Flickering and overscan

[Cisek]

Hi

Two things in mind:
1. Is there any option to make interlaced resolutions less flickery in soft15khz/crt_emudriver? Something like flicker filter? Using 640x480i for example flickers a lot. However consoles like Dremcast, PS2 or Xbox in the exact same resolution doesn't flicker at all. Is it because of some software filters, blurring, or? Maybe smoked plexi in front of the screen will reduce this flickering?
2. Is there option in groovymame to fit vertical games while playing them horizontally? I usually have overscan with them, but maybe there is some option to change their proportions so they will fit on crt, horizontally, in original game resolution?

[haynor666]

Long time ago there was program for amiga that did flicker less noticable by making visible only parity lines in all frames.
Right on PC connected to TV/arcade monitor probably the only way is use high refresh rate like 61Hz. Lowering contrast also helps a bit.

As for overscan you don't have much options. Everytime when you are switching by example from 320x240 to 320x256 bottom part of picture will go lover so setting overscan in tv service menu is the only way unless you don't care about integer stretch.

[Cisek]

The flickering lowers when image is blurred, for example when using bilinear filtering for emulators. I guess consoles like ps2 or xbox have this blur on default, because image in 640x480 is not as sharp as with soft15khz, and basically don't flicker at all.
So the ideal setup would be to have program like powerstrip to support adittional parameter for selected resolution like "focus".
I remember that when I was using s-video tvout with radeon card, there was "flicker filter" option in graphic card driver. Is it possible to write some script so it would work the same for the vga display?

[Calamity]

1. Is there any option to make interlaced resolutions less flickery in soft15khz/crt_emudriver? Something like flicker filter? Using 640x480i for example flickers a lot. However consoles like Dremcast, PS2 or Xbox in the exact same resolution doesn't flicker at all. Is it because of some software filters, blurring, or? Maybe smoked plexi in front of the screen will reduce this flickering?

GroovyMAME enables bilinear filtering when using interlaced modes because of this. The Windows desktop flickers so badly because it's full of 1-line sharp horizontal patterns. Interlaced video was designed for TV signals.

2. Is there option in groovymame to fit vertical games while playing them horizontally? I usually have overscan with them, but maybe there is some option to change their proportions so they will fit on crt, horizontally, in original game resolution?

What you do is to lower the "progressive lines max" value in a custom crt_range line. By default, it is set to 288 progressive lines, to make make possible for users to adjust v-size and enjoy the full progressive resolution. You can lower that value to 256. Also lower the "interlaced lines max" to be the double of the other figure (e.g. 512). An interlaced mode will be picked if the full progressive resolution can't be achieved. If you want to force a progressive mode, disable the "interlace" option in mame.ini.

[haynor666]

GroovyMAME enables bilinear filtering when using interlaced modes because of this. The Windows desktop flickers so badly because it's full of 1-line sharp horizontal patterns. Interlaced video was designed for TV signals.

I could swear I didn't see any filtering on games like Disc of Tron or Domino using their native resolutions though these games are probably switched to ddraw due 30 Hz modes. But on segas24/model1 and resolutions 992x480 I didn't see any filtering as well. Is it really enabled by default?

[Calamity]

I could swear I didn't see any filtering on games like Disc of Tron or Domino using their native resolutions though these games are probably switched to ddraw due 30 Hz modes. But on segas24/model1 and resolutions 992x480 I didn't see any filtering as well. Is it really enabled by default?

Yes it is:

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set_option_osd(machine, WINOPTION_FILTER, ((best_mode->result.weight & R_RES_STRETCH || best_mode->interlace) && !strcmp(options.video(), "d3d")));
... but only for D3D. For DDraw hwstretch does the same, but only applies if any actual stretching is going on:

Code: [Select]

set_option_osd(machine, WINOPTION_HWSTRETCH, (best_mode->result.weight & R_RES_STRETCH && !strcmp(options.video(), "ddraw")));
So you're right, in W7 because interlaced modes are forced through DirectDraw, filtering will only be set if fractional scaling concurs.