How can I decode ogg's back to wav?
Does oggenc support this function?
For Unix there's ogg123, for Windows you can use the ogg decoder plugin together with the disk writer plugin.
I thought something like LAME has (--decode).
Is it gona be implemented in oggenc in the future?
I have no idea. The encoder and decoder are seperate programs. I know ogg123 can do it on Linux just fine, but I don't know if that has a Windows version.
Maybe ask on the vorbis mailinglists?