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 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
