mirror of
https://github.com/signalwire/freeswitch.git
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331 lines
10 KiB
C
331 lines
10 KiB
C
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/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/*
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* decode_B.c
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*
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* This file contains definition of funtions for decoding.
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* Decoding of lower-band, including normal-decoding and RCU decoding.
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* Decoding of upper-band, including 8-12 kHz, when the bandwidth is
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* 0-12 kHz, and 8-16 kHz, when the bandwidth is 0-16 kHz.
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*
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*/
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#include "codec.h"
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#include "entropy_coding.h"
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#include "pitch_estimator.h"
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#include "bandwidth_estimator.h"
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#include "structs.h"
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#include "settings.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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* function to decode the bitstream
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* returns the total number of bytes in the stream
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*/
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int
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WebRtcIsac_DecodeLb(
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float* signal_out,
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ISACLBDecStruct* ISACdecLB_obj,
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WebRtc_Word16* current_framesamples,
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WebRtc_Word16 isRCUPayload)
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{
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int k, model;
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int len, err;
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WebRtc_Word16 bandwidthInd;
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float LP_dec_float[FRAMESAMPLES_HALF];
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float HP_dec_float[FRAMESAMPLES_HALF];
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double LPw[FRAMESAMPLES_HALF];
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double HPw[FRAMESAMPLES_HALF];
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double LPw_pf[FRAMESAMPLES_HALF];
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double lo_filt_coef[(ORDERLO+1)*SUBFRAMES];
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double hi_filt_coef[(ORDERHI+1)*SUBFRAMES];
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double real_f[FRAMESAMPLES_HALF];
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double imag_f[FRAMESAMPLES_HALF];
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double PitchLags[4];
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double PitchGains[4];
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double AvgPitchGain;
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WebRtc_Word16 PitchGains_Q12[4];
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WebRtc_Word16 AvgPitchGain_Q12;
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float gain;
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int frame_nb; /* counter */
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int frame_mode; /* 0 for 20ms and 30ms, 1 for 60ms */
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int processed_samples;
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(ISACdecLB_obj->bitstr_obj).W_upper = 0xFFFFFFFF;
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(ISACdecLB_obj->bitstr_obj).streamval = 0;
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(ISACdecLB_obj->bitstr_obj).stream_index = 0;
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len = 0;
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/* decode framelength and BW estimation - not used,
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only for stream pointer*/
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err = WebRtcIsac_DecodeFrameLen(&ISACdecLB_obj->bitstr_obj,
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current_framesamples);
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if (err < 0) { // error check
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return err;
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}
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/* frame_mode: 0, or 1 */
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frame_mode = *current_framesamples/MAX_FRAMESAMPLES;
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/* processed_samples: either 320 (20ms) or 480 (30, 60 ms) */
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processed_samples = *current_framesamples/(frame_mode+1);
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err = WebRtcIsac_DecodeSendBW(&ISACdecLB_obj->bitstr_obj, &bandwidthInd);
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if (err < 0) { // error check
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return err;
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}
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/* one loop if it's one frame (20 or 30ms), 2 loops if 2 frames
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bundled together (60ms) */
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for (frame_nb = 0; frame_nb <= frame_mode; frame_nb++) {
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/* decode & dequantize pitch parameters */
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err = WebRtcIsac_DecodePitchGain(&(ISACdecLB_obj->bitstr_obj),
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PitchGains_Q12);
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if (err < 0) { // error check
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return err;
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}
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err = WebRtcIsac_DecodePitchLag(&ISACdecLB_obj->bitstr_obj,
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PitchGains_Q12, PitchLags);
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if (err < 0) { // error check
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return err;
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}
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AvgPitchGain_Q12 = (PitchGains_Q12[0] + PitchGains_Q12[1] +
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PitchGains_Q12[2] + PitchGains_Q12[3])>>2;
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/* decode & dequantize FiltCoef */
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err = WebRtcIsac_DecodeLpc(&ISACdecLB_obj->bitstr_obj,
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lo_filt_coef,hi_filt_coef, &model);
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if (err < 0) { // error check
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return err;
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}
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/* decode & dequantize spectrum */
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len = WebRtcIsac_DecodeSpecLb(&ISACdecLB_obj->bitstr_obj,
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real_f, imag_f, AvgPitchGain_Q12);
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if (len < 0) { // error check
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return len;
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}
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/* inverse transform */
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WebRtcIsac_Spec2time(real_f, imag_f, LPw, HPw,
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&ISACdecLB_obj->fftstr_obj);
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/* convert PitchGains back to FLOAT for pitchfilter_post */
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for (k = 0; k < 4; k++) {
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PitchGains[k] = ((float)PitchGains_Q12[k])/4096;
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}
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if(isRCUPayload)
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{
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for (k = 0; k < 240; k++) {
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LPw[k] *= RCU_TRANSCODING_SCALE_INVERSE;
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HPw[k] *= RCU_TRANSCODING_SCALE_INVERSE;
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}
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}
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/* inverse pitch filter */
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WebRtcIsac_PitchfilterPost(LPw, LPw_pf,
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&ISACdecLB_obj->pitchfiltstr_obj, PitchLags, PitchGains);
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/* convert AvgPitchGain back to FLOAT for computation of gain */
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AvgPitchGain = ((float)AvgPitchGain_Q12)/4096;
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gain = 1.0f - 0.45f * (float)AvgPitchGain;
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for (k = 0; k < FRAMESAMPLES_HALF; k++) {
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/* reduce gain to compensate for pitch enhancer */
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LPw_pf[ k ] *= gain;
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}
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if(isRCUPayload)
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{
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for (k = 0; k < FRAMESAMPLES_HALF; k++) {
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/* compensation for transcoding gain changes*/
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LPw_pf[k] *= RCU_TRANSCODING_SCALE;
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HPw[k] *= RCU_TRANSCODING_SCALE;
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}
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}
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/* perceptual post-filtering (using normalized lattice filter) */
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WebRtcIsac_NormLatticeFilterAr(ORDERLO,
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ISACdecLB_obj->maskfiltstr_obj.PostStateLoF,
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(ISACdecLB_obj->maskfiltstr_obj).PostStateLoG,
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LPw_pf, lo_filt_coef, LP_dec_float);
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WebRtcIsac_NormLatticeFilterAr(ORDERHI,
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ISACdecLB_obj->maskfiltstr_obj.PostStateHiF,
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(ISACdecLB_obj->maskfiltstr_obj).PostStateHiG,
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HPw, hi_filt_coef, HP_dec_float);
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/* recombine the 2 bands */
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WebRtcIsac_FilterAndCombineFloat( LP_dec_float, HP_dec_float,
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signal_out + frame_nb * processed_samples,
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&ISACdecLB_obj->postfiltbankstr_obj);
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}
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return len;
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}
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/*
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* This decode function is called when the codec is operating in 16 kHz
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* bandwidth to decode the upperband, i.e. 8-16 kHz.
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*
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* Contrary to lower-band, the upper-band (8-16 kHz) is not split in
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* frequency, but split to 12 sub-frames, i.e. twice as lower-band.
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*/
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int
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WebRtcIsac_DecodeUb16(
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float* signal_out,
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ISACUBDecStruct* ISACdecUB_obj,
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WebRtc_Word16 isRCUPayload)
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{
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int len, err;
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double halfFrameFirst[FRAMESAMPLES_HALF];
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double halfFrameSecond[FRAMESAMPLES_HALF];
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double percepFilterParam[(UB_LPC_ORDER+1) * (SUBFRAMES<<1) +
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(UB_LPC_ORDER+1)];
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double real_f[FRAMESAMPLES_HALF];
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double imag_f[FRAMESAMPLES_HALF];
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len = 0;
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/* decode & dequantize FiltCoef */
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memset(percepFilterParam, 0, sizeof(percepFilterParam));
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err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj,
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percepFilterParam, isac16kHz);
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if (err < 0) { // error check
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return err;
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}
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/* decode & dequantize spectrum */
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len = WebRtcIsac_DecodeSpecUB16(&ISACdecUB_obj->bitstr_obj, real_f,
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imag_f);
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if (len < 0) { // error check
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return len;
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}
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if(isRCUPayload)
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{
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int n;
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for(n = 0; n < 240; n++)
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{
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real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
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imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
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}
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}
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/* inverse transform */
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WebRtcIsac_Spec2time(real_f, imag_f, halfFrameFirst, halfFrameSecond,
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&ISACdecUB_obj->fftstr_obj);
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/* perceptual post-filtering (using normalized lattice filter) */
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WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER,
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ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
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(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameFirst,
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&percepFilterParam[(UB_LPC_ORDER+1)], signal_out);
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WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER,
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ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
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(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameSecond,
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&percepFilterParam[(UB_LPC_ORDER + 1) * SUBFRAMES + (UB_LPC_ORDER+1)],
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&signal_out[FRAMESAMPLES_HALF]);
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return len;
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}
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/*
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* This decode function is called when the codec operates at 0-12 kHz
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* bandwidth to decode the upperband, i.e. 8-12 kHz.
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*
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* At the encoder the upper-band is split into two band, 8-12 kHz & 12-16
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* kHz, and only 8-12 kHz is encoded. At the decoder, 8-12 kHz band is
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* reconstructed and 12-16 kHz replaced with zeros. Then two bands
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* are combined, to reconstruct the upperband 8-16 kHz.
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*/
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int
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WebRtcIsac_DecodeUb12(
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float* signal_out,
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ISACUBDecStruct* ISACdecUB_obj,
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WebRtc_Word16 isRCUPayload)
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{
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int len, err;
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float LP_dec_float[FRAMESAMPLES_HALF];
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float HP_dec_float[FRAMESAMPLES_HALF];
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double LPw[FRAMESAMPLES_HALF];
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double HPw[FRAMESAMPLES_HALF];
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double percepFilterParam[(UB_LPC_ORDER+1)*SUBFRAMES];
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double real_f[FRAMESAMPLES_HALF];
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double imag_f[FRAMESAMPLES_HALF];
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len = 0;
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/* decode & dequantize FiltCoef */
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err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj,
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percepFilterParam, isac12kHz);
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if(err < 0) { // error check
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return err;
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}
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/* decode & dequantize spectrum */
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len = WebRtcIsac_DecodeSpecUB12(&ISACdecUB_obj->bitstr_obj,
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real_f, imag_f);
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if(len < 0) { // error check
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return len;
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}
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if(isRCUPayload)
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{
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int n;
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for(n = 0; n < 240; n++)
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{
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real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
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imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
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}
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}
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/* inverse transform */
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WebRtcIsac_Spec2time(real_f, imag_f, LPw, HPw, &ISACdecUB_obj->fftstr_obj);
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/* perceptual post-filtering (using normalized lattice filter) */
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WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER,
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ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
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(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, LPw,
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percepFilterParam, LP_dec_float);
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/* Zerro for upper-band */
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memset(HP_dec_float, 0, sizeof(float) * (FRAMESAMPLES_HALF));
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/* recombine the 2 bands */
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WebRtcIsac_FilterAndCombineFloat(HP_dec_float, LP_dec_float, signal_out,
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&ISACdecUB_obj->postfiltbankstr_obj);
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return len;
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}
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