Scale option / scandoubler fx cut off

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clarkkent
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Scale option / scandoubler fx cut off

Unread post by clarkkent »

Is there a reason why the scale option is not available in every core? With the option narrower hv-integer I have the best picture quality on my TFT display via DVI.

I‘m using native PAL and NTSC resolution on my display because it is supporting lower resolutions with 50 Hz for perfect scrolling as soft as butter.

I have to use the scandoubler fx option on them - but with this option sometimes the screen is cut off on the right side on vertical games. The 25% crt option would look the great but can’t use it when screen is cut off.

Any idea what this could be?
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Re: Scale option / scandoubler fx cut off

Unread post by FoxbatStargazer »

The HV integer scale options have to be programmed into each core, it's not a system-wide thing. Feel free to update the code if you like :p

By native you mean original system resolution, or the native resolution of your LCD display? Generally you want to use the latter if you can, then you don't have to mess with the scandoubler. vga_scaler=1 for the VGA side, and direct_video=0 for the HDMI side. vsync_adjust=2 will keep the lag extremely low. Then pick a video_mode suitable for your display.

Some displays I have used require extra vertical blanking to kick into smooth 50hz mode. For example, in the existing video modes, 0 is 720p@60, while 7 is 720p@50. So I have to set video_mode_ntsc=0, and video_mode_pal=7, even when using vsync_adjust=1 or 2. Mode 7 provides the extra vertical blanking that kicks the display into PAL mode and delivers smooth scrolling. Your display might have something similar. Bypassing the scaler with the original resolution (which I guess you are doing?) also tends to deliver the right vertical blanking but you should try to instead scale to match your display if you can.
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Re: Scale option / scandoubler fx cut off

Unread post by clarkkent »

I meant native PAL (720x576) and NTSC (720x480), my monitor (Benq BL912) is able to display that modes for 50 Hz fluid scrolling. I‘m using HDMI, VGA is here but won’t be used. So direct-video is off.

I‘m using vsync-adjust=1 because with 2 the video is not fully fluid. A little lag is no problem.

But the questing why vertical games are cut off at the right side when using scandoubler fx still remains. When it’s off picture is ok. But the scanlines are nicer here with 25% crt - with the filters the scanlines are not that nice.
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Re: Scale option / scandoubler fx cut off

Unread post by FoxbatStargazer »

I didn't realize you were using such low resolution! I think the issue is that there is a "direct to framebuffer" mode that is incapable of downscaling below native. This is used for Amiga RTG, vector monitors, and I'm guessing the rotation on arcade cores. The way vertical rotation works on the framebuffer I don't really have insight into, but I suspect that its related to the output at some point in the process being too large for your display. A game that is say 280 pixels wide for example, we double that to 540, and now that number is larger than your 480p display mode. I would bet if you can raise your output resolution that the issue would be resolved.

Scanline filters also don't seem to do anything until you are at least 3x scaling, i.e. 720p. So its another reason to try a bigger resolution instead of scandoubler.

Since I don't think you have to worry about PAL arcade games (?), you can use seperate video settings that cover all arcades (except neo-geo). Just make a section in your mister.ini headed by [arcade]. I bet if you can use a higher resolution that your monitor supports, it will not be cutting things off.
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