ref: 9492ec889bd77941c4d3d95327ac27b8160b19bd
parent: 8489d7b351ae6a93c633fdfc10a2ad6abd23592b
author: Paul Brossier <piem@piem.org>
date: Wed Nov 16 06:57:43 EST 2016
python/demos/demo_alsa.py: add example using alsaaudio (closes #72)
--- /dev/null
+++ b/python/demos/demo_alsa.py
@@ -1,0 +1,45 @@
+#! /usr/bin/env python
+
+import alsaaudio
+import numpy as np
+import aubio
+
+# constants
+samplerate = 44100
+win_s = 2048
+hop_s = win_s // 2
+framesize = hop_s
+
+# set up audio input
+recorder = alsaaudio.PCM(type=alsaaudio.PCM_CAPTURE)
+recorder.setperiodsize(framesize)
+recorder.setrate(samplerate)
+recorder.setformat(alsaaudio.PCM_FORMAT_FLOAT_LE)
+recorder.setchannels(1)
+
+# create aubio pitch detection (first argument is method, "default" is
+# "yinfft", can also be "yin", "mcomb", fcomb", "schmitt").
+pitcher = aubio.pitch("default", win_s, hop_s, samplerate)+# set output unit (can be 'midi', 'cent', 'Hz', ...)
+pitcher.set_unit("Hz")+# ignore frames under this level (dB)
+pitcher.set_silence(-40)
+
+print("Starting to listen, press Ctrl+C to stop")+
+# main loop
+while True:
+ try:
+ # read data from audio input
+ _, data = recorder.read()
+ # convert data to aubio float samples
+ samples = np.fromstring(data, dtype=aubio.float_type)
+ # pitch of current frame
+ freq = pitcher(samples)[0]
+ # compute energy of current block
+ energy = np.sum(samples**2)/len(samples)
+ # do something with the results
+ print("{:10.4f} {:10.4f}".format(freq,energy))+ except KeyboardInterrupt:
+ print("Ctrl+C pressed, exiting")+ break