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72 lines
3.8 KiB
72 lines
3.8 KiB
/*
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* Copyright (c) 2011-2019 Belledonne Communications SARL.
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*
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* This file is part of bcg729.
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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 General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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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 General Public License for more details.
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*
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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, see <http://www.gnu.org/licenses/>.
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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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/*****************************************************************************/
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/* decodeFixedCodeVector : compute the fixed codebook vector as in spec 4.1.4*/
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/* parameters: */
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/* -(i) signs: parameter S(4 signs bit) eq61 */
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/* -(i) positions: parameter C(4 3bits position and jx bit) eq62 */
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/* -(i) intPitchDelay: integer part of pitch Delay (T) */
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/* -(i) boundedPitchGain: Beta in eq47 and eq48, in Q14 */
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/* -(o) fixedCodebookVector: 40 values in Q13, range: [-1.8,+1.8] */
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/* */
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/*****************************************************************************/
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void decodeFixedCodeVector(uint16_t signs, uint16_t positions, int16_t intPitchDelay, word16_t boundedPitchGain,
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word16_t *fixedCodebookVector)
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{
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uint16_t positionsArray[4];
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uint16_t jx;
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int i;
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/* get the positions into an array: mapping according to eq62 and table7 in spec 3.8 */
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positionsArray[0] = (positions&(uint16_t)7)*5; /* m0 = 5*C, do not use macro here as whatever fixed or floating point computation we use, these are integers */
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positions = SHR(positions, 3); /* shift right by 3 to get the 3 next bits(m1/5) as LSB */
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positionsArray[1] = ((positions&(uint16_t)7)*5) + 1; /* m1 = 5*C + 1, do not use macro here as whatever fixed or floating point computation we use, these are integers */
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positions = SHR(positions, 3); /* shift right by 3 to get the 3 next bits(m2/5) as LSB */
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positionsArray[2] = ((positions&(uint16_t)7)*5) + 2; /* m2 = 5*C + 2, do not use macro here as whatever fixed or floating point computation we use, these are integers */
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positions = SHR(positions, 3); /* shift right by 3 to get the last 4 bits(m3/5 and jx) as LSB */
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jx = positions&(uint16_t)1; /* jx from eq62 is the last bit */
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positions = SHR(positions, 1); /* shift right by 1 to get the last 3 bits as LSB */
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positionsArray[3] = ((positions&(uint16_t)7)*5) + 3 + jx; /* m3 = 5*C + 3 + jx, do not use macro here as whatever fixed or floating point computation we use, these are integers */
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/* initialise the output Vector */
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for (i=0; i<L_SUBFRAME; i++) {
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fixedCodebookVector[i]=0;
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}
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/* get the signs and compute the fixedCodebookVector */
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for (i=0; i<4; i++) {
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if ((signs&(uint16_t)1) != 0) { /* sign bit is 1 */
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fixedCodebookVector[positionsArray[i]] = 8192; /* +1 in Q13 */
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} else {
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fixedCodebookVector[positionsArray[i]] = -8192; /* -1 in Q13 */
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}
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signs = SHR(signs, 1); /* shift signs right by one to get the next sign bit at next loop */
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}
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/* if intPitchDelay is smaller than subframe length, give some correction using boundedPitchGain according to eq48 */
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for (i=intPitchDelay; i<L_SUBFRAME; i++) {
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/* fixedCodebookVector[i] = fixedCodebookVector[i] + fixedCodebookVector[i-intPitchDelay]*boundedPitchGain */
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fixedCodebookVector[i] = ADD16(fixedCodebookVector[i], MULT16_16_P14(fixedCodebookVector[i-intPitchDelay], boundedPitchGain));
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}
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}
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