Software Support > GroovyMAME
Cropped CRT image in some modes
DrChek:
--- Quote from: Zebidee on September 22, 2022, 06:59:21 pm ---CRT TVs are not actually fixed at 240p. Maybe if set for NTSC only, but honestly have never seen that in a TV made later than early 80's. You'll likely be alright with anything up to 288 vertical lines. if the TV shows it, then you are good.
"Overscan" is a common issue with CRT TVs adapted for arcade use. Some Tvs allow adjustment via service menu.
Failing that, try deleting the 2560x256 and setting up a 2560x264 or 2560x272 super resolution. This will force GM to display the game in the higher res, while giving you extra lines into the overscan areas, so you don't lose game details. I know, is not perfect res frequency matching, but Groovymame will take up any slack and ensure your game runs at the right speed.
--- End quote ---
So I can create a 2560x264 mode and force its use, but all those extra lines of resolution are drawn outside of the active area and all you get are the same 240 lines. 2560x272 starts to induce vertical rolling.
It seems that this TV is actually (currently) locked at 240p, so the only working modes are the 240p and 480i ones. The TV is from the early 2000's so I have to believe there is a way to "unlock" it, I just don't know how. I know there are a ton of adjustments in the Service Menu, but the service manual (attached) is skimpy on details. As it stands the normal VPOS and VSIZE adjustments just move and stretch those 420 lines around...
Zebidee:
What monitor presets (monitor.ini) are you using when running VMMaker?
DrChek:
--- Quote from: Zebidee on September 22, 2022, 09:08:46 pm ---What monitor presets (monitor.ini) are you using when running VMMaker?
--- End quote ---
I've used the NTSC TV one, which just gives 240p/480i modes, which all work, and the GENERIC 15k one which give the 256p, etc.. modes, but they all have the issue where the extra lines are cut off.
Zebidee:
--- Quote from: Zebidee on September 22, 2022, 06:59:21 pm ---CRT TVs are not actually fixed at 240p. Maybe if set for NTSC only, but honestly have never seen that in a TV made later than early 80's.
--- End quote ---
I may need to backtrack slightly from this comment - it might be that some TVs sold in the US market were setup as NTSC only. Outside of the US TVs seem to mostly support both PAL and NTSC.
I had a look through your service mode pdf - did not see anything specific about NTSC/PAL settings, so not sure.
From what you described, it sounds like you have blanking lines set in the service mode. You could try playing with the *BLK settings (page 18, HBLK, LBLK, RBLK, VBLK), which may have some effect on this. Also HBLS on page 22.
On page 23 there are various H & V "FREERUN" settings, like HFUP (H FREERUN FREQUENCY UP), HFFR (FORCE FREERUN), BFRE (FORCE V FREERUN), and VF50 (FORCE V FREERUN 50hz) which might free your sync up. There are also various other V & H sync settings worth looking at.
You will have to have a look and experiment.
Regarding monitor presets - sometimes I find it works better if I use multiple sets of CRT_range values, such as:
--- Quote ---monitor "ChinaTV1", "China TV - 50/60 Hz", "4:3"
crt_range0 15625.00-15734.26, 49.50-55.00, 1.500, 4.700, 5.800, 0.191, 0.191, 1.056, 0, 0, 192, 288, 448, 576
crt_range1 15625.00-15734.26, 55.01-62.00, 1.500, 4.700, 4.700, 0.191, 0.191, 1.056, 0, 0, 192, 248, 448, 480
--- End quote ---
With this setup, CRTEMU will generate video modes based on "crt_range1" for modes up to 248 lines. If a mode needs more lines, then it uses "crt_range0". This will allow you to tweak the settings for "NTSC" vs "PAL" modes separately.
The bolded numbers are the maximum vertical lines each crt_range allows (progressive/interlaced).
The italic numbers I may tweak for a given TV, because they often they have problems with middle frequencies e.g. 52 to 58hz). This allows me to keep the modes close to 50hz and 60hz, while rejecting modes the TV has problems with.
You could also play around with the front/back porch settings for both horizontal and sync.
Hope this helps.
DrChek:
--- Quote from: Zebidee on September 23, 2022, 12:13:50 am ---From what you described, it sounds like you have blanking lines set in the service mode. You could try playing with the *BLK settings (page 18, HBLK, LBLK, RBLK, VBLK), which may have some effect on this. Also HBLS on page 22.
On page 23 there are various H & V "FREERUN" settings, like HFUP (H FREERUN FREQUENCY UP), HFFR (FORCE FREERUN), BFRE (FORCE V FREERUN), and VF50 (FORCE V FREERUN 50hz) which might free your sync up. There are also various other V & H sync settings worth looking at.
You will have to have a look and experiment.
--- End quote ---
It certainly seems like there is some sort of enforced "window" that is only allowing 240 visible lines, and even if I set up a mode for more, those extra lines are never visible. I've been through all those adjustments a couple of times and I couldn't find any that allow the extra lines to become visible, but maybe I just haven't hit upon the right combination yet. I do know that any mode less than ~55.5Hz is a no go on this CRT.
Well, at least all of my horizontal games look great now! The GreenAntz definitely helped out tremendously with that. I'm probably gonna live with having to stretch my vertical games to 480 (which is what I was doing with all my games before the new setup). Not the end of the world. Maybe one day someone else who figured this out with these CRTs will come along with the secret.
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