What is the best workflow for shooting greenscreen with red?
Should I pull a key from the r3d files or convert it to another format (prores..but it is only 422!),dpx or what else?
thanks
Tommaso
Re: Red greenscreen workflow by Uli Plank on May 6, 2008 at 8:49:09 am
IMHO 4:4:4 doesnt matter very much, the limitations are there from the start (Bayer pattern).
I'd consider depth more important for fine-tuning in post, and DPX is preserving all the depth you can get from your sensor, while 10 bit linear (either uncompressed or ProRes) is already throwing away some of it.
Regards,
Uli
Director of the Institute of Media Research (IMF) at Braunschweig University of Arts
Re: Red greenscreen workflow by Graeme Nattress on May 10, 2008 at 3:07:44 am
Uli, We take great care in the demosaic to ensure edges are correct. There is a resolution hit through the OLPF and demosaic, but, on the other side, that means very limited aliasing artifacts and the reconstruction of the image is to full RGB.
Bit depth is very important. If you're going out to 10bit DPX, I'd recommend either REC709 gamma or Redlog, both of which are good at preserving the 12bit sensor data precision. 10bit linear light is NOT recommended as you're loosing 2 stops precision which will show up as banding in the shadows.
Graeme
- www.nattress.com - Film Effects and Standards Conversion for FCP
Re: Red greenscreen workflow by Uli Plank on May 10, 2008 at 5:24:49 am
Looking at my images, I'm very sure you take great care of edges in them. Thanks for your excellent work!
We get great keys even from just pulling them in with Log & Transfer as ProRes using values from a firstlight from REDAlert.
As stated before: The best workflow depends on the deliverables you need. If it's for high quality film-out, go 4:4.4 DPX log. If it's for lower cost options, ProRes can look perfect.
Regards,
Uli
Director of the Institute of Media Research (IMF) at Braunschweig University of Arts
Re: Red greenscreen workflow by Russell Lasson on May 6, 2008 at 2:57:09 pm
DPX is 4:4:4 log. The Kona RBG codec had both a log and lin version. Uli is saying that 10-bit linear isn't keeping all of the data from the original sensor. That is great advice. I would also stay 4:4:4 because if you don't, you're automatically throwing away half of your color information. That's a big deal when you're trying to key out a certain color.
If I was doing a key, I would export to DPX at either 2K or 4K depending on my system and software.
Re: Red greenscreen workflow by gary adcock on May 6, 2008 at 5:44:42 pm
I am going to go back to the beginning..
what is your deliverable? this sounds as if you are new to the DPX / 4:4:4 requirement and needs.
In my experience 80% of users are fine Keying out from ProRes or 10bit UC footage rather than going the DPX route. I would not recommend the complexity of the DPX workflow for a new user without first testing on a small project, do to the shear number of files that need to be created and kept track of when you realize you are creating 86,400 files for every hour of content
did i mention that those frames in 2K are about 8MBs and at 4K they are 48 MBs EACH
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Inside look at the IoHD
Re: Red greenscreen workflow by Russell Lasson on May 6, 2008 at 6:29:33 pm
I agree with Gary. I was being ambitious to suggest DPX for a new user. Technically DPX is the best way, though depending on your system and workflow, it might not be smart to try to deal with such large files/processing.
Re: Red greenscreen workflow by tommaso cico on May 6, 2008 at 11:53:54 pm
thanks guys for the big help. I know working with dpx is not as simpe as others workflow but in autumn I will work in a post facility that owns a red camera and I want just to be prepared.
I have never pulled a key from film or red camera before with .dpx workflow. It seems hard but it gives a lot more room to work if compared to my hvx200..
Re: Red greenscreen workflow by Gunleik Groven on May 10, 2008 at 5:32:15 pm
I'll just add that for keying/compositing, I think you actually save a lot of time going the DPX route, even if you cannot play it vack in realtime. The files just behave extremely well and for the first time keing is what I thought it was supposed to be. Not so with the prores files.
Just my 2c
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