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/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/*
* decode_B.c
*
* This file contains definition of funtions for decoding.
* Decoding of lower-band, including normal-decoding and RCU decoding.
* Decoding of upper-band, including 8-12 kHz, when the bandwidth is
* 0-12 kHz, and 8-16 kHz, when the bandwidth is 0-16 kHz.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "modules/audio_coding/codecs/isac/main/source/codec.h"
#include "modules/audio_coding/codecs/isac/main/source/entropy_coding.h"
#include "modules/audio_coding/codecs/isac/main/source/pitch_estimator.h"
#include "modules/audio_coding/codecs/isac/main/source/bandwidth_estimator.h"
#include "modules/audio_coding/codecs/isac/main/source/structs.h"
#include "modules/audio_coding/codecs/isac/main/source/settings.h"
#include "modules/audio_coding/codecs/isac/main/source/pitch_filter.h"
/*
* function to decode the bitstream
* returns the total number of bytes in the stream
*/
int WebRtcIsac_DecodeLb(const TransformTables* transform_tables,
float* signal_out, ISACLBDecStruct* ISACdecLB_obj,
int16_t* current_framesamples,
int16_t isRCUPayload) {
int k;
int len, err;
int16_t bandwidthInd;
float LP_dec_float[FRAMESAMPLES_HALF];
float HP_dec_float[FRAMESAMPLES_HALF];
double LPw[FRAMESAMPLES_HALF];
double HPw[FRAMESAMPLES_HALF];
double LPw_pf[FRAMESAMPLES_HALF];
double lo_filt_coef[(ORDERLO + 1)*SUBFRAMES];
double hi_filt_coef[(ORDERHI + 1)*SUBFRAMES];
double real_f[FRAMESAMPLES_HALF];
double imag_f[FRAMESAMPLES_HALF];
double PitchLags[4];
double PitchGains[4];
double AvgPitchGain;
int16_t PitchGains_Q12[4];
int16_t AvgPitchGain_Q12;
float gain;
int frame_nb; /* counter */
int frame_mode; /* 0 30ms, 1 for 60ms */
/* Processed_samples: 480 (30, 60 ms). Cannot take other values. */
WebRtcIsac_ResetBitstream(&(ISACdecLB_obj->bitstr_obj));
len = 0;
/* Decode framelength and BW estimation - not used,
only for stream pointer*/
err = WebRtcIsac_DecodeFrameLen(&ISACdecLB_obj->bitstr_obj,
current_framesamples);
if (err < 0) {
return err;
}
/* Frame_mode:
* 0: indicates 30 ms frame (480 samples)
* 1: indicates 60 ms frame (960 samples) */
frame_mode = *current_framesamples / MAX_FRAMESAMPLES;
err = WebRtcIsac_DecodeSendBW(&ISACdecLB_obj->bitstr_obj, &bandwidthInd);
if (err < 0) {
return err;
}
/* One loop if it's one frame (20 or 30ms), 2 loops if 2 frames
bundled together (60ms). */
for (frame_nb = 0; frame_nb <= frame_mode; frame_nb++) {
/* Decode & de-quantize pitch parameters */
err = WebRtcIsac_DecodePitchGain(&ISACdecLB_obj->bitstr_obj,
PitchGains_Q12);
if (err < 0) {
return err;
}
err = WebRtcIsac_DecodePitchLag(&ISACdecLB_obj->bitstr_obj, PitchGains_Q12,
PitchLags);
if (err < 0) {
return err;
}
AvgPitchGain_Q12 = (PitchGains_Q12[0] + PitchGains_Q12[1] +
PitchGains_Q12[2] + PitchGains_Q12[3]) >> 2;
/* Decode & de-quantize filter coefficients. */
err = WebRtcIsac_DecodeLpc(&ISACdecLB_obj->bitstr_obj, lo_filt_coef,
hi_filt_coef);
if (err < 0) {
return err;
}
/* Decode & de-quantize spectrum. */
len = WebRtcIsac_DecodeSpec(&ISACdecLB_obj->bitstr_obj, AvgPitchGain_Q12,
kIsacLowerBand, real_f, imag_f);
if (len < 0) {
return len;
}
/* Inverse transform. */
WebRtcIsac_Spec2time(transform_tables, real_f, imag_f, LPw, HPw,
&ISACdecLB_obj->fftstr_obj);
/* Convert PitchGains back to float for pitchfilter_post */
for (k = 0; k < 4; k++) {
PitchGains[k] = ((float)PitchGains_Q12[k]) / 4096;
}
if (isRCUPayload) {
for (k = 0; k < 240; k++) {
LPw[k] *= RCU_TRANSCODING_SCALE_INVERSE;
HPw[k] *= RCU_TRANSCODING_SCALE_INVERSE;
}
}
/* Inverse pitch filter. */
WebRtcIsac_PitchfilterPost(LPw, LPw_pf, &ISACdecLB_obj->pitchfiltstr_obj,
PitchLags, PitchGains);
/* Convert AvgPitchGain back to float for computation of gain. */
AvgPitchGain = ((float)AvgPitchGain_Q12) / 4096;
gain = 1.0f - 0.45f * (float)AvgPitchGain;
for (k = 0; k < FRAMESAMPLES_HALF; k++) {
/* Reduce gain to compensate for pitch enhancer. */
LPw_pf[k] *= gain;
}
if (isRCUPayload) {
for (k = 0; k < FRAMESAMPLES_HALF; k++) {
/* Compensation for transcoding gain changes. */
LPw_pf[k] *= RCU_TRANSCODING_SCALE;
HPw[k] *= RCU_TRANSCODING_SCALE;
}
}
/* Perceptual post-filtering (using normalized lattice filter). */
WebRtcIsac_NormLatticeFilterAr(
ORDERLO, ISACdecLB_obj->maskfiltstr_obj.PostStateLoF,
(ISACdecLB_obj->maskfiltstr_obj).PostStateLoG, LPw_pf, lo_filt_coef,
LP_dec_float);
WebRtcIsac_NormLatticeFilterAr(
ORDERHI, ISACdecLB_obj->maskfiltstr_obj.PostStateHiF,
(ISACdecLB_obj->maskfiltstr_obj).PostStateHiG, HPw, hi_filt_coef,
HP_dec_float);
/* Recombine the 2 bands. */
WebRtcIsac_FilterAndCombineFloat(LP_dec_float, HP_dec_float,
signal_out + frame_nb * FRAMESAMPLES,
&ISACdecLB_obj->postfiltbankstr_obj);
}
return len;
}
/*
* This decode function is called when the codec is operating in 16 kHz
* bandwidth to decode the upperband, i.e. 8-16 kHz.
*
* Contrary to lower-band, the upper-band (8-16 kHz) is not split in
* frequency, but split to 12 sub-frames, i.e. twice as lower-band.
*/
int WebRtcIsac_DecodeUb16(const TransformTables* transform_tables,
float* signal_out, ISACUBDecStruct* ISACdecUB_obj,
int16_t isRCUPayload) {
int len, err;
double halfFrameFirst[FRAMESAMPLES_HALF];
double halfFrameSecond[FRAMESAMPLES_HALF];
double percepFilterParam[(UB_LPC_ORDER + 1) * (SUBFRAMES << 1) +
(UB_LPC_ORDER + 1)];
double real_f[FRAMESAMPLES_HALF];
double imag_f[FRAMESAMPLES_HALF];
const int16_t kAveragePitchGain = 0; /* No pitch-gain for upper-band. */
len = 0;
/* Decode & de-quantize filter coefficients. */
memset(percepFilterParam, 0, sizeof(percepFilterParam));
err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj,
percepFilterParam, isac16kHz);
if (err < 0) {
return err;
}
/* Decode & de-quantize spectrum. */
len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain,
kIsacUpperBand16, real_f, imag_f);
if (len < 0) {
return len;
}
if (isRCUPayload) {
int n;
for (n = 0; n < 240; n++) {
real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
}
}
/* Inverse transform. */
WebRtcIsac_Spec2time(transform_tables,
real_f, imag_f, halfFrameFirst, halfFrameSecond,
&ISACdecUB_obj->fftstr_obj);
/* Perceptual post-filtering (using normalized lattice filter). */
WebRtcIsac_NormLatticeFilterAr(
UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameFirst,
&percepFilterParam[(UB_LPC_ORDER + 1)], signal_out);
WebRtcIsac_NormLatticeFilterAr(
UB_LPC_ORDER, ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG, halfFrameSecond,
&percepFilterParam[(UB_LPC_ORDER + 1) * SUBFRAMES + (UB_LPC_ORDER + 1)],
&signal_out[FRAMESAMPLES_HALF]);
return len;
}
/*
* This decode function is called when the codec operates at 0-12 kHz
* bandwidth to decode the upperband, i.e. 8-12 kHz.
*
* At the encoder the upper-band is split into two band, 8-12 kHz & 12-16
* kHz, and only 8-12 kHz is encoded. At the decoder, 8-12 kHz band is
* reconstructed and 12-16 kHz replaced with zeros. Then two bands
* are combined, to reconstruct the upperband 8-16 kHz.
*/
int WebRtcIsac_DecodeUb12(const TransformTables* transform_tables,
float* signal_out, ISACUBDecStruct* ISACdecUB_obj,
int16_t isRCUPayload) {
int len, err;
float LP_dec_float[FRAMESAMPLES_HALF];
float HP_dec_float[FRAMESAMPLES_HALF];
double LPw[FRAMESAMPLES_HALF];
double HPw[FRAMESAMPLES_HALF];
double percepFilterParam[(UB_LPC_ORDER + 1)*SUBFRAMES];
double real_f[FRAMESAMPLES_HALF];
double imag_f[FRAMESAMPLES_HALF];
const int16_t kAveragePitchGain = 0; /* No pitch-gain for upper-band. */
len = 0;
/* Decode & dequantize filter coefficients. */
err = WebRtcIsac_DecodeInterpolLpcUb(&ISACdecUB_obj->bitstr_obj,
percepFilterParam, isac12kHz);
if (err < 0) {
return err;
}
/* Decode & de-quantize spectrum. */
len = WebRtcIsac_DecodeSpec(&ISACdecUB_obj->bitstr_obj, kAveragePitchGain,
kIsacUpperBand12, real_f, imag_f);
if (len < 0) {
return len;
}
if (isRCUPayload) {
int n;
for (n = 0; n < 240; n++) {
real_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
imag_f[n] *= RCU_TRANSCODING_SCALE_UB_INVERSE;
}
}
/* Inverse transform. */
WebRtcIsac_Spec2time(transform_tables,
real_f, imag_f, LPw, HPw, &ISACdecUB_obj->fftstr_obj);
/* perceptual post-filtering (using normalized lattice filter) */
WebRtcIsac_NormLatticeFilterAr(UB_LPC_ORDER,
ISACdecUB_obj->maskfiltstr_obj.PostStateLoF,
(ISACdecUB_obj->maskfiltstr_obj).PostStateLoG,
LPw, percepFilterParam, LP_dec_float);
/* Zero for 12-16 kHz. */
memset(HP_dec_float, 0, sizeof(float) * (FRAMESAMPLES_HALF));
/* Recombine the 2 bands. */
WebRtcIsac_FilterAndCombineFloat(HP_dec_float, LP_dec_float, signal_out,
&ISACdecUB_obj->postfiltbankstr_obj);
return len;
}