Midway 54hz games on CRT

[LordBarker]

Hi all,

Have just hooked up a Pi2SCART and it looks lovely on my CRT TV with everything running in original resolutions. With the Midway games, NBA JAM, MK etc. etc. I believe they ran about 54hz, is it possible to change this is Retroarch without having my TV go nuts? And will it make a difference? As while it isn't hugely noticeable, I can spot that it's not quite refreshing at the right rate.

Thanks

[strygo]

It depends entirely on the TV. Sony TVs won't handle these at all and the image will roll. Toshiba TVs on the other hand can handle the rate. I have a Toshiba CRT I keep around for this purpose.

[LordBarker]

interesting, thanks for the response. It's a Sony CRT 21", perhaps I'll source a cheap Toshiba and give it a shot. Thanks

[lettuce]

Wouldn't there be a pot on the Sony's neckboard that can be alter to allow more tolerance for refresh rate?

[MKL]

It depends entirely on the TV. Sony TVs won't handle these at all and the image will roll.

American Sonys... European Sonys handle that no problem. Heck I've never seen a TV that couldn't.

[BazookaBen]

My Sony Hi-scan TV could go from ~50hz up to 72hz as long as the horizontal was 33.75kHz.

For 15kHz TV's, you'll just have to experiment.

[LordBarker]

Hmmm, well I altered the refresh rate in the core to 54mhz and the TV was fine; it's a Euro Sony 21" CRT, but didn't seem to make much difference. The image isn't jerky at all. It just looks like the image has the refresh rate slightly off if that makes sense, like occasionally lines down on fast moving objects, hence it's very visible in NBA Jam.

[strygo]

Sorry - I should have qualified that I was referring to US Sony sets. Neither my SD or HD Wega sets handle the rate.

The Midway games have a refresh rate of 53.20 Hz. I wonder if you adjust it to that if that will resolve your issue.

[BazookaBen]

Yeah, if your PC's output refresh rate doesn't match your game's frame rate, you'll see stutter or tearing.

From what I understand, lots of MAME players use CRT Emudriver to solve this issue.

[paulb_nl]

If you're seeing tearing that means Vsync is off. You should be seeing only stutter if the refresh rate doesn't match. Does your Pi actually output 54Hz though?

On my pc I had to make a custom resolution for it with CRU to get my monitor to display 53.20Hz. In Mame I had to turn Match game refresh off and Sync to monitor refresh on. That way there was no stuttering.

I also ran MK on 60Hz with those settings but then it will run much too fast allthough still smooth.

[LordBarker]

That's a good point actually mate, and something so obvious I overlooked it, whether it outputs 54hz! It's not stuttering or tearing as such. The best way to describe it is if I have a Megadrive game emulated and set the region to something like Japanese PAL, when the characters move, lines sort of 'ripple' up the body. It seems to be where the PAL and NTSC number of lines don't match. It's not exactly that with NBA Jam, but something similar.

[Tatsuya79]

For MK1 I use a core override with video_refresh_rate = "54.7"
But that's on a LCD along a custom resolution with that refresh rate set in Nvidia control panel.

[paulb_nl]

Lines ripple up the body sounds exactly like Vsync off tearing to me.

It looks like you have to change hdmi_timings to output a different refresh rate. It is set with Pi2Scart by the runcommand-onstart.sh and runcommand-onend.sh scripts.

They have a tool to change hdmi_timings on their website: http://strike-devices.net/index.php/pi2 ... nter_image

[LordBarker]

Thanks mate. I can't actually get that tool to run, as it seems to need to be in the root of the Pi and I can't gain root access despite trying every way I know how. Have I misunderstood this? And if so, any ideas how I might get this working?
Cheers

[paulb_nl]

I don't know if you need root access for this tool but you might need to set the set_video.sh script to executable after transferring it to your Pi.

Code: Select all

chmod +x /folder/set_video.sh

[LordBarker]

Thanks mate. I've asked the author, to double-check like! It's no huge disaster if not, as I'm planning to build a tabletop Midway cabinet using a CRT TV or monitor separately anyhow. Slightly OT, but how does GroovyMAME and a Radeon cope with this refresh rate?
Cheers

[LordBarker]

Silly me, I forgot NBA Jam had a vertical resolution of 254! Combined with the rate switch this works well. Silly question maybe but is there anyway to scale the image now or not, since the increase in vertical resolution clips the top and bottom of the screen And don't really want to change it in the test menu on the TV each time!

[BazookaBen]

Silly me, I forgot NBA Jam had a vertical resolution of 254! Combined with the rate switch this works well. Silly question maybe but is there anyway to scale the image now or not, since the increase in vertical resolution clips the top and bottom of the screen And don't really want to change it in the test menu on the TV each time!

Oh yeah, I should have mentioned that. You have to increase vertical resolution when you decrease refresh rate so you can stay at 15kHz.

But yeah, you may have to use service menu every time. PVM's and BVM's have the ability to save a few presets, but TV's probably don't.