pouët.net

What happens if I run MS-DOS and Windows demos at 50Hz refresh rate?

category: general [glöplog]
My monitor can support 50Hz, and as such I've been able to relive my old Amiga days at a proper framerate, rather than running them at 60Hz with WinUAE and having them all look shit as a result. I was convinced that the framerate doesn't matter, so I'm guessing there's no issue? Besides, as with PC gaming, it's most likely that demos could run at much, much higher framerates anyway.

So tell me, does it really matter? Will it still work and not throw off timings, etc?
added on the 2017-02-02 21:08:06 by Foebane72 Foebane72
please god don't do it kid!!! your computer could explode!!!
added on the 2017-02-02 21:26:43 by 1in10 1in10
This depends on the coders knowledge about timing.
One can do it the wrong way, movement based on framecount, then the timing will be off with a different framerate than the coder used to make the demo.
But normally every coder knows how to do it properly: use deltatime (timespan that passed since the last frame) to animate stuff!
So the answer is: in most cases the timings should work no matter how many frames your rig renders per second.
Why would you want to run DOS-demos at 50Hz? As good as all PC-demos ran at higher refresh rates (60hz for CGA/EGA and 70hz for VGA, and some custom refresh rates here and there)
added on the 2017-02-02 21:29:32 by britelite britelite
nothing else matters.
Thanks, Hardy.

I have a whole bunch of other retro platforms under emulation with a bunch of demos for each, so they'll mostly be PAL 50Hz, and I just didn't want to switch back and forth between 50Hz and 60Hz.
added on the 2017-02-02 21:32:39 by Foebane72 Foebane72
I was only enquiring, but I did see some small glitches in demos like Frameskool and Lifeforce, and since the PC has always been 60Hz, I may as well stick with that for demos on that platform. It really only takes a few seconds to change the refresh rate on Nvidia cards, anyway.

As I said, the retro computer emulators I've got work best in 50Hz.
added on the 2017-02-02 21:49:14 by Foebane72 Foebane72
Get G-sync or Freesync graphics card & monitor and forget about refresh rate switching.
added on the 2017-02-02 23:26:40 by rutra80 rutra80
As for DOS stuff, there was no one standard way to do the timing back in the day so it totally depends on what you run. Some demos hang off the vertical refresh, some use it for some effects but not others, some don't use it at all & just throw everything at the gfx card as fast as they can. You'll have to experiment and see. :)
added on the 2017-02-03 00:10:29 by jmph jmph
PC has always been 60hz? VGA would disagree.
added on the 2017-02-03 01:41:53 by reptile reptile
Quote:
PC has always been 60hz? VGA would disagree.


I didn't know about that, but the thought occurred to me that there must've been many NTSC (60Hz) Amiga demos, too.

Damn, I'm cursed with making automatic assumptions.
added on the 2017-02-03 06:21:02 by Foebane72 Foebane72
Oldschool demos (roughly "everything on hardware that has a composite video output") normally run at the frame rate they're designed for, that is 50Hz for EU and 60 for US territory. Similar with VGA era DOS demos, they're running mostly at 70Hz for x200/x400 and at 60Hz for x240/x480 modes.

But the good news: Yes, changing your system refresh rate really works with emulators. Set a 50Hz mode and European C64/Amiga demos should run butter smooth with VICE or WinUAE.

Caveat though: Though most cheap (and even some expensive) monitors "support" 50Hz, they internally run at 60 and will look jerky anyway. Funny case in point is the setup we have at Revision - Though we have a full 50Hz recording/playback chain, oldschool demos run smoothly only on a) the CRT or LCD TV connected to the computer they run und, and b) the big screen. Every PC monitor in between gets it wrong.
added on the 2017-02-03 10:12:10 by kb_ kb_
Quote:
I didn't know about that, but the thought occurred to me that there must've been many NTSC (60Hz) Amiga demos, too.

Not many, the demoscene was mostly European.
added on the 2017-02-03 10:17:05 by absence absence
There were a few DOS demos in the mid 90s that supported 50 hz.. Sea Robot of Love was one of them. Anyone remember any others?
added on the 2017-02-03 16:27:01 by phoenix phoenix
My monitor is a BenQ GL2760H, and it supports 50Hz, apparently. It certainly looks good on that refresh rate.
added on the 2017-02-03 21:14:06 by Foebane72 Foebane72
My KVM's VGAs use 60 hz. :(
added on the 2017-02-04 03:23:15 by AntDude AntDude
There was a DOS mode that ran in 50hz, wasn't there? 320x256 or something?
added on the 2017-02-04 13:37:59 by Gargaj Gargaj
Mhhmm, yeah. Those beautiful 10 fps 3d scenes and raytracing attempts look ruined with some tearing. RUINED! ;)

(to have perfectly smooth text scrollers again is kinda nice, I guess...?)
added on the 2017-02-04 14:21:20 by tomaes tomaes
What happens if you run MS-DOS and Windows demos at 50Hz refresh rate?

The Helvetica Scenario
added on the 2017-02-04 14:35:02 by xeron xeron
Quote:
Mhhmm, yeah. Those beautiful 10 fps 3d scenes and raytracing attempts look ruined with some tearing. RUINED! ;)

(to have perfectly smooth text scrollers again is kinda nice, I guess...?)

haha! :D

on the other hand, when demo avg framerate is higher than 30-40fps then tearing\frameskip become more and more visible and annoying, in this case 50hz mode IMO is not a good choice ;)
added on the 2017-02-05 07:12:37 by wbc\\bz7 wbc\\bz7
Back in 96, we had an amiga artist who worked on our new demo, and since we didn't want to scale his art, we decided to use 320x256x50hz to make it look more amiga-like :) It was one of those mode x resolutions where the addressing wasnt linear, i remember having a text file full of asm init code for a bunch of different modes. Can't recall who wrote it.. he was quite famous for it back then.
added on the 2017-02-05 19:09:18 by reptile reptile
Fashion by Logic Design is full of switches from 320x200 to 320x256 to accomodate Danny and Lowlife's Amiga pictures. Which also made it a bitch to capture.
added on the 2017-02-05 19:51:34 by okkie okkie
^ mfx's debut demo switches through 5 different resolutions. Hard to beat. :)
added on the 2017-02-05 21:10:25 by tomaes tomaes
Quote:
As I said, the retro computer emulators I've got work best in 50Hz.


What Emulators are you talking about and how did you manage to switch to 50hz in order to get smooth animation.

Thx
Doc

login