Transcoding footage for keying.

[Tudor “ted” jelescu]

You have 4:2:0 in the original- not great for chroma, so you do not want to loose any more color info. You will not get anything more from transcoding as far as the color info goes, but it will be faster to key in AE if you use an uncompressed format. In your situation I would convert to an uncompressed format, key, composite and render to ProRes and then import for edit.

Tudor “Ted” Jelescu
Senior VFX Artist

[Albert Trevino]

That’s what I was thinking too. Converting to uncompressed would make the files almost too big for our current storage. We have about 1.3TB of footage in AVC/H.264 format. We would run out of space so quick.

Is there a reason to not use ProRes as a codec for keying footage? It would help with file size if I did in this process. Also being on a PC for the main editing wouldn’t allow us to render out as ProRes to send to Premiere.

[Tudor “ted” jelescu]

I would do the clips one at the time- transcode- key- comp – render, then delete the large transcoded file, but that’s my preference. The final format does not have to be ProRes, but whatever works with your PC Premiere workflow. I use a lot of MPEG2 for example.

Tudor “Ted” Jelescu
Senior VFX Artist

[Albert Trevino]

Thanks for your replies.

Main editing is on PC, so FCP isn’t an option nor do I have it.
The footage was taken by several different cameras and different locations, it wouldn’t be easy to set up one key setting and have it work with all the footage after cutting it up. Therefore, it would be easier to key it in advance then do the compositing/editing in premiere. So the workflow has to be AE first for keying, then Premiere Pro for editing/compositing.

Most likely going ProRes into AE then export with alpha channel for editing in Premiere.

My main questions now are now:

1) Using 5DtoRGB, does it matter on the Decoding Matrix setting? ITU-R BT.601 or ITU-R BT.709?

2) What about converting the AVC/H.264 original to AVI (Lagarith Codec)[RGB] instead of ProRes for keying?

3) What about not converting the footage and using the original AVC/H.264 footage in AE for keying?

4) What would be the best option (keeping HD space in mind) when exporting out of AE for a file with Alpha channel? I was thinking AVI Lagarith [RGBA]

[Albert Trevino]

I figured I couldn’t encode to ProRes out of AE without being on a MAC.

We actually went through all the footage in Premiere and using the ultra key plugin. It turned out ok, but some of the shots of people who have blonde hair and other odd aspects of each shot caused us to question our method. So maybe just using something more powerful with tweaks like AE for keying would work better overall.

I have read in several places that converting the footage from 8 bit 4:2:0 to 4:2:2 (or higher) using 5DtoRGB actually helps with color correction and keying in regards to color depth, etc. So this is why I am thinking of NOT using the original footage but instead converted footage.

Now coming out of AE into Premiere I could just use dynamic linking instead of exporting all the keyed footage. Just not sure about stressing out the computer to do basic editing with all that going on.

[Albert Trevino]

Hmmm…

Actually through further inspection. We only had one shoot that has 4:2:0 footage. One was shot on a RED and others on XDCAM EX 35 with all being 4:2:2.

So I am thinking revisiting all the already keyed attempts in Premiere we did and the one’s that look questionable, take those to After Effects for keying.

What a pain… but… with little budget we couldn’t get a consistent camera the whole time. We had to hire locally while the shots where at different places in different states.

Gotta work with what you got!

I am trying to keep the workflow simple and less taxing on computers and HD space.