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flac decoder by (Alex Beregszaszi <alex at fsn dot hu>) 

Originally committed as revision 2790 to svn://svn.ffmpeg.org/ffmpeg/trunk
tags/v0.5
Michael Niedermayer 22 years ago
parent
da16b2043f
commit
4f52c3126b
1 changed files with 651 additions and 0 deletions
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/*
* FLAC (Free Lossless Audio Codec) decoder
* Copyright (c) 2003 Alex Beregszaszi
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/

/**
* @file flac.c
* FLAC (Free Lossless Audio Codec) decoder
* @author Alex Beregszaszi
*/
#include "avcodec.h"
#include "golomb.h"

#define MAX_CHANNELS 8
#define MAX_BLOCKSIZE 65535

enum channel_order {
INDEPENDENT,
LEFT_SIDE,
RIGHT_SIDE,
MID_SIDE,
};

typedef struct FLACContext {
AVCodecContext *avctx;
GetBitContext gb;

int min_blocksize, max_blocksize;
int min_framesize, max_framesize;
int samplerate, channels;
int blocksize, last_blocksize;
int bps, curr_bps;
enum channel_order order;

uint8_t *residual[MAX_CHANNELS];
uint32_t *decoded[MAX_CHANNELS];
} FLACContext;

#define METADATA_TYPE_STREAMINFO 0

static int sample_rate_table[] =
{ 0, 0, 0, 0,
8000, 16000, 22050, 24000, 32000, 44100, 48000, 96000,
0, 0, 0, 0 };

static int sample_size_table[] =
{ 0, 8, 12, 0, 16, 20, 24, 0 };

static uint64_t get_uvlc(GetBitContext *gb, int is64)
{
uint64_t val = 0;
int i = 0;

while(i++ < 5+is64)
{
const int tmp = get_bits(gb, 8);
if (tmp & 0x80)
val = (val << 7) + tmp - 0x80;
else
return (val << 7) + tmp;
}
return -1;
}

static int flac_decode_init(AVCodecContext * avctx)
{
return 0;
}

static void dump_headers(FLACContext *s)
{
printf(" Blocksize: %d .. %d (%d)\n", s->min_blocksize, s->max_blocksize, s->blocksize);
printf(" Framesize: %d .. %d\n", s->min_framesize, s->max_framesize);
printf(" Samplerate: %d\n", s->samplerate);
printf(" Channels: %d\n", s->channels);
printf(" Bits: %d\n", s->bps);
}

static void metadata_streaminfo(FLACContext *s)
{
int i;

/* mandatory streaminfo */
s->min_blocksize = get_bits(&s->gb, 16);
s->max_blocksize = get_bits(&s->gb, 16);

s->min_framesize = get_bits_long(&s->gb, 24);
s->max_framesize = get_bits_long(&s->gb, 24);
s->samplerate = get_bits_long(&s->gb, 20);
s->channels = get_bits(&s->gb, 3) + 1;
s->bps = get_bits(&s->gb, 5) + 1;
s->avctx->channels = s->channels;
s->avctx->sample_rate = s->samplerate;

skip_bits(&s->gb, 36); /* total num of samples */
skip_bits(&s->gb, 64); /* md5 sum */
skip_bits(&s->gb, 64); /* md5 sum */

for (i = 0; i < s->channels; i++)
{
s->decoded[i] = av_realloc(s->decoded[i], sizeof(uint32_t)*s->max_blocksize);
s->residual[i] = av_realloc(s->residual[i], sizeof(uint8_t)*s->max_blocksize);
}
}

static int decode_residuals(FLACContext *s, int channel, int pred_order)
{
int i, tmp, partition, method_type, rice_order;
int sample = 0, samples;

method_type = get_bits(&s->gb, 2);
if (method_type != 0)
return -1;
rice_order = get_bits(&s->gb, 4);

samples = (rice_order > 0) ?
(s->blocksize >> rice_order) : (s->blocksize - pred_order);

for (partition = 0; partition < (1 << rice_order); partition++)
{
tmp = get_bits(&s->gb, 4);
if (tmp == 0)
{
i = (!rice_order || partition) ? 0 : pred_order;
for (; i < samples; i++, sample++)
s->residual[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, 0, 0);
printf("zero k\n");
}
else if (tmp == 15)
{
printf("fixed len partition\n");
tmp = get_bits(&s->gb, 5);
i = (!rice_order || partition) ? 0 : pred_order;
for (; i < samples; i++, sample++)
s->residual[channel][sample] = get_bits(&s->gb, tmp);
}
else
{
// printf("rice coded partition\n");
#if 1
i = (!rice_order || partition) ? 0 : pred_order;
for (; i < samples; i++, sample++)
s->residual[channel][sample] = get_sr_golomb_flac(&s->gb, tmp, 0, 0);
#else
i = ((!rice_order || partition) ? samples : samples - pred_order) + sample;
for (; sample < i; sample++)
s->residual[channel][sample] = get_ur_golomb(&s->gb, tmp, 0, 0);
// s->residual[channel][sample] = get_se_golomb(&s->gb);
#endif
}
}

printf("partitions: %d, samples: %d\n", 1 << rice_order, sample);

return 0;
}

static int decode_subframe_fixed(FLACContext *s, int channel, int pred_order)
{
int i;
printf(" SUBFRAME FIXED\n");
/* warm up samples */
printf(" warm up samples: %d\n", pred_order);
for (i = 0; i < pred_order; i++)
{
s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
printf(" %d: %d\n", i, s->decoded[channel][i]);
}
if (decode_residuals(s, channel, pred_order) < 0)
return -1;

switch(pred_order)
{
case 0:
for (i = pred_order; i < s->blocksize; i++)
s->decoded[channel][i] = s->residual[channel][i];
break;
case 1:
for (i = pred_order; i < s->blocksize; i++)
s->decoded[channel][i] = s->residual[channel][i] +
s->decoded[channel][i-1];
break;
case 2:
for (i = pred_order; i < s->blocksize; i++)
s->decoded[channel][i] = s->residual[channel][i] +
(s->decoded[channel][i-1] << 1) -
s->decoded[channel][i-2];
break;
case 3:
for (i = pred_order; i < s->blocksize; i++)
s->decoded[channel][i] = s->residual[channel][i] +
(((s->decoded[channel][i-1] -
s->decoded[channel][i-2]) << 1) +
(s->decoded[channel][i-1] -
s->decoded[channel][i-2])) +
s->decoded[channel][i-3];
break;
case 4:
for (i = pred_order; i < s->blocksize; i++)
s->decoded[channel][i] = s->residual[channel][i] +
((s->decoded[channel][i-1] +
s->decoded[channel][i-3]) << 2) -
((s->decoded[channel][i-2] << 2) +
(s->decoded[channel][i-2] << 1)) -
s->decoded[channel][i-4];
break;
}
return 0;
}

static int decode_subframe_lpc(FLACContext *s, int channel, int pred_order)
{
int sum, i, j;
int coeff_prec, qlevel;
int coeffs[pred_order];
printf(" SUBFRAME LPC\n");
/* warm up samples */
printf(" warm up samples: %d\n", pred_order);
for (i = 0; i < pred_order; i++)
{
s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
printf(" %d: %d\n", i, s->decoded[channel][i]);
}
coeff_prec = get_bits(&s->gb, 4) + 1;
if (coeff_prec == 16)
{
printf("invalid coeff precision\n");
return -1;
}
printf(" qlp coeff prec: %d\n", coeff_prec);
qlevel = get_bits(&s->gb, 5);
printf(" quant level: %d\n", qlevel);
for (i = 0; i < pred_order; i++)
{
coeffs[i] = get_bits(&s->gb, coeff_prec);
printf(" %d: %d\n", i, coeffs[i]);
}
if (decode_residuals(s, channel, pred_order) < 0)
return -1;

for (i = pred_order; i < s->blocksize; i++)
{
sum = 0;
for (j = 0; j < pred_order; j++)
sum += coeffs[j] * s->decoded[channel][i-j-1];
s->decoded[channel][i] = s->residual[channel][i] + (sum >> qlevel);
}
return 0;
}

static inline int decode_subframe(FLACContext *s, int channel)
{
int type, wasted = 0;
int i, tmp;
s->curr_bps = s->bps;
if (get_bits1(&s->gb))
{
printf("invalid subframe padding\n");
return -1;
}
type = get_bits(&s->gb, 6);
// wasted = get_bits1(&s->gb);
// if (wasted)
// {
// while (!get_bits1(&s->gb))
// wasted++;
// if (wasted)
// wasted++;
// s->curr_bps -= wasted;
// }

if (get_bits1(&s->gb))
{
wasted = 1;
while (!get_bits1(&s->gb))
wasted++;
s->curr_bps -= wasted;
}

if (type == 0)
{
printf("coding type: constant\n");
tmp = get_bits(&s->gb, s->curr_bps);
for (i = 0; i < s->blocksize; i++)
s->decoded[channel][i] = tmp;
}
else if (type == 1)
{
printf("coding type: verbatim\n");
for (i = 0; i < s->blocksize; i++)
s->decoded[channel][i] = get_bits(&s->gb, s->curr_bps);
}
else if ((type >= 8) && (type <= 12))
{
printf("coding type: fixed\n");
if (decode_subframe_fixed(s, channel, type & ~0x8) < 0)
return -1;
}
else if (type >= 32)
{
printf("coding type: lpc\n");
if (decode_subframe_lpc(s, channel, (type & ~0x20)+1) < 0)
return -1;
}
else
{
printf("invalid coding type\n");
return -1;
}
if (wasted)
{
int i;
for (i = 0; i < s->blocksize; i++)
s->decoded[channel][i] <<= wasted;
}

return 0;
}

static int decode_frame(FLACContext *s)
{
int blocksize_code, sample_rate_code, sample_size_code, assignment, i;
blocksize_code = get_bits(&s->gb, 4);
if (blocksize_code == 0)
s->blocksize = s->min_blocksize;
else if (blocksize_code == 1)
s->blocksize = 192;
else if (blocksize_code <= 5)
s->blocksize = 576 << (blocksize_code - 2);
else if (blocksize_code >= 8)
s->blocksize = 256 << (blocksize_code - 8);

sample_rate_code = get_bits(&s->gb, 4);
if ((sample_rate_code > 3) && (sample_rate_code < 12))
s->samplerate = sample_rate_table[sample_rate_code];
assignment = get_bits(&s->gb, 4); /* channel assignment */
if (assignment < 8)
{
s->order = INDEPENDENT;
if (s->channels != assignment+1)
printf("channel number and number of assigned channels differ!\n");
printf("channels: %d\n", assignment+1);
}
else if (assignment == 8)
{
s->order = LEFT_SIDE;
printf("left/side\n");
}
else if (assignment == 9)
{
s->order = RIGHT_SIDE;
printf("right/side\n");
}
else if (assignment == 10)
{
s->order = MID_SIDE;
printf("mid/side\n");
}
else
{
printf("unsupported channel assignment\n");
return -1;
}

if ((assignment >= 8) && (s->channels != 2))
{
return -1;
}
sample_size_code = get_bits(&s->gb, 3);
if (s->bps != 0)
s->bps = sample_size_table[sample_size_code];

if ((sample_size_code == 3) || (sample_size_code == 7))
{
printf("invalid sample size code (%d)\n", sample_size_code);
return -1;
}

if (get_bits1(&s->gb))
{
printf("broken stream, invalid padding\n");
// return -1;
}
if (((blocksize_code == 6) || (blocksize_code == 7)) &&
(s->min_blocksize != s->max_blocksize))
{
get_uvlc(&s->gb, 1);
}
else
get_uvlc(&s->gb, 0);
if (blocksize_code == 6)
s->blocksize = get_bits(&s->gb, 8)+1;
if (blocksize_code == 7)
s->blocksize = get_bits(&s->gb, 16)+1;

if ((sample_rate_code > 11) && (sample_rate_code < 15))
{
switch(sample_rate_code)
{
case 12:
s->samplerate = get_bits(&s->gb, 8) * 1000;
break;
case 13:
s->samplerate = get_bits(&s->gb, 16);
break;
case 14:
s->samplerate = get_bits(&s->gb, 16) * 10;
break;
}
}

skip_bits(&s->gb, 8); /* header crc */

dump_headers(s);

/* subframes */
for (i = 0; i < s->channels; i++)
{
if (s->blocksize != s->last_blocksize)
{
s->decoded[i] = av_realloc(s->decoded[i], sizeof(uint32_t)*s->blocksize);
s->residual[i] = av_realloc(s->residual[i], sizeof(uint8_t)*s->blocksize);
}
printf("decoded: %x residual: %x\n", s->decoded[i], s->residual[i]);
if (decode_subframe(s, i) < 0)
return -1;
}
align_get_bits(&s->gb);

/* frame footer */
skip_bits(&s->gb, 16); /* data crc */

return 0;
}

static int flac_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
FLACContext *s = avctx->priv_data;
int metadata_flag, metadata_type, metadata_size;
int tmp = 0, i, j = 0;
int16_t *samples = data, *left, *right;

*data_size = 0;

s->avctx = avctx;

init_get_bits(&s->gb, buf, buf_size*8);
/* fLaC signature (be) */
if (get_bits_long(&s->gb, 32) == bswap_32(ff_get_fourcc("fLaC")))
{
printf("STREAM HEADER\n");
do {
metadata_flag = get_bits(&s->gb, 1);
metadata_type = get_bits(&s->gb, 7);
metadata_size = get_bits_long(&s->gb, 24);
printf(" metadata block: flag = %d, type = %d, size = %d\n",
metadata_flag, metadata_type,
metadata_size);

switch(metadata_type)
{
case METADATA_TYPE_STREAMINFO:
metadata_streaminfo(s);
dump_headers(s);
break;
default:
while ((metadata_size -= 8) > 0)
skip_bits(&s->gb, 8);
}
} while(metadata_flag != 1);
}
else
{
init_get_bits(&s->gb, buf, buf_size*8);
tmp = get_bits(&s->gb, 16);
if (tmp == 0xfff8)
printf("FRAME HEADER\n");

if (decode_frame(s) < 0)
return -1;
}
#if 0
/* fix the channel order here */
if (s->order == MID_SIDE)
{
short *left = samples;
short *right = samples + s->blocksize;
for (i = 0; i < s->blocksize; i += 2)
{
uint32_t x = s->decoded[0][i];
uint32_t y = s->decoded[0][i+1];

right[i] = x - (y / 2);
left[i] = right[i] + y;
}
*data_size = 2 * s->blocksize;
}
else
{
for (i = 0; i < s->channels; i++)
{
switch(s->order)
{
case INDEPENDENT:
for (j = 0; j < s->blocksize; j++)
samples[(s->blocksize*i)+j] = s->decoded[i][j];
break;
case LEFT_SIDE:
case RIGHT_SIDE:
if (i == 0)
for (j = 0; j < s->blocksize; j++)
samples[(s->blocksize*i)+j] = s->decoded[0][j];
else
for (j = 0; j < s->blocksize; j++)
samples[(s->blocksize*i)+j] = s->decoded[0][j] - s->decoded[i][j];
break;
// case MID_SIDE:
// printf("mid-side unsupported\n");
}
*data_size += s->blocksize;
}
}
#else
switch(s->order)
{
case INDEPENDENT:
for (i = 0; i < s->channels; i++)
{
for (j = 0; j < s->blocksize; j++)
*(samples++) = s->decoded[i][j];
*data_size += s->blocksize;
}
break;
case LEFT_SIDE:
assert(s->channels == 2);
for (i = 0; i < s->blocksize; i++)
{
*(samples++) = s->decoded[0][i];
*(samples++) = s->decoded[0][i] - s->decoded[1][i];
}
*data_size = 2*s->blocksize;
break;
case RIGHT_SIDE:
assert(s->channels == 2);
for (i = 0; i < s->blocksize; i++)
{
*(samples++) = s->decoded[0][i] + s->decoded[1][i];
*(samples++) = s->decoded[1][i];
}
*data_size = 2*s->blocksize;
break;
case MID_SIDE:
assert(s->channels == 2);
for (i = 0; i < s->blocksize; i++)
{
int16_t mid, side;
mid = s->decoded[0][i];
side = s->decoded[1][i];
mid <<= 1;
if (side & 1)
mid++;
*(samples++) = (mid + side) >> 1;
*(samples++) = (mid - side) >> 1;
}
*data_size = 2*s->blocksize;
break;
}
#endif

// *data_size = (int8_t *)samples - (int8_t *)data;
printf("data size: %d\n", *data_size);

s->last_blocksize = s->blocksize;

return (get_bits_count(&s->gb)+7)/8;
}

static int flac_decode_close(AVCodecContext *avctx)
{
FLACContext *s = avctx->priv_data;
int i;
for (i = 0; i < s->channels; i++)
{
if (s->decoded[i])
av_free(s->decoded[i]);
if (s->residual[i])
av_free(s->residual[i]);
}
return 0;
}

AVCodec flac_decoder = {
"flac",
CODEC_TYPE_AUDIO,
CODEC_ID_FLAC,
sizeof(FLACContext),
flac_decode_init,
NULL,
flac_decode_close,
flac_decode_frame,
};

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