📄 dec_acelp.c
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/*
*===================================================================
* 3GPP AMR Wideband Floating-point Speech Codec
*===================================================================
*/
#include <memory.h>
#include "typedef.h"
#include "dec_util.h"
#define L_SUBFR 64 /* Subframe size */
#define PRED_ORDER 4
#define MEAN_ENER 30 /* average innovation energy */
extern const Word16 D_ROM_ph_imp_low[];
extern const Word16 D_ROM_ph_imp_mid[];
/*
* D_ACELP_add_pulse
*
* Parameters:
* pos I: position of pulse
* nb_pulse I: number of pulses
* track I: track
* code O: fixed codebook
*
* Function:
* Add pulses to fixed codebook
*
* Returns:
* void
*/
static void D_ACELP_add_pulse(Word32 pos[], Word32 nb_pulse,
Word32 track, Word16 code[])
{
Word32 i, k;
for(k = 0; k < nb_pulse; k++)
{
/* i = ((pos[k] & (16-1))*NB_TRACK) + track; */
i = ((pos[k] & (16 - 1)) << 2) + track;
if((pos[k] & 16) == 0)
{
code[i] = (Word16)(code[i] + 512);
}
else
{
code[i] = (Word16)(code[i] - 512);
}
}
return;
}
/*
* D_ACELP_decode_1p_N1
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 1 pulse with N+1 bits
*
* Returns:
* void
*/
static void D_ACELP_decode_1p_N1(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 i, pos1, mask;
mask = ((1 << N) - 1);
/*
* Decode 1 pulse with N+1 bits
*/
pos1 = ((index & mask) + offset);
i = ((index >> N) & 1);
if(i == 1)
{
pos1 += 16;
}
pos[0] = pos1;
return;
}
/*
* D_ACELP_decode_2p_2N1
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 2 pulses with 2*N+1 bits
*
* Returns:
* void
*/
static void D_ACELP_decode_2p_2N1(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 i, pos1, pos2;
Word32 mask;
mask = ((1 << N) - 1);
/*
* Decode 2 pulses with 2*N+1 bits
*/
pos1 = (((index >> N) & mask) + offset);
i = (index >> (2 * N)) & 1;
pos2 = ((index & mask) + offset);
if((pos2 - pos1) < 0)
{
if(i == 1)
{
pos1 += 16;
}
else
{
pos2 += 16;
}
}
else
{
if(i == 1)
{
pos1 += 16;
pos2 += 16;
}
}
pos[0] = pos1;
pos[1] = pos2;
return;
}
/*
* D_ACELP_decode_3p_3N1
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 3 pulses with 3*N+1 bits
*
* Returns:
* void
*/
static void D_ACELP_decode_3p_3N1(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 j, mask, idx;
/*
* Decode 3 pulses with 3*N+1 bits
*/
mask = ((1 << ((2 * N) - 1)) - 1);
idx = index & mask;
j = offset;
if(((index >> ((2 * N) - 1)) & 1) == 1)
{
j += (1 << (N - 1));
}
D_ACELP_decode_2p_2N1(idx, N - 1, j, pos);
mask = ((1 << (N + 1)) - 1);
idx = (index >> (2 * N)) & mask;
D_ACELP_decode_1p_N1(idx, N, offset, pos + 2);
return;
}
/*
* D_ACELP_decode_4p_4N1
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 4 pulses with 4*N+1 bits
*
* Returns:
* void
*/
static void D_ACELP_decode_4p_4N1(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 j, mask, idx;
/*
* Decode 4 pulses with 4*N+1 bits
*/
mask = ((1 << ((2 * N) - 1)) - 1);
idx = index & mask;
j = offset;
if(((index >> ((2 * N) - 1)) & 1) == 1)
{
j += (1 << (N - 1));
}
D_ACELP_decode_2p_2N1(idx, N - 1, j, pos);
mask = ((1 << ((2 * N) + 1)) - 1);
idx = (index >> (2 * N)) & mask;
D_ACELP_decode_2p_2N1(idx, N, offset, pos + 2);
return;
}
/*
* D_ACELP_decode_4p_4N
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 4 pulses with 4*N bits
*
* Returns:
* void
*/
static void D_ACELP_decode_4p_4N(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 j, n_1;
/*
* Decode 4 pulses with 4*N bits
*/
n_1 = N - 1;
j = offset + (1 << n_1);
switch((index >> ((4 * N) - 2)) & 3)
{
case 0:
if(((index >> ((4 * n_1) + 1)) & 1) == 0)
{
D_ACELP_decode_4p_4N1(index, n_1, offset, pos);
}
else
{
D_ACELP_decode_4p_4N1(index, n_1, j, pos);
}
break;
case 1:
D_ACELP_decode_1p_N1((index >> ((3 * n_1) + 1)), n_1, offset, pos);
D_ACELP_decode_3p_3N1(index, n_1, j, pos + 1);
break;
case 2:
D_ACELP_decode_2p_2N1((index >> ((2 * n_1) + 1)), n_1, offset, pos);
D_ACELP_decode_2p_2N1(index, n_1, j, pos + 2);
break;
case 3:
D_ACELP_decode_3p_3N1((index >> (n_1 + 1)), n_1, offset, pos);
D_ACELP_decode_1p_N1(index, n_1, j, pos + 3);
break;
}
return;
}
/*
* D_ACELP_decode_5p_5N
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 5 pulses with 5*N bits
*
* Returns:
* void
*/
static void D_ACELP_decode_5p_5N(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 j, n_1;
Word32 idx;
/*
* Decode 5 pulses with 5*N bits
*/
n_1 = N - 1;
j = offset + (1 << n_1);
idx = (index >> ((2 * N) + 1));
if(((index >> ((5 * N) - 1)) & 1) == 0)
{
D_ACELP_decode_3p_3N1(idx, n_1, offset, pos);
D_ACELP_decode_2p_2N1(index, N, offset, pos + 3);
}
else
{
D_ACELP_decode_3p_3N1(idx, n_1, j, pos);
D_ACELP_decode_2p_2N1(index, N, offset, pos + 3);
}
return;
}
/*
* D_ACELP_decode_6p_6N_2
*
* Parameters:
* index I: pulse index
* N I: number of bits for position
* offset I: offset
* pos O: position of the pulse
*
* Function:
* Decode 6 pulses with 6*N-2 bits
*
* Returns:
* void
*/
static void D_ACELP_decode_6p_6N_2(Word32 index, Word32 N,
Word32 offset, Word32 pos[])
{
Word32 j, n_1, offsetA, offsetB;
n_1 = N - 1;
j = offset + (1 << n_1);
offsetA = offsetB = j;
if(((index >> ((6 * N) - 5)) & 1) == 0)
{
offsetA = offset;
}
else
{
offsetB = offset;
}
switch((index >> ((6 * N) - 4)) & 3)
{
case 0:
D_ACELP_decode_5p_5N(index >> N, n_1, offsetA, pos);
D_ACELP_decode_1p_N1(index, n_1, offsetA, pos + 5);
break;
case 1:
D_ACELP_decode_5p_5N(index >> N, n_1, offsetA, pos);
D_ACELP_decode_1p_N1(index, n_1, offsetB, pos + 5);
break;
case 2:
D_ACELP_decode_4p_4N(index >> ((2 * n_1) + 1), n_1, offsetA, pos);
D_ACELP_decode_2p_2N1(index, n_1, offsetB, pos + 4);
break;
case 3:
D_ACELP_decode_3p_3N1(index >> ((3 * n_1) + 1), n_1, offset, pos);
D_ACELP_decode_3p_3N1(index, n_1, j, pos + 3);
break;
}
return;
}
/*
* D_ACELP_decode_2t
*
* Parameters:
* index I: 12 bits index
* code O: (Q9) algebraic (fixed) codebook excitation
*
* Function:
* 12 bits algebraic codebook decoder.
* 2 tracks x 32 positions per track = 64 samples.
*
* 12 bits --> 2 pulses in a frame of 64 samples.
*
* All pulses can have two (2) possible amplitudes: +1 or -1.
* Each pulse can have 32 possible positions.
*
* codevector length 64
* number of track 2
* number of position 32
*
* Returns:
* void
*/
void D_ACELP_decode_2t(Word16 index, Word16 code[])
{
Word32 i0, i1;
memset(code, 0, 64 * sizeof(Word16));
/* decode the positions and signs of pulses and build the codeword */
i0 = (index >> 5) & 0x0000003E;
i1 = ((index & 0x0000001F) << 1) + 1;
if(((index >> 6) & 32) == 0)
{
code[i0] = 512;
}
else
{
code[i0] = -512;
}
if((index & 32) == 0)
{
code[i1] = 512;
}
else
{
code[i1] = -512;
}
return;
}
/*
* D_ACELP_decode_4t
*
* Parameters:
* index I: index
* mode I: speech mode
* code I: (Q9) algebraic (fixed) codebook excitation
*
* Function:
* 20, 36, 44, 52, 64, 72, 88 bits algebraic codebook.
* 4 tracks x 16 positions per track = 64 samples.
*
* 20 bits 5+5+5+5 --> 4 pulses in a frame of 64 samples.
* 36 bits 9+9+9+9 --> 8 pulses in a frame of 64 samples.
* 44 bits 13+9+13+9 --> 10 pulses in a frame of 64 samples.
* 52 bits 13+13+13+13 --> 12 pulses in a frame of 64 samples.
* 64 bits 2+2+2+2+14+14+14+14 --> 16 pulses in a frame of 64 samples.
* 72 bits 10+2+10+2+10+14+10+14 --> 18 pulses in a frame of 64 samples.
* 88 bits 11+11+11+11+11+11+11+11 --> 24 pulses in a frame of 64 samples.
*
* All pulses can have two (2) possible amplitudes: +1 or -1.
* Each pulse can sixteen (16) possible positions.
*
* codevector length 64
* number of track 4
* number of position 16
*
* Returns:
* void
*/
void D_ACELP_decode_4t(Word16 index[], Word16 nbbits, Word16 code[])
{
Word32 k, L_index, pos[6];
memset(code, 0, 64 * sizeof(Word16));
/* decode the positions and signs of pulses and build the codeword */
if(nbbits == 20)
{
for(k = 0; k < 4; k++)
{
L_index = index[k];
D_ACELP_decode_1p_N1(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 1, k, code);
}
}
else if(nbbits == 36)
{
for(k = 0; k < 4; k++)
{
L_index = index[k];
D_ACELP_decode_2p_2N1(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 2, k, code);
}
}
else if(nbbits == 44)
{
for(k = 0; k < 4 - 2; k++)
{
L_index = index[k];
D_ACELP_decode_3p_3N1(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 3, k, code);
}
for(k = 2; k < 4; k++)
{
L_index = index[k];
D_ACELP_decode_2p_2N1(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 2, k, code);
}
}
else if(nbbits == 52)
{
for(k = 0; k < 4; k++)
{
L_index = index[k];
D_ACELP_decode_3p_3N1(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 3, k, code);
}
}
else if(nbbits == 64)
{
for(k = 0; k < 4; k++)
{
L_index = ((index[k] << 14) + index[k + 4]);
D_ACELP_decode_4p_4N(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 4, k, code);
}
}
else if(nbbits == 72)
{
for(k = 0; k < 4 - 2; k++)
{
L_index = ((index[k] << 10) + index[k + 4]);
D_ACELP_decode_5p_5N(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 5, k, code);
}
for(k = 2; k < 4; k++)
{
L_index = ((index[k] << 14) + index[k + 4]);
D_ACELP_decode_4p_4N(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 4, k, code);
}
}
else if(nbbits == 88)
{
for(k = 0; k < 4; k++)
{
L_index = ((index[k] << 11) + index[k + 4]);
D_ACELP_decode_6p_6N_2(L_index, 4, 0, pos);
D_ACELP_add_pulse(pos, 6, k, code);
}
}
return;
}
/*
* D_ACELP_phase_dispersion
*
* Parameters:
* gain_code I: (Q0) gain of code
* gain_pit I: (Q14) gain of pitch
* code I/O: code vector
* mode I: level, 0=hi, 1=lo, 2=off
* disp_mem I/O: static memory (size = 8)
*
* Function:
* An adaptive anti-sparseness post-processing procedure is
* applied to the fixed codebook vector in order to
* reduce perceptual artifacts arising from the sparseness
* of the algebraic fixed codebook vectors with only
* a few non-zero samples per subframe.
*
* Returns:
* void
*/
void D_ACELP_phase_dispersion(Word16 gain_code, Word16 gain_pit, Word16 code[],
Word16 mode, Word16 disp_mem[])
{
Word32 code2[2 * L_SUBFR] = {0};
Word32 i, j, state;
Word16 *prev_gain_pit, *prev_gain_code, *prev_state;
prev_state = disp_mem;
prev_gain_code = disp_mem + 1;
prev_gain_pit = disp_mem + 2;
if(gain_pit < 9830) /* 0.6 in Q14 */
{
state = 0;
}
else if(gain_pit < 14746) /* 0.9 in Q14 */
{
state = 1;
}
else
{
state = 2;
}
for(i = 5; i > 0; i--)
{
prev_gain_pit[i] = prev_gain_pit[i - 1];
}
prev_gain_pit[0] = gain_pit;
if((gain_code - *prev_gain_code) > (*prev_gain_code << 1))
{
/* onset */
if(state < 2)
{
state = state + 1;
}
}
else
{
j = 0;
for(i = 0; i < 6; i++)
{
if(prev_gain_pit[i] < 9830) /* 0.6 in Q14 */
j = (j + 1);
}
if(j > 2)
{
state = 0;
}
if((state - *prev_state) > 1)
{
state = state - 1;
}
}
*prev_gain_code = gain_code;
*prev_state = (Word16)state;
/* circular convolution */
state = state + mode; /* level of dispersion */
if(state == 0)
{
for(i = 0; i < L_SUBFR; i++)
{
if(code[i] != 0)
{
for(j = 0; j < L_SUBFR; j++)
{
code2[i + j] = code2[i + j] +
(((code[i] * D_ROM_ph_imp_low[j]) + 0x4000) >> 15);
}
}
}
}
else if(state == 1)
{
for(i = 0; i < L_SUBFR; i++)
{
if(code[i] != 0)
{
for(j = 0; j < L_SUBFR; j++)
{
code2[i + j] = code2[i + j] +
(((code[i] * D_ROM_ph_imp_mid[j]) + 0x4000) >> 15);
}
}
}
}
if(state < 2)
{
for(i = 0; i < L_SUBFR; i++)
{
code[i] = (Word16)(code2[i] + code2[i + L_SUBFR]);
}
}
return;
}
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