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Regard whitespace Rev 164 → Rev 165

/programs/media/ac97 mp3/trunk/mp3dec/l2init.c
0,0 → 1,205
#include "bstream.h"
#include "mp3dec.h"
#include <math.h>
 
extern MPEG_DECODE_OPTION m_option;
extern int m_frequency;
 
extern float m_sample[2304];
extern int m_nsb_limit;
extern int m_max_sb;
extern SBT_PROC m_sbt_proc;
 
extern float m_sf_table[64];
extern float m_look_c_valueL2[18];
extern char m_group3_table[32][3];
extern char m_group5_table[128][3];
extern short m_group9_table[1024][3];
extern int m_nbat[4];// = {3, 8, 12, 7};
extern int m_bat[4][16];
 
/* ABCD_INDEX = lookqt[mode][sr_index][br_index] */
/* -1 = invalid */
static const char lookqt[4][3][16] =
{
1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks stereo */
0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks joint stereo */
0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
1, -1, -1, -1, 2, -1, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 44ks dual chan */
0, -1, -1, -1, 2, -1, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, /* 48ks */
1, -1, -1, -1, 3, -1, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, /* 32ks */
// mono extended beyond legal br index
// 1,2,2,0,0,0,1,1,1,1,1,1,1,1,1,-1, /* 44ks single chan */
// 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,-1, /* 48ks */
// 1,3,3,0,0,0,1,1,1,1,1,1,1,1,1,-1, /* 32ks */
// legal mono
1, 2, 2, 0, 0, 0, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, /* 44ks single chan */
0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, /* 48ks */
1, 3, 3, 0, 0, 0, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, /* 32ks */
};
 
/* bit allocation table look up */
/* table per mpeg spec tables 3b2a/b/c/d /e is mpeg2 */
/* look_bat[abcd_index][4][16] */
static const unsigned char look_bat[5][4][16] =
{
/* LOOK_BATA */
0, 1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17,
0, 1, 2, 3, 4, 5, 6, 17, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 17, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* LOOK_BATB */
0, 1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17,
0, 1, 2, 3, 4, 5, 6, 17, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 17, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* LOOK_BATC */
0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* LOOK_BATD */
0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* LOOK_BATE */
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0, 0,
0, 1, 2, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
 
/* look_nbat[abcd_index]][4] */
static const unsigned char look_nbat[5][4] =
{
3, 8, 12, 4,
3, 8, 12, 7,
2, 0, 6, 0,
2, 0, 10, 0,
4, 0, 7, 19,
};
 
//extern "sbt.c"
void sbt_mono(float *sample, signed short *pcm, int ch);
void sbt_dual(float *sample, signed short *pcm, int ch);
void sbt16_mono(float *sample, signed short *pcm, int ch);
void sbt16_dual(float *sample, signed short *pcm, int ch);
void sbt8_mono(float *sample, signed short *pcm, int ch);
void sbt8_dual(float *sample, signed short *pcm, int ch);
void sbtB_mono(float *sample, unsigned char *pcm, int ch);
void sbtB_dual(float *sample, unsigned char *pcm, int ch);
void sbtB16_mono(float *sample, unsigned char *pcm, int ch);
void sbtB16_dual(float *sample, unsigned char *pcm, int ch);
void sbtB8_mono(float *sample, unsigned char *pcm, int ch);
void sbtB8_dual(float *sample, unsigned char *pcm, int ch);
 
static const SBT_PROC sbt_table[2][3][2] =
{
sbt_mono,
sbt_dual,
sbt16_mono,
sbt16_dual,
sbt8_mono,
sbt8_dual,
sbtB_mono,
sbtB_dual,
sbtB16_mono,
sbtB16_dual,
sbtB8_mono,
sbtB8_dual,
};
 
void L2table_init()
{
int i, j, code;
long stepL2[18] = {
0, 3, 5, 7, 9, 15, 31, 63, 127,
255, 511, 1023, 2047, 4095, 8191, 16383, 32767, 65535
};
//c_values (dequant)
for (i = 1; i < 18; i++) {
m_look_c_valueL2[i] = 2.0F / stepL2[i];
}
//scale factor table, scale by 32768 for 16 pcm output
for (i = 0; i < 64; i++) {
m_sf_table[i] = (float) (32768.0 * 2.0 * pow_test(2.0, -i / 3.0));
}
//grouped 3 level lookup table 5 bit token
for (i = 0; i < 32; i++) {
code = i;
for (j = 0; j < 3; j++) {
m_group3_table[i][j] = (char) ((code % 3) - 1);
code /= 3;
}
}
//grouped 5 level lookup table 7 bit token
for (i = 0; i < 128; i++) {
code = i;
for (j = 0; j < 3; j++) {
m_group5_table[i][j] = (char) ((code % 5) - 2);
code /= 5;
}
}
//grouped 9 level lookup table 10 bit token
for (i = 0; i < 1024; i++) {
code = i;
for (j = 0; j < 3; j++) {
m_group9_table[i][j] = (short) ((code % 9) - 4);
code /= 9;
}
}
}
 
int L2decode_start(MPEG_HEADER* h)
{
int i, j, k, bit_code, limit;
int abcd_index;
 
// compute abcd index for bit allo table selection
if (h->version == 1) // MPEG-1
abcd_index = lookqt[h->mode][h->fr_index][h->br_index];
else
abcd_index = 4; // MPEG-2, MPEG-2.5
if (abcd_index < 0)
return 0; // fail invalid Layer II bit rate index
 
for (i = 0; i < 4; i++) {
m_nbat[i] = look_nbat[abcd_index][i];
for (j = 0; j < 16; j++) {
m_bat[i][j] = look_bat[abcd_index][i][j];
}
}
m_max_sb = m_nbat[0] + m_nbat[1] + m_nbat[2] + m_nbat[3];
// compute nsb_limit
m_nsb_limit = (m_option.freqLimit * 64L + m_frequency / 2) / m_frequency;
// caller limit
// limit = 0.94*(32>>reduction_code);
limit = (32 >> m_option.reduction);
if (limit > 8)
limit--;
if (m_nsb_limit > limit)
m_nsb_limit = limit;
if (m_nsb_limit > m_max_sb)
m_nsb_limit = m_max_sb;
 
if (h->mode != 3) {
// adjust for 2 channel modes
for (i = 0; i < 4; i++)
m_nbat[i] *= 2;
m_max_sb *= 2;
m_nsb_limit *= 2;
}
 
// set sbt function
bit_code = (m_option.convert & 8) ? 1 : 0;
k = (h->mode == 3) ? 0 : (1 + m_option.convert);
m_sbt_proc = sbt_table[bit_code][m_option.reduction][k];//[2][3][2]
// clear sample buffer, unused sub bands must be 0
for (i = 0; i < 2304; i++)
m_sample[i] = 0.0F;
return 1;
}