Sunday, August 18, 2013

Arcade Original Resolutions and Scart-TV Geometry

This has been one of the hardest tasks... Achieving the real Arcade experience... Getting original Arcade resolutions on a SCART-TV.

Original Arcade Games where displayed on Arcade Monitors (off course, LOL!). Arcade CRT Monitors! CRT monitors that can do 15KHz frequencies (not 31KHz like Computer CRT Monitors).
Besides that, these monitors receive a RGB signal, giving a excellent image for these games.

These games (70's, 80's and 90's Arcade Games) were designed to be displayed on 15KHz RGB CRT Monitors, and for a certain resolution (for instance, 320x240 or 256x224).
When running MAME on a LCD computer monitor in full screen (let's say, with 1024x780 resolution), the game's image is stretched and the pixel's smoothed. The image doesn't look the real thing.

CRT technology is dead... you can't buy CRT's at a retail store. It's possible to buy used Arcade CRT monitors at eBay, or new at a few online stores (China and Taiwan). Weiya still produces CRT Arcade Monitors.

CRT Arcade Monitors are (still) expensive. Let's say you need a 13'' monitor replacement for a Pac-Man cabinet? A used monitor with more than 30 years can cost you more than 200€ on eBay.

Because of the cost, and when trying to find alternatives, Arcade hobbyists found something beautiful: CRT 4:3 TV's that have SCART work like an Arcade Monitor!
Why's that? Because (the majority of) SCART accepts a RGB Signal, like Arcade Monitors, a 15KHz signal!
CRT 4:3 TV's are are not produced or sold anymore, everyone is throwing them away! Grab a few if you want to start or maintain you BYOAC project!

This will solve the monitor part, but for connecting a PC to a SCART-TV, you'll need two more things:
- 1 VGA/DVI to SCART Cable
- Software that changes the PC signal from 31KHz to 15KHz, or a Hardware Conversor (VGA to CGA, for instance), or an Arcade VGA (Ultimarc's greatest invention)

Click Here to find very useful information and links to other resources related with connecting a PC to an Arcade Monitor or a SCART TV.

My Setup is the following:
- CPU running Windows XP SP2 64 bits;
- UMSA Adapter (check my previous post about it) + SCART Cable + VGA cable;
- ATI Radeon HD4350
- CRT Emu Driver 9.3 64 bits + VMMaker + GroovyMame64
- 4:3 28'' SCART (Beko CRT Tube, branded DPM) - one of the last sold in MediaMarkt in 2009...

After setting up everything (for more details check BYOAC forum), you'll may need to change the TV's geometry on the service menu. To access the service menu you'll need to find the secret code (usually inputed with the remote control).
In my case, to access the service code, on the remote, I press "Menu" and 9-3-0-1. Here's a picture of the "secret menu", with the 60Hz geometry highlighted.


Here's a clear picture of the 640x480 resolution on the TV through SCART (Testgrid and XP Desktop), after fine-tuning the TV's Geometry.



After installing CRT Emu Driver and running VMMaker, I got 109 15KHz modelines.
I ran GroovyMame64 to test the switchres mechanism and see if the games were presented with acceptable resolutions.

1st test: Golden Axe
- it displays with it's original resolution (320x224), horizontal size Ok, but the vertical size is too short (black vertical bars up and down).


2nd test: Bubble Bubble
- it displays with it's original resolution (256x224), horizontal overscan on the left, same size vertical bars.
3rd test: R-Type
- it displays with it's original resolution (384x256), horizontal overscan on the right, smaller vertical bars.


4th test: Indiana Jones and the Temple of Doom
- it displays with it's original resolution (336x240), almost fits the screen like 640x480. Tiny horizontal overscan on the right.


5th test: Double Dragon
- it displays with it's original resolution (256x240), size similar do R-Type, but with overscan on the right.


6th test: Mortal Kombat
- Doesn't display on it's original resolution, and the "Vertical Stop" is too high (it cuts the bottom of the game).



Just posted a few questions to Calamity (CRT Emu Driver and VMMaker developer): http://forum.arcadecontrols.com/index.php/topic,133668.0.html

It's much better than a year ago, I could live with this setup, it almost fits perfectly! Let's see if I can improve it even more, and go on with the other project (Vertical Bartop).

1 comment:

  1. I also faced difficulty while playing arcade video games because of screen resolution size. I think this was common for whole old arcade games list due to low resolution those days.

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