Add Swift example for generating subtitles (#318)

sherpa-onnx/c-api/c-api.cc

@@ -9,9 +9,11 @@
 #include <utility>
 #include <vector>
 
+#include "sherpa-onnx/csrc/circular-buffer.h"
 #include "sherpa-onnx/csrc/display.h"
 #include "sherpa-onnx/csrc/offline-recognizer.h"
 #include "sherpa-onnx/csrc/online-recognizer.h"
+#include "sherpa-onnx/csrc/voice-activity-detector.h"
 
 struct SherpaOnnxOnlineRecognizer {
   std::unique_ptr<sherpa_onnx::OnlineRecognizer> impl;
@@ -127,7 +129,7 @@ void DecodeMultipleOnlineStreams(SherpaOnnxOnlineRecognizer *recognizer,
   recognizer->impl->DecodeStreams(ss.data(), n);
 }
 
-SherpaOnnxOnlineRecognizerResult *GetOnlineStreamResult(
+const SherpaOnnxOnlineRecognizerResult *GetOnlineStreamResult(
     SherpaOnnxOnlineRecognizer *recognizer, SherpaOnnxOnlineStream *stream) {
   sherpa_onnx::OnlineRecognizerResult result =
       recognizer->impl->GetResult(stream->impl.get());
@@ -340,7 +342,7 @@ void DecodeMultipleOfflineStreams(SherpaOnnxOfflineRecognizer *recognizer,
   recognizer->impl->DecodeStreams(ss.data(), n);
 }
 
-SherpaOnnxOfflineRecognizerResult *GetOfflineStreamResult(
+const SherpaOnnxOfflineRecognizerResult *GetOfflineStreamResult(
     SherpaOnnxOfflineStream *stream) {
   const sherpa_onnx::OfflineRecognitionResult &result =
       stream->impl->GetResult();
@@ -372,3 +374,128 @@ void DestroyOfflineRecognizerResult(
   delete[] r->timestamps;
   delete r;
 }
+
+// ============================================================
+// For VAD
+// ============================================================
+//
+struct SherpaOnnxCircularBuffer {
+  std::unique_ptr<sherpa_onnx::CircularBuffer> impl;
+};
+
+SherpaOnnxCircularBuffer *SherpaOnnxCreateCircularBuffer(int32_t capacity) {
+  SherpaOnnxCircularBuffer *buffer = new SherpaOnnxCircularBuffer;
+  buffer->impl = std::make_unique<sherpa_onnx::CircularBuffer>(capacity);
+  return buffer;
+}
+
+void SherpaOnnxDestroyCircularBuffer(SherpaOnnxCircularBuffer *buffer) {
+  delete buffer;
+}
+
+void SherpaOnnxCircularBufferPush(SherpaOnnxCircularBuffer *buffer,
+                                  const float *p, int32_t n) {
+  buffer->impl->Push(p, n);
+}
+
+const float *SherpaOnnxCircularBufferGet(SherpaOnnxCircularBuffer *buffer,
+                                         int32_t start_index, int32_t n) {
+  std::vector<float> v = buffer->impl->Get(start_index, n);
+
+  float *p = new float[n];
+  std::copy(v.begin(), v.end(), p);
+  return p;
+}
+
+void SherpaOnnxCircularBufferFree(const float *p) { delete[] p; }
+
+void SherpaOnnxCircularBufferPop(SherpaOnnxCircularBuffer *buffer, int32_t n) {
+  buffer->impl->Pop(n);
+}
+
+int32_t SherpaOnnxCircularBufferSize(SherpaOnnxCircularBuffer *buffer) {
+  return buffer->impl->Size();
+}
+
+void SherpaOnnxCircularBufferReset(SherpaOnnxCircularBuffer *buffer) {
+  buffer->impl->Reset();
+}
+
+struct SherpaOnnxVoiceActivityDetector {
+  std::unique_ptr<sherpa_onnx::VoiceActivityDetector> impl;
+};
+
+SherpaOnnxVoiceActivityDetector *SherpaOnnxCreateVoiceActivityDetector(
+    const SherpaOnnxVadModelConfig *config, float buffer_size_in_seconds) {
+  sherpa_onnx::VadModelConfig vad_config;
+
+  vad_config.silero_vad.model = SHERPA_ONNX_OR(config->silero_vad.model, "");
+  vad_config.silero_vad.threshold =
+      SHERPA_ONNX_OR(config->silero_vad.threshold, 0.5);
+
+  vad_config.silero_vad.min_silence_duration =
+      SHERPA_ONNX_OR(config->silero_vad.min_silence_duration, 0.5);
+
+  vad_config.silero_vad.min_speech_duration =
+      SHERPA_ONNX_OR(config->silero_vad.min_speech_duration, 0.25);
+
+  vad_config.silero_vad.window_size =
+      SHERPA_ONNX_OR(config->silero_vad.window_size, 512);
+
+  vad_config.sample_rate = SHERPA_ONNX_OR(config->sample_rate, 16000);
+  vad_config.num_threads = SHERPA_ONNX_OR(config->num_threads, 1);
+  vad_config.provider = SHERPA_ONNX_OR(config->provider, "cpu");
+  vad_config.debug = SHERPA_ONNX_OR(config->debug, false);
+
+  if (vad_config.debug) {
+    fprintf(stderr, "%s\n", vad_config.ToString().c_str());
+  }
+
+  SherpaOnnxVoiceActivityDetector *p = new SherpaOnnxVoiceActivityDetector;
+  p->impl = std::make_unique<sherpa_onnx::VoiceActivityDetector>(
+      vad_config, buffer_size_in_seconds);
+
+  return p;
+}
+
+void SherpaOnnxDestroyVoiceActivityDetector(
+    SherpaOnnxVoiceActivityDetector *p) {
+  delete p;
+}
+
+void SherpaOnnxVoiceActivityDetectorAcceptWaveform(
+    SherpaOnnxVoiceActivityDetector *p, const float *samples, int32_t n) {
+  p->impl->AcceptWaveform(samples, n);
+}
+
+int32_t SherpaOnnxVoiceActivityDetectorEmpty(
+    SherpaOnnxVoiceActivityDetector *p) {
+  return p->impl->Empty();
+}
+
+SHERPA_ONNX_API void SherpaOnnxVoiceActivityDetectorPop(
+    SherpaOnnxVoiceActivityDetector *p) {
+  p->impl->Pop();
+}
+
+SHERPA_ONNX_API const SherpaOnnxSpeechSegment *
+SherpaOnnxVoiceActivityDetectorFront(SherpaOnnxVoiceActivityDetector *p) {
+  const sherpa_onnx::SpeechSegment &segment = p->impl->Front();
+
+  SherpaOnnxSpeechSegment *ans = new SherpaOnnxSpeechSegment;
+  ans->start = segment.start;
+  ans->samples = new float[segment.samples.size()];
+  std::copy(segment.samples.begin(), segment.samples.end(), ans->samples);
+  ans->n = segment.samples.size();
+
+  return ans;
+}
+
+void SherpaOnnxDestroySpeechSegment(const SherpaOnnxSpeechSegment *p) {
+  delete[] p->samples;
+  delete p;
+}
+
+void SherpaOnnxVoiceActivityDetectorReset(SherpaOnnxVoiceActivityDetector *p) {
+  p->impl->Reset();
+}