http://www.videohelp.com/software/Grass-Valley-HQX-Codec
Grass Valley HQX, as an intermediate codec, is specifically designed for editing and post-production: Can withstand re-encoding without significant quality loss. Is built for high speed and low-CPU usage. Allows accurate inter-frame cuts (not grouped around keyframes). Has well-defined chroma characteristics. It is available for both Windows and Macintosh platforms, handles many different video resolutions up to and including 8K (DCI), incorporates an alpha channel for graphics handling, and is available in 8-bit and 10-bit versions.
Used the videohelp.com url because if you go to the Grass Valley site they want sign in.
There are a few free codecs designed for intermediate files, e.g. UT Video is one, & Avid offers another. You would not use one of these if/when you were simply converting or re-encoding a video file. You would use one when/if you need to work on a video in more than one app, if you need to work on a file in stages etc. In those situations you do not want to use a format intended for final distribution or streaming because you'll lose too much data just encoding to that format.
A common example where you might use something like this is when you're resizing the video frame, e.g. going from an HD frame size like 1080p to something smaller your tablet can better handle, but want maximum quality & want to do the re-size as fast as possible. And/Or maybe the video is in an oddball format that your other software will not handle [or handle well].
In those cases you might use AviSynth & VirtualDub -- AviSynth will let you import almost anything, while both can manage the re-size faster & with better quality than most anything else [including NLEs costing many hundreds of dollars]. The problems with that approach however are that it does not support many output formats, & editing in VirtualDub is limited because it is not an Non Linear Editor, but a Linear one. Rendering your video in VirtualDub to a quality intermediate format, then opening or importing that intermediate video into your editor or encoder of choice, makes for a good solution.
Depending on your PC's/laptop's horsepower, using AviSynth + VirtualDub + your favorite video editor for re-sizing video may even be faster than using your editor or encoder alone -- the lower the amount of horsepower, the more AviSynth's & VirtualDub's efficiency can matter.
