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webrtc/modules/audio_processing/aec3/suppression_gain.cc
Niels Möller a12c42a6b2 Delete root header file typedef.h. 
Usage replaced with stdint.h, rtc_base/system/arch.h and
rtc_base/system/unused.h, as appropriate.

Bug: webrtc:6854
Change-Id: I97225465d14b969903d92979e2df3c3c05d35f18
Reviewed-on: https://webrtc-review.googlesource.com/90249
Reviewed-by: Niklas Enbom <niklas.enbom@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24100}
2018-07-25 14:59:26 +00:00

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/*
* Copyright (c) 2017 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 "modules/audio_processing/aec3/suppression_gain.h"
// Defines WEBRTC_ARCH_X86_FAMILY, used below.
#include "rtc_base/system/arch.h"
#if defined(WEBRTC_ARCH_X86_FAMILY)
#include <emmintrin.h>
#endif
#include <math.h>
#include <algorithm>
#include <functional>
#include <numeric>
#include "modules/audio_processing/aec3/moving_average.h"
#include "modules/audio_processing/aec3/vector_math.h"
#include "modules/audio_processing/logging/apm_data_dumper.h"
#include "rtc_base/atomicops.h"
#include "rtc_base/checks.h"
#include "system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
bool EnableTransparencyImprovements() {
return !field_trial::IsEnabled(
"WebRTC-Aec3TransparencyImprovementsKillSwitch");
}
bool EnableNewSuppression() {
return !field_trial::IsEnabled("WebRTC-Aec3NewSuppressionKillSwitch");
}
// Adjust the gains according to the presence of known external filters.
void AdjustForExternalFilters(std::array<float, kFftLengthBy2Plus1>* gain) {
// Limit the low frequency gains to avoid the impact of the high-pass filter
// on the lower-frequency gain influencing the overall achieved gain.
(*gain)[0] = (*gain)[1] = std::min((*gain)[1], (*gain)[2]);
// Limit the high frequency gains to avoid the impact of the anti-aliasing
// filter on the upper-frequency gains influencing the overall achieved
// gain. TODO(peah): Update this when new anti-aliasing filters are
// implemented.
constexpr size_t kAntiAliasingImpactLimit = (64 * 2000) / 8000;
const float min_upper_gain = (*gain)[kAntiAliasingImpactLimit];
std::for_each(
gain->begin() + kAntiAliasingImpactLimit, gain->end() - 1,
[min_upper_gain](float& a) { a = std::min(a, min_upper_gain); });
(*gain)[kFftLengthBy2] = (*gain)[kFftLengthBy2Minus1];
}
// Computes the gain to apply for the bands beyond the first band.
float UpperBandsGain(
const absl::optional<int>& narrow_peak_band,
bool saturated_echo,
const std::vector<std::vector<float>>& render,
const std::array<float, kFftLengthBy2Plus1>& low_band_gain) {
RTC_DCHECK_LT(0, render.size());
if (render.size() == 1) {
return 1.f;
}
if (narrow_peak_band &&
(*narrow_peak_band > static_cast<int>(kFftLengthBy2Plus1 - 10))) {
return 0.001f;
}
constexpr size_t kLowBandGainLimit = kFftLengthBy2 / 2;
const float gain_below_8_khz = *std::min_element(
low_band_gain.begin() + kLowBandGainLimit, low_band_gain.end());
// Always attenuate the upper bands when there is saturated echo.
if (saturated_echo) {
return std::min(0.001f, gain_below_8_khz);
}
// Compute the upper and lower band energies.
const auto sum_of_squares = [](float a, float b) { return a + b * b; };
const float low_band_energy =
std::accumulate(render[0].begin(), render[0].end(), 0.f, sum_of_squares);
float high_band_energy = 0.f;
for (size_t k = 1; k < render.size(); ++k) {
const float energy = std::accumulate(render[k].begin(), render[k].end(),
0.f, sum_of_squares);
high_band_energy = std::max(high_band_energy, energy);
}
// If there is more power in the lower frequencies than the upper frequencies,
// or if the power in upper frequencies is low, do not bound the gain in the
// upper bands.
float anti_howling_gain;
constexpr float kThreshold = kBlockSize * 10.f * 10.f / 4.f;
if (high_band_energy < std::max(low_band_energy, kThreshold)) {
anti_howling_gain = 1.f;
} else {
// In all other cases, bound the gain for upper frequencies.
RTC_DCHECK_LE(low_band_energy, high_band_energy);
RTC_DCHECK_NE(0.f, high_band_energy);
anti_howling_gain = 0.01f * sqrtf(low_band_energy / high_band_energy);
}
// Choose the gain as the minimum of the lower and upper gains.
return std::min(gain_below_8_khz, anti_howling_gain);
}
// Scales the echo according to assessed audibility at the other end.
void WeightEchoForAudibility(const EchoCanceller3Config& config,
rtc::ArrayView<const float> echo,
rtc::ArrayView<float> weighted_echo,
rtc::ArrayView<float> one_by_weighted_echo) {
RTC_DCHECK_EQ(kFftLengthBy2Plus1, echo.size());
RTC_DCHECK_EQ(kFftLengthBy2Plus1, weighted_echo.size());
RTC_DCHECK_EQ(kFftLengthBy2Plus1, one_by_weighted_echo.size());
auto weigh = [](float threshold, float normalizer, size_t begin, size_t end,
rtc::ArrayView<const float> echo,
rtc::ArrayView<float> weighted_echo,
rtc::ArrayView<float> one_by_weighted_echo) {
for (size_t k = begin; k < end; ++k) {
if (echo[k] < threshold) {
float tmp = (threshold - echo[k]) * normalizer;
weighted_echo[k] = echo[k] * std::max(0.f, 1.f - tmp * tmp);
} else {
weighted_echo[k] = echo[k];
}
one_by_weighted_echo[k] =
weighted_echo[k] > 0.f ? 1.f / weighted_echo[k] : 1.f;
}
};
float threshold = config.echo_audibility.floor_power *
config.echo_audibility.audibility_threshold_lf;
float normalizer = 1.f / (threshold - config.echo_audibility.floor_power);
weigh(threshold, normalizer, 0, 3, echo, weighted_echo, one_by_weighted_echo);
threshold = config.echo_audibility.floor_power *
config.echo_audibility.audibility_threshold_mf;
normalizer = 1.f / (threshold - config.echo_audibility.floor_power);
weigh(threshold, normalizer, 3, 7, echo, weighted_echo, one_by_weighted_echo);
threshold = config.echo_audibility.floor_power *
config.echo_audibility.audibility_threshold_hf;
normalizer = 1.f / (threshold - config.echo_audibility.floor_power);
weigh(threshold, normalizer, 7, kFftLengthBy2Plus1, echo, weighted_echo,
one_by_weighted_echo);
}
// Computes the gain to reduce the echo to a non audible level.
void GainToNoAudibleEchoFallback(
const EchoCanceller3Config& config,
bool low_noise_render,
bool saturated_echo,
bool linear_echo_estimate,
bool enable_transparency_improvements,
const std::array<float, kFftLengthBy2Plus1>& nearend,
const std::array<float, kFftLengthBy2Plus1>& weighted_echo,
const std::array<float, kFftLengthBy2Plus1>& masker,
const std::array<float, kFftLengthBy2Plus1>& min_gain,
const std::array<float, kFftLengthBy2Plus1>& max_gain,
const std::array<float, kFftLengthBy2Plus1>& one_by_weighted_echo,
std::array<float, kFftLengthBy2Plus1>* gain) {
float nearend_masking_margin = 0.f;
if (linear_echo_estimate) {
nearend_masking_margin =
low_noise_render
? config.gain_mask.m9
: (saturated_echo ? config.gain_mask.m2 : config.gain_mask.m3);
} else {
nearend_masking_margin = config.gain_mask.m7;
}
RTC_DCHECK_LE(0.f, nearend_masking_margin);
RTC_DCHECK_GT(1.f, nearend_masking_margin);
const float masker_margin =
linear_echo_estimate
? (enable_transparency_improvements ? config.gain_mask.m0
: config.gain_mask.m1)
: config.gain_mask.m8;
for (size_t k = 0; k < gain->size(); ++k) {
// TODO(devicentepena): Experiment by removing the reverberation estimation
// from the nearend signal before computing the gains.
const float unity_gain_masker = std::max(nearend[k], masker[k]);
RTC_DCHECK_LE(0.f, nearend_masking_margin * unity_gain_masker);
if (weighted_echo[k] <= nearend_masking_margin * unity_gain_masker ||
unity_gain_masker <= 0.f) {
(*gain)[k] = 1.f;
} else {
RTC_DCHECK_LT(0.f, unity_gain_masker);
(*gain)[k] =
std::max(0.f, (1.f - config.gain_mask.gain_curve_slope *
weighted_echo[k] / unity_gain_masker) *
config.gain_mask.gain_curve_offset);
(*gain)[k] = std::max(masker_margin * masker[k] * one_by_weighted_echo[k],
(*gain)[k]);
}
(*gain)[k] = std::min(std::max((*gain)[k], min_gain[k]), max_gain[k]);
}
}
// TODO(peah): Make adaptive to take the actual filter error into account.
constexpr size_t kUpperAccurateBandPlus1 = 29;
// Computes the signal output power that masks the echo signal.
void MaskingPower(const EchoCanceller3Config& config,
bool enable_transparency_improvements,
const std::array<float, kFftLengthBy2Plus1>& nearend,
const std::array<float, kFftLengthBy2Plus1>& comfort_noise,
const std::array<float, kFftLengthBy2Plus1>& last_masker,
const std::array<float, kFftLengthBy2Plus1>& gain,
std::array<float, kFftLengthBy2Plus1>* masker) {
if (enable_transparency_improvements) {
std::copy(comfort_noise.begin(), comfort_noise.end(), masker->begin());
return;
}
// Apply masking over time.
float masking_factor = config.gain_mask.temporal_masking_lf;
auto limit = config.gain_mask.temporal_masking_lf_bands;
std::transform(
comfort_noise.begin(), comfort_noise.begin() + limit, last_masker.begin(),
masker->begin(),
[masking_factor](float a, float b) { return a + masking_factor * b; });
masking_factor = config.gain_mask.temporal_masking_hf;
std::transform(
comfort_noise.begin() + limit, comfort_noise.end(),
last_masker.begin() + limit, masker->begin() + limit,
[masking_factor](float a, float b) { return a + masking_factor * b; });
// Apply masking only between lower frequency bands.
std::array<float, kFftLengthBy2Plus1> side_band_masker;
float max_nearend_after_gain = 0.f;
for (size_t k = 0; k < gain.size(); ++k) {
const float nearend_after_gain = nearend[k] * gain[k];
max_nearend_after_gain =
std::max(max_nearend_after_gain, nearend_after_gain);
side_band_masker[k] = nearend_after_gain + comfort_noise[k];
}
RTC_DCHECK_LT(kUpperAccurateBandPlus1, gain.size());
for (size_t k = 1; k < kUpperAccurateBandPlus1; ++k) {
(*masker)[k] += config.gain_mask.m5 *
(side_band_masker[k - 1] + side_band_masker[k + 1]);
}
// Add full-band masking as a minimum value for the masker.
const float min_masker = max_nearend_after_gain * config.gain_mask.m6;
std::for_each(masker->begin(), masker->end(),
[min_masker](float& a) { a = std::max(a, min_masker); });
}
// Limits the gain in the frequencies for which the adaptive filter has not
// converged. Currently, these frequencies are not hardcoded to the frequencies
// which are typically not excited by speech.
// TODO(peah): Make adaptive to take the actual filter error into account.
void AdjustNonConvergedFrequencies(
std::array<float, kFftLengthBy2Plus1>* gain) {
constexpr float oneByBandsInSum =
1 / static_cast<float>(kUpperAccurateBandPlus1 - 20);
const float hf_gain_bound =
std::accumulate(gain->begin() + 20,
gain->begin() + kUpperAccurateBandPlus1, 0.f) *
oneByBandsInSum;
std::for_each(gain->begin() + kUpperAccurateBandPlus1, gain->end(),
[hf_gain_bound](float& a) { a = std::min(a, hf_gain_bound); });
}
} // namespace
int SuppressionGain::instance_count_ = 0;
// Computes the gain to reduce the echo to a non audible level.
void SuppressionGain::GainToNoAudibleEcho(
const std::array<float, kFftLengthBy2Plus1>& nearend,
const std::array<float, kFftLengthBy2Plus1>& echo,
const std::array<float, kFftLengthBy2Plus1>& masker,
const std::array<float, kFftLengthBy2Plus1>& min_gain,
const std::array<float, kFftLengthBy2Plus1>& max_gain,
std::array<float, kFftLengthBy2Plus1>* gain) const {
for (size_t k = 0; k < gain->size(); ++k) {
float enr = echo[k] / (nearend[k] + 1.f); // Echo-to-nearend ratio.
float emr = echo[k] / (masker[k] + 1.f); // Echo-to-masker (noise) ratio.
float g = 1.0f;
if (enr > enr_transparent_[k] && emr > emr_transparent_[k]) {
g = (enr_suppress_[k] - enr) / (enr_suppress_[k] - enr_transparent_[k]);
g = std::max(g, emr_transparent_[k] / emr);
}
(*gain)[k] = std::max(std::min(g, max_gain[k]), min_gain[k]);
}
}
// TODO(peah): Add further optimizations, in particular for the divisions.
void SuppressionGain::LowerBandGain(
bool low_noise_render,
const AecState& aec_state,
const std::array<float, kFftLengthBy2Plus1>& nearend,
const std::array<float, kFftLengthBy2Plus1>& echo,
const std::array<float, kFftLengthBy2Plus1>& comfort_noise,
std::array<float, kFftLengthBy2Plus1>* gain) {
const bool saturated_echo = aec_state.SaturatedEcho();
const bool linear_echo_estimate = aec_state.UsableLinearEstimate();
// Weight echo power in terms of audibility. // Precompute 1/weighted echo
// (note that when the echo is zero, the precomputed value is never used).
std::array<float, kFftLengthBy2Plus1> weighted_echo;
std::array<float, kFftLengthBy2Plus1> one_by_weighted_echo;
WeightEchoForAudibility(config_, echo, weighted_echo, one_by_weighted_echo);
// Compute the minimum gain as the attenuating gain to put the signal just
// above the zero sample values.
std::array<float, kFftLengthBy2Plus1> min_gain;
const float min_echo_power =
low_noise_render ? config_.echo_audibility.low_render_limit
: config_.echo_audibility.normal_render_limit;
if (!saturated_echo) {
for (size_t k = 0; k < nearend.size(); ++k) {
const float denom = std::min(nearend[k], weighted_echo[k]);
min_gain[k] = denom > 0.f ? min_echo_power / denom : 1.f;
min_gain[k] = std::min(min_gain[k], 1.f);
}
if (enable_transparency_improvements_) {
for (size_t k = 0; k < 6; ++k) {
// Make sure the gains of the low frequencies do not decrease too
// quickly after strong nearend.
if (last_nearend_[k] > last_echo_[k]) {
min_gain[k] =
std::max(min_gain[k],
last_gain_[k] * config_.gain_updates.max_dec_factor_lf);
min_gain[k] = std::min(min_gain[k], 1.f);
}
}
}
} else {
min_gain.fill(0.f);
}
// Compute the maximum gain by limiting the gain increase from the previous
// gain.
std::array<float, kFftLengthBy2Plus1> max_gain;
if (enable_transparency_improvements_) {
for (size_t k = 0; k < gain->size(); ++k) {
max_gain[k] =
std::min(std::max(last_gain_[k] * config_.gain_updates.max_inc_factor,
config_.gain_updates.floor_first_increase),
1.f);
}
} else {
for (size_t k = 0; k < gain->size(); ++k) {
max_gain[k] =
std::min(std::max(last_gain_[k] * gain_increase_[k],
config_.gain_updates.floor_first_increase),
1.f);
}
}
// Iteratively compute the gain required to attenuate the echo to a non
// noticeable level.
std::array<float, kFftLengthBy2Plus1> masker;
if (enable_new_suppression_) {
GainToNoAudibleEcho(nearend, weighted_echo, comfort_noise, min_gain,
max_gain, gain);
AdjustForExternalFilters(gain);
} else {
gain->fill(0.f);
for (int k = 0; k < 2; ++k) {
MaskingPower(config_, enable_transparency_improvements_, nearend,
comfort_noise, last_masker_, *gain, &masker);
GainToNoAudibleEchoFallback(
config_, low_noise_render, saturated_echo, linear_echo_estimate,
enable_transparency_improvements_, nearend, weighted_echo, masker,
min_gain, max_gain, one_by_weighted_echo, gain);
AdjustForExternalFilters(gain);
}
}
// Adjust the gain for frequencies which have not yet converged.
AdjustNonConvergedFrequencies(gain);
// Update the allowed maximum gain increase.
UpdateGainIncrease(low_noise_render, linear_echo_estimate, saturated_echo,
weighted_echo, *gain);
// Store data required for the gain computation of the next block.
std::copy(nearend.begin(), nearend.end(), last_nearend_.begin());
std::copy(weighted_echo.begin(), weighted_echo.end(), last_echo_.begin());
std::copy(gain->begin(), gain->end(), last_gain_.begin());
MaskingPower(config_, enable_transparency_improvements_, nearend,
comfort_noise, last_masker_, *gain, &last_masker_);
aec3::VectorMath(optimization_).Sqrt(*gain);
// Debug outputs for the purpose of development and analysis.
data_dumper_->DumpRaw("aec3_suppressor_min_gain", min_gain);
data_dumper_->DumpRaw("aec3_suppressor_max_gain", max_gain);
data_dumper_->DumpRaw("aec3_suppressor_masker", masker);
data_dumper_->DumpRaw("aec3_suppressor_last_masker", last_masker_);
}
SuppressionGain::SuppressionGain(const EchoCanceller3Config& config,
Aec3Optimization optimization,
int sample_rate_hz)
: data_dumper_(
new ApmDataDumper(rtc::AtomicOps::Increment(&instance_count_))),
optimization_(optimization),
config_(config),
state_change_duration_blocks_(
static_cast<int>(config_.filter.config_change_duration_blocks)),
coherence_gain_(sample_rate_hz,
config_.suppressor.bands_with_reliable_coherence),
enable_transparency_improvements_(EnableTransparencyImprovements()),
enable_new_suppression_(EnableNewSuppression()),
moving_average_(kFftLengthBy2Plus1,
config.suppressor.nearend_average_blocks) {
RTC_DCHECK_LT(0, state_change_duration_blocks_);
one_by_state_change_duration_blocks_ = 1.f / state_change_duration_blocks_;
last_gain_.fill(1.f);
last_masker_.fill(0.f);
gain_increase_.fill(1.f);
last_nearend_.fill(0.f);
last_echo_.fill(0.f);
// Compute per-band masking thresholds.
constexpr size_t kLastLfBand = 5;
constexpr size_t kFirstHfBand = 8;
RTC_DCHECK_LT(kLastLfBand, kFirstHfBand);
auto& lf = config.suppressor.mask_lf;
auto& hf = config.suppressor.mask_hf;
RTC_DCHECK_LT(lf.enr_transparent, lf.enr_suppress);
RTC_DCHECK_LT(hf.enr_transparent, hf.enr_suppress);
for (size_t k = 0; k < kFftLengthBy2Plus1; k++) {
float a;
if (k <= kLastLfBand) {
a = 0.f;
} else if (k < kFirstHfBand) {
a = (k - kLastLfBand) / static_cast<float>(kFirstHfBand - kLastLfBand);
} else {
a = 1.f;
}
enr_transparent_[k] = (1 - a) * lf.enr_transparent + a * hf.enr_transparent;
enr_suppress_[k] = (1 - a) * lf.enr_suppress + a * hf.enr_suppress;
emr_transparent_[k] = (1 - a) * lf.emr_transparent + a * hf.emr_transparent;
}
}
SuppressionGain::~SuppressionGain() = default;
void SuppressionGain::GetGain(
const std::array<float, kFftLengthBy2Plus1>& nearend_spectrum,
const std::array<float, kFftLengthBy2Plus1>& echo_spectrum,
const std::array<float, kFftLengthBy2Plus1>& comfort_noise_spectrum,
const FftData& linear_aec_fft,
const FftData& render_fft,
const FftData& capture_fft,
const RenderSignalAnalyzer& render_signal_analyzer,
const AecState& aec_state,
const std::vector<std::vector<float>>& render,
float* high_bands_gain,
std::array<float, kFftLengthBy2Plus1>* low_band_gain) {
RTC_DCHECK(high_bands_gain);
RTC_DCHECK(low_band_gain);
std::array<float, kFftLengthBy2Plus1> nearend_average;
moving_average_.Average(nearend_spectrum, nearend_average);
// Compute gain for the lower band.
bool low_noise_render = low_render_detector_.Detect(render);
const absl::optional<int> narrow_peak_band =
render_signal_analyzer.NarrowPeakBand();
LowerBandGain(low_noise_render, aec_state, nearend_average, echo_spectrum,
comfort_noise_spectrum, low_band_gain);
// Adjust the gain for bands where the coherence indicates not echo.
if (config_.suppressor.bands_with_reliable_coherence > 0 &&
!enable_transparency_improvements_) {
std::array<float, kFftLengthBy2Plus1> G_coherence;
coherence_gain_.ComputeGain(linear_aec_fft, render_fft, capture_fft,
G_coherence);
for (size_t k = 0; k < config_.suppressor.bands_with_reliable_coherence;
++k) {
(*low_band_gain)[k] = std::max((*low_band_gain)[k], G_coherence[k]);
}
}
// Limit the gain of the lower bands during start up and after resets.
const float gain_upper_bound = aec_state.SuppressionGainLimit();
if (gain_upper_bound < 1.f) {
for (size_t k = 0; k < low_band_gain->size(); ++k) {
(*low_band_gain)[k] = std::min((*low_band_gain)[k], gain_upper_bound);
}
}
// Compute the gain for the upper bands.
*high_bands_gain = UpperBandsGain(narrow_peak_band, aec_state.SaturatedEcho(),
render, *low_band_gain);
}
void SuppressionGain::SetInitialState(bool state) {
initial_state_ = state;
if (state) {
initial_state_change_counter_ = state_change_duration_blocks_;
} else {
initial_state_change_counter_ = 0;
}
}
void SuppressionGain::UpdateGainIncrease(
bool low_noise_render,
bool linear_echo_estimate,
bool saturated_echo,
const std::array<float, kFftLengthBy2Plus1>& echo,
const std::array<float, kFftLengthBy2Plus1>& new_gain) {
float max_inc;
float max_dec;
float rate_inc;
float rate_dec;
float min_inc;
float min_dec;
RTC_DCHECK_GE(state_change_duration_blocks_, initial_state_change_counter_);
if (initial_state_change_counter_ > 0) {
if (--initial_state_change_counter_ == 0) {
initial_state_ = false;
}
}
RTC_DCHECK_LE(0, initial_state_change_counter_);
// EchoCanceller3Config::GainUpdates
auto& p = config_.gain_updates;
if (!linear_echo_estimate) {
max_inc = p.nonlinear.max_inc;
max_dec = p.nonlinear.max_dec;
rate_inc = p.nonlinear.rate_inc;
rate_dec = p.nonlinear.rate_dec;
min_inc = p.nonlinear.min_inc;
min_dec = p.nonlinear.min_dec;
} else if (initial_state_ && !saturated_echo) {
if (initial_state_change_counter_ > 0) {
float change_factor =
initial_state_change_counter_ * one_by_state_change_duration_blocks_;
auto average = [](float from, float to, float from_weight) {
return from * from_weight + to * (1.f - from_weight);
};
max_inc = average(p.initial.max_inc, p.normal.max_inc, change_factor);
max_dec = average(p.initial.max_dec, p.normal.max_dec, change_factor);
rate_inc = average(p.initial.rate_inc, p.normal.rate_inc, change_factor);
rate_dec = average(p.initial.rate_dec, p.normal.rate_dec, change_factor);
min_inc = average(p.initial.min_inc, p.normal.min_inc, change_factor);
min_dec = average(p.initial.min_dec, p.normal.min_dec, change_factor);
} else {
max_inc = p.initial.max_inc;
max_dec = p.initial.max_dec;
rate_inc = p.initial.rate_inc;
rate_dec = p.initial.rate_dec;
min_inc = p.initial.min_inc;
min_dec = p.initial.min_dec;
}
} else if (low_noise_render) {
max_inc = p.low_noise.max_inc;
max_dec = p.low_noise.max_dec;
rate_inc = p.low_noise.rate_inc;
rate_dec = p.low_noise.rate_dec;
min_inc = p.low_noise.min_inc;
min_dec = p.low_noise.min_dec;
} else if (!saturated_echo) {
max_inc = p.normal.max_inc;
max_dec = p.normal.max_dec;
rate_inc = p.normal.rate_inc;
rate_dec = p.normal.rate_dec;
min_inc = p.normal.min_inc;
min_dec = p.normal.min_dec;
} else {
max_inc = p.saturation.max_inc;
max_dec = p.saturation.max_dec;
rate_inc = p.saturation.rate_inc;
rate_dec = p.saturation.rate_dec;
min_inc = p.saturation.min_inc;
min_dec = p.saturation.min_dec;
}
for (size_t k = 0; k < new_gain.size(); ++k) {
auto increase_update = [](float new_gain, float last_gain,
float current_inc, float max_inc, float min_inc,
float change_rate) {
return new_gain > last_gain ? std::min(max_inc, current_inc * change_rate)
: min_inc;
};
if (echo[k] > last_echo_[k]) {
gain_increase_[k] =
increase_update(new_gain[k], last_gain_[k], gain_increase_[k],
max_inc, min_inc, rate_inc);
} else {
gain_increase_[k] =
increase_update(new_gain[k], last_gain_[k], gain_increase_[k],
max_dec, min_dec, rate_dec);
}
}
}
// Detects when the render signal can be considered to have low power and
// consist of stationary noise.
bool SuppressionGain::LowNoiseRenderDetector::Detect(
const std::vector<std::vector<float>>& render) {
float x2_sum = 0.f;
float x2_max = 0.f;
for (auto x_k : render[0]) {
const float x2 = x_k * x_k;
x2_sum += x2;
x2_max = std::max(x2_max, x2);
}
constexpr float kThreshold = 50.f * 50.f * 64.f;
const bool low_noise_render =
average_power_ < kThreshold && x2_max < 3 * average_power_;
average_power_ = average_power_ * 0.9f + x2_sum * 0.1f;
return low_noise_render;
}
} // namespace webrtc
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