = get_bits(&s->gb, 4);
276 samples= s->blocksize >> rice_order;
277 if (pred_order > samples) {
278 av_log(s->avctx, AV_LOG_ERROR, "invalid predictor order: %i > %i\n",
279 pred_order, samples);
285 for (partition = 0; partition < (1 << rice_order); partition++) {
286 tmp = get_bits(&s->gb, method_type == 0 ? 4 : 5);
287 if (tmp == (method_type == 0 ? 15 : 31)) {
288 tmp = get_bits(&s->gb, 5);
289 for (; i < samples; i++, sample++)
290 s->decoded[channel][sample] = get_sbits_long(&s->gb, tmp);
292 for (; i < samples; i++, sample++) {
293 s->decoded[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, INT_MAX, 0);
302 static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
304 const int blocksize = s->blocksize;
305 int32_t *decoded = s->decoded[channel];
306 int av_uninit(a), av_uninit(b), av_uninit(c), av_uninit(d), i;
308 /* warm up samples */
309 for (i = 0; i < pred_order; i++) {
310 decoded[i] = get_sbits_long(&s->gb, s->curr_bps);
313 if (decode_residuals(s, channel, pred_order) < 0)
317 a = decoded[pred_order-1];
319 b = a - decoded[pred_order-2];
321 c = b - decoded[pred_order-2] + decoded[pred_order-3];
323 d = c - decoded[pred_order-2] + 2*decoded[pred_order-3] - decoded[pred_order-4];
325 switch (pred_order) {
329 for (i = pred_order; i < blocksize; i++)
330 decoded[i] = a += decoded[i];
333 for (i = pred_order; i < blocksize; i++)
334 decoded[i] = a += b += decoded[i];
337 for (i = pred_order; i < blocksize; i++)
338 decoded[i] = a += b += c += decoded[i];
341 for (i = pred_order; i < blocksize; i++)
342 decoded[i] = a += b += c += d += decoded[i];
345 av_log(s->avctx, AV_LOG_ERROR, "illegal pred order %d\n", pred_order);
352 static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
355 int coeff_prec, qlevel;
356 int coeffs[pred_order];
357 int32_t *decoded = s->decoded[channel];
359 /* warm up samples */
360 for (i = 0; i < pred_order; i++) {
361 decoded[i] = get_sbits_long(&s->gb, s->curr_bps);
364 coeff_prec = get_bits(&s->gb, 4) + 1;
365 if (coeff_prec == 16) {
366 av_log(s->avctx, AV_LOG_ERROR, "invalid coeff precision\n");
369 qlevel = get_sbits(&s->gb, 5);
371 av_log(s->avctx, AV_LOG_ERROR, "qlevel %d not supported, maybe buggy stream\n",
376 for (i = 0; i < pred_order; i++) {
377 coeffs[i] = get_sbits(&s->gb, coeff_prec);
380 if (decode_residuals(s, channel, pred_order) < 0)
385 for (i = pred_order; i < s->blocksize; i++) {
387 for (j = 0; j < pred_order; j++)
388 sum += (int64_t)coeffs[j] * decoded[i-j-1];
389 decoded[i] += sum >> qlevel;
392 for (i = pred_order; i < s->blocksize-1; i += 2) {
394 int d = decoded[i-pred_order];
396 for (j = pred_order-1; j > 0; j--) {
404 d = decoded[i] += s0 >> qlevel;
406 decoded[i+1] += s1 >> qlevel;
408 if (i < s->blocksize) {
410 for (j = 0; j < pred_order; j++)
411 sum += coeffs[j] * decoded[i-j-1];
412 decoded[i] += sum >> qlevel;
419 static inline int decode_subframe(FLACContext *s, int channel)
421 int type, wasted = 0;
424 s->curr_bps = s->bps;
426 if (s->decorrelation == RIGHT_SIDE)
429 if (s->decorrelation == LEFT_SIDE || s->decorrelation == MID_SIDE)
432 if (s->curr_bps > 32) {
433 ff_log_missing_feature(s->avctx, "decorrelated bit depth > 32", 0);
437 if (get_bits1(&s->gb)) {
438 av_log(s->avctx, AV_LOG_ERROR, "invalid subframe padding\n");
441 type = get_bits(&s->gb, 6);
443 if (get_bits1(&s->gb)) {
445 while (!get_bits1(&s->gb))
447 s->curr_bps -= wasted;
450 //FIXME use av_log2 for types
452 tmp = get_sbits_long(&s->gb, s->curr_bps);
453 for (i = 0; i < s->blocksize; i++)
454 s->decoded[channel][i] = tmp;
455 } else if (type == 1) {
456 for (i = 0; i < s->blocksize; i++)
457 s->decoded[channel][i] = get_sbits_long(&s->gb, s->curr_bps);
458 } else if ((type >= 8) && (type <= 12)) {
459 if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
461 } else if (type >= 32) {
462 if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
465 av_log(s->avctx, AV_LOG_ERROR, "invalid coding type\n");
471 for (i = 0; i < s->blocksize; i++)
472 s->decoded[channel][i] <<= wasted;
478 static int decode_frame(FLACContext *s, int alloc_data_size)
480 int blocksize_code, sample_rate_code, sample_size_code, assignment, i, crc8;
481 int decorrelation, bps, blocksize, samplerate;
483 blocksize_code = get_bits(&s->gb, 4);
485 sample_rate_code = get_bits(&s->gb, 4);
487 assignment = get_bits(&s->gb, 4); /* channel assignment */
488 if (assignment < 8 && s->channels == assignment+1)
489 decorrelation = INDEPENDENT;
490 else if (assignment >=8 && assignment < 11 && s->channels == 2)
491 decorrelation = LEFT_SIDE + assignment - 8;
493 av_log(s->avctx, AV_LOG_ERROR, "unsupported channel assignment %d (channels=%d)\n",
494 assignment, s->channels);
498 sample_size_code = get_bits(&s->gb, 3);
499 if (sample_size_code == 0)
501 else if ((sample_size_code != 3) && (sample_size_code != 7))
502 bps = sample_size_table[sample_size_code];
504 av_log(s->avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
509 s->avctx->sample_fmt = SAMPLE_FMT_S32;
510 s->sample_shift = 32 - bps;
513 s->avctx->sample_fmt = SAMPLE_FMT_S16;
514 s->sample_shift = 16 - bps;
517 s->bps = s->avctx->bits_per_raw_sample = bps;
519 if (get_bits1(&s->gb)) {
520 av_log(s->avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
524 if (get_utf8(&s->gb) < 0) {
525 av_log(s->avctx, AV_LOG_ERROR, "utf8 fscked\n");
529 if (blocksize_code == 0) {
530 av_log(s->avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
532 } else if (blocksize_code == 6)
533 blocksize = get_bits(&s->gb, 8)+1;
534 else if (blocksize_code == 7)
535 blocksize = get_bits(&s->gb, 16)+1;
537 blocksize = blocksize_table[blocksize_code];
539 if (blocksize > s->max_blocksize) {
540 av_log(s->avctx, AV_LOG_ERROR, "blocksize %d > %d\n", blocksize,
545 if (blocksize * s->channels * sizeof(int16_t) > alloc_data_size)
548 if (sample_rate_code == 0)
549 samplerate= s->samplerate;
550 else if (sample_rate_code < 12)
551 samplerate = sample_rate_table[sample_rate_code];
552 else if (sample_rate_code == 12)
553 samplerate = get_bits(&s->gb, 8) * 1000;
554 else if (sample_rate_code == 13)
555 samplerate = get_bits(&s->gb, 16);
556 else if (sample_rate_code == 14)
557 samplerate = get_bits(&s->gb, 16) * 10;
559 av_log(s->avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
564 skip_bits(&s->gb, 8);
565 crc8 = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0,
566 s->gb.buffer, get_bits_count(&s->gb)/8);
568 av_log(s->avctx, AV_LOG_ERROR, "header crc mismatch crc=%2X\n", crc8);
572 s->blocksize = blocksize;
573 s->samplerate = samplerate;
575 s->decorrelation= decorrelation;
577 // dump_headers(s->avctx, (FLACStreaminfo *)s);
580 for (i = 0; i < s->channels; i++) {
581 if (decode_subframe(s, i) < 0)
585 align_get_bits(&s->gb);
588 skip_bits(&s->gb, 16); /* data crc */
593 static int flac_decode_frame(AVCodecContext *avctx,
594 void *data, int *data_size,
595 const uint8_t *buf, int buf_size)
597 FLACContext *s = avctx->priv_data;
598 int tmp = 0, i, j = 0, input_buf_size = 0;
599 int16_t *samples_16 = data;
600 int32_t *samples_32 = data;
601 int alloc_data_size= *data_size;
605 if (s->max_framesize == 0) {
606 s->max_framesize= FFMAX(4, buf_size); // should hopefully be enough for the first header
607 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
610 if (1 && s->max_framesize) { //FIXME truncated
611 if (s->bitstream_size < 4 || AV_RL32(s->bitstream) != MKTAG('f','L','a','C'))
612 buf_size= FFMIN(buf_size, s->max_framesize - FFMIN(s->bitstream_size, s->max_framesize));
613 input_buf_size= buf_size;
615 if (s->bitstream_size + buf_size < buf_size || s->bitstream_index + s->bitstream_size + buf_size < s->bitstream_index)
618 if (s->allocated_bitstream_size < s->bitstream_size + buf_size)
619 s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->bitstream_size + buf_size);
621 if (s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size) {
622 memmove(s->bitstream, &s->bitstream[s->bitstream_index],
624 s->bitstream_index=0;
626 memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size],
628 buf= &s->bitstream[s->bitstream_index];
629 buf_size += s->bitstream_size;
630 s->bitstream_size= buf_size;
632 if (buf_size < s->max_framesize && input_buf_size) {
633 return input_buf_size;
637 init_get_bits(&s->gb, buf, buf_size*8);
639 if (metadata_parse(s))
642 tmp = show_bits(&s->gb, 16);
643 if ((tmp & 0xFFFE) != 0xFFF8) {
644 av_log(s->avctx, AV_LOG_ERROR, "FRAME HEADER not here\n");
645 while (get_bits_count(&s->gb)/8+2 < buf_size && (show_bits(&s->gb, 16) & 0xFFFE) != 0xFFF8)
646 skip_bits(&s->gb, 8);
647 goto end; // we may not have enough bits left to decode a frame, so try next time
649 skip_bits(&s->gb, 16);
650 if (decode_frame(s, alloc_data_size) < 0) {
651 av_log(s->avctx, AV_LOG_ERROR, "decode_frame() failed\n");
653 s->bitstream_index=0;
657 #define DECORRELATE(left, right)\
658 assert(s->channels == 2);\
659 for (i = 0; i < s->blocksize; i++) {\
660 int a= s->decoded[0][i];\
661 int b= s->decoded[1][i];\
663 *samples_32++ = (left) << s->sample_shift;\
664 *samples_32++ = (right) << s->sample_shift;\
666 *samples_16++ = (left) << s->sample_shift;\
667 *samples_16++ = (right) << s->sample_shift;\
672 switch (s->decorrelation) {
674 for (j = 0; j < s->blocksize; j++) {
675 for (i = 0; i < s->channels; i++) {
677 *samples_32++ = s->decoded[i][j] << s->sample_shift;
679 *samples_16++ = s->decoded[i][j] << s->sample_shift;
688 DECORRELATE( (a-=b>>1) + b, a)
691 *data_size = s->blocksize * s->channels * (s->is32 ? 4 : 2);
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 av_cold int flac_decode_close(AVCodecContext *avctx)
712 FLACContext *s = avctx->priv_data;
715 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)
725 FLACContext *s = avctx->priv_data;
728 s->bitstream_index= 0;
731 AVCodec flac_decoder = {
742 .long_name= NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),