Audiogen
========
The ``audiogen`` package provides time domain audio processing tools
using Python generators.
This makes some types of audio sample generation and processing pretty
easy::
# mix 440 Hz and 445 Hz tones to get 5 Hz beating
beats = audiogen.mixer(
(audiogen.tone(440), audiogen.tone(445)),
[(constant(1), constant(1)),]
)
The actual samples won't be generated or stored in memory until they're
actually consumed – for instance, when they're being written out to disk
in a wave \file::
with open("output.wav", "wb") as f:
audiogen.sampler.write_wav(f, beats)
Generators' at-consumption-time computation also allows creating
infinitely long output, e.g. to stream to speakers rather than a file on
disk::
audiogen.sampler.write_wav(sys.stdout, audiogen.tone(440))
Or just::
audiogen.sampler.play(audiogen.tone(440))
You can also use standard generator tools, e.g. the itertools module, to
handle audio data::
beep_silence = itertools.chain(audiogen.beep(), audiogen.silence(0.5))
infinite_beeps = itertools.cycle(beep_silence)
audiogen.sampler.write_wav(sys.stdout, infinite_beeps)
Soundcard output
----------------
The easiest way to play directly to a soundcard output is to use the
``audiogen.sampler.play`` function, which will play your samples using
PyAudio::
import audiogen
import itertools
import sys
audiogen.sampler.play(
itertools.cycle(itertools.chain(audiogen.beep(), audiogen.silence(0.5)))
)
Alternatively, you could write your wave data to ``stdout``, e.g. ``myaudio.py``::
import audiogen
import itertools
import sys
audiogen.sampler.write_wav(
sys.stdout,
itertools.cycle(itertools.chain(audiogen.beep(), audiogen.silence(0.5)))
)
Then pipe to a command line audio player like Sox_::
python myaudio.py | play -t wav -
Installation
------------
Install with::
$ pip install audiogen
$ pip install --allow-external PyAudio --allow-unverified PyAudio PyAudio
PyAudio is optional. If it's not installed, playing audio via the soundcard with
``audiogen.sampler.play()`` will not be available, but generating Wave files –
including for piping to an external player, like ``sox`` – will work just fine.
Note that to install PyAudio on Mac OS X, you'll need to first install `portaudio`::
$ brew install portaudio
See also
--------
Projects built with ``audiogen``:
- `koch <https://github.com/casebeer/koch>`__, a Koch method Morse code trainer and audio generator
- `afsk <https://github.com/casebeer/afsk>`__, a ham radio APRS/Bell-202 audio frequency shift keying encoder
Contributing
------------
Get the source and report any bugs on Github:
https://github.com/casebeer/audiogen
Version history
---------------
- 0.1.2 - Add band pass and band stop IIR filters; custom beep lengths from @jhobbs
- 0.1.1 - Fix multiplexing bug causing increase in pitch when using mixer() to produce
more than one output channel
- 0.1.0 - Breaking changes: new arguments to tone(), play() blocks by default
.. _Sox: http://sox.sourceforge.net/
