Libavcodec with audio

[marmistrz]

Hi
I'm trying to program in c++ with libavcodec. I'm using Linux, but the program is meant not to be only for POSIX.
Could somebody tell me how should I read AVCodecContext from an audio file?
All the tutorials are for video files and I'm using audio.
PS. If there are other differences between libavcodec with video and audio, please tell me, as probably they'll appear here later :)
Thanks in advance
marmistrz