Will ArcadeVGA be able to output 57.550644Hz refresh rate?

[Dave_K.]

According to the ultimarc website, the Arcadevga "contains 28 built-in 15Khz video graphics modes tailored specially for emulation." of which "All 240-line modes have an exact 60Hz vertical refresh rate for best performance in scrolling games."   Does this mean games which do not natively output 60hz will not emulate perfectly?

Maybe this is a holy grail type question, but I'm looking for perfect video emulation of certain games in mame, one of which uses the above refresh rate.

I've currently got a Radeon 7500 and have tried using AdvanceMame and Powerstrip to drive a real standard res arcade monitor, and can never get the refresh to match exactly what mame is outputting, as I end up with very slight tearing.  (before anyone responds back with Mame options for tripple buffer or what not, this is not what I'm after, I'm looking for a card with the exact pixel clock modes to be able to output specific refresh rates).

Before I shell out money to try the ArcadeVGA card, can anyone tell me if what I'm after is a pipedream, or is this card up to the task?  BTW: the above refresh rate is for the game Do Don Pachi.

[wpcmame]

First: The AVGA doesn't have a built in 57.550644Hz mode. You need to use advancemame or powerstrip to create such a resolution.

Second: You are trying to do the impossible, i.e. have mame run on one clock (on the PC) and the monitor on another (on the graphics card). These clocks will never be completly in sync.

What you should do is to tell mame to use the graphics card clock ("-matchrefresh" option) and you will not get any tearing.

(The game speed will depend on the refreshrate you use, but with 57Hz it will be only 1% off)

[alank2]

The option you want is -syncrefresh, not -matchrefresh.  I use -syncrefresh for all games between 58.5 and 61.5 fps on my setup.

Here is the deal:  You will have the refresh rate issue with arcadevga or regular vga.  What I would use to decide between arcadevga or regular vga is this - do you want to run a standard resolution arcade monitor or a multisync PC monitor.

I've not seen arcadevga with an actual arcade monitor, but I have heard those who have it like it.  I had a WG U3100 VGA monitor (arcade resolution, vga interface) and I found the resolution too low for my tastes.  My frontend font was blurry and vector games did not look very clear.  I ended up switching to a 21" PC Monitor and have been happy with the trade.

Windows MAME currently has a couple bugs related to -syncrefresh, so if you want to use it let me know and I'll post my fixes to the source code.  To use them you will need to know how to compile MAME.

Good Luck!

SA Dev

[rugby1]

What you should do is to tell mame to use the graphics card clock ("-matchrefresh" option) and you will not get any tearing.

I'm relatively new to emulation software.

[elvis]

I'm relatively new to emulation software.  I have heard about what you stated above about "tearing" but am not exactly sure what it is or is not?  Can you give me a quick, in a nutshell explanation of what tearing is ?  Thanks

Tearing occurs when the input signal to the monitor does not match the monitor refresh.   What happens is half way through a drawing refresh of the monitor, the input signal changes.  The end result is the top half of the screen plays one frame, and the bottom half the next.  If the game has a lot of sprites or backgrounds that move quickly, the result to the naked eye is like if you were to get a photo, tear it in half, and glue it back together slightly off.  Hence the "tearing" analogy.

Ways to fix tearing are either to used matched syncs, have a bigger buffer between the game and output (eg: use triple buffering instead of double buffering) or turn on v-sync.  All of them require slowing the game down ever so slightly, which results in non-perfect emulation.  But as mentioned above, this is often only a few percent out, and all but the most hard core of purists would quite probably not even notice.