AEC3: Average the spectrum of multiple nearend frames in the suppressor.
Reduce noise of the nearend spectrum estimation by averaging multiple
frames.
Bug: webrtc:9420,chromium:853699
Change-Id: Iad7e68b1209a369e263b2d892791943e42bfbb3f
Reviewed-on: https://webrtc-review.googlesource.com/83960
Reviewed-by: Jesus de Vicente Pena <devicentepena@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23655}diff --git a/api/audio/echo_canceller3_config.h b/api/audio/echo_canceller3_config.h
index ed39b66..98bd463 100644
--- a/api/audio/echo_canceller3_config.h
+++ b/api/audio/echo_canceller3_config.h
@@ -157,6 +157,7 @@
struct Suppressor {
size_t bands_with_reliable_coherence = 5;
+ size_t nearend_average_blocks = 4;
} suppressor;
};
} // namespace webrtc
diff --git a/modules/audio_processing/aec3/BUILD.gn b/modules/audio_processing/aec3/BUILD.gn
index c0f632a..237f71a 100644
--- a/modules/audio_processing/aec3/BUILD.gn
+++ b/modules/audio_processing/aec3/BUILD.gn
@@ -69,6 +69,8 @@
"matched_filter_lag_aggregator.h",
"matrix_buffer.cc",
"matrix_buffer.h",
+ "moving_average.cc",
+ "moving_average.h",
"render_buffer.cc",
"render_buffer.h",
"render_delay_buffer.cc",
diff --git a/modules/audio_processing/aec3/echo_canceller3.cc b/modules/audio_processing/aec3/echo_canceller3.cc
index 3acb31b..0caf179 100644
--- a/modules/audio_processing/aec3/echo_canceller3.cc
+++ b/modules/audio_processing/aec3/echo_canceller3.cc
@@ -41,6 +41,11 @@
return !field_trial::IsEnabled("WebRTC-Aec3ReverbModellingKillSwitch");
}
+bool EnableSuppressorNearendAveraging() {
+ return !field_trial::IsEnabled(
+ "WebRTC-Aec3SuppressorNearendAveragingKillSwitch");
+}
+
// Method for adjusting config parameter dependencies..
EchoCanceller3Config AdjustConfig(const EchoCanceller3Config& config) {
EchoCanceller3Config adjusted_cfg = config;
@@ -89,6 +94,10 @@
adjusted_cfg.ep_strength.reverb_based_on_render = false;
}
+ if (!EnableSuppressorNearendAveraging()) {
+ adjusted_cfg.suppressor.nearend_average_blocks = 1;
+ }
+
return adjusted_cfg;
}
diff --git a/modules/audio_processing/aec3/moving_average.cc b/modules/audio_processing/aec3/moving_average.cc
new file mode 100644
index 0000000..e9d64e6
--- /dev/null
+++ b/modules/audio_processing/aec3/moving_average.cc
@@ -0,0 +1,58 @@
+
+/*
+ * Copyright (c) 2018 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/moving_average.h"
+
+#include <algorithm>
+#include <functional>
+
+namespace webrtc {
+namespace aec3 {
+
+MovingAverage::MovingAverage(size_t num_elem, size_t mem_len)
+ : num_elem_(num_elem),
+ mem_len_(mem_len - 1),
+ scaling_(1.0f / static_cast<float>(mem_len)),
+ memory_(num_elem * mem_len_, 0.f),
+ mem_index_(0) {
+ RTC_DCHECK(num_elem_ > 0);
+ RTC_DCHECK(mem_len > 0);
+}
+
+MovingAverage::~MovingAverage() = default;
+
+void MovingAverage::Average(rtc::ArrayView<const float> input,
+ rtc::ArrayView<float> output) {
+ RTC_DCHECK(input.size() == num_elem_);
+ RTC_DCHECK(output.size() == num_elem_);
+
+ // Sum all contributions.
+ std::copy(input.begin(), input.end(), output.begin());
+ for (auto i = memory_.begin(); i < memory_.end(); i += num_elem_) {
+ std::transform(i, i + num_elem_, output.begin(), output.begin(),
+ std::plus<float>());
+ }
+
+ // Divide by mem_len_.
+ for (float& o : output) {
+ o *= scaling_;
+ }
+
+ // Update memory.
+ if (mem_len_ > 0) {
+ std::copy(input.begin(), input.end(),
+ memory_.begin() + mem_index_ * num_elem_);
+ mem_index_ = (mem_index_ + 1) % mem_len_;
+ }
+}
+
+} // namespace aec3
+} // namespace webrtc
diff --git a/modules/audio_processing/aec3/moving_average.h b/modules/audio_processing/aec3/moving_average.h
new file mode 100644
index 0000000..94497d7
--- /dev/null
+++ b/modules/audio_processing/aec3/moving_average.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2018 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.
+ */
+
+#ifndef MODULES_AUDIO_PROCESSING_AEC3_MOVING_AVERAGE_H_
+#define MODULES_AUDIO_PROCESSING_AEC3_MOVING_AVERAGE_H_
+
+#include <vector>
+
+#include "api/array_view.h"
+
+namespace webrtc {
+namespace aec3 {
+
+class MovingAverage {
+ public:
+ // Creates an instance of MovingAverage that accepts inputs of length num_elem
+ // and averages over mem_len inputs.
+ MovingAverage(size_t num_elem, size_t mem_len);
+ ~MovingAverage();
+
+ // Computes the average of input and mem_len-1 previous inputs and stores the
+ // result in output.
+ void Average(rtc::ArrayView<const float> input, rtc::ArrayView<float> output);
+
+ private:
+ const size_t num_elem_;
+ const size_t mem_len_;
+ const float scaling_;
+ std::vector<float> memory_;
+ size_t mem_index_;
+};
+
+} // namespace aec3
+} // namespace webrtc
+
+#endif // MODULES_AUDIO_PROCESSING_AEC3_MOVING_AVERAGE_H_
diff --git a/modules/audio_processing/aec3/suppression_gain.cc b/modules/audio_processing/aec3/suppression_gain.cc
index 2098fc2..6b86b87 100644
--- a/modules/audio_processing/aec3/suppression_gain.cc
+++ b/modules/audio_processing/aec3/suppression_gain.cc
@@ -20,6 +20,7 @@
#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"
@@ -386,7 +387,9 @@
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_transparency_improvements_(EnableTransparencyImprovements()),
+ 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);
@@ -413,11 +416,14 @@
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_spectrum, echo_spectrum,
+ 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.
diff --git a/modules/audio_processing/aec3/suppression_gain.h b/modules/audio_processing/aec3/suppression_gain.h
index f3719ee..ced3666 100644
--- a/modules/audio_processing/aec3/suppression_gain.h
+++ b/modules/audio_processing/aec3/suppression_gain.h
@@ -18,6 +18,7 @@
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/aec_state.h"
#include "modules/audio_processing/aec3/coherence_gain.h"
+#include "modules/audio_processing/aec3/moving_average.h"
#include "modules/audio_processing/aec3/render_signal_analyzer.h"
#include "rtc_base/constructormagic.h"
@@ -85,6 +86,7 @@
int initial_state_change_counter_ = 0;
CoherenceGain coherence_gain_;
const bool enable_transparency_improvements_;
+ aec3::MovingAverage moving_average_;
RTC_DISALLOW_COPY_AND_ASSIGN(SuppressionGain);
};
