What compression do you suggest for greenscreen?

[Naim Sutherland]

Hey guys,

I have a green screen shoot tomorrow on Epic Dragon, and I'm wondering what compression ratio is recommended. I ample light, not worried about exposure.

I also have some high speed stuff to do tomorrow. I'm thinking it may be better to drop to 4k to get a better compression ratio at ~72-90fps rather than stay at 6k or 5k.

What are you thoughts and best practices?

Thanks!

 

[Lakis Amarantithis]

The lower the compression the better the quality of the footage and as a result the easier to do the separation.
But I'll not go to 4k just for that. Instead I'll light better the scene. More lights to left, right and top, maybe even back. I don't know your shot so I can't tell you more but lighting can help you a lot with quality high rates.
I assume you have some very powerful lights AND know how to use them. Usually that's the biggest problem ;-)

 

[Ted Parkes]

I agree. Shoot with the least amount of compression for the frame rate. 4K with low compression for a 1080 finish works very well.

 

[PatrickFaith]

The new GIO scope I have found really useful for this, i click on the bottom two squares (that make dark sections purple), and make sure there is no green screen area covered in purple. (I have found this more important then the compression setting, as long as the redcode is bellow 7)

 

[Florin Danilov]

I used for a project, 5K, 5:1 compression ratio... and lots of lights..

 

[Bob Gundu]

I used for a project, 5K, 5:1 compression ratio... and lots of lights..

Actually Florin, you didn't even need a green screen for these shots. Looks like a simple roto matte would suffice.

 

[Florin Danilov]

it was a more complicated project. With cranes, a lot of movement with depth paralax needed for inserting the artist in the virtual environment. But I know what are you saying...

I wanted a backup solution, if only the wooden bridge won't work well for a full 3D tracking

 

[Eryc Tramonn]

it was a more complicated project. With cranes, a lot of movement with depth paralax needed for inserting the artist in the virtual environment. But I know what are you saying...

I wanted a backup solution, if only the wooden bridge won't work well for a full 3D tracking

No offense to Bob, but I was wondering how he could ascertain what was happening within the shot. Sure, if the shot and talent were static there would be no need for green screen. But it is impossible to tell if the subject, or camera, is moving from this frame. I noticed you have tracking markers on the screen, so that indicates camera movement to me. Otherwise it wouldn't make sense to have them in the shot. Tracking markers used in conjunction with a static camera would require roto, or secondary keys -- and that's no fun.

 

[Phil Holland]

Just to chime in on the topic as everybody is on the same page.

Occasionally it's worth adding a green screen into the mix even on a simple roto setup to make it easier for workflow based on just pulling keys and also this moderately protects you from potential chaos in case you have a stray hand leaving your boundary which would add expense to a roto pipe and not necessarily a keyed pipe.

And yep. Lower REDCODE compression ratios yield nice results for keying. Especially on hair and weird fabric. Extra resolution can help too.