Green Screen Export Anomaly or Something Wrong?

Hello folks. I am exporting a segment of my cut to for green screen/tracking work that I'll do in Motion or DaVinci (if I can figure the latter out). Something strange is happening on the export whereas the clip is keyed (the green somewhat replaced) even when there's no video beneath it. I wanted to run this by you all in case it's just my ignorance/human error at play here. I could go back to the original of course, but I did some slight color adjustments on the clip already. The clip shows up solid green in my timeline as it should.

In preparation for Motion or another app, I've exported the clip as a ProRes 422, ProRes 4444, made sure the FCP X Keyer was disabled and/or not present at all, and tried putting the clip in it's own project before these exported formats. In each export is goes from solid green to keyed. See images of before export and after.

"I've exported the clip as a ProRes 422, ProRes 4444,"

I don't understand this. Are you exporting 422 or 4444?

I also don't understand the image on the right. If the green is being keyed out where is the blue background coming from?

I can't reproduce the problem exporting 4444.

Hey there Tom. That's the confusion for me as well. To your first question though - I have exported multiple types of files from my storyline including those formats and this yields the same results.

The image on the right happens even on a clean project storyline with no video beneath it. This is all very strange.

Today I tried exporting by sending to Compressor and still the same thing happened.

New development: I tried setting the Camera LUT to "None" which makes the clip look flat the clip exported just fine with no keyed look to it as in the picture above.

I don't have a clue why this is happening. I wondered if it was a Quicktime playback issue so I tried it in other apps. Same results. For some reason FCP X and Compressor will not allow me to export video that has chroma key elements that are affected by a LUT even though FCP X is applying the LUT assigned by the camera and set in the metadata. It's not a LUT i brought in and applied on my own. FCP X recognized the LUT automatically.

I've never seen this happen.

Well what do you know...I changed the LUT to Panasonic V-Log, exported a ProRes 4444 and it came out just fine. The green stayed in tact. This was just a test to see what would happen if I changed one of the built-in LUT options.

What is the source of your video, what codec?

Sony FS7 4K (3840x2160) @Rec 709, Sony S-Log3/S-Gamut3.Cine LUT recognized by and applied in FCP X.

Can you upload a 1 second (or even half-second) clip of that video as 422 or 4444 somewhere so we can download it and see if the same thing happens.

I've tried to attach the file but the forum system won't let me submit it. It's 116 MB

GoogleDrive it or something.

Here you go:

drive.google.com/file/d/16aG5Q5CdCm11dT4...kcH/view?usp=sharing

OK I dropped that footage into an existing 1080p project I happened to have open and the Sony LUT was applied automagically. I dropped the normal keyer on there and it worked perfectly, save for the edge of the guy's face there there's some motion blur. I was able to export it just fine as well. I am unable to recreate the issue.

When I exported I just exported as the timeline preset, which for me is ProRes 422 HQ.

Exporting with the keyed on is not the issue. It exports fine for me as well. The issue is having the clip with the LUT applied, no keyed, and then exporting yields the results in the image above. It should still export with the screen being solid green, but it doesn't. Not even on a clean project storyline and no media beneath it. So far the only way I can get the clip to export from FCP X with the solid green still in tact is changing the LUT or setting it to "none".

Since Apple Motion doesn't recognize the LUT automagically like FCP X. My hope was to export the portion of the clip that I'll use out of FC P X with the LUT applied, but it won't work. The green doesn't maintain. Instead it exports as if a keyer filter was on with a dark background behind (underneath) the clip when there really never was...as seen in the photo above.

Hope this is more clear.

I get the same thing.
The Sony S-Log 3/S-Gamut3.Cine (1-1-1) is applied automatically. If I export as ANYTHING ProRes (422, 4444, 4444HQ), the green is completely munged up and is mostly turned to blue, apart from a halo of green around the actor. No keyer has been applied, this is just the original shot with the green screen in the background.

I applied a different LUT (ARRI-C) and it exported perfectly.

Export it without keying it. The green is all messed up, at least on mine.

Oh OK so you're trying to bake in the LUT. OK I tried it again, just importing it, placing it on a timeline and then exporting, no changes. It exported fine. I reimported what I exported and it was fine as well.... in 1080p.

Then I tried the same thing in 4K. New timeline. Exported and I have your issue in the exported file. Seems to be a problem with 4K specifically.

I did find a workaround however. If you put a blank adjustment layer on top of it... anything that makes FCP want to render, it will export fine. If you don't have an adjustment layer, just put a title on top of everything and delete all of the text. Then export. It will be perfectly fine!

This is definitely some kind of bug that should be reported to Apple. Link them to this thread.

Interesting find that it doesn't work on the 4K project but does in the 1080p project. I'm thinking this is a definite bug.

The reason it works in a 1080p timeline is because it needs to be resized, and thus rendered during export. Anything that makes FCP want to render will negate the issue. It's very weird.