Anyone know of a vorbis decoder library that can be used on Windows Phone 7?
The lack of native code interop make re-using any of the native code implementations difficult (impossible?) but if there are tricks to do that, I'm open to that as well.
There is a managed implementation for mono called csvorbis, it includes a sample which outputs a wav file this didn't need many changes to work with XNA's SoundEffect class. I did a whole track at once, this took a few seconds in the emulator so you may need to stream it using DynamicSoundEffect for better results. The mooncodecs folder has a codec for the desktop version based on csvorbis which may be worth a look aswell.