Settings for a DLP projector ?

Hi BudSpencer,

Starting with Switchres v0.015, you have these two presets in GroovyMAME:

pc_31_120: a preset for 120Hz capable PC CRT monitors, at 31kHz (VGA). Designed for hardware scanlines by frequency doubling. Black frame insertion recommended.

pc_70_120: same as pc_31_120, but for monitors capable of up to 70kHz (SXGA).

If your DLP projector can safely do 720p at 120Hz, then it will support the second preset (pc_70_120). Notice you need to enable -black_frame_insertion in mame.ini explicitly, otherwise GM will just duplicate each frame.

You can use this setting with any video card, although you will be limited to the standard refresh rates (60 Hz, 120/2). Because -black_frame_insertion requires -syncrefresh enabled to work properly, this means you will be accelerating/decelerating all games that don't run at exactly 60 Hz (majority of arcade games).

That's the reason why CRT Emudriver is recommended.

Basically once you understand how the CRT timings themselves work the preset values are self-explanatory, being the only GroovyMAME specific part the last 4 values that indicate the vertical resolution limits where each crt_range applies. So for instance, the pc_70_120 preset is defined as:

      crt_range0  30000-70000, 100-130, 2.201, 0.275, 4.678, 0.063, 0.032, 0.633, 0, 0, 192, 320, 0, 0
      crt_range1  30000-70000, 50-65, 2.201, 0.275, 4.678, 0.063, 0.032, 0.633, 0, 0, 400, 1024, 0, 0

Meaning that the timing values in crt_range0 apply to resolutions of 192 to 320 progressive lines, and the ones in crt_range1 apply to 400 to 1024 progressive lines. The two ending zeroes mean we won't allow interlaced modes for those ranges.

As you see crt_range0 only allows vertical frequencies from 100 to 130 Hz. Here's where the magic happens: all incoming frequencies will be "scaled" to fit that range, so 55 Hz will become 110 Hz, 60 Hz will be 120 Hz, etc.

As for crt_range1, no frequency scaling is performed, so resolutions starting from 400p will be calculated with their native refresh.

Regarding the values in the middle, those are the ones that define the CRT timings and its geometry as a result. I'm afraid there're no intellectual shortcuts to manage those but to understand how it works, although if you just need to move the picture a bit to the right or left I can help you with that.

I thought that was implicit in my previous post. Simply, GM will be able to use any custom refresh rate that is required (e.g. R-type will be able to run at 110 Hz (55 Hz x 2) instead of 120 Hz).

No, it's not, even if the driver gets installed you the custom modes won't work.

Hi BudSpencer,

May I ask why you want to run games at 110-120 Hz with black frame insertion? The typical reason is to be able to use low resolutions (~240p) with genuine hardware scanlines.

If you want line doubling, then refresh doubling becomes redundant.

On the other hand, you can't use the "pc_31_120" preset for that, because 480p at 120 Hz is 60-70 kHz, not 31 kHz. Besides, if you define a custom preset (it's not clear to me if you're using "custom" rather than "pc_31_120" here), and allow it to use a range of 50-130 Hz, it won't double the refresh rates. You need to make the lower limit something like 100 Hz so anything below that is forced to be doubled.

Finally, VMMaker can't use the "pc_31_120" preset, check this.

Ok, now I see what you want. If you want your custom ranges to be applied, you must use "monitor custom" instead of any of the existing presets, like "pc_70_120":

monitor custom
crt_range0  30000-70000, 100-130, 2.201, 0.275, 4.678, 0.063, 0.032, 0.633, 0, 0, 400, 1024, 0, 0

Only mame.ini.

Yes, Switchres is right. Try lowering that value to 512.

ok the problem happens with Black Frame Insertion set to 1.
Set to 0, MAME will use double refresh rate (exemple metal slug 3 run at 688x512p @118.371 Hz).

But the problem is that the game is too fast now and no black frame insertion. Is it possible to fix this ?

Thanks.

Yes my projector dont support 240p (but support many different refresh rates) so I try to use GroovyMAME as a linedoubler with fake scanlines (I would need a CRT projector for hardware scanlines).
Just missing the black frames (and so I need to double the refresh rate) ;).

If I try with LCD monitor preset (mame.ini), I dont have the problem with black frame set to 1, but I just have 120Hz for all games, no more custom refresh rates (lcd range set to AUTO, if I try 100-130 switchres doesnt like).

I probably use GroovyMAME too differently that I'm supposed to, I'm just sharing my results :).