PAL Compatibility Tip for LCDs

Discussion about displays and related hardware including MiSTer filters and video settings.
FoxbatStargazer
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PAL Compatibility Tip for LCDs

Unread post by FoxbatStargazer »

This is kind of the dumbest thing I just figured out but it might be helpful to others...

If you're going to use vsync_adjust=1 or 2, and want to view some PAL content on a flat panel, try setting video_mode_ntsc and video_mode_pal. Even if you are using the same "resolution" for both modes!

Example, using a 1080p panel?
video_mode_ntsc=8 ;1920x1080@60hz
video_mode_pal=9 ;1920x1080@50hz

This bizzarely made some of my displays work better with PAL, rather than just relying on video_mode=8.
A Sony x850c 4K TV can read both modes, but scrolling is jerky on mode 8, and silky smooth on mode 9. (It is a 120hz TV so that might be related.)
An old cheap VGA/DVI 1080p flat-panel, in mode 8 the screen/scanning is misaligned and the edge of the screen appears in the middle, but in mode 9 its completely perfect with smooth scrolling.
A modern 60-hz LG 4K monitor (with freesync only over DP), in mode 8 you get jerky scrolling, in mode 9 you get a black screen.

The short of it is, letting Mister adjust the refresh rate alone won't always yield the same results as supplying different video mode lines. Give this a try if you're trying to find a display that will show your PAL content in its original refresh (or even at all...)
Insert Disk Two
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Re: PAL Compatibility Tip for LCDs

Unread post by Insert Disk Two »

I'm a bit confused. Why were you passing PAL stuff as NTSC by using option 8?
FoxbatStargazer
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Re: PAL Compatibility Tip for LCDs

Unread post by FoxbatStargazer »

That's a more philosophical question then you might think...

Remember vsync_adjust=1 or 2, the refresh rate of whatever mode you supply is ignored, it takes it from the emulated system. So if you run PAL software or core option Mister will push out 50 hz, even if you use mode 8. I thought that would be fine, and indeed it is for some displays, but for others they will not treat it correctly unless you use mode 9. Both options are sending 1920x1080 at 50 hz, and yet there is something different about the two modes that matters for some displays. So its just a PSA to try filling in the pal/ntsc mode lines (which are commented out by default) with appropriate values for 50 and 60hz when trying to get PAL running correctly under vsync_adjust, because apparently not all 50hz 1080p output is made equal.
zakk4223
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Re: PAL Compatibility Tip for LCDs

Unread post by zakk4223 »

To quote the comments in the mister.ini for the vsync_adjust option

"Adjusting is done by changing pixel clock. Not every display supports variable pixel clock. For proper adjusting and to reduce possible out of range pixel clock, use 60Hz HDMI video modes as a base even for 50hz systems."
paulbnl
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Re: PAL Compatibility Tip for LCDs

Unread post by paulbnl »

That comment was in MiSTer.ini before video_mode_pal was added. It is invalid now.

video_mode_pal was added specifically for compatibility reasons to switch to 720p50 or 1080p50 with 50Hz content because they have longer Horizontal blanking compared to their 60hz modes.
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