pyvorbis - a Python wrapper for the Ogg/Vorbis library

Ogg/Vorbis is available at http://www.xiph.org

This is the Vorbis module. You will need to download and install the
Python ogg module (available wherever you got this) before you can
build the vorbis module.

Access this module via "import ogg.vorbis" or "from ogg.vorbis import
*". You can now write Python programs to encode and decode Ogg Vorbis
files (encoding is quite a bit more involved). The module is
self-documenting, though I need to update quite a bit of it. Look at
test/ogg123.py, test/short.py, and test/enc.py for very simple
demonstrations of the module interface.

And if anyone is wondering why I have things separated into a main
module "ogg" and a submodule "ogg.vorbis", vorbis is the audio subset
of the ogg bitstream. In the future there will likely be a video part
of the ogg bistream, and nothing in the ogg modulue really has to know
about anything specific in the vorbis module.
 
To build, you need the distutils package, availible from
http://www.python.org/sigs/distutils-sig/download.html (it comes with
Python 2.0). Run config_unix.py first to generate a Setup file. Then
run "python setup.py build" to build and then as root run "python
setup.py install".  You may need to run config_unix.py with a
"--prefix" option if you installed your ogg or vorbis libraries in a
weird place.

To decode, you'll basically want to create a VorbisFile object and
read data from that.  You can then write the data to a sound
device. I've used both the pyao wrapper (also by me) and the
linuxsounddev module present in Python2.0.

To encode, you need to feed a VorbisDSPState object PCM data as one
array of floating point values ranging from -1.0 ... 1.0 per
channel. You can do this in pure Python, but it almost doubles the
time it takes to encode (less if you optimize it, I suppose).

Perhaps you are wondering how much of a performance hit you'll be
taking using the Python bindings versus straight C. Well, I've tried
to make things as fast as possible, but of course nothing's
perfect. Decoding a file, top reports about the same CPU usage for my
ogg123.py and the C implementation of ogg123. For encoding, it's about
twice as slow if you're using my test enc.py file. It can probably
stand some speedup, though.