Personally for stuff like that i use a program from the MS DirectX SDK - "graph edit". It enables you to build customised networks of DirectShow filters that perform their own discrete little tasks.. It's kinda fun mucking about with a filter graph.
You can do some pretty neat things with it, too. I for example, use it to play DVDs using a combination of filters from windvd and powerDVD. (i find powerDVDs sound options preferable, but windvds picture looks a little sharper, and it can use the radeons hardware motion compensation (which powerDVD can't for some reason)).. I was able to use the stock directshow dvd navigator, while attaching the video decoder of windvd to the video stream, and attaching powerdvds AC3 decoder to the sound stream output of the DV navigator..
But yeah, doing conversions this way seems ok in speed terms.
The bad point is that you don't get all the nice interfaces you would get when using apps designed for specific purposes..
This message has been edited by DuSTman on May 14, 2001 at 10:33 PM