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MAME - Do you stretch your screen? for fullscreen?

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Jack Burton:
About pixel ratio:

A game has an aspect ratio and a pixel ratio.  The aspect ratio refers to the ratio of the display the game is intended to be played on.

For almost all arcade games that ratio is 4:3.

However, not all games use a resolution that has a ratio of 4:3. 

For example, the CPS1 and CPS2 use a resolution of 384x224.  This is a ratio that is slightly wider than a 4:3 ratio. 

On a real game pcb when the game is connected to a 4:3 monitor the monitor will automatically squish the image back into the 4:3 ratio.  Sometimes this required a little adjustment of the monitors horizontal and vertical size though.

In MAME when you select the pixel aspect ratio it will make it so that all the pixels of the game will be exactly the same size and shape.  They will not be squished or stretched in any way.  But when you do this the image will automatically be set to the ratio of the resolution.

So here you will have three choices. 

1. You can live with bordering.  I wouldn't do this since the pixel aspect ratio is not really the way the game was meant to be seen. 

2. You can use your monitors controls to manually stretch the image to fit the screen.  This is what I do, and is the most accurate way to play the game.  Especially if you're using the native resolution already.

3.  Select 4:3 and let MAME do the stretching.  This will introduce scaling artifacts and other undesirables sometimes, but is the easiest solution.  On a widescreen HDTVyou can choose a high resolution and it will help out a lot with the artifacts. 

You should never use the 5:4 ratio.  That ratio is the ratio of many early LCD pc monitors and there are no arcade games that use it.  If it is selectable then I am betting you have one.  You can use 4:3 and have a little letterboxing. 

ark_ader:
I use a plastic magnifier lens.

DJ_Izumi:
I have a question.

All PC monitors and new HDTVs have a Pixel Aspect Ratio of 1:1, as in the pixels are SQUARE.  All NTSC Televisions had a PAR of about 12:11, slightly rectangular.  This is why DVD and television signals are 'square' at 720x480 an not 640x480.  What was the common PAR on arcade monitors?  Did they share PAR with PCs or with TVs?

Jack Burton:
Well I think CRT's themselves don't have a set pixel aspect ratio.  They just automagically try to squish whatever you send them into full screen.  

If you send random resolutions to a Studio monitor over RGB it will try to fit them into the screen.  I bet an arcade monitor would do exactly the same thing.

Now, I think they do have some manner of default settings to the timings they accept.  So if you send a raw SNES signal to a pc monitor that accepts CGA but has been set up for VGA video then the SNES video will appear squashed vertically.  Or at least that's what happened to mine.  

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