Add VAD examples using ALSA for recording (#739)

python-api-examples/vad-microphone.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+
+import argparse
+import os
+import sys
+from pathlib import Path
+
+try:
+    import sounddevice as sd
+except ImportError:
+    print("Please install sounddevice first. You can use")
+    print()
+    print("  pip install sounddevice")
+    print()
+    print("to install it")
+    sys.exit(-1)
+
+import sherpa_onnx
+
+
+def get_args():
+    parser = argparse.ArgumentParser(
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter
+    )
+
+    parser.add_argument(
+        "--silero-vad-model",
+        type=str,
+        required=True,
+        help="Path to silero_vad.onnx",
+    )
+
+    return parser.parse_args()
+
+
+def main():
+    args = get_args()
+    if not Path(args.silero_vad_model).is_file():
+        raise RuntimeError(
+            f"{args.silero_vad_model} does not exist. Please download it from "
+            "https://github.com/snakers4/silero-vad/blob/master/files/silero_vad.onnx"
+        )
+
+    mic_sample_rate = 16000
+    if "SHERPA_ONNX_MIC_SAMPLE_RATE" in os.environ:
+        mic_sample_rate = int(os.environ.get("SHERPA_ONNX_MIC_SAMPLE_RATE"))
+        print(f"Change microphone sample rate to {mic_sample_rate}")
+
+    sample_rate = 16000
+    samples_per_read = int(0.1 * sample_rate)  # 0.1 second = 100 ms
+
+    config = sherpa_onnx.VadModelConfig()
+    config.silero_vad.model = args.silero_vad_model
+    config.sample_rate = sample_rate
+
+    vad = sherpa_onnx.VoiceActivityDetector(config, buffer_size_in_seconds=30)
+
+    # python3 -m sounddevice
+    # can also be used to list all devices
+
+    devices = sd.query_devices()
+    if len(devices) == 0:
+        print("No microphone devices found")
+        print(
+            "If you are using Linux and you are sure there is a microphone "
+            "on your system, please use "
+            "./vad-alsa.py"
+        )
+        sys.exit(0)
+
+    print(devices)
+
+    if "SHERPA_ONNX_MIC_DEVICE" in os.environ:
+        input_device_idx = int(os.environ.get("SHERPA_ONNX_MIC_DEVICE"))
+        sd.default.device[0] = input_device_idx
+        print(f'Use selected device: {devices[input_device_idx]["name"]}')
+    else:
+        input_device_idx = sd.default.device[0]
+        print(f'Use default device: {devices[input_device_idx]["name"]}')
+
+    print("Started! Please speak. Press Ctrl C to exit")
+
+    printed = False
+    k = 0
+    try:
+        with sd.InputStream(
+            channels=1, dtype="float32", samplerate=mic_sample_rate
+        ) as s:
+            while True:
+                samples, _ = s.read(samples_per_read)  # a blocking read
+                samples = samples.reshape(-1)
+
+                if mic_sample_rate != sample_rate:
+                    import librosa
+
+                    samples = librosa.resample(
+                        samples, orig_sr=mic_sample_rate, target_sr=sample_rate
+                    )
+
+                vad.accept_waveform(samples)
+
+                if vad.is_speech_detected() and not printed:
+                    print("Detected speech")
+                    printed = True
+
+                if not vad.is_speech_detected():
+                    printed = False
+
+                while not vad.empty():
+                    samples = vad.front.samples
+                    duration = len(samples) / sample_rate
+                    filename = f"seg-{k}-{duration:.3f}-seconds.wav"
+                    k += 1
+                    sherpa_onnx.write_wave(filename, samples, sample_rate)
+                    print(f"Duration: {duration:.3f} seconds")
+                    print(f"Saved to {filename}")
+                    print("----------")
+
+                    vad.pop()
+    except KeyboardInterrupt:
+        print("\nCaught Ctrl + C. Exit")
+
+
+if __name__ == "__main__":
+    main()