Are you sure about that? I'd actually looked into A52decX previously and it says nothing about it being able to split 6 channel audio into it's individual channels. Everything it says about it indicates it just converts the ac3 into an individual AIFF. No discrete elements.

The only program I've seen that's meant to perform the task you say is mac3dec (which I mention in my guide) but it no longer works under leopard or snow leopard, otherwise I'd be using it.

And yes, you can of course demux the audio and video into m2v and ac3 in MacTheRipper without ripping the entire DVD, but you'd be doing it blind without being able to preview the clip to be able to tell what part it was. It's only really useful for the main feature as it is labelled (MF).

And even then, you'd still need a program to split the ac3 into 6 unique channels, and everything I've read about A52decX indicates it doesn't. If it does, they really ought to have listed it as a feature rather than just saying "a52decX converts an AC-3 file being used for the sound of DVD-Video into an AIFF file". Have you actually tried it yourself and can confirm it's resulted in 6 individual channels? e.g. LFE (low frequence effects) should just be an occasional low rumble and nothing else.

Additionally you have to use MPEGStreamclip for the video encoding anyway, so it's not like I've added an extra unnecessary program to my steps :-p