AVGA or monitor issue?

[shorthair]

This posting is to cover all the bases. Maybe Andy will see this:

I have a Billabs 27" pentamode and an AVGA. When I use the following Mame resolutions in Mame: 256x240 (for 256x224 games), 352x256 (for 256x240 games - 256x240 zooms the image way up close with loss off the screen), and 336x240 (for indytemp) - my Billabs will default to 620x244. The problem is each res needs different geometry settings. Is this a monitor issue, strictly?

[RayB]

You basically have to choose a sizing that accomodates most resolution modes, OR set MAME to force all games to the same resolution.

Read this in its entirety:
http://www.mameworld.net/pc2jamma/monitors.html

[shorthair]

I remember reading some about this, at Ultimarc I think. Strangely, Soft-15khz doesn't do this with my monitor. Need more testing.

[northerngames]

have you tried the AVRES TOOL?

[shorthair]

Yes, I have. It seems that my monitor will display more than one resolution in one 'resolution'. That is, when I select a res in Mame, when the game is run the monitor OSD shows a different resolution and groups a few of the Mame res's within that one mode.

Avres makes the same Mame resolution for various games: 352x256 in Mame for games that have res's of 224x256, 240x256, and some others (all of which the monitor OSD will put in 640x224). In the case of 224x256 (say, Congo Bongo or Gyruss), I chose 352x264 in Mame, and this made the monitor do 320x250, so I can size those differently from games of 240x256. But some horizontal games, such as indiana jones or robotron also are 640x224 on the monitor, and sizing of these interferes with the sizing of 240x256 games.

[RayB]

When you talk about "sizing" are you referring to tweaking the H and V sizing with the monitor's sizing controls?

[shorthair]

Yes.

[RayB]

OK well then you have to pick a sizing that kinda fits all of the resolutions.  Unless your specific monitor has "memory" for all different resolutions...

[shorthair]

Yeah. I remember reading about this but wanted to know a little more. Below is Andy's response, adding to yours.

...that means that the parameters of the two resolutions are not sufficiently different for the monitor to recognise them as different resolutions. Various monitors distinguish between resolutions in different ways with different levels of granularity of H freq, V freq etc. Not sure this can be fixed unfortunately.