www.pudn.com > p_voice.rar > UTILCNG2.C
/*
**
** File: "utilcng2.c"
**
** Description: General Comfort Noise Generation functions
**
**
** Functions: Calc_Exc_Rand() Computes random excitation
** used both by coder & decoder
** Qua_SidGain() Quantization of SID gain
** used by coder
** Dec_SidGain() Decoding of SID gain
** used both by coder & decoder
**
** Local functions :
** random_number()
*/
/*
ITU-T G.723.1 Floating Point Speech Coder ANSI C Source Code. Version 5.1F
copyright (c) 1995, AudioCodes, DSP Group, France Telecom,
Universite de Sherbrooke. All rights reserved.
Floating-point code copyright (c) 1996,
Intel Corporation and France Telecom (CNET).
All rights reserved.
*/
#include
#include
#include
#include "typedef2.h"
#include "cst2.h"
#include "tab2.h"
#include "util2.h"
#include "exc2.h"
#include "utilcng2.h"
/* Declaration of local functions */
static Word16 random_number(Word16 np1, Word16 *nRandom);
/*
**
** Function: Calc_Exc_Rand()
**
** Description: Computation of random excitation for inactive frames:
** Adaptive codebook entry selected randomly
** Higher rate innovation pattern selected randomly
** Computes innovation gain to match curGain
**
** Links to text:
**
** Arguments:
**
** FLOAT curGain current average gain to match
** FLOAT *PrevExc previous/current excitation (updated)
** FLOAT *DataExc current frame excitation
** Word16 *nRandom random generator status (input/output)
** LINEDEF *Line
**
** Outputs:
**
** FLOAT *PrevExc
** FLOAT *DataExc
** Word16 *nRandom
** LINEDEF *Line
**
** Return value: None
**
*/
void Calc_Exc_Rand(FLOAT curGain, FLOAT *PrevExc, FLOAT *DataExc,
Word16 *nRandom, LINEDEF *Line)
{
int i, i_subfr, iblk;
Word16 temp16;
Word16 j;
Word16 TabPos[2*NbPulsBlk], *ptr_TabPos;
FLOAT TabSign[2*NbPulsBlk], *ptr_TabSign;
Word16 *ptr1;
FLOAT *curExc;
FLOAT x1, x2, ener_ltp, inter_exc, delta, b0, c;
Word16 tmp[SubFrLen/Sgrid];
Word16 offset[SubFrames];
/*
* generate LTP codes
*/
Line->Olp[0] = random_number(21, nRandom) + 123;
Line->Olp[1] = random_number(21, nRandom) + 123;
for (i_subfr=0; i_subfrSfs[i_subfr].AcGn = random_number(NbFilt, nRandom) + (Word16)1;
}
Line->Sfs[0].AcLg = 1;
Line->Sfs[1].AcLg = 0;
Line->Sfs[2].AcLg = 1;
Line->Sfs[3].AcLg = 3;
/*
* Random innovation :
* Selection of the grids, signs and pulse positions
*/
/* Signs and Grids */
ptr_TabSign = TabSign;
ptr1 = offset;
for (iblk=0; iblk>= 1;
*ptr1++ = (Word16) (SubFrLen + (temp16 & 0x0001));
for (i=0; i>= 1;
*ptr_TabSign++= (FLOAT) 2. * (FLOAT)(temp16 & 0x0001) - (FLOAT) 1.;
}
}
/* Positions */
ptr_TabPos = TabPos;
for (i_subfr=0; i_subfrOlp[iblk],
Line->Sfs[i_subfr].AcLg, Line->Sfs[i_subfr].AcGn);
Decod_Acbk(&curExc[SubFrLen], &PrevExc[SubFrLen], Line->Olp[iblk],
Line->Sfs[i_subfr+1].AcLg, Line->Sfs[i_subfr+1].AcGn);
ener_ltp = DotProd(curExc, curExc, SubFrLenD);
inter_exc = (FLOAT) 0.;
for (i=0; i 0 */
else {
delta = (FLOAT) sqrt(delta);
x1 = - b0 + delta;
x2 = b0 + delta;
if (fabs(x2) < fabs(x1))
x1 = - x2;
}
/* Update DataExc */
if (x1 > Gexc_Max)
x1 = Gexc_Max;
if (x1 < -Gexc_Max)
x1 = -Gexc_Max;
for (i=0; i (FLOAT) 32766.5)
curExc[i] = (FLOAT) 32767.0;
else if (curExc[i] < (FLOAT) -32767.5)
curExc[i] = (FLOAT) -32768.0;
}
/* update PrevExc */
for (i=SubFrLenD; i> 15);
return(temp);
}
/*
**
** Function: Qua_SidGain()
**
** Description: Quantization of Sid gain
** Pseudo-log quantizer in 3 segments
** 1st segment : length = 16, resolution = 2
** 2nd segment : length = 16, resolution = 4
** 3rd segment : length = 32, resolution = 8
** quantizes a sum of energies
**
** Links to text:
**
** Arguments:
**
** FLOAT *Ener table of the energies
** Word16 nq if nq >= 1 : quantization of nq energies
** for SID gain calculation in function Cod_Cng()
** if nq = 0 : in function Comp_Info(),
** quantization of saved estimated excitation energy
**
** Outputs: None
**
**
** Return value: index of quantized energy
**
*/
Word16 Qua_SidGain(FLOAT *Ener, Word16 nq)
{
Word16 temp16, iseg, iseg_p1;
Word32 j, j2, k, exp;
FLOAT temp, x, y, z;
int i;
if (nq == 0) {
/* Quantize energy saved for frame erasure case */
/* x = ffact[0] * Ener[0] with ffact[0] = 1/(2*SubFrLen) */
x = ffact[0] * Ener[0];
}
else {
/*
* Compute weighted average of energies
* x = ffact[nq] x SUM(i=0->nq-1) Ener[i]
* with ffact[nq] = fact_mul x fact_mul / nq x Frame
*/
for (i=0, x=(FLOAT)0.; i= bseg[2])
return(63);
/* Compute segment number iseg */
if (x >= bseg[1]) {
iseg = 2;
exp = 4;
}
else {
exp = 3;
if (x >= bseg[0])
iseg = 1;
else
iseg = 0;
}
iseg_p1 = (Word16) (iseg + 1);
j = 1 << exp;
k = j >> 1;
/* Binary search in segment iseg */
for (i=0; i= y)
j += k;
else
j -= k;
k = k >> 1;
}
temp = base[iseg] + (FLOAT) (j << iseg_p1);
y = (temp * temp) - x;
if (y <= (FLOAT)0.0) {
j2 = j + 1;
temp = base[iseg] + (FLOAT) (j2 << iseg_p1);
z = x - (temp * temp);
if (y > z)
temp16 = (Word16) ((iseg<<4) + j);
else
temp16 = (Word16) ((iseg<<4) + j2);
}
else {
j2 = j - 1;
temp = base[iseg] + (FLOAT) (j2 << iseg_p1);
z = x - (temp * temp);
if (y < z)
temp16 = (Word16) ((iseg<<4) + j);
else
temp16 = (Word16) ((iseg<<4) + j2);
}
return(temp16);
}
/*
**
** Function: Dec_SidGain()
**
** Description: Decoding of quantized Sid gain
** (corresponding to sqrt of average energy)
**
** Links to text:
**
** Arguments:
**
** Word16 iGain index of quantized Sid Gain
**
** Outputs: None
**
** Return value: decoded gain value << 5
**
*/
FLOAT Dec_SidGain(Word16 iGain)
{
Word16 i, iseg;
FLOAT temp;
iseg = (Word16) (iGain >> 4);
if (iseg == 3)
iseg = 2;
i = (Word16) (iGain - (iseg << 4));
temp = base[iseg] + (FLOAT) (i << (iseg + 1));
return(temp);
}