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88 lines
5.1 KiB
88 lines
5.1 KiB
/*
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computeWeightedSpeech.c
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Copyright (C) 2011 Belledonne Communications, Grenoble, France
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Author : Johan Pascal
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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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 General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include "typedef.h"
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#include "codecParameters.h"
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#include "basicOperationsMacros.h"
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#include "utils.h"
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#include "computeWeightedSpeech.h"
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/*****************************************************************************/
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/* computeWeightedSpeech: compute wieghted speech according to spec A3.3.3 */
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/* parameters: */
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/* -(i) inputSignal : 90 values buffer accessed in range [-10, 79] in Q0*/
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/* -(i) qLPCoefficients: 20 coefficients(10 for each subframe) in Q12 */
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/* -(i) weightedqLPCoefficients: 20 coefficients(10 for each subframe) */
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/* in Q12 */
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/* -(i/o) weightedInputSignal: 90 values in Q0: [-10, -1] as input */
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/* [0,79] as output in Q0 */
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/* -(o) LPResidualSignal: 80 values of residual signal in Q0 */
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/* */
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/*****************************************************************************/
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void computeWeightedSpeech(word16_t inputSignal[], word16_t qLPCoefficients[], word16_t weightedqLPCoefficients[], word16_t weightedInputSignal[], word16_t LPResidualSignal[])
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{
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/* algo as specified in A3.3.3: */
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/* first compute LPResidualSignal[n] = inputSignal[n] + ∑(i=1..10)qLP[i]*inputSignal[n-i] specA3.3.3 eqA.3 */
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/* then compute qLP' coefficients as qLP'[i] = weightedqLP[i] - 0.7*weightedqLP[i-1] */
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/* finally get the weightedInputSignal[n] = LPResidualSignal[n] - ∑(i=1..10)qLP'[i]*weightedInputSignal[n-i] spec A3.3.3 eqA.2 */
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int i,j;
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/*** compute LPResisualSignal (spec A3.3.3 eqA.3) in Q0 ***/
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/* compute residual signal for the first subframe: use the first 10 qLPCoefficients */
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for (i=0; i<L_SUBFRAME; i++) {
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word32_t acc = SHL((word32_t)inputSignal[i], 12); /* inputSignal in Q0 is shifted to set acc in Q12 */
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for (j=0; j<NB_LSP_COEFF; j++) {
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acc = MAC16_16(acc, qLPCoefficients[j],inputSignal[i-j-1]); /* qLPCoefficients in Q12, inputSignal in Q0 -> acc in Q12 */
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}
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LPResidualSignal[i] = (word16_t)SATURATE(PSHR(acc, 12), MAXINT16); /* shift back acc to Q0 and saturate it to avoid overflow when going back to 16 bits */
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}
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/* compute residual signal for the second subframe: use the second part of qLPCoefficients */
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for (i=L_SUBFRAME; i<L_FRAME; i++) {
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word32_t acc = SHL((word32_t)inputSignal[i], 12); /* inputSignal in Q0 is shifted to set acc in Q12 */
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for (j=0; j<NB_LSP_COEFF; j++) {
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acc = MAC16_16(acc, qLPCoefficients[NB_LSP_COEFF+j],inputSignal[i-j-1]); /* qLPCoefficients in Q12, inputSignal in Q0 -> acc in Q12 */
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}
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LPResidualSignal[i] = (word16_t)SATURATE(PSHR(acc, 12), MAXINT16); /* shift back acc to Q0 and saturate it to avoid overflow when going back to 16 bits */
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}
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/*** compute weightedqLPLowPassCoefficients and weightedInputSignal for first subframe ***/
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/* spec A3.3.3 a' = weightedqLPLowPassCoefficients[i] = weightedqLP[i] - 0.7*weightedqLP[i-1] */
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word16_t weightedqLPLowPassCoefficients[NB_LSP_COEFF]; /* in Q12 */
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weightedqLPLowPassCoefficients[0] = SUB16(weightedqLPCoefficients[0],O7_IN_Q12); /* weightedqLP[-1] = 1 -> weightedqLPLowPassCoefficients[0] = weightedqLPCoefficients[0] - 0.7 */
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for (i=1; i<NB_LSP_COEFF; i++) {
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weightedqLPLowPassCoefficients[i] = SUB16(weightedqLPCoefficients[i], MULT16_16_Q12(weightedqLPCoefficients[i-1], O7_IN_Q12));
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}
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/* weightedInputSignal for the first subframe: synthesis filter 1/[A'(z)] */
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synthesisFilter(LPResidualSignal, weightedqLPLowPassCoefficients, weightedInputSignal);
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/*** compute weightedqLPLowPassCoefficients and weightedInputSignal for second subframe ***/
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/* spec A3.3.3 a' = weightedqLPLowPassCoefficients[i] = weightedqLP[i] - 0.7*weightedqLP[i-1] */
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weightedqLPLowPassCoefficients[0] = SUB16(weightedqLPCoefficients[NB_LSP_COEFF],O7_IN_Q12); /* weightedqLP[-1] = 1 -> weightedqLPLowPassCoefficients[0] = weightedqLPCoefficients[0] - 0.7 */
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for (i=1; i<NB_LSP_COEFF; i++) {
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weightedqLPLowPassCoefficients[i] = SUB16(weightedqLPCoefficients[NB_LSP_COEFF+i], MULT16_16_Q12(weightedqLPCoefficients[NB_LSP_COEFF+i-1], O7_IN_Q12));
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}
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/* weightedInputSignal for the second subframe: synthesis filter 1/[A'(z)] */
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synthesisFilter(&(LPResidualSignal[L_SUBFRAME]), weightedqLPLowPassCoefficients, &(weightedInputSignal[L_SUBFRAME]));
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}
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