Basic beat detection

main.py

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+#!/usr/bin/python
+
+
+import pyaudio
+import aubio
+import numpy as np
+from time import sleep
+
+
+seconds = 10 # how long this script should run
+
+bufferSize = 512
+windowSizeMultiple = 2 # or 4 for higher accuracy, but more computational cost
+
+audioInputDeviceIndex = 7 # use 'arecord -l' to check available audio devices
+audioInputChannels = 1
+
+
+pa = pyaudio.PyAudio()
+
+info = pa.get_host_api_info_by_index(0)
+num_devices = info.get('deviceCount')
+for i in range(0, num_devices):
+    if (pa.get_device_info_by_host_api_device_index(0, i).get('maxInputChannels')) > 0:
+        print("Input Device id ", i, " - ", pa.get_device_info_by_host_api_device_index(0, i).get('name'))
+
+
+audioInputDevice = pa.get_device_info_by_index(audioInputDeviceIndex)
+audioInputSampleRate = int(audioInputDevice['defaultSampleRate'])
+
+# create the aubio tempo detection:
+hopSize = bufferSize
+winSize = hopSize * windowSizeMultiple
+tempoDetection = aubio.tempo(method='default', buf_size=winSize, hop_size=hopSize, samplerate=audioInputSampleRate)
+
+
+# this function gets called by the input stream, as soon as enough samples are collected from the audio input:
+def readAudioFrames(in_data, frame_count, time_info, status):
+
+    signal = np.frombuffer(in_data, dtype=np.float32)
+
+    beat = tempoDetection(signal)
+    if beat:
+        bpm = tempoDetection.get_bpm()
+        print("beat! (running with "+str(bpm)+" bpm)")
+
+    return (in_data, pyaudio.paContinue)
+
+
+# create and start the input stream
+
+inputStream = pa.open(format=pyaudio.paFloat32,
+                input=True,
+                channels=audioInputChannels,
+                input_device_index=audioInputDeviceIndex,
+                frames_per_buffer=bufferSize,
+                rate=audioInputSampleRate,
+                stream_callback=readAudioFrames)
+
+while True:
+    pass
+
+# because the input stream runs asynchronously, we just wait for a few seconds here before stopping the script:
+sleep(seconds)
+
+inputStream.stop_stream()
+inputStream.close()
+pa.terminate()