Bump to WebRTC M120 release

Some API deprecation -- ExperimentalAgc and ExperimentalNs are gone.
We're continuing to carry iSAC even though it's gone upstream, but maybe
we'll want to drop that soon.

webrtc/modules/audio_processing/agc2/vad_wrapper.h

@@ -0,0 +1,82 @@
+/*
+ *  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_AGC2_VAD_WRAPPER_H_
+#define MODULES_AUDIO_PROCESSING_AGC2_VAD_WRAPPER_H_
+
+#include <memory>
+#include <vector>
+
+#include "api/array_view.h"
+#include "common_audio/resampler/include/push_resampler.h"
+#include "modules/audio_processing/agc2/cpu_features.h"
+#include "modules/audio_processing/include/audio_frame_view.h"
+
+namespace webrtc {
+
+// Wraps a single-channel Voice Activity Detector (VAD) which is used to analyze
+// the first channel of the input audio frames. Takes care of resampling the
+// input frames to match the sample rate of the wrapped VAD and periodically
+// resets the VAD.
+class VoiceActivityDetectorWrapper {
+ public:
+  // Single channel VAD interface.
+  class MonoVad {
+   public:
+    virtual ~MonoVad() = default;
+    // Returns the sample rate (Hz) required for the input frames analyzed by
+    // `ComputeProbability`.
+    virtual int SampleRateHz() const = 0;
+    // Resets the internal state.
+    virtual void Reset() = 0;
+    // Analyzes an audio frame and returns the speech probability.
+    virtual float Analyze(rtc::ArrayView<const float> frame) = 0;
+  };
+
+  // Ctor. Uses `cpu_features` to instantiate the default VAD.
+  VoiceActivityDetectorWrapper(const AvailableCpuFeatures& cpu_features,
+                               int sample_rate_hz);
+
+  // Ctor. `vad_reset_period_ms` indicates the period in milliseconds to call
+  // `MonoVad::Reset()`; it must be equal to or greater than the duration of two
+  // frames. Uses `cpu_features` to instantiate the default VAD.
+  VoiceActivityDetectorWrapper(int vad_reset_period_ms,
+                               const AvailableCpuFeatures& cpu_features,
+                               int sample_rate_hz);
+  // Ctor. Uses a custom `vad`.
+  VoiceActivityDetectorWrapper(int vad_reset_period_ms,
+                               std::unique_ptr<MonoVad> vad,
+                               int sample_rate_hz);
+
+  VoiceActivityDetectorWrapper(const VoiceActivityDetectorWrapper&) = delete;
+  VoiceActivityDetectorWrapper& operator=(const VoiceActivityDetectorWrapper&) =
+      delete;
+  ~VoiceActivityDetectorWrapper();
+
+  // Initializes the VAD wrapper.
+  void Initialize(int sample_rate_hz);
+
+  // Analyzes the first channel of `frame` and returns the speech probability.
+  // `frame` must be a 10 ms frame with the sample rate specified in the last
+  // `Initialize()` call.
+  float Analyze(AudioFrameView<const float> frame);
+
+ private:
+  const int vad_reset_period_frames_;
+  int frame_size_;
+  int time_to_vad_reset_;
+  PushResampler<float> resampler_;
+  std::unique_ptr<MonoVad> vad_;
+  std::vector<float> resampled_buffer_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_AUDIO_PROCESSING_AGC2_VAD_WRAPPER_H_