1 files changed, 113 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/agc2/vad_wrapper.cc b/third_party/libwebrtc/modules/audio_processing/agc2/vad_wrapper.cc
new file mode 100644
index 0000000000..af6325dea7
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/agc2/vad_wrapper.cc
@@ -0,0 +1,113 @@
+/*
+ *  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/agc2/vad_wrapper.h"
+
+#include <array>
+#include <utility>
+
+#include "api/array_view.h"
+#include "common_audio/resampler/include/push_resampler.h"
+#include "modules/audio_processing/agc2/agc2_common.h"
+#include "modules/audio_processing/agc2/rnn_vad/common.h"
+#include "modules/audio_processing/agc2/rnn_vad/features_extraction.h"
+#include "modules/audio_processing/agc2/rnn_vad/rnn.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace {
+
+constexpr int kNumFramesPerSecond = 100;
+
+class MonoVadImpl : public VoiceActivityDetectorWrapper::MonoVad {
+ public:
+  explicit MonoVadImpl(const AvailableCpuFeatures& cpu_features)
+      : features_extractor_(cpu_features), rnn_vad_(cpu_features) {}
+  MonoVadImpl(const MonoVadImpl&) = delete;
+  MonoVadImpl& operator=(const MonoVadImpl&) = delete;
+  ~MonoVadImpl() = default;
+
+  int SampleRateHz() const override { return rnn_vad::kSampleRate24kHz; }
+  void Reset() override { rnn_vad_.Reset(); }
+  float Analyze(rtc::ArrayView<const float> frame) override {
+    RTC_DCHECK_EQ(frame.size(), rnn_vad::kFrameSize10ms24kHz);
+    std::array<float, rnn_vad::kFeatureVectorSize> feature_vector;
+    const bool is_silence = features_extractor_.CheckSilenceComputeFeatures(
+        /*samples=*/{frame.data(), rnn_vad::kFrameSize10ms24kHz},
+        feature_vector);
+    return rnn_vad_.ComputeVadProbability(feature_vector, is_silence);
+  }
+
+ private:
+  rnn_vad::FeaturesExtractor features_extractor_;
+  rnn_vad::RnnVad rnn_vad_;
+};
+
+}  // namespace
+
+VoiceActivityDetectorWrapper::VoiceActivityDetectorWrapper(
+    const AvailableCpuFeatures& cpu_features,
+    int sample_rate_hz)
+    : VoiceActivityDetectorWrapper(kVadResetPeriodMs,
+                                   cpu_features,
+                                   sample_rate_hz) {}
+
+VoiceActivityDetectorWrapper::VoiceActivityDetectorWrapper(
+    int vad_reset_period_ms,
+    const AvailableCpuFeatures& cpu_features,
+    int sample_rate_hz)
+    : VoiceActivityDetectorWrapper(vad_reset_period_ms,
+                                   std::make_unique<MonoVadImpl>(cpu_features),
+                                   sample_rate_hz) {}
+
+VoiceActivityDetectorWrapper::VoiceActivityDetectorWrapper(
+    int vad_reset_period_ms,
+    std::unique_ptr<MonoVad> vad,
+    int sample_rate_hz)
+    : vad_reset_period_frames_(
+          rtc::CheckedDivExact(vad_reset_period_ms, kFrameDurationMs)),
+      time_to_vad_reset_(vad_reset_period_frames_),
+      vad_(std::move(vad)) {
+  RTC_DCHECK(vad_);
+  RTC_DCHECK_GT(vad_reset_period_frames_, 1);
+  resampled_buffer_.resize(
+      rtc::CheckedDivExact(vad_->SampleRateHz(), kNumFramesPerSecond));
+  Initialize(sample_rate_hz);
+}
+
+VoiceActivityDetectorWrapper::~VoiceActivityDetectorWrapper() = default;
+
+void VoiceActivityDetectorWrapper::Initialize(int sample_rate_hz) {
+  RTC_DCHECK_GT(sample_rate_hz, 0);
+  frame_size_ = rtc::CheckedDivExact(sample_rate_hz, kNumFramesPerSecond);
+  int status =
+      resampler_.InitializeIfNeeded(sample_rate_hz, vad_->SampleRateHz(),
+                                    /*num_channels=*/1);
+  constexpr int kStatusOk = 0;
+  RTC_DCHECK_EQ(status, kStatusOk);
+  vad_->Reset();
+}
+
+float VoiceActivityDetectorWrapper::Analyze(AudioFrameView<const float> frame) {
+  // Periodically reset the VAD.
+  time_to_vad_reset_--;
+  if (time_to_vad_reset_ <= 0) {
+    vad_->Reset();
+    time_to_vad_reset_ = vad_reset_period_frames_;
+  }
+  // Resample the first channel of `frame`.
+  RTC_DCHECK_EQ(frame.samples_per_channel(), frame_size_);
+  resampler_.Resample(frame.channel(0).data(), frame_size_,
+                      resampled_buffer_.data(), resampled_buffer_.size());
+
+  return vad_->Analyze(resampled_buffer_);
+}
+
+}  // namespace webrtc