Add CXX API for VAD (#2077)

sherpa-onnx/csrc/sherpa-onnx-vad.cc

@@ -0,0 +1,110 @@
+// sherpa-onnx/csrc/sherpa-onnx-vad.cc
+//
+// Copyright (c)  2025  Xiaomi Corporation
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <algorithm>
+#include <iomanip>
+
+#include "sherpa-onnx/csrc/voice-activity-detector.h"
+#include "sherpa-onnx/csrc/wave-reader.h"
+#include "sherpa-onnx/csrc/wave-writer.h"
+
+int32_t main(int32_t argc, char *argv[]) {
+  const char *kUsageMessage = R"usage(
+This program shows how to use VAD in sherpa-onnx
+to remove silences from a file.
+
+  ./bin/sherpa-onnx-vad \
+    --silero-vad-model=/path/to/silero_vad.onnx \
+    /path/to/input.wav
+    /path/to/output.wav
+
+Please download silero_vad.onnx from
+https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/silero_vad.onnx
+
+For instance, use
+wget https://github.com/snakers4/silero-vad/raw/master/src/silero_vad/data/silero_vad.onnx
+
+input.wav should be 16kHz.
+)usage";
+
+  sherpa_onnx::ParseOptions po(kUsageMessage);
+  sherpa_onnx::VadModelConfig config;
+
+  config.Register(&po);
+  po.Read(argc, argv);
+  if (po.NumArgs() != 2) {
+    fprintf(
+        stderr,
+        "Please provide only 2 argument2: the input wav and the output wav\n");
+    po.PrintUsage();
+    exit(EXIT_FAILURE);
+  }
+
+  fprintf(stderr, "%s\n", config.ToString().c_str());
+
+  if (!config.Validate()) {
+    fprintf(stderr, "Errors in config!\n");
+    return -1;
+  }
+
+  std::string wav_filename = po.GetArg(1);
+  int32_t sampling_rate = -1;
+
+  bool is_ok = false;
+  std::vector<float> samples =
+      sherpa_onnx::ReadWave(wav_filename, &sampling_rate, &is_ok);
+
+  if (!is_ok) {
+    fprintf(stderr, "Failed to read '%s'\n", wav_filename.c_str());
+    return -1;
+  }
+
+  if (sampling_rate != 16000) {
+    fprintf(stderr, "Support only 16000Hz. Given: %d\n", sampling_rate);
+    return -1;
+  }
+
+  auto vad = std::make_unique<sherpa_onnx::VoiceActivityDetector>(config);
+
+  int32_t window_size = config.silero_vad.window_size;
+
+  int32_t i = 0;
+  bool is_eof = false;
+
+  std::vector<float> samples_without_silence;
+
+  while (!is_eof) {
+    if (i + window_size < samples.size()) {
+      vad->AcceptWaveform(samples.data() + i, window_size);
+      i += window_size;
+    } else {
+      vad->Flush();
+      is_eof = true;
+    }
+
+    while (!vad->Empty()) {
+      const auto &segment = vad->Front();
+      float start_time = segment.start / static_cast<float>(sampling_rate);
+      float end_time = start_time + segment.samples.size() /
+                                        static_cast<float>(sampling_rate);
+
+      fprintf(stderr, "%.3f -- %.3f\n", start_time, end_time);
+      samples_without_silence.insert(samples_without_silence.end(),
+                                     segment.samples.begin(),
+                                     segment.samples.end());
+      vad->Pop();
+    }
+  }
+
+  sherpa_onnx::WriteWave(po.GetArg(2), sampling_rate,
+                         samples_without_silence.data(),
+                         samples_without_silence.size());
+
+  fprintf(stderr, "Saved to %s\n", po.GetArg(2).c_str());
+
+  return 0;
+}