1 /*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 ** http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17 /***********************************************************************
18 * File: int_lpc.c *
19 * *
20 * Description:Interpolation of the LP parameters in 4 subframes. *
21 * *
22 ************************************************************************/
23
24 #include "typedef.h"
25 #include "basic_op.h"
26 #include "cnst.h"
27 #include "acelp.h"
28
29 #define MP1 (M+1)
30
31
Int_isp(Word16 isp_old[],Word16 isp_new[],Word16 frac[],Word16 Az[])32 void Int_isp(
33 Word16 isp_old[], /* input : isps from past frame */
34 Word16 isp_new[], /* input : isps from present frame */
35 Word16 frac[], /* input : fraction for 3 first subfr (Q15) */
36 Word16 Az[] /* output: LP coefficients in 4 subframes */
37 )
38 {
39 Word32 i, k;
40 Word16 fac_old, fac_new;
41 Word16 isp[M];
42 Word32 L_tmp;
43
44 for (k = 0; k < 3; k++)
45 {
46 fac_new = frac[k];
47 fac_old = (32767 - fac_new) + 1; /* 1.0 - fac_new */
48
49 for (i = 0; i < M; i++)
50 {
51 L_tmp = (isp_old[i] * fac_old)<<1;
52 L_tmp += (isp_new[i] * fac_new)<<1;
53 isp[i] = (L_tmp + 0x8000)>>16;
54 }
55 Isp_Az(isp, Az, M, 0);
56 Az += MP1;
57 }
58
59 /* 4th subframe: isp_new (frac=1.0) */
60 Isp_Az(isp_new, Az, M, 0);
61
62 return;
63 }
64
65
66
67