Add Silero VAD (#313)

sherpa-onnx/csrc/voice-activity-detector.cc

@@ -0,0 +1,104 @@
+// sherpa-onnx/csrc/voice-activity-detector.cc
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/voice-activity-detector.h"
+
+#include <queue>
+#include <utility>
+
+#include "sherpa-onnx/csrc/circular-buffer.h"
+#include "sherpa-onnx/csrc/vad-model.h"
+
+namespace sherpa_onnx {
+
+class VoiceActivityDetector::Impl {
+ public:
+  explicit Impl(const VadModelConfig &config, float buffer_size_in_seconds = 60)
+      : model_(VadModel::Create(config)),
+        config_(config),
+        buffer_(buffer_size_in_seconds * config.sample_rate) {}
+
+  void AcceptWaveform(const float *samples, int32_t n) {
+    buffer_.Push(samples, n);
+
+    bool is_speech = model_->IsSpeech(samples, n);
+    if (is_speech) {
+      if (start_ == -1) {
+        // beginning of speech
+        start_ = buffer_.Tail() - 2 * model_->WindowSize() -
+                 model_->MinSpeechDurationSamples();
+      }
+    } else {
+      // non-speech
+      if (start_ != -1) {
+        // end of speech, save the speech segment
+        int32_t end = buffer_.Tail() - model_->MinSilenceDurationSamples();
+
+        std::vector<float> samples = buffer_.Get(start_, end - start_);
+        SpeechSegment segment;
+
+        segment.start = start_;
+        segment.samples = std::move(samples);
+
+        segments_.push(std::move(segment));
+
+        buffer_.Pop(end - buffer_.Head());
+      }
+
+      start_ = -1;
+    }
+  }
+
+  bool Empty() const { return segments_.empty(); }
+
+  void Pop() { segments_.pop(); }
+
+  const SpeechSegment &Front() const { return segments_.front(); }
+
+  void Reset() {
+    std::queue<SpeechSegment>().swap(segments_);
+
+    model_->Reset();
+    buffer_.Reset();
+
+    start_ = -1;
+  }
+
+  bool IsSpeechDetected() const { return start_ != -1; }
+
+ private:
+  std::queue<SpeechSegment> segments_;
+
+  std::unique_ptr<VadModel> model_;
+  VadModelConfig config_;
+  CircularBuffer buffer_;
+
+  int32_t start_ = -1;
+};
+
+VoiceActivityDetector::VoiceActivityDetector(
+    const VadModelConfig &config, float buffer_size_in_seconds /*= 60*/)
+    : impl_(std::make_unique<Impl>(config, buffer_size_in_seconds)) {}
+
+VoiceActivityDetector::~VoiceActivityDetector() = default;
+
+void VoiceActivityDetector::AcceptWaveform(const float *samples, int32_t n) {
+  impl_->AcceptWaveform(samples, n);
+}
+
+bool VoiceActivityDetector::Empty() const { return impl_->Empty(); }
+
+void VoiceActivityDetector::Pop() { impl_->Pop(); }
+
+const SpeechSegment &VoiceActivityDetector::Front() const {
+  return impl_->Front();
+}
+
+void VoiceActivityDetector::Reset() { impl_->Reset(); }
+
+bool VoiceActivityDetector::IsSpeechDetected() const {
+  return impl_->IsSpeechDetected();
+}
+
+}  // namespace sherpa_onnx