[ezechiel1917]

Hello,
I just noticed that when using VDPAU as video decoder/mixer any other upscaling than nearest neighbour produces artifact line at the top of the playing video.
This artifact line corresponds to bottom line of the video.

Example:
https://postimg.cc/rRRDQ3XN

Its happens when playing any video with lower resolution than displays resolution, for example 720p -> 1080p, 1080p -> 1440p, 1080p -> 2160p etc.
Unfortunately at higher resolutions it is very distracting.

No artifact line when using nearest neighbour upscaling (horrible quality).
No artifact line when using software decoder.


Is there a way to fix this?


Thanks for any help

[ezechiel1917]

after closer inspection, i have found out that all 4 sides are mixed up !

bottom line appears on top,
top line appears on bottom
left side column appears on right side
right side column appears on left side

you will most likely see this when there is large difference in picture contrast on both sides, like bright picture on one side while darker picture on the other.

Interestingly I discovered this on 1080p upsacling to 2160p display where it is most obvious, but it is definitely present even with lower resolution upscales.

Is there any "cure"? 

[ezechiel1917]

Turns out that using advancedsettings.xml
<vdpauscaling>true</vdpauscaling>
fixes the issue.

This scaler is not as good as lanczos3 optimized, however setting also VDPAU Sharpness to 0.20 in video settings produces almost identical image as lanczos3 optimized upscaler alone.

I hope there won't be any issues with vdpauscaling.