forked from auracaster/pyalsaaudio
ae5c4aad9b
it's very primitive, but it shows adequately what can happen and what to do about it minimally (that is, complain and move on).
67 lines
1.8 KiB
Python
Executable File
67 lines
1.8 KiB
Python
Executable File
#!/usr/bin/env python3
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# -*- mode: python; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-
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## recordtest.py
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##
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## This is an example of a simple sound capture script.
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##
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## The script opens an ALSA pcm device for sound capture, sets
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## various attributes of the capture, and reads in a loop,
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## writing the data to standard out.
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##
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## To test it out do the following:
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## python recordtest.py out.raw # talk to the microphone
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## aplay -r 8000 -f S16_LE -c 1 out.raw
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#!/usr/bin/env python
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from __future__ import print_function
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import sys
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import time
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import getopt
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import alsaaudio
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def usage():
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print('usage: recordtest.py [-d <device>] <file>', file=sys.stderr)
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sys.exit(2)
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if __name__ == '__main__':
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device = 'default'
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opts, args = getopt.getopt(sys.argv[1:], 'd:')
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for o, a in opts:
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if o == '-d':
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device = a
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if not args:
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usage()
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f = open(args[0], 'wb')
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# Open the device in nonblocking capture mode in mono, with a sampling rate of 44100 Hz
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# and 16 bit little endian samples
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# The period size controls the internal number of frames per period.
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# The significance of this parameter is documented in the ALSA api.
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# For our purposes, it is suficcient to know that reads from the device
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# will return this many frames. Each frame being 2 bytes long.
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# This means that the reads below will return either 320 bytes of data
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# or 0 bytes of data. The latter is possible because we are in nonblocking
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# mode.
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inp = alsaaudio.PCM(alsaaudio.PCM_CAPTURE, alsaaudio.PCM_NONBLOCK,
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channels=1, rate=44100, format=alsaaudio.PCM_FORMAT_S16_LE,
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periodsize=160, device=device)
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loops = 1000000
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while loops > 0:
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loops -= 1
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# Read data from device
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l, data = inp.read()
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if l < 0:
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print("Capture buffer overrun! Continuing nonetheless ...")
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elif l:
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f.write(data)
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time.sleep(.001)
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