Avid DNxHD Codec in Final Cut - YUV or RGB?

Esoteric question -- an all Avid shop digitized some HD footage to DNxHD Quicktime codec which works fine in Final Cut - but rendering out the movie and then compressing to other formats - WMV Ipod Movies etc....there's color shifting and flashes in any transition effect

I'm assuming it's a problem with YUV vs RGB but I'm not sure which DNxHD is -- can anyone lend some advice on how to avoid/fix this? - Thanks - Andy

I'm pretty sure using DNxHD in Final Cut isn't officially supported by either Apple or Avid, so truthfully, it could be anything.

I don't know what you mean by "color shifting," but that kinda doesn't sound like YUV-RGB, and the "flashes in any transition" bit definitely doesn't. Going from YUV-to-RGB usually won't cause any harm, though depending on exactly how you do it you can get gamma shifts; it's going back that causes the problem, due to the inherent ambiguity of mapping the 0-255 dynamic range of 8-bit RGB to the 64-940 dynamic range of 10-bit YUV. But that doesn't add up to "flashes in any transition," I don't think.

Here's what I'd try: You've got a DNxHD timeline in Final Cut, right? Duplicate it (for backup purposes), then hit command-0. Change your timeline compressor from DNxHD to ProRes 422. Don't change anything else. Then just render your timeline and re-export to another Quicktime. That may make your problem disappear, because when you render, Final Cut will invoke Quicktime to decompress the DNxHD material on your timeline (which, since you said FCP is handling it fine, I'm going to bet will happen without a hitch) and then convert it to ProRes 422. Once you've got a ProRes 422 Quicktime master, you can convert that to the output format of your choice, and you should be golden.

But the thing to remember is that DNxHD is not, as far as I know, officially supported in Final Cut by either Avid or Apple. So you're kind of out of luck if you're unable to find a solution to your problem. Batch-converting all your footage from DNxHD to ProRes when you bring it into Final Cut is obviously not a good solution, because it takes time and disk space, but it's the reliable solution.

Thanks Jeff -- I'm going to try it - it's a long overnight re-render -- I've been shooting XDCAM HD and then using Automatic Duck to get the timeline from FCP to AVID (all their field producers are on FCP -- but they finish in AVID - go figure)

If I deliver the output from AVID DNxHD - it comes out fine on their end - but I have to also compress for their web operation and that's where I'm having the problem (outputting the AVID DNXHD - then taking into Episode Pro (or even out of QUICKTIME into something else - WMV - IPOD VIDEO - where I'm getting the odd flashes in transitions -- one pass in Episode using the DNxHD codec gave me completely washed out video in converting it to WMV -- something odd is going on under the hood

So I'll try the ProRes Export and see how it fares - will report back

By the way -- the DNxHD edits fine in FINAL CUT - but leaves you with a timeline without a lot of options (you can't chose various speed up rendering options in the timeline pull down -- and it won't let you switch from YUV to RGB in the timeline settings --

Thanks for your advice - Andy

That did the trick - rerendering timeline in ProRes got rid of the problems - Thanks!

DNxHD and ProRes are technically quite different, but functionally equivalent. Whenever you find yourself on a Final Cut system (or needing to be on a Final Cut system) and you're in DNxHD-land, your first question should be "How can I get into ProRes-world?" And vice-versa, but even more so, since Final Cut can kinda-sorta-sometimes-a-little-bit deal with DNxHD media while Media Composer can't handle ProRes media directly at all.

Glad Avid and Final Cut are playing nice - kinda sorta sometimes (read somewhere where AVID is making it's unity servers compatible with Final Cut files -- or maybe it was just a dream......

On that topic - now I have a beautifully fixed Pro-Res File - must I convert it back to DNxHD to deliver to the Avid folks?

Reverse engineer it in the timeline or just from the finished file? Thanks for your advice. Andy

I don't think so. Somebody with more up-to-date Avid experience can say for sure, but I believe on a Windows- or Mac-based Avid system with Quicktime 7.5.5 or later, you can just import a ProRes Quicktime into Media Composer like you'd import any other Quicktime.

Well that would be nice if they weren't a PC based AVID shop -- it's always something - Thanks

Read again, buddy. On either a Windows- or Mac-based system, you can play ProRes media as long as you have a sufficiently recent version of Quicktime installed. I believe, like I said, that version is 7.5.5, but I'm not sure. I'm also not sure what versions of Quicktime the various versions of Media Composer use, so that may or may not be an option. But it's not a simple Windows-versus-Mac thing.

yep - or just install the ProRes for Windows Decoder from Apple

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Sorry my eyes bleary from too much encoding! Thanks