89 lines
2.8 KiB
C
89 lines
2.8 KiB
C
/*
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* broadvoice - a library for the BroadVoice 16 and 32 codecs
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*
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* excdec.c - Excitation signal decoding including long-term synthesis.
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*
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* Adapted by Steve Underwood <steveu@coppice.org> from code which is
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* Copyright 2000-2009 Broadcom Corporation
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: bv32excdec.c,v 1.1.1.1 2009/11/19 12:10:48 steveu Exp $
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*/
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/*! \file */
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#if defined(HAVE_CONFIG_H)
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#include "config.h"
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#endif
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#include "typedef.h"
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#include "bv32externs.h"
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void bv32_excdec_w_LT_synth(Float *ltsymd, /* long-term synthesis filter memory at decoder*/
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int16_t *idx, /* excitation codebook index array for current subframe */
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Float *gainq, /* quantized linear gains for sub-subframes */
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Float *b, /* coefficient of 3-tap pitch predictor */
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int16_t pp, /* pitch period (# of 8 kHz samples) */
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Float *EE)
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{
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Float a0;
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Float *fp1;
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Float *fp2;
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const Float *fp3;
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Float gain;
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int i;
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int m;
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int n;
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int id;
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int16_t *ip;
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Float E;
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Float t;
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ip = idx;
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fp1 = <symd[LTMOFF]; /* fp1 points to 1st sample of current subframe */
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fp2 = <symd[LTMOFF - pp + 1];
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for (i = 0; i < NSF; i++) /* loop through sub-subframes */
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{
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E = 0.0;
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for (m = 0; m < SFRSZ; m += VDIM) /* loop thru vectors in sub-subframe */
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{
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id = *ip++; /* get codebook index of current vector */
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if (id < CBSZ)
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{
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gain = gainq[i];
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}
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else
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{
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gain = -gainq[i];
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id -= CBSZ;
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}
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fp3 = &bv32_cccb[id*VDIM];
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for (n = 0; n < VDIM; n++)
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{
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a0 = b[0] * *fp2--;
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a0 += b[1] * *fp2--;
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a0 += b[2] * *fp2;/* a0=pitch predicted value of LT syn filt */
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t = *fp3++ * gain;
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E += t*t;
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*fp1++ = a0 + t; /* add scale codevector to a0 */
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fp2 = &fp2[3]; /* prepare fp2 for filtering next sample */
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}
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}
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}
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*EE = E;
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}
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