question for pal users (regarding palette)

[Shannon]

I was tinkering around with some code that was posted up on the A800 sourceforge cvs that now provides seperate NTSC and PAL palette support. When I implemented the code (assuming I didn't foobar something) I noticed that the PAL palette's black level seemed kinda off. See below pictures.

 

Now this guy took pictures. See links below. Now the guy said this..

Atari PAL and NTSC colors are actually a little bit different. As you might know, PAL stands for "phase alternating line" - the color phase is shifted by 180° every other line. But Atari didn't manage to build a perfect 180° phase shift into the PAL GTIA. As a result (the TV set reverses the phase shift and averages the color vectors) the color saturation is reduced - the colors look a little bit 'washed out' (especially red doesn't look too great IMHO).

But the thing is he said that the picture was taken from an S-video modded Atari.

 

His pictures look closer to NTSC than the ones produced by the new NTSC palette.

 

So my first question is, would the output from an s-video mod not have the phase shift issues that a regular RF signal to a TV would? If so would that make a PAL atari hooked up to either a monitor or an s-video mod more likely to look like an NTSC palette.

 

My second question is (for you PAL users hooked up to a TV thru RF or whatever you guys use) does the newly generated PAL palette look right?

 

Third question. With the PAL palette in the emu in MS. Pacman the cherry's are green. Is that the case on a real PAL machine?

 

Another odd thing is if I apply the default saturation of 100 and color shift of 30 that earlier versions of colours.c would apply to the PAL palette it almost appears to be exactly the same as the NTSC palette.

 

Thanks for your responses!

 

new NTSC new PAL Svideo PAL

[Rybags]

In my experience, SVideo and composite don't drastically alter the PAL colours. They tend to give a clearer signal with better edge definition and less interference.

 

Although, I've only used SVideo through my capture card.

 

With PAL machines though, there are two major differences to NTSC (assuming your colour is trimmed properly):

 

- Colour 4 is purplish where NTSC is more reddish.

- Colours 1 and 15 are identical.

 

So far as emulator palettes go, common issues I see are: they're oversaturated, and the luminence graduations are usually out.

[emkay]

In my experience, SVideo and composite don't drastically alter the PAL colours. They tend to give a clearer signal with better edge definition and less interference.

 

Although, I've only used SVideo through my capture card.

 

With PAL machines though, there are two major differences to NTSC (assuming your colour is trimmed properly):

 

- Colour 4 is purplish where NTSC is more reddish.

- Colours 1 and 15 are identical.

 

So far as emulator palettes go, common issues I see are: they're oversaturated, and the luminence graduations are usually out.

 

The colours of 1 and 15 are not "identical". Using "255" instead of "31" gives a better yellow and the dark colour is more "earth brown". On XE machines, the last colour turned more into green (crap desicion imho)

Only when using "DLI bars", the PAL signal mixes the colours so they look same coloured. With S-Video they are different.

[Heaven/TQA]

emkay, on my PAL machines poke 710,$18 and poke 712,$f8 are the same?

[Kr0tki]

What a coincidence, Shannon, as I've also started tinkering with atari800's palette code a few weeks ago. Using algorithms from this thread and values from this document about NTSC GTIA, I've put together a code which generates fairly good renditions of the NTSC and PAL palettes. Feel free to examine my changes; if it compiles for you, check out the new controls in the emulator's Display settings.

 

So my first question is, would the output from an s-video mod not have the phase shift issues that a regular RF signal to a TV would?

The chrominance signal in the s-video output is still encoded in PAL or NTSC, so I don't see any reason why the colors should change (aside from the artifact effects).

 

My second question is (for you PAL users hooked up to a TV thru RF or whatever you guys use) does the newly generated PAL palette look right?

Looks just like my 65XE, but the background should be black. It really depends on how the brightness is set on the TV.

 

Third question. With the PAL palette in the emu in MS. Pacman the cherry's are green. Is that the case on a real PAL machine?

Dunno, but the palettes are fine, so it seems the game sets wrong colors for PAL.

Have you looked at Pole Position? This game also has some code which sets colors according to the TV system, and it does so much better.

atari800_2.0.3_kr0tki.tar.gz

Edited January 8, 2008 by Kr0tki

[Shannon]

Great! I'll give them a try. I'm not exactly the best when it comes to colors. But the way the new code is I feel the PAL palette's brightness is off and just a couple colors in the NTSC. At least compared to what I see on my 5200, although I may need to mess with the tint and try it on another tv.

 

I've messed with pole position as well, apparently star league baseball does the same (changes the sky color).

[emkay]

emkay, on my PAL machines poke 710,$18 and poke 712,$f8 are the same?

 

Not really. The colours are a "circle" through the colour spectrum. The colours are only turned off for having colours 0-15 in black and white. Probably some TV sets mix the colours up.

 

Have a look at the "Jakub" palette. It is the most correct palette, because it cycles the colour correct. And there is no colour mixing during the brightness changes.

The only wrong setting here is that the palette doesn't start with black. It looks like someone always has adjusted his tv set too bright. Luckily the emulator allows "apply adjustment". So I always have the same picture inside the emulater, as it is on the real " PAL XL".

[Kr0tki]

Great! I'll give them a try. I'm not exactly the best when it comes to colors. But the way the new code is I feel the PAL palette's brightness is off and just a couple colors in the NTSC. At least compared to what I see on my 5200, although I may need to mess with the tint and try it on another tv.

 

I've messed with pole position as well, apparently star league baseball does the same (changes the sky color).

Star League Baseball, are you sure? My (cracked) copy does not do any color change. Do you have a dump of your copy?

[Shannon]

Great! I'll give them a try. I'm not exactly the best when it comes to colors. But the way the new code is I feel the PAL palette's brightness is off and just a couple colors in the NTSC. At least compared to what I see on my 5200, although I may need to mess with the tint and try it on another tv.

 

I've messed with pole position as well, apparently star league baseball does the same (changes the sky color).

Star League Baseball, are you sure? My (cracked) copy does not do any color change. Do you have a dump of your copy?

 

Really? Ah well. I was just going by what someone said over on the atari800 sourceforge mailing list. Maybe they were wrong? It's the baseball game by first star that they were talking about.

[Kr0tki]

It's by Gamestar. Yeah, I'm pretty sure it was a mistake, as I don't think such a small company would ever had Europe and its colours in mind.