/* | |
** 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: int_lpc.c * | |
* * | |
* Description:Interpolation of the LP parameters in 4 subframes. * | |
* * | |
************************************************************************/ | |
#include "typedef.h" | |
#include "basic_op.h" | |
#include "cnst.h" | |
#include "acelp.h" | |
#define MP1 (M+1) | |
void Int_isp( | |
Word16 isp_old[], /* input : isps from past frame */ | |
Word16 isp_new[], /* input : isps from present frame */ | |
Word16 frac[], /* input : fraction for 3 first subfr (Q15) */ | |
Word16 Az[] /* output: LP coefficients in 4 subframes */ | |
) | |
{ | |
Word32 i, k; | |
Word16 fac_old, fac_new; | |
Word16 isp[M]; | |
Word32 L_tmp; | |
for (k = 0; k < 3; k++) | |
{ | |
fac_new = frac[k]; | |
fac_old = (32767 - fac_new) + 1; /* 1.0 - fac_new */ | |
for (i = 0; i < M; i++) | |
{ | |
L_tmp = (isp_old[i] * fac_old)<<1; | |
L_tmp += (isp_new[i] * fac_new)<<1; | |
isp[i] = (L_tmp + 0x8000)>>16; | |
} | |
Isp_Az(isp, Az, M, 0); | |
Az += MP1; | |
} | |
/* 4th subframe: isp_new (frac=1.0) */ | |
Isp_Az(isp_new, Az, M, 0); | |
return; | |
} | |