37b7bccc61
#72 - Should eliminate probs on VMWI #41 - Dynamic add survives reload #73 - Make festival honor its arguments #93 - Make events on FXO interfaces more logical #26 - Prefer "bindaddr" to logical address for registrations ??? - Record crashes AGI git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1338 65c4cc65-6c06-0410-ace0-fbb531ad65f3
67 lines
1.5 KiB
C
Executable file
67 lines
1.5 KiB
C
Executable file
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/******************************************************************
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iLBC Speech Coder ANSI-C Source Code
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syntFilter.c
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Copyright (c) 2001,
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Global IP Sound AB.
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All rights reserved.
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******************************************************************/
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#include "iLBC_define.h"
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#include "syntFilter.h"
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/*----------------------------------------------------------------*
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* LP synthesis filter.
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*---------------------------------------------------------------*/
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void syntFilter(
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float *Out, /* (i/o) Signal to be filtered */
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float *a, /* (i) LP parameters */
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int len, /* (i) Length of signal */
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float *mem /* (i/o) Filter state */
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){
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int i, j;
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float *po, *pi, *pa, *pm;
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po=Out;
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/* Filter first part using memory from past */
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for (i=0;i<LPC_FILTERORDER;i++) {
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pi=&Out[i-1];
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pa=&a[1];
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pm=&mem[LPC_FILTERORDER-1];
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for (j=1;j<=i;j++) {
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*po-=(*pa++)*(*pi--);
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}
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for (j=i+1;j<LPC_FILTERORDER+1;j++) {
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*po-=(*pa++)*(*pm--);
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}
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po++;
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}
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/* Filter last part where the state is entierly in
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the output vector */
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for (i=LPC_FILTERORDER;i<len;i++) {
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pi=&Out[i-1];
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pa=&a[1];
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for (j=1;j<LPC_FILTERORDER+1;j++) {
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*po-=(*pa++)*(*pi--);
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}
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po++;
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}
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/* Update state vector */
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memcpy(mem, &Out[len-LPC_FILTERORDER],
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LPC_FILTERORDER*sizeof(float));
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}
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