CRT EmuDriver 640x480@60i Mode Issues - Geometry, "Clipping" and Whites/colors

[PhantomP]

Hello,

I am having at least three issues which I have numbered 1 through 3 below:

CRT EmuDriver 1.2b "Generic 15kHz"
Windows XP
ATI Radeon X1300
Sony WEGA CRT
VGA to SCART Transcoder (Ultimate SCART Adapater) + SCART to Component Transcoder (RetroTINK RGB2COMP)

1. See the one geometry problem I am having per the Arcade OSD screenshot. Vertical "wave" on upper and lower left side and upper right side. I don't want to rely totally on the TV service menu functions. I can somewhat improve the geometry with the service menu functions PAMP (Pincushion Amp) and VBOW (Bow distortion correction vertical lines). Is there any way to address this geometry in the software (VMMaker, Arcade OSD, etc.)?

2. It is not totally clear from the Arcade OSD screenshot.. the windows desktop is being "clipped" on the bottom. See photo of windows desktop where the bottom bars are clipped (Start button, etc.)

3. White level -- when I am moving around in Arcade OSD the whites (fonts, etc.) go from being very white to less white. When I ALT-TAB between the windows desktop and mame a similar effect occurs (see series of 4 images where I am switching from folder on desktop back into mame and the colors go from cooler to warmer). I am taking these photos in burst mode while I am hitting ALT-TAB so you can see the white/color shifts

I'd be happy if someone can comment on all three or any one of the three items above.

Please help. Thank you.

[Calamity]

Hi PhantomP,

For your 1 and 3 issues, there's no software fix. Geometry is problematic on flat tubes due to their own nature. The problem with colors might be caused by your transcoding stack, specially if there's any signal amplification happening.

With regards to your issue 2, you can shift the image up by adding lines to the vertical front porch. Check if you can do it from Arcade OSD itself (keep in mind you can't modify the mode that's currently used by the desktop, either test it on a different mode or switch your desktop mode to something else before attempting a modification.

If this works, then you'll need to port that change to a custom crt_range that can be applied both to VMMaker and GM, so new modes are created that already inherit that change.

[PhantomP]

Hi Calamity,

Thanks for the quick response.

I will improve the geometry using the TV service menu. Thanks for confirming that this is the only option. I've been able to improve it quite a bit and once I get comfortable with some of the less obvious geometry functions I think I can do even better.

Regarding the white level/color issue that I illustrated I also thought it might be something with my two transcoders (like you say my transcoding stack). I can't explain it but I am happy about it, I left my system running overnight and the issue resolved itself (whites and colors are way better and they stay that way). I haven't shut everything down and disconnected the transcoder power supplies to see if it is in fact related to run time.

Now on the matter of the bottom of the screen/desktop being cut off... thank you for the advice relating to the porch values. All in ArcadeOSD making sure I switched back and forth to 640x480 being my desktop mode in between edits I first tried to add lines to the vertical front porch. This did not seem to help reveal more of what was being cut off at the bottom. By instead reducing the vertical back porch value I was able to reveal all that was being cut off at the bottom (at the expense of losing lines on the top).

I tried a whole bunch of combinations of vertical front and back porch values and couldn't find a combination that was able to reveal all of the expected image on the bottom and top of the screen at the same time. I spent probably 20 minutes trying to optimize.

I unlocked Vfreq and made a few arbitrary changes to dotclock than decided I didn't know what I was doing there. I didn't do anything with V sync pulse.  Otherwise all Arcade OSD's other vertical geometry parameters are fixed or calculated values (V active, V blanking, V total).

Other than the vertical porch values can you think of anything else that may be causing me to have to sacrifice the top, bottom or a bit of both? 

Your contributions to the scene with CRT EmuDriver and Groovymame are amazing. I've been observing for years and finally trying to get my own configuration working well.