256p and 288p vertical games on horizontal 14" CRT TV

[quartex73]

Hi all.

First: sorry for my english.

My setup is:
14" TV CRT 15Khz Philips 14pt1501 (horizontal)
Windows 7 64 bit
AMD Radeon R9 380
crt_emudriver_&_tools_2.0_beta_15_18.5.1_W.7-64

Using groovymame 0.229 and super resolutions.
Arcade_15

I Used mode 2560x240 for horizontal centering in Arcade OSD,
avoiding stretching (I only moved Hcenter from 52/65 to 45/65).

So in mame.ini I modified the default
crt_range0   15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 192, 288, 448, 576

in:
crt_range0      15625-16200, 49.50-65.00, 3.070, 4.758, 6.907, 0.064, 0.192, 1.024, 0, 0, 192, 288, 448, 576

(by the way, is correct to modify in mame.ini the pulse sync value too?)



About vertical games 256p and 288p I'm experiencing of course some cutoff and some weird zigzag effect.
See screenshots:

donkey kong 2560x256


1942 2560x256


digdug 2560x288



Looks like 256p is worse than 288p, and I'm surprised about that (and I can't understand why).
With 256p there is terrible zigzag in the bottom (look at mario in donkey kong...)
With 288p there is some zigzag in the top

Since my goal is pixel perfect and I'm ok with some cutoff I tried to fix the zigzag effect.

For 2560x256 in arcade OSD I moved both Vfront and Vback (Vfront from 2 to 1 and Vback from 16 to 1).
I did horizontal centering too.

Then I created a vertical.ini:

crt_range0      15625-16200, 49.50-65.00, 3.120, 4.992, 7.487, 0.066, 0.197, 0.066, 0, 0, 256, 256, 448, 576
crt_range1   15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 192, 255, 448, 576
crt_range2   15625-16200, 49.50-65.00, 2.000, 4.700, 8.000, 0.064, 0.192, 1.024, 0, 0, 257, 288, 448, 576

crt_range0 (with modified values from arcade OSD) for 256p
and crt_range1 and crt_range2 for all other vertical resolutions (same values as crt_range0 in mame.ini).

And this is the result I get for vertical 256p (donkey kong, 1942).





Is this the right way to fix my issue for pixel perfect?
Since I touched directly Vfront and Vback in arcadeOSD, I presume this is not anymore pixel perfect, isn't it?


Is there anything different I can do?
I presume there is no way to avoid cutoff at least for 256p mantaining pixel perfect.

Thanks in advance for your help and your tips

[makya]

If your TV is EURO you can display "pixel perfect" 288 lines, but not at 60 Hz.

At 60 Hz, you will get 240 lines, maybe 244 MAX. In your case I would display 240p with option intoverscan activated.

# CORE RENDER OPTIONS
#
intoverscan             1

[haynor666]

If You have two CRTs I recommned to get 2 CRTs setup - one for vertical games and one for horizontal games. While overscan allows to play games with 256 lines visible area in most cases is far too limited. You can't see scores, lives, bombs etc.

[Zebidee]

How exactly do you input video into your TV? Home-made SCART cable? How do you create the composite sync?

Your zigzags may be a symptom of poor sync. This is particularly an issue with "smushy sync", where the H&V wires are simply twisted together, possibly through a resistor. It leaves a lot of "junk" in the vertical sync period, which is what tells the TV when to start drawing a new frame. Now the TV has trouble locking onto the vertical sync. After a few more confused microseconds the TV works it out anyway, but that short time where it is left floating leaves you with a zigzag.

The issue with the top/bottom getting cut off is mostly to do with overscan and your TV vertical size settings. Both of these can probably be adjusted via the TV service menu, very little can be achieved via CRT_emudriver. Entering service menu usually involves performing some arcane, codified ritual with the original remote control, and is different for every manufacturer and for most model families too. Search online, I hope you have the original remote.

It is possible to get 288-line vertical games (like Galaga) to display on a horizontal TV, but you'll probably always lose at least some lines and the game will be playing at 50hz (rather than the original's 60hz). You can use the sliders built into MAME to cut a few lines out, if you need to.

You can also get 256-line and 240-line games to fill the screen, possibly with no missing lines, if you *force* them to display in a 288-line video mode. These vertical games will/can be "pixel perfect", except for the scan lines running the wrong way (you will always have scan lines running the wrong way if you display vertical games horizontally). Fortunately, with Groovymame working it's magic and automatically adjusting the game speed for you, you might not even notice the mismatched frame rates. If you squint a little then maybe you won't notice the scanlines.

Vertical games will always look better if you rotate the monitor 90 degrees, and set appropriate rotation options within MAME.