If I may pop in, the knowledgeable Dfactor is correct, you cannot use 'every' codec that is installed in your system (and some are Decoder-only, as well, which cannot be used for Recording).
In the case of Avid's DNxHD, the little bit that I have read about it, it seems to 'prefer' MXF and MOV wrappers and may have problems with AVI (but I have not Tested it myself)... It also is slightly restrictive in the resolutions you can record in (they must be Standard/Broadcast resolutions, such as 1280x720 or 1920x1080 - and something like 1366x768 may not work). Here is a link to Avid's White Paper on the Codec, if you want more detailed information on it specifically:http://www.avid.com/static/resources/US ... /DNxHD.pdf
Whatever you decide, good luck with it