ref: c78ac707b07a3c8dea4685274cb6f1b3ba1ea93f
dir: /amr-wb/d4t64fx.c/
/*-------------------------------------------------------------------*
* D2T64FX.C *
*-------------------------------------------------------------------*
* 20, 36, 44, 52, 64, 72, 88 bits algebraic codebook decoder. *
* 4 tracks x 16 positions per track = 64 samples. *
* *
* 20 bits --> 4 pulses in a frame of 64 samples. *
* 36 bits --> 8 pulses in a frame of 64 samples. *
* 44 bits --> 10 pulses in a frame of 64 samples. *
* 52 bits --> 12 pulses in a frame of 64 samples. *
* 64 bits --> 16 pulses in a frame of 64 samples. *
* 72 bits --> 18 pulses in a frame of 64 samples. *
* 88 bits --> 24 pulses in a frame of 64 samples. *
* *
* All pulses can have two (2) possible amplitudes: +1 or -1. *
* Each pulse can have sixteen (16) possible positions. *
* *
* See c36_64fx.c for more details of the algebraic code. *
*-------------------------------------------------------------------*/
#include "typedef.h"
#include "basic_op.h"
#include "count.h"
#include "cnst.h"
#include "q_pulse.h"
#define L_CODE 64 /* codevector length */
#define NB_TRACK 4 /* number of track */
#define NB_POS 16 /* number of position */
/* local function */
static void add_pulses(Word16 pos[], Word16 nb_pulse, Word16 track, Word16 code[]);
void DEC_ACELP_4t64_fx(
Word16 index[], /* (i) : index (20): 5+5+5+5 = 20 bits. */
/* (i) : index (36): 9+9+9+9 = 36 bits. */
/* (i) : index (44): 13+9+13+9 = 44 bits. */
/* (i) : index (52): 13+13+13+13 = 52 bits. */
/* (i) : index (64): 2+2+2+2+14+14+14+14 = 64 bits. */
/* (i) : index (72): 10+2+10+2+10+14+10+14 = 72 bits. */
/* (i) : index (88): 11+11+11+11+11+11+11+11 = 88 bits. */
Word16 nbbits, /* (i) : 20, 36, 44, 52, 64, 72 or 88 bits */
Word16 code[] /* (o) Q9: algebraic (fixed) codebook excitation */
)
{
Word16 i, k, pos[6];
Word32 L_index;
for (i = 0; i < L_CODE; i++)
{
code[i] = 0; move16();
}
/* decode the positions and signs of pulses and build the codeword */
test();test();test();test();test();test();test();
if (sub(nbbits, 20) == 0)
{
for (k = 0; k < NB_TRACK; k++)
{
L_index = index[k]; move32();
dec_1p_N1(L_index, 4, 0, pos);
add_pulses(pos, 1, k, code);
}
} else if (sub(nbbits, 36) == 0)
{
for (k = 0; k < NB_TRACK; k++)
{
L_index = index[k]; move32();
dec_2p_2N1(L_index, 4, 0, pos);
add_pulses(pos, 2, k, code);
}
} else if (sub(nbbits, 44) == 0)
{
for (k = 0; k < NB_TRACK - 2; k++)
{
L_index = index[k]; move32();
dec_3p_3N1(L_index, 4, 0, pos);
add_pulses(pos, 3, k, code);
}
for (k = 2; k < NB_TRACK; k++)
{
L_index = index[k]; move32();
dec_2p_2N1(L_index, 4, 0, pos);
add_pulses(pos, 2, k, code);
}
} else if (sub(nbbits, 52) == 0)
{
for (k = 0; k < NB_TRACK; k++)
{
L_index = index[k]; move32();
dec_3p_3N1(L_index, 4, 0, pos);
add_pulses(pos, 3, k, code);
}
} else if (sub(nbbits, 64) == 0)
{
for (k = 0; k < NB_TRACK; k++)
{
L_index = L_add(L_shl(index[k], 14), index[k + NB_TRACK]);
dec_4p_4N(L_index, 4, 0, pos);
add_pulses(pos, 4, k, code);
}
} else if (sub(nbbits, 72) == 0)
{
for (k = 0; k < NB_TRACK - 2; k++)
{
L_index = L_add(L_shl(index[k], 10), index[k + NB_TRACK]);
dec_5p_5N(L_index, 4, 0, pos);
add_pulses(pos, 5, k, code);
}
for (k = 2; k < NB_TRACK; k++)
{
L_index = L_add(L_shl(index[k], 14), index[k + NB_TRACK]);
dec_4p_4N(L_index, 4, 0, pos);
add_pulses(pos, 4, k, code);
}
} else if (sub(nbbits, 88) == 0)
{
for (k = 0; k < NB_TRACK; k++)
{
L_index = L_add(L_shl(index[k], 11), index[k + NB_TRACK]);
dec_6p_6N_2(L_index, 4, 0, pos);
add_pulses(pos, 6, k, code);
}
}
return;
}
static void add_pulses(Word16 pos[], Word16 nb_pulse, Word16 track, Word16 code[])
{
Word16 i, k;
for (k = 0; k < nb_pulse; k++)
{
/* i = ((pos[k] & (NB_POS-1))*NB_TRACK) + track; */
i = (Word16) (add(shl((Word16) (pos[k] & (NB_POS - 1)), 2), track)); logic16();
test();logic16();
if ((pos[k] & NB_POS) == 0)
code[i] = add(code[i], 512);
else
code[i] = sub(code[i], 512);
}
return;
}