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/*
* Copyright (c) 2013 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.
*/
#include <stddef.h>
#include <stdlib.h>
#include "modules/audio_processing/aecm/aecm_core.h"
extern "C" {
#include "common_audio/ring_buffer.h"
#include "common_audio/signal_processing/include/real_fft.h"
}
#include "modules/audio_processing/aecm/echo_control_mobile.h"
#include "modules/audio_processing/utility/delay_estimator_wrapper.h"
extern "C" {
#include "system_wrappers/include/cpu_features_wrapper.h"
}
#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_conversions.h"
#include "rtc_base/sanitizer.h"
// Square root of Hanning window in Q14.
static const ALIGN8_BEG int16_t WebRtcAecm_kSqrtHanning[] ALIGN8_END = {
0, 399, 798, 1196, 1594, 1990, 2386, 2780, 3172, 3562, 3951,
4337, 4720, 5101, 5478, 5853, 6224, 6591, 6954, 7313, 7668, 8019,
8364, 8705, 9040, 9370, 9695, 10013, 10326, 10633, 10933, 11227, 11514,
11795, 12068, 12335, 12594, 12845, 13089, 13325, 13553, 13773, 13985, 14189,
14384, 14571, 14749, 14918, 15079, 15231, 15373, 15506, 15631, 15746, 15851,
15947, 16034, 16111, 16179, 16237, 16286, 16325, 16354, 16373, 16384};
#ifdef AECM_WITH_ABS_APPROX
// Q15 alpha = 0.99439986968132 const Factor for magnitude approximation
static const uint16_t kAlpha1 = 32584;
// Q15 beta = 0.12967166976970 const Factor for magnitude approximation
static const uint16_t kBeta1 = 4249;
// Q15 alpha = 0.94234827210087 const Factor for magnitude approximation
static const uint16_t kAlpha2 = 30879;
// Q15 beta = 0.33787806009150 const Factor for magnitude approximation
static const uint16_t kBeta2 = 11072;
// Q15 alpha = 0.82247698684306 const Factor for magnitude approximation
static const uint16_t kAlpha3 = 26951;
// Q15 beta = 0.57762063060713 const Factor for magnitude approximation
static const uint16_t kBeta3 = 18927;
#endif
static const int16_t kNoiseEstQDomain = 15;
static const int16_t kNoiseEstIncCount = 5;
static void ComfortNoise(AecmCore* aecm,
const uint16_t* dfa,
ComplexInt16* out,
const int16_t* lambda);
static void WindowAndFFT(AecmCore* aecm,
int16_t* fft,
const int16_t* time_signal,
ComplexInt16* freq_signal,
int time_signal_scaling) {
int i = 0;
// FFT of signal
for (i = 0; i < PART_LEN; i++) {
// Window time domain signal and insert into real part of
// transformation array |fft|
int16_t scaled_time_signal = time_signal[i] * (1 << time_signal_scaling);
fft[i] = (int16_t)((scaled_time_signal * WebRtcAecm_kSqrtHanning[i]) >> 14);
scaled_time_signal = time_signal[i + PART_LEN] * (1 << time_signal_scaling);
fft[PART_LEN + i] = (int16_t)(
(scaled_time_signal * WebRtcAecm_kSqrtHanning[PART_LEN - i]) >> 14);
}
// Do forward FFT, then take only the first PART_LEN complex samples,
// and change signs of the imaginary parts.
WebRtcSpl_RealForwardFFT(aecm->real_fft, fft, (int16_t*)freq_signal);
for (i = 0; i < PART_LEN; i++) {
freq_signal[i].imag = -freq_signal[i].imag;
}
}
static void InverseFFTAndWindow(AecmCore* aecm,
int16_t* fft,
ComplexInt16* efw,
int16_t* output,
const int16_t* nearendClean) {
int i, j, outCFFT;
int32_t tmp32no1;
// Reuse |efw| for the inverse FFT output after transferring
// the contents to |fft|.
int16_t* ifft_out = (int16_t*)efw;
// Synthesis
for (i = 1, j = 2; i < PART_LEN; i += 1, j += 2) {
fft[j] = efw[i].real;
fft[j + 1] = -efw[i].imag;
}
fft[0] = efw[0].real;
fft[1] = -efw[0].imag;
fft[PART_LEN2] = efw[PART_LEN].real;
fft[PART_LEN2 + 1] = -efw[PART_LEN].imag;
// Inverse FFT. Keep outCFFT to scale the samples in the next block.
outCFFT = WebRtcSpl_RealInverseFFT(aecm->real_fft, fft, ifft_out);
for (i = 0; i < PART_LEN; i++) {
ifft_out[i] = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(
ifft_out[i], WebRtcAecm_kSqrtHanning[i], 14);
tmp32no1 = WEBRTC_SPL_SHIFT_W32((int32_t)ifft_out[i],
outCFFT - aecm->dfaCleanQDomain);
output[i] = (int16_t)WEBRTC_SPL_SAT(WEBRTC_SPL_WORD16_MAX,
tmp32no1 + aecm->outBuf[i],
WEBRTC_SPL_WORD16_MIN);
tmp32no1 =
(ifft_out[PART_LEN + i] * WebRtcAecm_kSqrtHanning[PART_LEN - i]) >> 14;
tmp32no1 = WEBRTC_SPL_SHIFT_W32(tmp32no1, outCFFT - aecm->dfaCleanQDomain);
aecm->outBuf[i] = (int16_t)WEBRTC_SPL_SAT(WEBRTC_SPL_WORD16_MAX, tmp32no1,
WEBRTC_SPL_WORD16_MIN);
}
// Copy the current block to the old position
// (aecm->outBuf is shifted elsewhere)
memcpy(aecm->xBuf, aecm->xBuf + PART_LEN, sizeof(int16_t) * PART_LEN);
memcpy(aecm->dBufNoisy, aecm->dBufNoisy + PART_LEN,
sizeof(int16_t) * PART_LEN);
if (nearendClean != NULL) {
memcpy(aecm->dBufClean, aecm->dBufClean + PART_LEN,
sizeof(int16_t) * PART_LEN);
}
}
// Transforms a time domain signal into the frequency domain, outputting the
// complex valued signal, absolute value and sum of absolute values.
//
// time_signal [in] Pointer to time domain signal
// freq_signal_real [out] Pointer to real part of frequency domain array
// freq_signal_imag [out] Pointer to imaginary part of frequency domain
// array
// freq_signal_abs [out] Pointer to absolute value of frequency domain
// array
// freq_signal_sum_abs [out] Pointer to the sum of all absolute values in
// the frequency domain array
// return value The Q-domain of current frequency values
//
static int TimeToFrequencyDomain(AecmCore* aecm,
const int16_t* time_signal,
ComplexInt16* freq_signal,
uint16_t* freq_signal_abs,
uint32_t* freq_signal_sum_abs) {
int i = 0;
int time_signal_scaling = 0;
int32_t tmp32no1 = 0;
int32_t tmp32no2 = 0;
// In fft_buf, +16 for 32-byte alignment.
int16_t fft_buf[PART_LEN4 + 16];
int16_t* fft = (int16_t*)(((uintptr_t)fft_buf + 31) & ~31);
int16_t tmp16no1;
#ifndef WEBRTC_ARCH_ARM_V7
int16_t tmp16no2;
#endif
#ifdef AECM_WITH_ABS_APPROX
int16_t max_value = 0;
int16_t min_value = 0;
uint16_t alpha = 0;
uint16_t beta = 0;
#endif
#ifdef AECM_DYNAMIC_Q
tmp16no1 = WebRtcSpl_MaxAbsValueW16(time_signal, PART_LEN2);
time_signal_scaling = WebRtcSpl_NormW16(tmp16no1);
#endif
WindowAndFFT(aecm, fft, time_signal, freq_signal, time_signal_scaling);
// Extract imaginary and real part, calculate the magnitude for
// all frequency bins
freq_signal[0].imag = 0;
freq_signal[PART_LEN].imag = 0;
freq_signal_abs[0] = (uint16_t)WEBRTC_SPL_ABS_W16(freq_signal[0].real);
freq_signal_abs[PART_LEN] =
(uint16_t)WEBRTC_SPL_ABS_W16(freq_signal[PART_LEN].real);
(*freq_signal_sum_abs) =
(uint32_t)(freq_signal_abs[0]) + (uint32_t)(freq_signal_abs[PART_LEN]);
for (i = 1; i < PART_LEN; i++) {
if (freq_signal[i].real == 0) {
freq_signal_abs[i] = (uint16_t)WEBRTC_SPL_ABS_W16(freq_signal[i].imag);
} else if (freq_signal[i].imag == 0) {
freq_signal_abs[i] = (uint16_t)WEBRTC_SPL_ABS_W16(freq_signal[i].real);
} else {
// Approximation for magnitude of complex fft output
// magn = sqrt(real^2 + imag^2)
// magn ~= alpha * max(|imag|,|real|) + beta * min(|imag|,|real|)
//
// The parameters alpha and beta are stored in Q15
#ifdef AECM_WITH_ABS_APPROX
tmp16no1 = WEBRTC_SPL_ABS_W16(freq_signal[i].real);
tmp16no2 = WEBRTC_SPL_ABS_W16(freq_signal[i].imag);
if (tmp16no1 > tmp16no2) {
max_value = tmp16no1;
min_value = tmp16no2;
} else {
max_value = tmp16no2;
min_value = tmp16no1;
}
// Magnitude in Q(-6)
if ((max_value >> 2) > min_value) {
alpha = kAlpha1;
beta = kBeta1;
} else if ((max_value >> 1) > min_value) {
alpha = kAlpha2;
beta = kBeta2;
} else {
alpha = kAlpha3;
beta = kBeta3;
}
tmp16no1 = (int16_t)((max_value * alpha) >> 15);
tmp16no2 = (int16_t)((min_value * beta) >> 15);
freq_signal_abs[i] = (uint16_t)tmp16no1 + (uint16_t)tmp16no2;
#else
#ifdef WEBRTC_ARCH_ARM_V7
__asm __volatile(
"smulbb %[tmp32no1], %[real], %[real]\n\t"
"smlabb %[tmp32no2], %[imag], %[imag], %[tmp32no1]\n\t"
: [tmp32no1] "+&r"(tmp32no1), [tmp32no2] "=r"(tmp32no2)
: [real] "r"(freq_signal[i].real), [imag] "r"(freq_signal[i].imag));
#else
tmp16no1 = WEBRTC_SPL_ABS_W16(freq_signal[i].real);
tmp16no2 = WEBRTC_SPL_ABS_W16(freq_signal[i].imag);
tmp32no1 = tmp16no1 * tmp16no1;
tmp32no2 = tmp16no2 * tmp16no2;
tmp32no2 = WebRtcSpl_AddSatW32(tmp32no1, tmp32no2);
#endif // WEBRTC_ARCH_ARM_V7
tmp32no1 = WebRtcSpl_SqrtFloor(tmp32no2);
freq_signal_abs[i] = (uint16_t)tmp32no1;
#endif // AECM_WITH_ABS_APPROX
}
(*freq_signal_sum_abs) += (uint32_t)freq_signal_abs[i];
}
return time_signal_scaling;
}
int RTC_NO_SANITIZE("signed-integer-overflow") // bugs.webrtc.org/8200
WebRtcAecm_ProcessBlock(AecmCore* aecm,
const int16_t* farend,
const int16_t* nearendNoisy,
const int16_t* nearendClean,
int16_t* output) {
int i;
uint32_t xfaSum;
uint32_t dfaNoisySum;
uint32_t dfaCleanSum;
uint32_t echoEst32Gained;
uint32_t tmpU32;
int32_t tmp32no1;
uint16_t xfa[PART_LEN1];
uint16_t dfaNoisy[PART_LEN1];
uint16_t dfaClean[PART_LEN1];
uint16_t* ptrDfaClean = dfaClean;
const uint16_t* far_spectrum_ptr = NULL;
// 32 byte aligned buffers (with +8 or +16).
// TODO(kma): define fft with ComplexInt16.
int16_t fft_buf[PART_LEN4 + 2 + 16]; // +2 to make a loop safe.
int32_t echoEst32_buf[PART_LEN1 + 8];
int32_t dfw_buf[PART_LEN2 + 8];
int32_t efw_buf[PART_LEN2 + 8];
int16_t* fft = (int16_t*)(((uintptr_t)fft_buf + 31) & ~31);
int32_t* echoEst32 = (int32_t*)(((uintptr_t)echoEst32_buf + 31) & ~31);
ComplexInt16* dfw = (ComplexInt16*)(((uintptr_t)dfw_buf + 31) & ~31);
ComplexInt16* efw = (ComplexInt16*)(((uintptr_t)efw_buf + 31) & ~31);
int16_t hnl[PART_LEN1];
int16_t numPosCoef = 0;
int16_t nlpGain = ONE_Q14;
int delay;
int16_t tmp16no1;
int16_t tmp16no2;
int16_t mu;
int16_t supGain;
int16_t zeros32, zeros16;
int16_t zerosDBufNoisy, zerosDBufClean, zerosXBuf;
int far_q;
int16_t resolutionDiff, qDomainDiff, dfa_clean_q_domain_diff;
const int kMinPrefBand = 4;
const int kMaxPrefBand = 24;
int32_t avgHnl32 = 0;
// Determine startup state. There are three states:
// (0) the first CONV_LEN blocks
// (1) another CONV_LEN blocks
// (2) the rest
if (aecm->startupState < 2) {
aecm->startupState =
(aecm->totCount >= CONV_LEN) + (aecm->totCount >= CONV_LEN2);
}
// END: Determine startup state
// Buffer near and far end signals
memcpy(aecm->xBuf + PART_LEN, farend, sizeof(int16_t) * PART_LEN);
memcpy(aecm->dBufNoisy + PART_LEN, nearendNoisy, sizeof(int16_t) * PART_LEN);
if (nearendClean != NULL) {
memcpy(aecm->dBufClean + PART_LEN, nearendClean,
sizeof(int16_t) * PART_LEN);
}
// Transform far end signal from time domain to frequency domain.
far_q = TimeToFrequencyDomain(aecm, aecm->xBuf, dfw, xfa, &xfaSum);
// Transform noisy near end signal from time domain to frequency domain.
zerosDBufNoisy =
TimeToFrequencyDomain(aecm, aecm->dBufNoisy, dfw, dfaNoisy, &dfaNoisySum);
aecm->dfaNoisyQDomainOld = aecm->dfaNoisyQDomain;
aecm->dfaNoisyQDomain = (int16_t)zerosDBufNoisy;
if (nearendClean == NULL) {
ptrDfaClean = dfaNoisy;
aecm->dfaCleanQDomainOld = aecm->dfaNoisyQDomainOld;
aecm->dfaCleanQDomain = aecm->dfaNoisyQDomain;
dfaCleanSum = dfaNoisySum;
} else {
// Transform clean near end signal from time domain to frequency domain.
zerosDBufClean = TimeToFrequencyDomain(aecm, aecm->dBufClean, dfw, dfaClean,
&dfaCleanSum);
aecm->dfaCleanQDomainOld = aecm->dfaCleanQDomain;
aecm->dfaCleanQDomain = (int16_t)zerosDBufClean;
}
// Get the delay
// Save far-end history and estimate delay
WebRtcAecm_UpdateFarHistory(aecm, xfa, far_q);
if (WebRtc_AddFarSpectrumFix(aecm->delay_estimator_farend, xfa, PART_LEN1,
far_q) == -1) {
return -1;
}
delay = WebRtc_DelayEstimatorProcessFix(aecm->delay_estimator, dfaNoisy,
PART_LEN1, zerosDBufNoisy);
if (delay == -1) {
return -1;
} else if (delay == -2) {
// If the delay is unknown, we assume zero.
// NOTE: this will have to be adjusted if we ever add lookahead.
delay = 0;
}
if (aecm->fixedDelay >= 0) {
// Use fixed delay
delay = aecm->fixedDelay;
}
// Get aligned far end spectrum
far_spectrum_ptr = WebRtcAecm_AlignedFarend(aecm, &far_q, delay);
zerosXBuf = (int16_t)far_q;
if (far_spectrum_ptr == NULL) {
return -1;
}
// Calculate log(energy) and update energy threshold levels
WebRtcAecm_CalcEnergies(aecm, far_spectrum_ptr, zerosXBuf, dfaNoisySum,
echoEst32);
// Calculate stepsize
mu = WebRtcAecm_CalcStepSize(aecm);
// Update counters
aecm->totCount++;
// This is the channel estimation algorithm.
// It is base on NLMS but has a variable step length,
// which was calculated above.
WebRtcAecm_UpdateChannel(aecm, far_spectrum_ptr, zerosXBuf, dfaNoisy, mu,
echoEst32);
supGain = WebRtcAecm_CalcSuppressionGain(aecm);
// Calculate Wiener filter hnl[]
for (i = 0; i < PART_LEN1; i++) {
// Far end signal through channel estimate in Q8
// How much can we shift right to preserve resolution
tmp32no1 = echoEst32[i] - aecm->echoFilt[i];
aecm->echoFilt[i] +=
rtc::dchecked_cast<int32_t>((int64_t{tmp32no1} * 50) >> 8);
zeros32 = WebRtcSpl_NormW32(aecm->echoFilt[i]) + 1;
zeros16 = WebRtcSpl_NormW16(supGain) + 1;
if (zeros32 + zeros16 > 16) {
// Multiplication is safe
// Result in
// Q(RESOLUTION_CHANNEL+RESOLUTION_SUPGAIN+
// aecm->xfaQDomainBuf[diff])
echoEst32Gained =
WEBRTC_SPL_UMUL_32_16((uint32_t)aecm->echoFilt[i], (uint16_t)supGain);
resolutionDiff = 14 - RESOLUTION_CHANNEL16 - RESOLUTION_SUPGAIN;
resolutionDiff += (aecm->dfaCleanQDomain - zerosXBuf);
} else {
tmp16no1 = 17 - zeros32 - zeros16;
resolutionDiff =
14 + tmp16no1 - RESOLUTION_CHANNEL16 - RESOLUTION_SUPGAIN;
resolutionDiff += (aecm->dfaCleanQDomain - zerosXBuf);
if (zeros32 > tmp16no1) {
echoEst32Gained = WEBRTC_SPL_UMUL_32_16((uint32_t)aecm->echoFilt[i],
supGain >> tmp16no1);
} else {
// Result in Q-(RESOLUTION_CHANNEL+RESOLUTION_SUPGAIN-16)
echoEst32Gained = (aecm->echoFilt[i] >> tmp16no1) * supGain;
}
}
zeros16 = WebRtcSpl_NormW16(aecm->nearFilt[i]);
RTC_DCHECK_GE(zeros16, 0); // |zeros16| is a norm, hence non-negative.
dfa_clean_q_domain_diff = aecm->dfaCleanQDomain - aecm->dfaCleanQDomainOld;
if (zeros16 < dfa_clean_q_domain_diff && aecm->nearFilt[i]) {
tmp16no1 = aecm->nearFilt[i] * (1 << zeros16);
qDomainDiff = zeros16 - dfa_clean_q_domain_diff;
tmp16no2 = ptrDfaClean[i] >> -qDomainDiff;
} else {
tmp16no1 = dfa_clean_q_domain_diff < 0
? aecm->nearFilt[i] >> -dfa_clean_q_domain_diff
: aecm->nearFilt[i] * (1 << dfa_clean_q_domain_diff);
qDomainDiff = 0;
tmp16no2 = ptrDfaClean[i];
}
tmp32no1 = (int32_t)(tmp16no2 - tmp16no1);
tmp16no2 = (int16_t)(tmp32no1 >> 4);
tmp16no2 += tmp16no1;
zeros16 = WebRtcSpl_NormW16(tmp16no2);
if ((tmp16no2) & (-qDomainDiff > zeros16)) {
aecm->nearFilt[i] = WEBRTC_SPL_WORD16_MAX;
} else {
aecm->nearFilt[i] = qDomainDiff < 0 ? tmp16no2 * (1 << -qDomainDiff)
: tmp16no2 >> qDomainDiff;
}
// Wiener filter coefficients, resulting hnl in Q14
if (echoEst32Gained == 0) {
hnl[i] = ONE_Q14;
} else if (aecm->nearFilt[i] == 0) {
hnl[i] = 0;
} else {
// Multiply the suppression gain
// Rounding
echoEst32Gained += (uint32_t)(aecm->nearFilt[i] >> 1);
tmpU32 =
WebRtcSpl_DivU32U16(echoEst32Gained, (uint16_t)aecm->nearFilt[i]);
// Current resolution is
// Q-(RESOLUTION_CHANNEL+RESOLUTION_SUPGAIN- max(0,17-zeros16- zeros32))
// Make sure we are in Q14
tmp32no1 = (int32_t)WEBRTC_SPL_SHIFT_W32(tmpU32, resolutionDiff);
if (tmp32no1 > ONE_Q14) {
hnl[i] = 0;
} else if (tmp32no1 < 0) {
hnl[i] = ONE_Q14;
} else {
// 1-echoEst/dfa
hnl[i] = ONE_Q14 - (int16_t)tmp32no1;
if (hnl[i] < 0) {
hnl[i] = 0;
}
}
}
if (hnl[i]) {
numPosCoef++;
}
}
// Only in wideband. Prevent the gain in upper band from being larger than
// in lower band.
if (aecm->mult == 2) {
// TODO(bjornv): Investigate if the scaling of hnl[i] below can cause
// speech distortion in double-talk.
for (i = 0; i < PART_LEN1; i++) {
hnl[i] = (int16_t)((hnl[i] * hnl[i]) >> 14);
}
for (i = kMinPrefBand; i <= kMaxPrefBand; i++) {
avgHnl32 += (int32_t)hnl[i];
}
RTC_DCHECK_GT(kMaxPrefBand - kMinPrefBand + 1, 0);
avgHnl32 /= (kMaxPrefBand - kMinPrefBand + 1);
for (i = kMaxPrefBand; i < PART_LEN1; i++) {
if (hnl[i] > (int16_t)avgHnl32) {
hnl[i] = (int16_t)avgHnl32;
}
}
}
// Calculate NLP gain, result is in Q14
if (aecm->nlpFlag) {
for (i = 0; i < PART_LEN1; i++) {
// Truncate values close to zero and one.
if (hnl[i] > NLP_COMP_HIGH) {
hnl[i] = ONE_Q14;
} else if (hnl[i] < NLP_COMP_LOW) {
hnl[i] = 0;
}
// Remove outliers
if (numPosCoef < 3) {
nlpGain = 0;
} else {
nlpGain = ONE_Q14;
}
// NLP
if ((hnl[i] == ONE_Q14) && (nlpGain == ONE_Q14)) {
hnl[i] = ONE_Q14;
} else {
hnl[i] = (int16_t)((hnl[i] * nlpGain) >> 14);
}
// multiply with Wiener coefficients
efw[i].real = (int16_t)(
WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(dfw[i].real, hnl[i], 14));
efw[i].imag = (int16_t)(
WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(dfw[i].imag, hnl[i], 14));
}
} else {
// multiply with Wiener coefficients
for (i = 0; i < PART_LEN1; i++) {
efw[i].real = (int16_t)(
WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(dfw[i].real, hnl[i], 14));
efw[i].imag = (int16_t)(
WEBRTC_SPL_MUL_16_16_RSFT_WITH_ROUND(dfw[i].imag, hnl[i], 14));
}
}
if (aecm->cngMode == AecmTrue) {
ComfortNoise(aecm, ptrDfaClean, efw, hnl);
}
InverseFFTAndWindow(aecm, fft, efw, output, nearendClean);
return 0;
}
static void ComfortNoise(AecmCore* aecm,
const uint16_t* dfa,
ComplexInt16* out,
const int16_t* lambda) {
int16_t i;
int16_t tmp16;
int32_t tmp32;
int16_t randW16[PART_LEN];
int16_t uReal[PART_LEN1];
int16_t uImag[PART_LEN1];
int32_t outLShift32;
int16_t noiseRShift16[PART_LEN1];
int16_t shiftFromNearToNoise = kNoiseEstQDomain - aecm->dfaCleanQDomain;
int16_t minTrackShift;
RTC_DCHECK_GE(shiftFromNearToNoise, 0);
RTC_DCHECK_LT(shiftFromNearToNoise, 16);
if (aecm->noiseEstCtr < 100) {
// Track the minimum more quickly initially.
aecm->noiseEstCtr++;
minTrackShift = 6;
} else {
minTrackShift = 9;
}
// Estimate noise power.
for (i = 0; i < PART_LEN1; i++) {
// Shift to the noise domain.
tmp32 = (int32_t)dfa[i];
outLShift32 = tmp32 << shiftFromNearToNoise;
if (outLShift32 < aecm->noiseEst[i]) {
// Reset "too low" counter
aecm->noiseEstTooLowCtr[i] = 0;
// Track the minimum.
if (aecm->noiseEst[i] < (1 << minTrackShift)) {
// For small values, decrease noiseEst[i] every
// |kNoiseEstIncCount| block. The regular approach below can not
// go further down due to truncation.
aecm->noiseEstTooHighCtr[i]++;
if (aecm->noiseEstTooHighCtr[i] >= kNoiseEstIncCount) {
aecm->noiseEst[i]--;
aecm->noiseEstTooHighCtr[i] = 0; // Reset the counter
}
} else {
aecm->noiseEst[i] -=
((aecm->noiseEst[i] - outLShift32) >> minTrackShift);
}
} else {
// Reset "too high" counter
aecm->noiseEstTooHighCtr[i] = 0;
// Ramp slowly upwards until we hit the minimum again.
if ((aecm->noiseEst[i] >> 19) > 0) {
// Avoid overflow.
// Multiplication with 2049 will cause wrap around. Scale
// down first and then multiply
aecm->noiseEst[i] >>= 11;
aecm->noiseEst[i] *= 2049;
} else if ((aecm->noiseEst[i] >> 11) > 0) {
// Large enough for relative increase
aecm->noiseEst[i] *= 2049;
aecm->noiseEst[i] >>= 11;
} else {
// Make incremental increases based on size every
// |kNoiseEstIncCount| block
aecm->noiseEstTooLowCtr[i]++;
if (aecm->noiseEstTooLowCtr[i] >= kNoiseEstIncCount) {
aecm->noiseEst[i] += (aecm->noiseEst[i] >> 9) + 1;
aecm->noiseEstTooLowCtr[i] = 0; // Reset counter
}
}
}
}
for (i = 0; i < PART_LEN1; i++) {
tmp32 = aecm->noiseEst[i] >> shiftFromNearToNoise;
if (tmp32 > 32767) {
tmp32 = 32767;
aecm->noiseEst[i] = tmp32 << shiftFromNearToNoise;
}
noiseRShift16[i] = (int16_t)tmp32;
tmp16 = ONE_Q14 - lambda[i];
noiseRShift16[i] = (int16_t)((tmp16 * noiseRShift16[i]) >> 14);
}
// Generate a uniform random array on [0 2^15-1].
WebRtcSpl_RandUArray(randW16, PART_LEN, &aecm->seed);
// Generate noise according to estimated energy.
uReal[0] = 0; // Reject LF noise.
uImag[0] = 0;
for (i = 1; i < PART_LEN1; i++) {
// Get a random index for the cos and sin tables over [0 359].
tmp16 = (int16_t)((359 * randW16[i - 1]) >> 15);
// Tables are in Q13.
uReal[i] =
(int16_t)((noiseRShift16[i] * WebRtcAecm_kCosTable[tmp16]) >> 13);
uImag[i] =
(int16_t)((-noiseRShift16[i] * WebRtcAecm_kSinTable[tmp16]) >> 13);
}
uImag[PART_LEN] = 0;
for (i = 0; i < PART_LEN1; i++) {
out[i].real = WebRtcSpl_AddSatW16(out[i].real, uReal[i]);
out[i].imag = WebRtcSpl_AddSatW16(out[i].imag, uImag[i]);
}
}