View Full Version : Greenscreen Compositing Red Footage

08 August 2011, 11:19 AM
I'm primarily a motion graphics artist but the editing facility I work at is being asked to do more and more Vfx work.

The situation I have is as follows:

A program the facility is working on has some greenscreen effects stuff in it that has been Shot on RED camera. The program output its 1080 and the greenscreen has been shot at Either 2k or 4k resolutions. The RED footage was originally conformed into the avid at 1080 and one of our Online editors has attempted to do the key and composite. However hes had some real struggles with spill etc so it has been suggested that we in Gfx now do the vfx. Weve
Successfully got the original RED media into Premiere using an .aaf from the avid with links to the original media. So I now have the 2k & 4K r3d files on my premiere timeline, which is great however Im now ready to begin the keying and am wandering what the best approach would be.

I know you can alter the source settings of the RED media and this is where my knowledge especially regarding colour spaces etc comes to an end. The red media as it comes on to my timeline is at the settings shown in the attached file. The footage is really quite bleached out and I was wandering if There was anything I can do at a source level to help overall before keying in after effects / Nuke?

Also, Ive been scouring fourms etc looking for tips and help and some suggestions Ive seen is to work on dpx File sequences as opposed to the red files. Any thoughts or advice on that? Any performance gains on working
on dpx as opposed to r3d file? If so how can anyone suggest I get the dpx sequence out and at what settings as when i've tried thus far the greenscreen file sequence looks remarkably different to r3d file?

Any help or advice on this would be greatly appreciated. Id really like to get this right with regards to the colour Space etc as its not something that we deal with often but are likely to have to do more of in the future.

09 September 2011, 10:44 PM
As someone who has had to key RED footage on numerous occasions I can concur completely on transcoding the RED footage to DPX or 10/16 bit Tiffs for keying. While RED footage is excellent quality I have found that the debayering of R3Ds cause issues in getting clean, noiseless keys. In both Keylight for AE and in Smoke, DPX or Tiffs gave me far superior results.

My general workflow was to take the select clips into REDCine-X, do a white-balance while adjusting nothing else. Then, transcode to DPX or Tiff with the Gamma set to REDgamma2 and Color Space to REDColor2, at 2k or 4k (or the HD related size) with my Debayer set to full. Once rendered, import into AE (if using Keylight), preserving the RGB, then key, composite and render out my final needed codec. If I was just keying with no composite, then just render out whatever image sequence was needed with the alpha.

Hope that helps with your work.

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09 September 2011, 10:44 PM
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