[mad-dev] rio receiver replacement software

I'm currently working on an open-source re-write of the client software for the rio receiver (http://www.reza.net/rrr.html). The device is based on a linux ARM processor built by the empeg team. I've noticed the audio_empeg.c file which is probably the way I want to go, but I'm not sure what to use for documentation. I've looked at both minimad.c and madlld.c files, but I still don't have a good feel for the best way to go about implementing the code. I basically have two buffers, one with raw MP3 data, and one where I need to write the post-processed data in empeg-friendly format. Any suggestions for a good reference? Should I go the low-level or high-level route?

Thanks, Reza