[Mordion]

I assumed that the reason there is no 4.5x mode (which is just alternating 4x and 5x every line) is because it looks terrible not because it’s hard to implement. I think that implementing a 4.5x mode would be an easier task than the scanline lookup table being proposed so I took it as a given. The intention of my post is to demonstrate the value of implementing the proposed feature.

[Mordion]

The console needs to have hardware support of VRR to gain any benefit. The lag reduction of VRR comes from the fact that 3D consoles generate frames asynchronously and then wait until the start of the next frame to scan out. VRR eliminates this lag by letting them scan out as soon as the frame is done. Old consoles generate the picture as it scans out so there’s no lag there to eliminate.

[Mordion]

I’d like to show my support for independent mask lines. If we had this feature we could implement proper band-limited scanlines (via lookup). Not band-limiting them is why scanlines look bad at 4.5x scale. If you use a 9-entry table in a 4.5x mode scanlines can look good at couch distances.

Super Metroid 4.5x Scanlines

Here are the weights I use in the shader I wrote for emulators. 51.5% 79.3% 100.0% 79.3% 51.5% 62.5% 94.2% 94.2% 62.5%
The order has to be flipped if the first line is 4x and the second line is 5x.

The formula is cos((x-2)*pi/4.5)^2 * .5 + .5
The -2 is to adjust the phase so that the 100% coefficient is in the middle of the group of 5 lines not the group of 4.
The 4.5 corresponds to the ‘X’ of the image scale.
The two .5 on the end make 50% scanline intensity.
(Yes, I know that cos^2 is only an approximation of the “real” scanline formula.)

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