pick specific game resolution

[stiegi]

Hello!

I have got a small problem with games at the resolution of 240p such as Centipede. When I run the game in groovymame 0.149 with a standard Philips Tv groovymame switches to 256x240 at 60hz which is fine but some of the lines on the left side of the screen (the tv is mounted vertically) are not displayed correctly. I adjusted the 256x240p modeline in arcade osd and achieved a correct picture but this is only possible if the vertical refresh rate is at about 59,5 Hz. Everything about this value means that some of the lines are not displayed correctly. With the value of 59,5 Hz the picture is ok but you get a little scrolling issue from time to time.

My idea is to display the game at 256x224p 60Hz and then adjust the left and right black borders with the potis on the tv chassis. In order to achieve this I wrote a 256x224p modeline into the ini file of centipede but groovymame will not take this and switch to 256x240p again.

Does anyone know how and if it is possible to force groovymame (0.149) to pick up a certain modeline/resolution for a specific game? The other thing is does it display the whole screen of centipede or does the programm cut off some lines?

regards,

[M_W]

Is your monitor an NTSC television? What are you using to connect it?

[stiegi]

Hello!

It is a standard European crt tv set made in Italy. On the tube itself it says PAL.

Looks like only a crt TV with NTSC standard can display a resolution of 256x240 lines correctly.

Can someone confirm this statement or does someone use a European (PAL) Tv which can display

240p without any picture issues? I would assume that an original Centipede arcade machine which

uses an arcade monitor is NTSC (American standard) by default.

The Tv is connected to the vga output of an ati radeon x600 via UMSA Scart adapter.

Any ideas are welcome

regards,

[R-Typer]

Hey, only older (I mean really old) tvs bought in europe dont display NTSC. Anything new from early 90s will display NTSC and 240p signal.

Sony TV is a sure bet. They are amazing CRTs.

All emulators display 240p correctly: groovymame, nes, snes, genesis, psx etc.


Although I live in Europe and I can use PAL roms, I do not. I prefer to play my games in NTSC because there is less flickering on TV since NTSC is being displayed in 60hz.