So export as ProRes.
I don't know if the conversions or transcodes are actually "re-compressing" the file. The original file was tiny to begin with. I would be fascinated to know what transcoding actually does to the file. I doubt that any actual compression, so to speak, happens. I am not an expert though, but I imagine DNxHD 175 10bit as a BIG box, into which you put a VERY SMALL file, comparatively.
For color correction, the biggest thing is going to be the fact that the file started as 8-bit. That is limiting. Putting it in a 10-bit box may help, but I don't think it will harm it. You certainly aren't going to get any MORE bit-depth or any MORE resolution no matter what you do.
My guess is that you won't get any LESS with either 1:1 or DNxHD 175. But that's a lot of mathematics in those conversions, so I don't know.
It's not exactly like "going down generations" used to be on tape. These are digits being compared and copied and transformed to other digits.
As for AMA, I think you might have done something wrong. Linking AMA transcoded files to originals for re-transcoding to other higher res files should work. You might want to track down a white paper or workflow paper if you think you're going to try this again on another project.
BTW, DaVinci Resolve can open and read DNxHD files "natively." So if they're grading on Resolve, they should be able to use DNxHD. If they're using Color, you must really LOVE that colorist... or be out of options. Avid to Resolve and back is a pretty easy thing. They can even use your actual sequence data and files. No need to grade across dissolves or anything like that (you are sending them the complete cut as a single QT file, right?). You could send an AAF file to Resolve and have it link to the actual DNxHD files (no need to recompress or anything). That way you will have the ability to get a grade back on individual shots instead of an edited piece. That way, if you had to trim or add a transition or something after the CC, you still could. This also allows you to drop in effects and graphics on top of the original Avid sequence
Steve Hullfish
contributor: www.provideocoalition.com
author: "The Art and Technique of Digital Color Correction"
On Dec 13, 2011, at 1:39 PM, mike cardeiro wrote:
> > From: Steve Hullfish <steve4lists@veralith.com>
>
> >Canon 5D files are massively compressed to begin with (I know, I own this camera). Taking it to DNxHD is a good thing.
>
> my thinking is this. Its already compressed. I transcode to dnx for the avid it is compressed again. Color correct does their thing and now they give it back to me pro res qt (their format) so its compressed again, now I have to take it back into the avid and transcode to dnx (compressed again) export to after effects, composite render out as dnx compressed again...thats like 4 passes of compression
>
> >And if you use AMA, I thought you should be able to re-AMA them without the hand-picking you described. Or didn't you use AMA to bring them in and convert them? Stick with the 175 10bit file. That contains all of the information and bit depth you're ever going to get out of 5D files, which, I'm >pretty sure are only 8bit to start with.
>
> when I opened them up in AMA they had a different timecode than the transcoded files, and I did trancode directly from the ama bin.
>
[Non-text portions of this message have been removed]
No comments:
Post a Comment