DIY, Engadget: How to scale video
The
talented Engadget crew has a
fantastic tutorial showing you how to build your own HD video scaler. The pic above shows a before (clearly on the
left) and after (even more clear on the right) using the DIY setup. Descaler is the free software app that the Engadget
team uses, so you'll want to download that when you get a chance. If you've got a home theater PC with a capture card like we do, just follow the simple
steps and you'll increase video quality on your PC in a simple and painless way. Note: This pics above are from a VHS
copy of Titanic by by Mark Rejhon.

















My first two HTPC's powered my NEC VT540 projector via DScaler. Nice app and great (free) price!
Yes, DScaler is a decent app indeed. I am anxiously awaiting a more mature version of DScaler 5 but they seem to be pretty knee deep in developing a MPEG2 decoder.
I use FFDSHOW (http://www.free-codecs.com/download/FFDShow.htm) to control DScaler... works pretty well.