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Yurkie

Visual differences between PAL and NTSC

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I would like to know from those experienced collector of 7800 carts and CIBs if there is a way to differentiate a PAL from an NTSC cartridge or box.

 

Secondarily is there a difference with the manuals?

 

Thanks in andvance for sharing your knowledge.

 

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The NTSC 7800 requires native carts to be "signed" in order to prevent unauthorised games from being made for the system. The BIOS checks that the cart has a valid signature before starting it. It takes some time to validate the signature so thats the reason why you see the multicoloured Atari splash screen at power on. The signing method used could not be exported to other countries back in the day so PAL systems don't have it. Consequently legacy PAL games will often not pass the signature check on an NTSC machine so they won't actually play. PAL carts can also have a small black square letter "P". But that can be removed or be lost over time.

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^ what the Bee said. Essentially the box, manual and cartridge labels are the same in both PAL and NTSC lands, so the only true fire way of determining what format a game is, is to plug it into a 7800 and see what happens.

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As you may know, the PAL 7800 boots in Black&White for about the duration of the Atari logo on a NTSC system before showing colors.

Could this be related to what you say above ? Some kind of check of the cartridge to determine if it's a NTSC or PAL one ? (NTSC 7800 carts are mostly OK on PAL systems as far as I know)

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As you may know, the PAL 7800 boots in Black&White for about the duration of the Atari logo on a NTSC system before showing colors.

 

No it doesn't. It starts the cart in full colour in the blink of an eye at power on.

 

Could this be related to what you say above ? Some kind of check of the cartridge to determine if it's a NTSC or PAL one ? (NTSC 7800 carts are mostly OK on PAL systems as far as I know)

 

PAL systems do not check if a cart is NTSC or PAL. NTSC carts on PAL will nearly always play slower, play tunes slower, have the wrong colours and maybe junk at the bottom of the screen due to a short Display List List (DLL). They might also crash randomly while playing or even hang. However some homebrews adjust themselves automatically to the TV region.

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I only have NTSC and PAL machines so I've never seen that behaviour on either type of machine. I suspect its more likely something to do with extra video PCB on a SCART machine.

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Do carts that auto-adjust use hand picked palette tables for PAL and NTSC or is their an easy conversion function somewhere?

 

I hand pick the colours. For real hardware testing I always play on PAL first with occasional NTSC checks. The NTSC palette used in the emulators isn't the same as seeing the colours on a real machine. My games also adjust any movement tables, game delays and Display List Lists (DLLs) to match the TV region too.

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Do carts that auto-adjust use hand picked palette tables for PAL and NTSC or is their an easy conversion function somewhere?

 

I hand pick the colours. For real hardware testing I always play on PAL first with occasional NTSC checks. The NTSC palette used in the emulators isn't the same as seeing the colours on a real machine. My games also adjust any movement tables, game delays and Display List Lists (DLLs) to match the TV region too.

The NTSC palettes I released for Prosystem, which Trebor later adapted for MESS are as close to perfectly matching the NTSC color palette before it gets mangled in the RF unit as can be made. I used screen caps of the 7800 color map diagnostic cart from a CC2 and matched the hex color values in the emulator palette file. The CRT TV used to produce the screen caps was first properly calibrated using X-Rite professional color calibration equipment.

 

With RF in the middle, and even just using CRT TVs in general, there will always be a slight color variance. The palettes in the latest versions of prosystem and MESS represent proper NTSC values under best conditions.

 

The PAL colors in these emulators are incorrect, because no one has taken the time to get them right like I have.

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Hi Groovybee,

 

I have 2 and both of them do this (output to SCART) and I can confirm 2 other French guy from the Yaronet forum have this too. Maybe it's related to SCART output only...

link --> http://www.yaronet.c...sl=172&s=148858 (sorry, it's in French :) )

 

Yes, the issue is only seen on the SCART 7800s.

 

Also worth noting, while the Atari released games are identical as far as cart label, manual and box, the third party games are noticeable different.

 

Mitch

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