The idea of the Sydney audio API is to have a powerful, but easy to use cross-platform API for PCM audio capture and playback. So it would sit right on top of ALSA, pulseaudio, OSS, ... and abstract away all hardware-related complexity (e.g. having to check whether a card supports XYZ on ALSA before using it).
The API was named after the location of FOMS2007, which was held in Sydney, Australia.
- http://svn.annodex.net/libsydneyaudio/trunk This is a lightweight implementation used by Mozilla Firefox
- http://git.0pointer.de/repos/libsydney.git/ Lennart Poettering's implementation
There is talk of merging these implementations. Alternatively, they can be considered as drop-in replacements for each other depending on platform needs.