Cineform

CineForm produce a codec for HD editing. HD footage is stored in various ways - some like MPEG based HDV are actually composed of partial frames so that they are quite hard for the computer to deal with. Most programs edit the "native" footage - i.e.: if it starts as MPEG it stays as MPEG all the way through the editing process. How well they perform will depend on how good the computer is and the program concerned. However, any program that edits MPEG footage cannot manage much in terms of realtime performance. Straight cuts will play fine but add a cross dissolve, maybe some titles etc and the computer will start to struggle. In fact the only combination of software and hardware that can achieve anything like decent HD performance would be the Matrox RT.X2 & Axio cards coupled with Premiere.

This gets even worse with more highly compressed formats. AVCHD is a very nice filming format - small but good quality - but really horrible to edit.  Only Adobe Premeire Pro CS4 does a good job of actually playing AVCHD back with a modicum of decent performance, most programs normally stutter and stop playing.

To get better performance, which in the end means more responsive editing you can change the footage into something else. Grass Valley Edius does this using Grass Valley HQ format, and can achieve more in realtime than most other edit systems with HDV and AVCHD. Cineform does exactly the same thing - it converts footage from the original format into Cineform's own wavelet compression. This takes up a bit more space on the PC (2-3 times as much space as HDV native footage, up to 10 x the size of AVCHD files) but maintains the quality and is much nicer to edit.

Cineform produce a range of products that use their codec.  All of them give you the codec and ways to convert your footage, some offer higher than HD size or additional realtime plug-ins for programs like Adobe Premiere Pro.