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The Dorkside
Dec 26, 2017

Standard config for 50Hz is point-filtered in amibian 1.4 :(

3 comments

Edited: Jan 22, 2018

 

Just downloaded version 1.4 of Amibian to find out that the built in 50Hz option for LCD-screens uses point-filtering and the terrible resolution of 800x600, making all pixles wobble in motion. I know some people like pixel perfect point-filtering, but to me pixels must be either integer scaled or linear filtered in order to look good. What do I do?

 

ANSWER:

 

linear-filtering in 50Hz mode

the option scaling_kernel in the config file sets the filtering. Use 'scaling_kernel=7' for a super-soft filter that even blur out raster pattern somewhat. To me it seemed more authentic and how I remembered my Amiga 1200 AGA-graphics on a CRT-TV. :) if you don't like it experiment with other modes.

 

For a soft CRT-like image on a modern 1080p screen, use these settings:

  • hdmi_cvt=1920 1080 50 3

  • hdmi_group=2

  • hdmi_mode=87

  • hdmi_drive=2

  • scaling_kernal=7

 

Point-filtering with integer scale in 50Hz mode.

If you are going for point-filtered image (scaling_kernel=8), and are lucky enough to own a 1280x1024 screen at home (that can output 50Hz). You will be able to get a perfect 4x scale of 256p. (You must also set UAE's display setting to 640x256)

  • hdmi_cvt=1280 x 1024 50 4

  • hdmi_group=2

  • hdmi_mode=87

  • hdmi_drive=2

  • scaling_kernal=8

Gunnar
Jan 7, 2018

There is.. And if only i remembered it 😂 you can do it by editing config.txt if im not mistaken.

digtic
Jan 19, 2018

I don't find nothing setting from there. All working fine, only what I miss now is some scanline filter.

The Dorkside
Jan 22, 2018

After some more tinkering I realized why I was stuck with point-filtering. I had activated the standard 50Hz mode for flat screens. It sets the screen to 800x600@50Hz with scaling_kernel=8. Unfortunately the 800x600 doesn't scale well with Amiga resolutions. (I would recommend 1366x768 with point-filtering since it scales the height of 256px with an even 3x integer scale)

 

After learning that "scaling_kernel" handles the filtering, I tried out different scaling modes by altering this option. I have tried with 1-8 and those works without hassle (although some of the scaling modes are terrible in terms of image quality)

 

I went for 1080p with a super soft scaling technique. I guess it's not for everyone, but the good thing is that the filtering even blur out raster-patterns in graphics making the whole image look a bit more soft and authentic, even on a 1080p screen. Due to the low resolution and soft filtering, integer scaling isn't really needed.

 

These are my settings

hdmi_cvt=1920 1080 50 3

hdmi_group=2

hdmi_mode=87

hdmi_drive=2

scaling_kernal=7

 

For the first time in a very long time I can re-live and enjoy the Amiga in a proper 50Hz mode (without any hassle) connected to a modern TV. Like digtic I would love to simulate scanlines as well. don't know if that is possible?

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