535 lines
13 KiB
C
535 lines
13 KiB
C
/*
|
|
* libmad - MPEG audio decoder library
|
|
* Copyright (C) 2000-2004 Underbit Technologies, Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
* $Id: layer12.c,v 1.17 2004/02/05 09:02:39 rob Exp $
|
|
*/
|
|
|
|
# ifdef HAVE_CONFIG_H
|
|
# include "config.h"
|
|
# endif
|
|
|
|
# include "global.h"
|
|
|
|
# ifdef HAVE_LIMITS_H
|
|
# include <limits.h>
|
|
# else
|
|
# define CHAR_BIT 8
|
|
# endif
|
|
|
|
# include "fixed.h"
|
|
# include "bit.h"
|
|
# include "stream.h"
|
|
# include "frame.h"
|
|
# include "layer12.h"
|
|
|
|
/*
|
|
* scalefactor table
|
|
* used in both Layer I and Layer II decoding
|
|
*/
|
|
static
|
|
mad_fixed_t const sf_table[64] = {
|
|
# include "sf_table.dat"
|
|
};
|
|
|
|
/* --- Layer I ------------------------------------------------------------- */
|
|
|
|
/* linear scaling table */
|
|
static
|
|
mad_fixed_t const linear_table[14] = {
|
|
MAD_F(0x15555555), /* 2^2 / (2^2 - 1) == 1.33333333333333 */
|
|
MAD_F(0x12492492), /* 2^3 / (2^3 - 1) == 1.14285714285714 */
|
|
MAD_F(0x11111111), /* 2^4 / (2^4 - 1) == 1.06666666666667 */
|
|
MAD_F(0x10842108), /* 2^5 / (2^5 - 1) == 1.03225806451613 */
|
|
MAD_F(0x10410410), /* 2^6 / (2^6 - 1) == 1.01587301587302 */
|
|
MAD_F(0x10204081), /* 2^7 / (2^7 - 1) == 1.00787401574803 */
|
|
MAD_F(0x10101010), /* 2^8 / (2^8 - 1) == 1.00392156862745 */
|
|
MAD_F(0x10080402), /* 2^9 / (2^9 - 1) == 1.00195694716243 */
|
|
MAD_F(0x10040100), /* 2^10 / (2^10 - 1) == 1.00097751710655 */
|
|
MAD_F(0x10020040), /* 2^11 / (2^11 - 1) == 1.00048851978505 */
|
|
MAD_F(0x10010010), /* 2^12 / (2^12 - 1) == 1.00024420024420 */
|
|
MAD_F(0x10008004), /* 2^13 / (2^13 - 1) == 1.00012208521548 */
|
|
MAD_F(0x10004001), /* 2^14 / (2^14 - 1) == 1.00006103888177 */
|
|
MAD_F(0x10002000) /* 2^15 / (2^15 - 1) == 1.00003051850948 */
|
|
};
|
|
|
|
/*
|
|
* NAME: I_sample()
|
|
* DESCRIPTION: decode one requantized Layer I sample from a bitstream
|
|
*/
|
|
static
|
|
mad_fixed_t I_sample(struct mad_bitptr *ptr, unsigned int nb)
|
|
{
|
|
mad_fixed_t sample;
|
|
|
|
sample = mad_bit_read(ptr, nb);
|
|
|
|
/* invert most significant bit, extend sign, then scale to fixed format */
|
|
|
|
sample ^= 1 << (nb - 1);
|
|
sample |= -(sample & (1 << (nb - 1)));
|
|
|
|
sample <<= MAD_F_FRACBITS - (nb - 1);
|
|
|
|
/* requantize the sample */
|
|
|
|
/* s'' = (2^nb / (2^nb - 1)) * (s''' + 2^(-nb + 1)) */
|
|
|
|
sample += MAD_F_ONE >> (nb - 1);
|
|
|
|
return mad_f_mul(sample, linear_table[nb - 2]);
|
|
|
|
/* s' = factor * s'' */
|
|
/* (to be performed by caller) */
|
|
}
|
|
|
|
/*
|
|
* NAME: layer->I()
|
|
* DESCRIPTION: decode a single Layer I frame
|
|
*/
|
|
int mad_layer_I(struct mad_stream *stream, struct mad_frame *frame)
|
|
{
|
|
struct mad_header *header = &frame->header;
|
|
unsigned int nch, bound, ch, s, sb, nb;
|
|
unsigned char allocation[2][32], scalefactor[2][32];
|
|
|
|
nch = MAD_NCHANNELS(header);
|
|
|
|
bound = 32;
|
|
if (header->mode == MAD_MODE_JOINT_STEREO) {
|
|
header->flags |= MAD_FLAG_I_STEREO;
|
|
bound = 4 + header->mode_extension * 4;
|
|
}
|
|
|
|
/* check CRC word */
|
|
|
|
if (header->flags & MAD_FLAG_PROTECTION) {
|
|
header->crc_check =
|
|
mad_bit_crc(stream->ptr, 4 * (bound * nch + (32 - bound)),
|
|
header->crc_check);
|
|
|
|
if (header->crc_check != header->crc_target &&
|
|
!(frame->options & MAD_OPTION_IGNORECRC)) {
|
|
stream->error = MAD_ERROR_BADCRC;
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* decode bit allocations */
|
|
|
|
for (sb = 0; sb < bound; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
nb = mad_bit_read(&stream->ptr, 4);
|
|
|
|
if (nb == 15) {
|
|
stream->error = MAD_ERROR_BADBITALLOC;
|
|
return -1;
|
|
}
|
|
|
|
allocation[ch][sb] = nb ? nb + 1 : 0;
|
|
}
|
|
}
|
|
|
|
for (sb = bound; sb < 32; ++sb) {
|
|
nb = mad_bit_read(&stream->ptr, 4);
|
|
|
|
if (nb == 15) {
|
|
stream->error = MAD_ERROR_BADBITALLOC;
|
|
return -1;
|
|
}
|
|
|
|
allocation[0][sb] =
|
|
allocation[1][sb] = nb ? nb + 1 : 0;
|
|
}
|
|
|
|
/* decode scalefactors */
|
|
|
|
for (sb = 0; sb < 32; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
if (allocation[ch][sb]) {
|
|
scalefactor[ch][sb] = mad_bit_read(&stream->ptr, 6);
|
|
|
|
# if defined(OPT_STRICT)
|
|
/*
|
|
* Scalefactor index 63 does not appear in Table B.1 of
|
|
* ISO/IEC 11172-3. Nonetheless, other implementations accept it,
|
|
* so we only reject it if OPT_STRICT is defined.
|
|
*/
|
|
if (scalefactor[ch][sb] == 63) {
|
|
stream->error = MAD_ERROR_BADSCALEFACTOR;
|
|
return -1;
|
|
}
|
|
# endif
|
|
}
|
|
}
|
|
}
|
|
|
|
/* decode samples */
|
|
|
|
for (s = 0; s < 12; ++s) {
|
|
for (sb = 0; sb < bound; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
nb = allocation[ch][sb];
|
|
frame->sbsample[ch][s][sb] = nb ?
|
|
mad_f_mul(I_sample(&stream->ptr, nb),
|
|
sf_table[scalefactor[ch][sb]]) : 0;
|
|
}
|
|
}
|
|
|
|
for (sb = bound; sb < 32; ++sb) {
|
|
if ((nb = allocation[0][sb])) {
|
|
mad_fixed_t sample;
|
|
|
|
sample = I_sample(&stream->ptr, nb);
|
|
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
frame->sbsample[ch][s][sb] =
|
|
mad_f_mul(sample, sf_table[scalefactor[ch][sb]]);
|
|
}
|
|
}
|
|
else {
|
|
for (ch = 0; ch < nch; ++ch)
|
|
frame->sbsample[ch][s][sb] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* --- Layer II ------------------------------------------------------------ */
|
|
|
|
/* possible quantization per subband table */
|
|
static
|
|
struct {
|
|
unsigned int sblimit;
|
|
unsigned char const offsets[30];
|
|
} const sbquant_table[5] = {
|
|
/* ISO/IEC 11172-3 Table B.2a */
|
|
{ 27, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, /* 0 */
|
|
3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0 } },
|
|
/* ISO/IEC 11172-3 Table B.2b */
|
|
{ 30, { 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, /* 1 */
|
|
3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0 } },
|
|
/* ISO/IEC 11172-3 Table B.2c */
|
|
{ 8, { 5, 5, 2, 2, 2, 2, 2, 2 } }, /* 2 */
|
|
/* ISO/IEC 11172-3 Table B.2d */
|
|
{ 12, { 5, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 } }, /* 3 */
|
|
/* ISO/IEC 13818-3 Table B.1 */
|
|
{ 30, { 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, /* 4 */
|
|
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 } }
|
|
};
|
|
|
|
/* bit allocation table */
|
|
static
|
|
struct {
|
|
unsigned short nbal;
|
|
unsigned short offset;
|
|
} const bitalloc_table[8] = {
|
|
{ 2, 0 }, /* 0 */
|
|
{ 2, 3 }, /* 1 */
|
|
{ 3, 3 }, /* 2 */
|
|
{ 3, 1 }, /* 3 */
|
|
{ 4, 2 }, /* 4 */
|
|
{ 4, 3 }, /* 5 */
|
|
{ 4, 4 }, /* 6 */
|
|
{ 4, 5 } /* 7 */
|
|
};
|
|
|
|
/* offsets into quantization class table */
|
|
static
|
|
unsigned char const offset_table[6][15] = {
|
|
{ 0, 1, 16 }, /* 0 */
|
|
{ 0, 1, 2, 3, 4, 5, 16 }, /* 1 */
|
|
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 }, /* 2 */
|
|
{ 0, 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 }, /* 3 */
|
|
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16 }, /* 4 */
|
|
{ 0, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 } /* 5 */
|
|
};
|
|
|
|
/* quantization class table */
|
|
static
|
|
struct quantclass {
|
|
unsigned short nlevels;
|
|
unsigned char group;
|
|
unsigned char bits;
|
|
mad_fixed_t C;
|
|
mad_fixed_t D;
|
|
} const qc_table[17] = {
|
|
# include "qc_table.dat"
|
|
};
|
|
|
|
/*
|
|
* NAME: II_samples()
|
|
* DESCRIPTION: decode three requantized Layer II samples from a bitstream
|
|
*/
|
|
static
|
|
void II_samples(struct mad_bitptr *ptr,
|
|
struct quantclass const *quantclass,
|
|
mad_fixed_t output[3])
|
|
{
|
|
unsigned int nb, s, sample[3];
|
|
|
|
if ((nb = quantclass->group)) {
|
|
unsigned int c, nlevels;
|
|
|
|
/* degrouping */
|
|
c = mad_bit_read(ptr, quantclass->bits);
|
|
nlevels = quantclass->nlevels;
|
|
|
|
for (s = 0; s < 3; ++s) {
|
|
sample[s] = c % nlevels;
|
|
c /= nlevels;
|
|
}
|
|
}
|
|
else {
|
|
nb = quantclass->bits;
|
|
|
|
for (s = 0; s < 3; ++s)
|
|
sample[s] = mad_bit_read(ptr, nb);
|
|
}
|
|
|
|
for (s = 0; s < 3; ++s) {
|
|
mad_fixed_t requantized;
|
|
|
|
/* invert most significant bit, extend sign, then scale to fixed format */
|
|
|
|
requantized = sample[s] ^ (1 << (nb - 1));
|
|
requantized |= -(requantized & (1 << (nb - 1)));
|
|
|
|
requantized <<= MAD_F_FRACBITS - (nb - 1);
|
|
|
|
/* requantize the sample */
|
|
|
|
/* s'' = C * (s''' + D) */
|
|
|
|
output[s] = mad_f_mul(requantized + quantclass->D, quantclass->C);
|
|
|
|
/* s' = factor * s'' */
|
|
/* (to be performed by caller) */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* NAME: layer->II()
|
|
* DESCRIPTION: decode a single Layer II frame
|
|
*/
|
|
int mad_layer_II(struct mad_stream *stream, struct mad_frame *frame)
|
|
{
|
|
struct mad_header *header = &frame->header;
|
|
struct mad_bitptr start;
|
|
unsigned int index, sblimit, nbal, nch, bound, gr, ch, s, sb;
|
|
unsigned char const *offsets;
|
|
unsigned char allocation[2][32], scfsi[2][32], scalefactor[2][32][3];
|
|
mad_fixed_t samples[3];
|
|
|
|
nch = MAD_NCHANNELS(header);
|
|
|
|
if (header->flags & MAD_FLAG_LSF_EXT)
|
|
index = 4;
|
|
else if (header->flags & MAD_FLAG_FREEFORMAT)
|
|
goto freeformat;
|
|
else {
|
|
unsigned long bitrate_per_channel;
|
|
|
|
bitrate_per_channel = header->bitrate;
|
|
if (nch == 2) {
|
|
bitrate_per_channel /= 2;
|
|
|
|
# if defined(OPT_STRICT)
|
|
/*
|
|
* ISO/IEC 11172-3 allows only single channel mode for 32, 48, 56, and
|
|
* 80 kbps bitrates in Layer II, but some encoders ignore this
|
|
* restriction. We enforce it if OPT_STRICT is defined.
|
|
*/
|
|
if (bitrate_per_channel <= 28000 || bitrate_per_channel == 40000) {
|
|
stream->error = MAD_ERROR_BADMODE;
|
|
return -1;
|
|
}
|
|
# endif
|
|
}
|
|
else { /* nch == 1 */
|
|
if (bitrate_per_channel > 192000) {
|
|
/*
|
|
* ISO/IEC 11172-3 does not allow single channel mode for 224, 256,
|
|
* 320, or 384 kbps bitrates in Layer II.
|
|
*/
|
|
stream->error = MAD_ERROR_BADMODE;
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
if (bitrate_per_channel <= 48000)
|
|
index = (header->samplerate == 32000) ? 3 : 2;
|
|
else if (bitrate_per_channel <= 80000)
|
|
index = 0;
|
|
else {
|
|
freeformat:
|
|
index = (header->samplerate == 48000) ? 0 : 1;
|
|
}
|
|
}
|
|
|
|
sblimit = sbquant_table[index].sblimit;
|
|
offsets = sbquant_table[index].offsets;
|
|
|
|
bound = 32;
|
|
if (header->mode == MAD_MODE_JOINT_STEREO) {
|
|
header->flags |= MAD_FLAG_I_STEREO;
|
|
bound = 4 + header->mode_extension * 4;
|
|
}
|
|
|
|
if (bound > sblimit)
|
|
bound = sblimit;
|
|
|
|
start = stream->ptr;
|
|
|
|
/* decode bit allocations */
|
|
|
|
for (sb = 0; sb < bound; ++sb) {
|
|
nbal = bitalloc_table[offsets[sb]].nbal;
|
|
|
|
for (ch = 0; ch < nch; ++ch)
|
|
allocation[ch][sb] = mad_bit_read(&stream->ptr, nbal);
|
|
}
|
|
|
|
for (sb = bound; sb < sblimit; ++sb) {
|
|
nbal = bitalloc_table[offsets[sb]].nbal;
|
|
|
|
allocation[0][sb] =
|
|
allocation[1][sb] = mad_bit_read(&stream->ptr, nbal);
|
|
}
|
|
|
|
/* decode scalefactor selection info */
|
|
|
|
for (sb = 0; sb < sblimit; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
if (allocation[ch][sb])
|
|
scfsi[ch][sb] = mad_bit_read(&stream->ptr, 2);
|
|
}
|
|
}
|
|
|
|
/* check CRC word */
|
|
|
|
if (header->flags & MAD_FLAG_PROTECTION) {
|
|
header->crc_check =
|
|
mad_bit_crc(start, mad_bit_length(&start, &stream->ptr),
|
|
header->crc_check);
|
|
|
|
if (header->crc_check != header->crc_target &&
|
|
!(frame->options & MAD_OPTION_IGNORECRC)) {
|
|
stream->error = MAD_ERROR_BADCRC;
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* decode scalefactors */
|
|
|
|
for (sb = 0; sb < sblimit; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
if (allocation[ch][sb]) {
|
|
scalefactor[ch][sb][0] = mad_bit_read(&stream->ptr, 6);
|
|
|
|
switch (scfsi[ch][sb]) {
|
|
case 2:
|
|
scalefactor[ch][sb][2] =
|
|
scalefactor[ch][sb][1] =
|
|
scalefactor[ch][sb][0];
|
|
break;
|
|
|
|
case 0:
|
|
scalefactor[ch][sb][1] = mad_bit_read(&stream->ptr, 6);
|
|
/* fall through */
|
|
|
|
case 1:
|
|
case 3:
|
|
scalefactor[ch][sb][2] = mad_bit_read(&stream->ptr, 6);
|
|
}
|
|
|
|
if (scfsi[ch][sb] & 1)
|
|
scalefactor[ch][sb][1] = scalefactor[ch][sb][scfsi[ch][sb] - 1];
|
|
|
|
# if defined(OPT_STRICT)
|
|
/*
|
|
* Scalefactor index 63 does not appear in Table B.1 of
|
|
* ISO/IEC 11172-3. Nonetheless, other implementations accept it,
|
|
* so we only reject it if OPT_STRICT is defined.
|
|
*/
|
|
if (scalefactor[ch][sb][0] == 63 ||
|
|
scalefactor[ch][sb][1] == 63 ||
|
|
scalefactor[ch][sb][2] == 63) {
|
|
stream->error = MAD_ERROR_BADSCALEFACTOR;
|
|
return -1;
|
|
}
|
|
# endif
|
|
}
|
|
}
|
|
}
|
|
|
|
/* decode samples */
|
|
|
|
for (gr = 0; gr < 12; ++gr) {
|
|
for (sb = 0; sb < bound; ++sb) {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
if ((index = allocation[ch][sb])) {
|
|
index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1];
|
|
|
|
II_samples(&stream->ptr, &qc_table[index], samples);
|
|
|
|
for (s = 0; s < 3; ++s) {
|
|
frame->sbsample[ch][3 * gr + s][sb] =
|
|
mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]);
|
|
}
|
|
}
|
|
else {
|
|
for (s = 0; s < 3; ++s)
|
|
frame->sbsample[ch][3 * gr + s][sb] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
for (sb = bound; sb < sblimit; ++sb) {
|
|
if ((index = allocation[0][sb])) {
|
|
index = offset_table[bitalloc_table[offsets[sb]].offset][index - 1];
|
|
|
|
II_samples(&stream->ptr, &qc_table[index], samples);
|
|
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
for (s = 0; s < 3; ++s) {
|
|
frame->sbsample[ch][3 * gr + s][sb] =
|
|
mad_f_mul(samples[s], sf_table[scalefactor[ch][sb][gr / 4]]);
|
|
}
|
|
}
|
|
}
|
|
else {
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
for (s = 0; s < 3; ++s)
|
|
frame->sbsample[ch][3 * gr + s][sb] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
for (ch = 0; ch < nch; ++ch) {
|
|
for (s = 0; s < 3; ++s) {
|
|
for (sb = sblimit; sb < 32; ++sb)
|
|
frame->sbsample[ch][3 * gr + s][sb] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|