Mercurial > hg > audiostuff
view intercom/ilbc/LPCdecode.c @ 6:22a74b01a099 default tip
implement more meaningful test program
author | Peter Meerwald <pmeerw@cosy.sbg.ac.at> |
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date | Fri, 25 Jun 2010 16:14:50 +0200 |
parents | 13be24d74cd2 |
children |
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/****************************************************************** iLBC Speech Coder ANSI-C Source Code LPC_decode.c Copyright (C) The Internet Society (2004). All Rights Reserved. ******************************************************************/ #include <math.h> #include <string.h> #include "helpfun.h" #include "lsf.h" #include "iLBC_define.h" #include "constants.h" /*---------------------------------------------------------------* * interpolation of lsf coefficients for the decoder *--------------------------------------------------------------*/ void LSFinterpolate2a_dec(float *a, /* (o) lpc coefficients for a sub-frame */ float *lsf1, /* (i) first lsf coefficient vector */ float *lsf2, /* (i) second lsf coefficient vector */ float coef, /* (i) interpolation weight */ int length /* (i) length of lsf vectors */ ) { float lsftmp[LPC_FILTERORDER]; interpolate(lsftmp, lsf1, lsf2, coef, length); lsf2a(a, lsftmp); } /*---------------------------------------------------------------* * obtain dequantized lsf coefficients from quantization index *--------------------------------------------------------------*/ void SimplelsfDEQ(float *lsfdeq, /* (o) dequantized lsf coefficients */ int *index, /* (i) quantization index */ int lpc_n /* (i) number of LPCs */ ) { int i, j, pos, cb_pos; /* decode first LSF */ pos = 0; cb_pos = 0; for (i = 0; i < LSF_NSPLIT; i++) { for (j = 0; j < dim_lsfCbTbl[i]; j++) { lsfdeq[pos + j] = lsfCbTbl[cb_pos + (long) (index[i]) * dim_lsfCbTbl[i] + j]; } pos += dim_lsfCbTbl[i]; cb_pos += size_lsfCbTbl[i] * dim_lsfCbTbl[i]; } if (lpc_n > 1) { /* decode last LSF */ pos = 0; cb_pos = 0; for (i = 0; i < LSF_NSPLIT; i++) { for (j = 0; j < dim_lsfCbTbl[i]; j++) { lsfdeq[LPC_FILTERORDER + pos + j] = lsfCbTbl[cb_pos + (long) (index[LSF_NSPLIT + i]) * dim_lsfCbTbl[i] + j]; } pos += dim_lsfCbTbl[i]; cb_pos += size_lsfCbTbl[i] * dim_lsfCbTbl[i]; } } } /*----------------------------------------------------------------* * obtain synthesis and weighting filters form lsf coefficients *---------------------------------------------------------------*/ void DecoderInterpolateLSF(float *syntdenum, /* (o) synthesis filter coefficients */ float *weightdenum, /* (o) weighting denumerator coefficients */ float *lsfdeq, /* (i) dequantized lsf coefficients */ int length, /* (i) length of lsf coefficient vector */ iLBC_Dec_Inst_t * iLBCdec_inst /* (i) the decoder state structure */ ) { int i, pos, lp_length; float lp[LPC_FILTERORDER + 1], *lsfdeq2; lsfdeq2 = lsfdeq + length; lp_length = length + 1; if (iLBCdec_inst->mode == 30) { /* sub-frame 1: Interpolation between old and first */ LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold, lsfdeq, lsf_weightTbl_30ms[0], length); memcpy(syntdenum, lp, lp_length * sizeof(float)); bwexpand(weightdenum, lp, LPC_CHIRP_WEIGHTDENUM, lp_length); /* sub-frames 2 to 6: interpolation between first and last LSF */ pos = lp_length; for (i = 1; i < 6; i++) { LSFinterpolate2a_dec(lp, lsfdeq, lsfdeq2, lsf_weightTbl_30ms[i], length); memcpy(syntdenum + pos, lp, lp_length * sizeof(float)); bwexpand(weightdenum + pos, lp, LPC_CHIRP_WEIGHTDENUM, lp_length); pos += lp_length; } } else { pos = 0; for (i = 0; i < iLBCdec_inst->nsub; i++) { LSFinterpolate2a_dec(lp, iLBCdec_inst->lsfdeqold, lsfdeq, lsf_weightTbl_20ms[i], length); memcpy(syntdenum + pos, lp, lp_length * sizeof(float)); bwexpand(weightdenum + pos, lp, LPC_CHIRP_WEIGHTDENUM, lp_length); pos += lp_length; } } /* update memory */ if (iLBCdec_inst->mode == 30) memcpy(iLBCdec_inst->lsfdeqold, lsfdeq2, length * sizeof(float)); else memcpy(iLBCdec_inst->lsfdeqold, lsfdeq, length * sizeof(float)); }