/* | |
** Copyright 2003-2010, VisualOn, Inc. | |
** | |
** Licensed under the Apache License, Version 2.0 (the "License"); | |
** you may not use this file except in compliance with the License. | |
** You may obtain a copy of the License at | |
** | |
** http://www.apache.org/licenses/LICENSE-2.0 | |
** | |
** Unless required by applicable law or agreed to in writing, software | |
** distributed under the License is distributed on an "AS IS" BASIS, | |
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
** See the License for the specific language governing permissions and | |
** limitations under the License. | |
*/ | |
/*********************************************************************** | |
* File: isp_az.c * | |
* * | |
* Description:Compute the LPC coefficients from isp (order=M) * | |
* * | |
************************************************************************/ | |
#include "typedef.h" | |
#include "basic_op.h" | |
#include "oper_32b.h" | |
#include "cnst.h" | |
#define NC (M/2) | |
#define NC16k (M16k/2) | |
/* local function */ | |
static void Get_isp_pol(Word16 * isp, Word32 * f, Word16 n); | |
static void Get_isp_pol_16kHz(Word16 * isp, Word32 * f, Word16 n); | |
void Isp_Az( | |
Word16 isp[], /* (i) Q15 : Immittance spectral pairs */ | |
Word16 a[], /* (o) Q12 : predictor coefficients (order = M) */ | |
Word16 m, | |
Word16 adaptive_scaling /* (i) 0 : adaptive scaling disabled */ | |
/* 1 : adaptive scaling enabled */ | |
) | |
{ | |
Word32 i, j; | |
Word16 hi, lo; | |
Word32 f1[NC16k + 1], f2[NC16k]; | |
Word16 nc; | |
Word32 t0; | |
Word16 q, q_sug; | |
Word32 tmax; | |
nc = (m >> 1); | |
if(nc > 8) | |
{ | |
Get_isp_pol_16kHz(&isp[0], f1, nc); | |
for (i = 0; i <= nc; i++) | |
{ | |
f1[i] = f1[i] << 2; | |
} | |
} else | |
Get_isp_pol(&isp[0], f1, nc); | |
if (nc > 8) | |
{ | |
Get_isp_pol_16kHz(&isp[1], f2, (nc - 1)); | |
for (i = 0; i <= nc - 1; i++) | |
{ | |
f2[i] = f2[i] << 2; | |
} | |
} else | |
Get_isp_pol(&isp[1], f2, (nc - 1)); | |
/*-----------------------------------------------------* | |
* Multiply F2(z) by (1 - z^-2) * | |
*-----------------------------------------------------*/ | |
for (i = (nc - 1); i > 1; i--) | |
{ | |
f2[i] = vo_L_sub(f2[i], f2[i - 2]); /* f2[i] -= f2[i-2]; */ | |
} | |
/*----------------------------------------------------------* | |
* Scale F1(z) by (1+isp[m-1]) and F2(z) by (1-isp[m-1]) * | |
*----------------------------------------------------------*/ | |
for (i = 0; i < nc; i++) | |
{ | |
/* f1[i] *= (1.0 + isp[M-1]); */ | |
hi = f1[i] >> 16; | |
lo = (f1[i] & 0xffff)>>1; | |
t0 = Mpy_32_16(hi, lo, isp[m - 1]); | |
f1[i] = vo_L_add(f1[i], t0); | |
/* f2[i] *= (1.0 - isp[M-1]); */ | |
hi = f2[i] >> 16; | |
lo = (f2[i] & 0xffff)>>1; | |
t0 = Mpy_32_16(hi, lo, isp[m - 1]); | |
f2[i] = vo_L_sub(f2[i], t0); | |
} | |
/*-----------------------------------------------------* | |
* A(z) = (F1(z)+F2(z))/2 * | |
* F1(z) is symmetric and F2(z) is antisymmetric * | |
*-----------------------------------------------------*/ | |
/* a[0] = 1.0; */ | |
a[0] = 4096; | |
tmax = 1; | |
for (i = 1, j = m - 1; i < nc; i++, j--) | |
{ | |
/* a[i] = 0.5*(f1[i] + f2[i]); */ | |
t0 = vo_L_add(f1[i], f2[i]); /* f1[i] + f2[i] */ | |
tmax |= L_abs(t0); | |
a[i] = (Word16)(vo_L_shr_r(t0, 12)); /* from Q23 to Q12 and * 0.5 */ | |
/* a[j] = 0.5*(f1[i] - f2[i]); */ | |
t0 = vo_L_sub(f1[i], f2[i]); /* f1[i] - f2[i] */ | |
tmax |= L_abs(t0); | |
a[j] = (Word16)(vo_L_shr_r(t0, 12)); /* from Q23 to Q12 and * 0.5 */ | |
} | |
/* rescale data if overflow has occured and reprocess the loop */ | |
if(adaptive_scaling == 1) | |
q = 4 - norm_l(tmax); /* adaptive scaling enabled */ | |
else | |
q = 0; /* adaptive scaling disabled */ | |
if (q > 0) | |
{ | |
q_sug = (12 + q); | |
for (i = 1, j = m - 1; i < nc; i++, j--) | |
{ | |
/* a[i] = 0.5*(f1[i] + f2[i]); */ | |
t0 = vo_L_add(f1[i], f2[i]); /* f1[i] + f2[i] */ | |
a[i] = (Word16)(vo_L_shr_r(t0, q_sug)); /* from Q23 to Q12 and * 0.5 */ | |
/* a[j] = 0.5*(f1[i] - f2[i]); */ | |
t0 = vo_L_sub(f1[i], f2[i]); /* f1[i] - f2[i] */ | |
a[j] = (Word16)(vo_L_shr_r(t0, q_sug)); /* from Q23 to Q12 and * 0.5 */ | |
} | |
a[0] = shr(a[0], q); | |
} | |
else | |
{ | |
q_sug = 12; | |
q = 0; | |
} | |
/* a[NC] = 0.5*f1[NC]*(1.0 + isp[M-1]); */ | |
hi = f1[nc] >> 16; | |
lo = (f1[nc] & 0xffff)>>1; | |
t0 = Mpy_32_16(hi, lo, isp[m - 1]); | |
t0 = vo_L_add(f1[nc], t0); | |
a[nc] = (Word16)(L_shr_r(t0, q_sug)); /* from Q23 to Q12 and * 0.5 */ | |
/* a[m] = isp[m-1]; */ | |
a[m] = vo_shr_r(isp[m - 1], (3 + q)); /* from Q15 to Q12 */ | |
return; | |
} | |
/*-----------------------------------------------------------* | |
* procedure Get_isp_pol: * | |
* ~~~~~~~~~~~ * | |
* Find the polynomial F1(z) or F2(z) from the ISPs. * | |
* This is performed by expanding the product polynomials: * | |
* * | |
* F1(z) = product ( 1 - 2 isp_i z^-1 + z^-2 ) * | |
* i=0,2,4,6,8 * | |
* F2(z) = product ( 1 - 2 isp_i z^-1 + z^-2 ) * | |
* i=1,3,5,7 * | |
* * | |
* where isp_i are the ISPs in the cosine domain. * | |
*-----------------------------------------------------------* | |
* * | |
* Parameters: * | |
* isp[] : isp vector (cosine domaine) in Q15 * | |
* f[] : the coefficients of F1 or F2 in Q23 * | |
* n : == NC for F1(z); == NC-1 for F2(z) * | |
*-----------------------------------------------------------*/ | |
static void Get_isp_pol(Word16 * isp, Word32 * f, Word16 n) | |
{ | |
Word16 hi, lo; | |
Word32 i, j, t0; | |
/* All computation in Q23 */ | |
f[0] = vo_L_mult(4096, 1024); /* f[0] = 1.0; in Q23 */ | |
f[1] = vo_L_mult(isp[0], -256); /* f[1] = -2.0*isp[0] in Q23 */ | |
f += 2; /* Advance f pointer */ | |
isp += 2; /* Advance isp pointer */ | |
for (i = 2; i <= n; i++) | |
{ | |
*f = f[-2]; | |
for (j = 1; j < i; j++, f--) | |
{ | |
hi = f[-1]>>16; | |
lo = (f[-1] & 0xffff)>>1; | |
t0 = Mpy_32_16(hi, lo, *isp); /* t0 = f[-1] * isp */ | |
t0 = t0 << 1; | |
*f = vo_L_sub(*f, t0); /* *f -= t0 */ | |
*f = vo_L_add(*f, f[-2]); /* *f += f[-2] */ | |
} | |
*f -= (*isp << 9); /* *f -= isp<<8 */ | |
f += i; /* Advance f pointer */ | |
isp += 2; /* Advance isp pointer */ | |
} | |
return; | |
} | |
static void Get_isp_pol_16kHz(Word16 * isp, Word32 * f, Word16 n) | |
{ | |
Word16 hi, lo; | |
Word32 i, j, t0; | |
/* All computation in Q23 */ | |
f[0] = L_mult(4096, 256); /* f[0] = 1.0; in Q23 */ | |
f[1] = L_mult(isp[0], -64); /* f[1] = -2.0*isp[0] in Q23 */ | |
f += 2; /* Advance f pointer */ | |
isp += 2; /* Advance isp pointer */ | |
for (i = 2; i <= n; i++) | |
{ | |
*f = f[-2]; | |
for (j = 1; j < i; j++, f--) | |
{ | |
VO_L_Extract(f[-1], &hi, &lo); | |
t0 = Mpy_32_16(hi, lo, *isp); /* t0 = f[-1] * isp */ | |
t0 = L_shl2(t0, 1); | |
*f = L_sub(*f, t0); /* *f -= t0 */ | |
*f = L_add(*f, f[-2]); /* *f += f[-2] */ | |
} | |
*f = L_msu(*f, *isp, 64); /* *f -= isp<<8 */ | |
f += i; /* Advance f pointer */ | |
isp += 2; /* Advance isp pointer */ | |
} | |
return; | |
} | |