Here is how I think it would work - please correct me if I am wrong. the status file gives a list for the supported features and the current state of each. If particular hardware does not support mu-law then no state is displayed for it and the application layer can decide to emulate a mu-law table or report the problem to the user and give up.
I do think that thought needs to be given to how a combined audio and video player would be inplemented - ensuring correct lipsink at a minimum. also, might I suggest that the application level tools live in aud/xxx or audio/xxx - I think it is a shame that the image manipulation tools are not in img/xxx -Steve