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/legacy_noise_suppression.h b/modules/audio_processing/legacy_noise_suppression.h
new file mode 100644
index 0000000..c2435db
--- /dev/null
+++ b/modules/audio_processing/legacy_noise_suppression.h
@@ -0,0 +1,57 @@
+/*
+ * 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_LEGACY_NOISE_SUPPRESSION_H_
+#define MODULES_AUDIO_PROCESSING_LEGACY_NOISE_SUPPRESSION_H_
+
+#include <memory>
+#include <vector>
+
+namespace webrtc {
+
+class AudioBuffer;
+
+// The noise suppression (NS) component attempts to remove noise while
+// retaining speech. Recommended to be enabled on the client-side.
+class NoiseSuppression {
+ public:
+ // Determines the aggressiveness of the suppression. Increasing the level
+ // will reduce the noise level at the expense of a higher speech distortion.
+ enum class Level { kLow, kModerate, kHigh, kVeryHigh };
+
+ NoiseSuppression(size_t channels, int sample_rate_hz, Level level);
+ ~NoiseSuppression();
+
+ NoiseSuppression(NoiseSuppression&) = delete;
+ NoiseSuppression& operator=(NoiseSuppression&) = delete;
+
+ void AnalyzeCaptureAudio(AudioBuffer* audio);
+ void ProcessCaptureAudio(AudioBuffer* audio);
+
+ // LEGACY: Returns the internally computed prior speech probability of current
+ // frame averaged over output channels. This is not supported in fixed point,
+ // for which |kUnsupportedFunctionError| is returned.
+ float speech_probability() const;
+
+ // LEGACY: Returns the size of the noise vector returned by NoiseEstimate().
+ static size_t num_noise_bins();
+
+ // LEGACY: Returns the noise estimate per frequency bin averaged over all
+ // channels.
+ std::vector<float> NoiseEstimate();
+
+ private:
+ class Suppressor;
+
+ std::vector<std::unique_ptr<Suppressor>> suppressors_;
+};
+} // namespace webrtc
+
+#endif // MODULES_AUDIO_PROCESSING_LEGACY_NOISE_SUPPRESSION_H_