Fine black or white line showing up in splitscreens

Hey,

I encountered a problem I had some time ago again and this time my workaround isn't really working in a few cases:

We need to do splitscreens or picture in picture effects with 2 or 3 clips seemingly random on the screen. I only used size and position parameters on the edit page to get the clips to show up where I want them and they do. However, sometimes a fine white or black line appears around some of the clips.
When you click on the timeline, sometimes the lines are there, sometimes not. When playing back and exporting they almost always appear. My old workaround used to set a value of -1 to the "softness" slider in the "cropping" section. However in some cases when there is a horizontal or vertical splitscreen this doesn't help.
It seems like there is some alpha problem around the edges.

Anybody else knows of this error / knows a fix?
I'm working with braw in the newest Beta 17 on Windows but as I said, I've had this problem in the past.

Thanks for your help!

The black or white lines in these pictures are not intentional and should not be there,

1.png (22.21 KiB) Viewed 1343 times

2.png (31.01 KiB) Viewed 1343 times

3.png (114.27 KiB) Viewed 1343 times

I found this thread from 2015, is there really no fix for this in 6 years?

viewtopic.php?f=21&t=38156

viewtopic.php?f=21&t=125567

Hi Jim,

thank you for your feedback. As I stated, I had this issue before back to v15 and the guy in my linked thread had this problem in v11. So I don't think this is a new bug with the beta version and does indeed belong here.

Just a guess, but try cropping one pixel off the edge of the clip showing the line.

Just a guess, but try cropping one pixel off the edge of the clip showing the line.

It doesn't matter how many pixels I crop in the cropping panel on the edit page, the line stays. Only "softness" in that section fixes it sometimes. In a few cases it only gets worse though.
I think this is a general problem with how Resolve handles alpha mattes.