I have a white 960x480px background where I move clips on via camera.
These clips have ugly edges. Partially even higher contrast values can't solve it. The f_vignette filter does something (in contrast to a statement given in an earlier forum post), but not useful for this need.
Do you have an idea how to deal with that?
In general a vignette function could solve that but this function is kind weird. It doesn't handle the edges as it should be the inner core are and what is really aweful the white background (to black) though the white background is at another armed !! video track.
You can see the clip here at my site -> https://radszene.de/equipment/bikes/rose-backroad-gravelbikes_2026/
Suggestion from Andrew-R: May be rendering at much higher resolution will solve it, at expense of speed drop?? (I think ugly edges are due to aliasing?)
You probably have the idea for that.
I see that already in the editor so I propably should have upscale before start the editing.
I'm going to try to blur out the alpha channel to feather the edges.
BTW: I checked the clips in avidemux and I don't see them.
unsharp and zoom-unsharp do help.
Unfortunately the advanced unsharp (blur) with selective color channels doesn't because is affects the edge extending it when the alpha-channel only has been chosen.
The unsharp is some kind of mix sharpener/unsharpener. Usind low values helps to reduce the needed contrast.
Very high effort but it enhances the final result. And finally this is what it is most important.
For future jobs I 'm going to upscale while converting from mp4 to DNX to avoid alpha aliasing problems during edit and finally render with lower resolutions - or render full res and downscale later. Need to see how things behave.
@cincity Is the resolution between the background image and the foreground high?
You could try using a higher resolution background...
The resolution is native.
The foreground imported clips always are 480x480
960x480 is a plain white background image
Timeline is set to 960x480
It is low-res but IMHO It should play out. I'm using RGBA-8 Bit (no changes with RGBA-FLOAT) to display images with letters and alpha.
In the past we had PAL or NTSC with similar resolutions. So it should play out but it doesn't.
I think it's a bad behaviour of the alpha channel dealing with edges. A kind if aliasing but not in classic understanding like with high contrasts. Here white on white but Cin creates something inbetween, creating dark colors at (sub-pixel?) video clip edges.
For dark clips it would be perfect, but white/white combos are bad with dark edges of course.
Maybe hacking around with upscaling?!
Workflow wise this doesn't make any sense to me. Upscaling the native stuff because the editor otherwise creates glitches. Then again downscaling to the desired resolution.
But would even that help?
BTW: the last version has improved but the issue is still visible. I just don't have time to optimize that. Needs to wait a while 🙁
