DNG Lossless VFX Workflow?

[EvanZazula]

Hi,

I'm wondering about a lossless workflow for editing, VFX (Keying, 3D, Compositing), and color grading.

My current workflow is this:

1. Import CDNG sequences into Resolve
2. Export 244 proxies
3. Edit proxies in Premiere
4. Export EDL
5. Conform original DNG sequences to the EDL
6. Grade
7. Send to AE for vfx
8. Export

The problem with this workflow arises when I want to do any keying, motion tracking, retiming, 3d work, ect... I can't really do some of these things on final graded footage. How, and where should I do my VFX?
I would like to avoid using ACR (Adobe Camera Raw) and stick to using one debayer, Resolve's.

What do studios do?

Any help is appreciated!
Thanks!

[SteveScout]

Well .. studios (big ones) would go with a workflow that involves linear EXR´s and/or a log DPX output .. but that´s a little bit too much for the beginning.

Try it like this:

1. Create proxies in resolve in case you don´t want to use ACR in After Effects for the same task.
2. Edit Proxies in Premiere.
3. Replace VFX shots with AFX comps in the timeline to create your VFX. Replace the footage in AFX with the DNG sequences (this is where you did the color correction first, but it should not be done before.
In case you can´t work on the colors as they are .. use LUTs on GUIDE Adjustment Layers that don´t render out.

3. Export finished film and EDL from Premiere (in case you´re using resolve and not Speedgrade which does not need an EDL).
4. Grade the film, export as uncompressed file sequence and ..
5. Compress the sequence to your end format with Media Encoder.

cheers,
Steffen

[EvanZazula]

I never thought about replacing the ae comp footage, good idea. The only problem I see is that when Import the DNG into ae, It uses ACR to debayer it. This is a problem because I grade on the log footage (BMD Film decoding) and ACR doesn't have this to my knowledge.

[SteveScout]

Well, easy .. then you just output the vfx shots from Resolve as log 10bit DPX files, so you have the same basis as for color correction. And on top of the Premiere timeline you can add a adjustment layer with a LUT to see "proper images" when editing.

If it´s too much of a hassle outputting shots then think about CINELOG (http://magiclantern.fm/forum/index.php?topic=10151.175;topicseen)  - I am mixing BMDlog and Cinelog in my current project and with the right color correction/LUTs it matches perfectly.

Steffen

[EvanZazula]

That should work, Thanks! One more thing though. If I'm compositing stock footage thats not log, how should I deal with that? Should I apply a Rec.709 to log Lut to it, then adjust it to match my footage?

Thanks!

[SteveScout]

With the Cineon Converter you can go "backwards" as well, from rec709 to log (there´s the linear to log preset for it), so you can mix your footage (apply LUTs or the cineon converter effect), comp it and output it back to log in the end. Don´t know how BMD film log behaves (normally I´m using Alexa LOG C material), but you can create your own preset for it by putting the same shots side by side and using the cineon filter forward (log to linear) and immediately backwards (back to log) after another and then tweak the values until it loos very similar to the unaltered file. Will be hard to match it exactly, but you can get close.

[EvanZazula]

So the comp should look like this?
709->log lut
Composites
Log->709
Base log Dpx sequence

The only problem with using 2 opposite luts on the base footage is that they are lossy. So if the log to 709 lut clips the blacks a bit, the 709 to log lut won't be able to recover them.

Thanks

[SteveScout]

Err .. no .. the other way around. You want to comp in rec709 color space and convert back to log in the end. So your log footage that needs to be mixed with other material needs to come from log->709 and then in the end the finals go 709->-log.
If the values are set right (no clamping) and if you´re working in 32bit there should be no visual loss to your footage.

[EvanZazula]

I wrote it top down, like how it shows up in after effects, so the final result is log. I was using luts but those were lossy, even in 32 bit floating point, so i tried the cineon converter and after tweaking some of the settings I got it to work without clipping! Thanks!