Reply To: 1080p scaling and scanlines without borders from integer scaling

[patrickm]

[quote=101999]
nope, it’s not being scaled. my overlays are 1080p, so if you set your retroarch video output to 1080p, no scaling takes place. i have scaled the scanlines ahead of time in gimp, but it seems to be a subtler effect, and not noticeable (to me) – see my screenshots.[/quote]

This is what I meant, though. You have scaled the overlay in gimp using linear filter. If you zoom in, you will see that this results in a blurring effect and alters the appearance of the scanlines in an irregular fashion. In addition, I think this darkens the image more.

It may not be noticeable except when vertically scrolling, when it can be very distracting. The moire effect you describe is consistent with what occurs when you use linear filter on the overlay in gimp or photoshop. You want to use “nearest” or “none” to avoid this.

The only other thing I can think of that would cause this is that your tv is not doing 1:1 pixel mapping, as in you are not in fullscreen mode but are zooming/stretching the picture somehow.

[quote]
nope, I was using 216 instead of 224, in the scenario I was talking about (this is the visible area you end up with when trying to 5x integer scale on a 224 line system). you can’t show 224 lines on a 1080p screen in a 5x integer scale (5*224=1120)[/quote]

The games were designed with overscan in mind- the safe area is 90% of the vertical area on an NTSC CRT. So if you integer scale 240 by 5x to get 1200, you lose 120 lines on a 1080p display, or exactly 10% of the vertical area. So what gets cropped corresponds exactly to the overscan area, which is perfect. You don’t want to see overscan, do you?

[quote]
Do you have a way of measuring this? None of the retroarch emulators seem to be able to display framerate for me.[/quote]

I think there’s an option to display frame rate under video settings, but I tested input lag and frame rate by just walking back and forth in Final Fantasy III. Every so often there is a skipped frame when using the dotmask shader. I’ve attempted to recreate the dotmask effect via an overlay, but the pi is doing something strange that causes bizarre artifacts when I attempt to add vertical lines that are 1px wide.

Also, regarding the note you added, it isn’t quite correct. It just varies from system to system whether overscan is cropped or not; it causes a lot of confusion and is why crop overscan is probably going away in a future version. Crop overscan behavior is very core dependent, there’s really no generalization you can make, here.