Questions about PAL/NTSC compatibility in Amiga games

[arkpandora]

I think that CDTV can play both PAL and NTSC games.

Does it mean that a PAL CDTV can also display NTSC, or that the game has both PAL and NTSC code ?  Does your monitor/TV display the game in NTSC ?


@SamuraiCrow

Do you mean that the composite signal on a non-AGA Amiga is bound to only one standard even if the computer can display both ?

[Phantom]

@ arkpandora

I'm using my CDTV with an LCD TV. But I never heard about PAL or NTSC Amiga games however.

[arkpandora]

Maybe your TV can tell you whether the signal is PAL or NTSC.

At least I suppose there are PAL CDTV and NTSC CDTV, as more than the other Amigae (except the CD32) it was intented to be used on the home TV rather than a monitor, and I suppose that most TVs sold in the USA at that time were not PAL-compatible.

[Phantom]

At least I suppose there are PAL CDTV and NTSC CDTV

I don't think so. So why the games cover don't mention anywhere if it's PAL or NTSC?

[arkpandora]

I don't know - mystery.

Probably because no video game has ever done that, has it ?

[alenppc]

There are also lots of PAL only games which will not run on NTSC (with graphics freezing, stuttering and so on). Some games also came in two formats.

[Phantom]

@ alenppc

Can you name a few? :-?

[arkpandora]

@Phantom

As said earlier in the thread, it seems only normal for games to be programmed for either PAL or NTSC, or include both versions in the code (if this situation exists), since each standard requires different coding (at least for animation).

The question is : why does your NTSC game work well on your PAL CDTV ?

[Phantom]

The question is : why does your NTSC game work well on your PAL CDTV ?

I dunno really. I'm waiting Lemmings for CDTV from US. I will check it out when I got it and I will tell you also if this game works.

I have another question. Is these games NTSC or PAL, or maybe they are region free?

[SamuraiCrow]

arkpandora wrote:
@SamuraiCrow

Do you mean that the composite signal on a non-AGA Amiga is bound to only one standard even if the computer can display both ?

No.  I am saying that the AGA systems and A600 that came with a built-in composite signal output can only display the colorburst (or chromanence) signal for the standard that it was generated from.

For example:  I had a 1084S monitor for years and used it in both PAL and NTSC modes on my A1200 and it worked fine in either mode.

If I sent my A1200 to England and switched my power supply to 50 Hz it still would not work with the TV sets in England in color because my A1200 has an NTSC composite RF modulator built in.  If I bought a SCART adapter that uses the RGB video outputs on the A1200 then it would work on a SCART TV in PAL mode only even though my system is NTSC.  (Assuming, of course, that I double mouse-buttoned the startup to be PAL and changed the screenmode preferences file.)

If I left my A1200 in my bedroom here in the U.S. and hooked it up to a U.S. TV set it would work but only in NTSC mode.

[rkauer]

 There is not a real problem running NTSC games on PAL Amigas (the minor drawback is the game will play a bit slowly, but I call it a good feature, since you can beat the machine more easily :-D).

 The NTSC screens are 320x200, PAL is 320x256, so any NTSC will play, maybe with a black border under it. The other situation is the problem: you can't "fit" a 256 lines screen in a 200 lines resolution, so this is why PAL games don't work on NTSC machines.

[persia]

In the US those god awful tube TVs were NTSC only, but all modern TVs are capable of NTSC & PAL.  They all come out of the same factory in China, they just throw in a different tuner and plug depending on the destination.

[arkpandora]

@Phantom

"Region free" is what I meant by "include both versions in the code".  But also a game or demo may be "region free" if by itself it doesn't use any feature that is specific to only one standard, for example when the software is OS-friendly, or when it has only 200 Low Res pixel lines and no continuous sequence of sounds that is tied to animation (because then sound must be designed for only one animation speed in other words for either PAL or NTSC).  Your "Defender of the Crown" may well fall in the latter category : in that case I suppose that it should be slower than the PAL version, like Rkauer says.


@SamuraiCrow

Thanks.  If I understand, instead of "No" you might have begun by "Yes but", since in my question only the "non-AGA" was wrong - and I had to add "through RGB" at the end.


@rkauer

Thanks for confirming.

[Phantom]

@ arkpandora

Hm. I will try that to see if it's slow than PAL version (I have it on my A1200 also). But I played a little yesterday and it seemed normal to me.

[darkcoder]

hi,, as far as I can tell:

1. staring form model 8372A, Agnus chip is capable of generating both 50Hz and 60Hz timings. Hence an Amiga that has this chip, (provided that the game sets it correctly) can run PAL games at 50Hz and NTSC games at 60hz.
 The 8372A or later is present on later revision of the A500 and the A2000, all ECS and all AGA Amigas. Note that a NTSC Amiga running PAL game will generate the so-called NTSC/50 video signal from the composite output, i.e. a 50hz image with the NTSC color component. It depends on the monitor wheteher this can be displayed or not. Conversely a PAL Amiga runs a NTSC game generate PAL/60. The signal generated through RGB port is the same, though (there is no color encoding in the RGB signal).
 
On Amiga with an Agnus model earlier than 8372A:
 if you run a PAL game on a NTSC Amiga, you won't see the bottom 56 lines, and the game run faster than intended
 in the opposite situation you see a big black border at the bottom, and the game plays slower.

I don't think there are many games/animation coded in 2 versions: usually the same code was sold, giving different results on different machine.
Note, however that sound syncronization should not be an issue: this is because Amiga audio is inherently syncronized with an internal clock which is (usually, it can be changed by switches on the motherboard) the same frequency of the display (i.e. 50 or 60Hz). The drawback is that audio will sound different: on NTSC notes have an higher pitch.

edited: more exactly, the audio on NTSC will sound a bit faster (so it will finish earlier) and notes have an higher pitch. But it should stay syncronized.
The approach used (one version for both PAL NTSC) has the drawback that an anim in NTSC runs faster (thus is shorter) but on both machines it will be smooth, since there is no repetition of frames (to adjust the 50hz anim to 60 hz) or frame skip (to adjust the 60hz anim to 50hz).
On PCs, where refresh frequency may vary more from machine to other machine, anim are often coded to adjust speed by repeating/skipping frames, and this may decrease the "smoothness" of the anim.

please excuse my horrible english! :-)

[arkpandora]

Darkcoder,

Your comment is very informative and everything is clearer for me now - thank you.