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QuantumII
February 2nd, 2009, 05:46 AM
Hi all,

I am wondering, is there a difference between games on the C64(c) considering PAL and NTSC video standards ?

Is the video mode hardcoded into each game or is it decided by the C64 ? Also, are there other issues? I've read something about timing differences between PAL and NTSC machines.

I have a PAL one btw..

carlsson
February 2nd, 2009, 07:05 AM
Yes, a couple of games come in different versions for PAL and NTSC. The newer game, the less likely it is to run on both. It is possible to detect in software which video mode the computer runs in, and possibly some games will adjust themselves to this.

There is no lock out, bad colours or such stuff, just that some games tied hard to the raster line may fall out of sync, not having enough time to complete a screen full. While the NTSC C64 is slightly faster, it also has fewer raster lines per screen which means less graphics stuff in the borders and other effects timed to it.

Some of the earliest examples of US games that required partial rewrites (thus getting delayed) to be launched in Europe were Epyx' "Pitstop II" and "Break Dance" from 1984. I can understand Pitstop II, but frankly I don't see what Break Dance does that would break (!) timing on PAL computers.

In modern times, many of the demos are either PAL or NTSC. Some of the popular ones have been converted, but again it may be a tedious task since demos heavily rely on exact timing and using every possible clock cycle from the hardware. More than once an effect may have to be completely re-implemented or omitted when a program has been adapted to the other video system.

QuantumII
February 2nd, 2009, 08:50 AM
Ok, no major hassles in other words.

If I get a few D64 images off the 'net and write them to a C64 floppy I should be fine, sans some issues I might encounter if there are PAL and NTSC differences if I understood you correctly ?

BG101
February 2nd, 2009, 02:26 PM
Now, this is something I hadn't thought of. I have a couple of emulators and neither will run software I've written, which relies on raster interrupts (and precise timing) to give a "widescreen" effect (outer border top and bottom, inner border for the remaining border area). The program just crashes and returns to the startup screen.

Maybe the emulators are working in NTSC mode?


BG

Trixter
February 2nd, 2009, 04:46 PM
Or maybe you haven't tried the right emulator...

vwestlife
February 2nd, 2009, 07:33 PM
The timing is slightly different. An NTSC C64 runs at 1.02 MHz with a 60 Hz video refresh rate, while a PAL C64 runs at 0.985 MHz with a 50 Hz video refresh rate. Thus "PAL" programs will run slightly faster on NTSC machines and "NTSC" programs will run slightly slower on PAL machines.

I'm not sure if the C64 hardware supports this, but using a program of the opposite specification might also cause your C64's video display to switch to the corresponding video refresh rate. I know when I run a PAL program on my NTSC Atari 520ST, the video output switches to 50 Hz refresh rate, which displays fine on most NTSC monitors with a manual V-Hold control, but usually cannot be displayed on most modern TV sets with automatic picture adjustment, since the 50 Hz refresh rate (vs. 60) is too far out-of-range for them to deal with.

Fallo
February 2nd, 2009, 07:45 PM
Ok, no major hassles in other words.

If I get a few D64 images off the 'net and write them to a C64 floppy I should be fine, sans some issues I might encounter if there are PAL and NTSC differences if I understood you correctly ?

It goes without saying that you should always test the game in an emulator before writing it to a real disk, because you never know if it's fixed for a different video standard than your machine uses.

It's mainly raster interrupts that are affected by NTSC/PAL, but music will also sound slightly different.

QuantumII
February 3rd, 2009, 01:13 AM
It goes without saying that you should always test the game in an emulator before writing it to a real disk, because you never know if it's fixed for a different video standard than your machine uses.


How can I tell by running it in an emulator ?

carlsson
February 3rd, 2009, 07:28 AM
At least VICE has a setting "Options -> Video standard" to let you choose between PAL-G, NTSC-M and Old NTSC-M.

QuantumII
February 3rd, 2009, 01:31 PM
Thanks.

What about this? Mssiah SID Cartridge ? http://www.8bitventures.com/mssiah/

carlsson
February 3rd, 2009, 01:49 PM
I've never looked into the MSSIAH, but I have friends who are overjoyed by it. I suppose you need to be dedicated to use a C64 in a sound studio or live performances to get the full value of it. Casual gamers and programmers probably would have more use of e.g. MMC Replay or similar cartridges, if you're looking for a newly produced hardware item to burn some cash on.

QuantumII
February 4th, 2009, 02:40 AM
I've never looked into the MSSIAH, but I have friends who are overjoyed by it. I suppose you need to be dedicated to use a C64 in a sound studio or live performances to get the full value of it. Casual gamers and programmers probably would have more use of e.g. MMC Replay or similar cartridges, if you're looking for a newly produced hardware item to burn some cash on.

My "sound studio" and the living room with the C64 is the same room, therefore I will get full use of it :-) MMC Replay is also planned for the future.