Reland "Refactoring of the noise suppressor and adding true multichannel support"
This is a reland of 87a7b82520b83a6cf42da27cdc46142c2eb6248c
Original change's description:
> Refactoring of the noise suppressor and adding true multichannel support
>
> This CL adds proper multichannel support to the noise suppressor.
> To accomplish that in a safe way, a full refactoring of the noise
> suppressor code has been done.
>
> Due to floating point precision, the changes made are not entirely
> bitexact. They are, however, very close to being bitexact.
>
> As a safety measure, the former noise suppressor code is preserved
> and a kill-switch is added to allow revering to the legacy noise
> suppressor in case issues arise.
>
> Bug: webrtc:10895, b/143344262
> Change-Id: I0b071011b23265ac12e6d4b3956499d122286657
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158407
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#29646}
Bug: webrtc:10895, b/143344262
Change-Id: I236f1e67bb0baa4e30908a4cf7a8a7bb55fbced3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158747
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29663}
diff --git a/modules/audio_processing/ns/noise_estimator.h b/modules/audio_processing/ns/noise_estimator.h
new file mode 100644
index 0000000..0c0466a
--- /dev/null
+++ b/modules/audio_processing/ns/noise_estimator.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2019 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_NS_NOISE_ESTIMATOR_H_
+#define MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_
+
+#include <array>
+
+#include "api/array_view.h"
+#include "modules/audio_processing/ns/ns_common.h"
+#include "modules/audio_processing/ns/quantile_noise_estimator.h"
+#include "modules/audio_processing/ns/suppression_params.h"
+
+namespace webrtc {
+
+// Class for estimating the spectral characteristics of the noise in an incoming
+// signal.
+class NoiseEstimator {
+ public:
+ explicit NoiseEstimator(const SuppressionParams& suppression_params);
+
+ // Prepare the estimator for analysis of a new frame.
+ void PrepareAnalysis();
+
+ // Performs the first step of the estimator update.
+ void PreUpdate(int32_t num_analyzed_frames,
+ rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
+ float signal_spectral_sum);
+
+ // Performs the second step of the estimator update.
+ void PostUpdate(
+ rtc::ArrayView<const float> speech_probability,
+ rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum);
+
+ // Returns the noise spectral estimate.
+ rtc::ArrayView<const float, kFftSizeBy2Plus1> get_noise_spectrum() const {
+ return noise_spectrum_;
+ }
+
+ // Returns the noise from the previous frame.
+ rtc::ArrayView<const float, kFftSizeBy2Plus1> get_prev_noise_spectrum()
+ const {
+ return prev_noise_spectrum_;
+ }
+
+ // Returns a noise spectral estimate based on white and pink noise parameters.
+ rtc::ArrayView<const float, kFftSizeBy2Plus1> get_parametric_noise_spectrum()
+ const {
+ return parametric_noise_spectrum_;
+ }
+ rtc::ArrayView<const float, kFftSizeBy2Plus1>
+ get_conservative_noise_spectrum() const {
+ return conservative_noise_spectrum_;
+ }
+
+ private:
+ const SuppressionParams& suppression_params_;
+ float white_noise_level_ = 0.f;
+ float pink_noise_numerator_ = 0.f;
+ float pink_noise_exp_ = 0.f;
+ std::array<float, kFftSizeBy2Plus1> prev_noise_spectrum_;
+ std::array<float, kFftSizeBy2Plus1> conservative_noise_spectrum_;
+ std::array<float, kFftSizeBy2Plus1> parametric_noise_spectrum_;
+ std::array<float, kFftSizeBy2Plus1> noise_spectrum_;
+ QuantileNoiseEstimator quantile_noise_estimator_;
+};
+
+} // namespace webrtc
+
+#endif // MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_