Maybe you should look at
ffmpeg. It supports capture from firewire device (DV). It is small and power pack. Really fast encoding.
A comparison of performance in Mac Os X; it is probably more then 1000 times faster then Final Cut Pro HD Compressor. It is very fast on Slackware-Current (Athlon XP-1800) as well.
Very easy to compile (./configure, make, make install -- you may want to look at ./configure --help first.). I advice you to get the CVS version from the link given above. Read the manual, it is fairly easy to use. Not sure whether you need extra library to get it working with firewire. Did not try that yet. No DV Camera to play with.