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
123 lines
3.8 KiB
C
Executable file
123 lines
3.8 KiB
C
Executable file
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/******************************************************************
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iLBC Speech Coder ANSI-C Source Code
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LPC_decode.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 <math.h>
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#include <string.h>
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#include "helpfun.h"
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#include "lsf.h"
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#include "iLBC_define.h"
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#include "constants.h"
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#include "LPCdecode.h"
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/*----------------------------------------------------------------*
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* interpolation of lsf coefficients for the decoder
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*---------------------------------------------------------------*/
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void LSFinterpolate2a_dec(
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float *a, /* (o) lpc coefficients for a sub frame */
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float *lsf1, /* (i) first lsf coefficient vector */
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float *lsf2, /* (i) second lsf coefficient vector */
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float coef, /* (i) interpolation weight */
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int length /* (i) length of lsf vectors */
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){
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float lsftmp[LPC_FILTERORDER];
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interpolate(lsftmp, lsf1, lsf2, coef, length);
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lsf2a(a, lsftmp);
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}
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/*----------------------------------------------------------------*
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* obtain dequantized lsf coefficients from quantization index
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*---------------------------------------------------------------*/
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void SimplelsfDEQ(
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float *lsfdeq, /* (o) dequantized lsf coefficients */
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int *index /* (i) quantization index */
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){
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int i,j, pos, cb_pos;
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/* decode first LSF */
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pos = 0;
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cb_pos = 0;
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for (i = 0; i < LSF_NSPLIT; i++) {
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for (j = 0; j < dim_lsfCbTbl[i]; j++) {
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lsfdeq[pos + j] = lsfCbTbl[cb_pos +
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(long)(index[i])*dim_lsfCbTbl[i] + j];
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}
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pos += dim_lsfCbTbl[i];
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cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
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}
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/* decode last LSF */
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pos = 0;
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cb_pos = 0;
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for (i = 0; i < LSF_NSPLIT; i++) {
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for (j = 0; j < dim_lsfCbTbl[i]; j++) {
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lsfdeq[LPC_FILTERORDER + pos + j] = lsfCbTbl[cb_pos +
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(long)(index[LSF_NSPLIT + i])*dim_lsfCbTbl[i] + j];
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}
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pos += dim_lsfCbTbl[i];
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cb_pos += size_lsfCbTbl[i]*dim_lsfCbTbl[i];
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}
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}
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/*----------------------------------------------------------------*
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* obtain synthesis and weighting filters form lsf coefficients
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*---------------------------------------------------------------*/
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void DecoderInterpolateLSF(
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float *syntdenum, /* (o) synthesis filter coefficients */
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float *weightdenum, /* (o) weighting denumerator
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coefficients */
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float *lsfdeq, /* (i) dequantized lsf coefficients */
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int length, /* (i) length of lsf coefficient vector */
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iLBC_Dec_Inst_t *iLBCdec_inst
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/* (i) the decoder state structure */
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){
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int i, pos, lp_length;
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float lp[LPC_FILTERORDER + 1], *lsfdeq2;
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lsfdeq2 = lsfdeq + length;
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lp_length = length + 1;
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/* subframe 1: Interpolation between old and first */
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LSFinterpolate2a_dec(lp, (*iLBCdec_inst).lsfdeqold, lsfdeq,
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lsf_weightTbl[0], length);
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memcpy(syntdenum,lp,lp_length*sizeof(float));
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bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM, lp_length);
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/* subframes 2 to 6: interpolation between first and last
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LSF */
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pos = lp_length;
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for (i = 1; i < 6; i++) {
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LSFinterpolate2a_dec(lp, lsfdeq, lsfdeq2, lsf_weightTbl[i],
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length);
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memcpy(syntdenum + pos,lp,lp_length*sizeof(float));
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bwexpand(weightdenum + pos, lp,
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LPC_CHIRP_WEIGHTDENUM, lp_length);
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pos += lp_length;
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}
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/* update memory */
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memcpy((*iLBCdec_inst).lsfdeqold, lsfdeq2, length*sizeof(float));
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}
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