Custom Overlays and Pixel Peek

Hey FCP community. I have an issue with Final Cut Pro's custom overlay feature which is a handy alternative than using a matte generator. I've been trying to use an overlay for various cropping such as 2.35:1 or 2.39:1. Every overlay I've created even wit format-specific dimensions (like 3840x2160) never goes edge to edge in the viewer window. There's always video from the storyline around the edges that peeks through which is distracting when editing. I've tried making adjustments to my overlay dimensions to be larger than the required dimensions such and nothing gets rid of this issue. Scaling the size of the viewer window doesn't help either.

Attached is a sample 4K UHD overlay (red for matching against a burned in crop) . Have any of you encountered this and found a remedy?

Also attached is a screen grab of my viewer with the custom overlay applied. My timeline is set to  3840x2160 as is the dimensions of the custom overlay.

FCP 10.6.5

I just did a quick test on my loaded 2019 iMac, and can confirm... but ONLY when the viewer is set to 'Fit'. All the specific percentages fill to the edges as expected.

EDIT: spoke a bit too soon.  12.5% also leaves a thin line at the top.

I'm not seeing any "pixel peek" at the predefined Viewer sizes. I am seeing it for non-whole number frame dimensions (e.g., 2160/(decimal percentage) ≠ whole number). 

It's likely due to non-whole-number dimensions from scaling the Viewer, in that we're dealing with pixel images and not vectors. Hence, a limitation of scaling raster images (the ovleray). I tried converting the overlay to a PDF file and that seemed to work without any "pixel peek" in my limited testing.

Thanks or checking it out. It's a nice feature to have, but very distracting if it doesn't work (scale) correctly.

This is so very odd. I was running a test and DID get the peek you got momentarily but then it went away while compiling screen shots. Came back briefly after a restart.





The technique that never fails is to place it atop the video as a mask.
 

Thanks for checking into this Dave. I tried your file and I agree that the pdf seems to work better. Shame on my if I missed that caveat in the instructions on how to use this feature correctly.  I didn't think to try PDF.  At one point I thought about trying an SVG, but likely got sidetracked with work and didn't make the attempt.

I used the red just so I could have higher contrast and better see if if there is pixel peek or not. Even still, based on your tests would you say it's still working correctly? I would think that even if the source image is a jpg or png that scaling would degrade the image, but not change the resolution (scaled) with the viewer scaling. We're essentially missing entire horizontal and/or vertical pixels along typically on one or both sides of the image.

This happens to me too. It's not consistent. As I mentioned above, using black bars may make it difficult to see so the red really helps solidify how this works or doesn't work. It's yet to be said if this is a bug or not and maybe it's trivial. Though when I'm editing I want to be confident about everything that I am seeing and using the overlays seems to be far less resource heavy than adding two cropped custom solid generators on the timeline or one generator with a mask to create the same effect.

Tangier, I also tried an SVG but FCP wouldn't import it.

With the PDF version, I don't see any pixel peek.

I doubt that it's a bug, or that Apple would consider it so but who knows (with the PNG or JPG overlays). It's most likely a scaling issue and FCP, the OS, GPU drivers, etc. gets stuck trying to deal with that partial pixel-sized border (for non-whole-number dimensions).

I do recall reading in Apple's docs (maybe it was in pre-X versions of FCP), or it was well-known at the time, that when resizing the Viewer to "non-standard"  percentage amounts performance of playback could be affected.

Besides manually adding a generator-mask, or importing the overlay as a clip and putting that over everything, how about just changing the timeline dimensions (and adjusting the clip Spatial Conform setting, as needed) so no overlay is needed?