NTSC vs. PAL System Setup Options

[Atari2600.com]

Need some help determining the output given various PAL NTSC game/system setups on a PAL television. Here is a table with the various connection possiblites.

 

Cart Format........A2600 System Format....Television Format...Output

PAL....................PAL..................................PAL.........................OK

NTSC.................PAL..................................PAL..........................?

PAL....................NTSC...............................PAL..........................?

NTSC.................NTSC...............................PAL..........................?

 

What will the result be of using a NTSC game in an PAL system on a PAL television?

What will the result be of using a PAL game in an NTSC system on a PAL television?

[Andrew Davie]

Need some help determining the output given various PAL NTSC game/system setups on a PAL television.  Here is a table with the various connection possiblites.

 

Cart Format........A2600 System Format....Television Format...Output

PAL....................PAL..................................PAL.........................OK

NTSC.................PAL..................................PAL..........................?

PAL....................NTSC...............................PAL..........................?

NTSC.................NTSC...............................PAL..........................?

 

What will the result be of using a NTSC game in an PAL system on a PAL television?

What will the result be of using a PAL game in an NTSC system on a PAL television?

 

 

This should be in a FAQ somewhere.

 

OK, the first thing to understand is that a typical NTSC TV frame is composed of two fields displayed alternately at 30Hz. Each of these fields is 262(.5) lines deep - giving a total vertical (interlaced) resolution of 525 lines. Hence the 'standard' Atari 2600 frame of 262 lines, displayed at 60Hz. The above shows how/why the '2600 *can* generate a 525 line display... view the stella list for a discussion on this.

 

Back to your questions... NTSC TV field is 262(.5) lines, and PAL is 312(.5) - that's half of the vertical interlaced resolution of 625 lines.

 

Now, TV's don't have a "line counter" which tells them how many lines to draw. They just get passed an analogue signal which, among other things, controls the sweep of the TV's electron beam(s) across and down the screen. Provided you send a signal within a particular TV's capabilities - or margin of error - then we'll get a recognisable signal.

 

PAL TV's operate at 50Hz (that is, 50 frames per second) and NTSC TV's operate at 60Hz. This is closely tied to the mains frequency of the countries in which these differring TV systems operate. But the systems are essentially the same, with minor variations.

 

One of those minor variations is the location of the encoded colour information for the TV frame image. If you have a PAL TV and you send it a NTSC signal - then the basic format of that signal is the same for NTSC or PAL, but the colour information is in a different 'position' or frequency range than what the TV expects. SO the TV won't be able to get the colour - and hence you will see things in black and white.

 

This goes for viewing PAL on NTSC, or NTSC on PAL - you lose the colour information and your image is in black and white.

 

However, you will also be feeding a 312 line image to a TV which expects a 262 line image (PAL->NTSC) or a 262 line image to a TV which expects a 312 line image (NTSC->PAL). The upshot of this is that rather than receiving a frame at 60Hz (NTSC), you may end up sending the TV a frame at 50Hz (ie: if you plug in a PAL game, which generates 312 lines at 50Hz into a NTSC TV which expects 262 lines at 60Hz).

 

And what happens then? Well, if your TV is like most, the image will 'roll'.

 

Now some TVs have adjustment (particularly older ones, which had a knob at the back) for vertical hold. What this is really doing is adjusting the TV to 'expect' frames at a different rate. You may be lucky and have enough margin of adjustment to allow you to stop your screen rolling. And if you are (so lucky), then you will quite happily be able to play NTSC games on your PAL system, or PAL games on your NTSC system.

 

But, as noted, they will be in black and white.

 

Now the other case, what if you use a NTSC console on a PAL TV. This, too, will depend on the game that you play, as it is the actual game which determines the frequency and vertical height of frames. But it's the console that determines the encoding of the TV signal (and in particular, the colour information).

 

So let's assume you're playing a NTSC game on a NTSC system, and viewing on a PAL TV. Then the game will be sending 60Hz signals, 262 lines deep, and colour would be encoded for NTSC by the console. So your TV (if it could synch) would display a narrow (ie: vertically shrunk) frame in black and white.

 

Now let's look at a PAL game on a PAL system, and viewing on a NTSC TV. Then the game will be sending 50Hz signals, 312 lines deep, and colour would be encoded for PAL by the console. So your TV (if it could synch) would display a vertically stretched frame in black and white.

 

Basically, PAL people are lucky. NTSC televisions are generally fairly poor at colour reproduction, and the colour resolution of that encoding system is lower than that of PAL. Furthermore, most PAL televisions sold today can automatically detect and/or switch to NTSC compatibility. We get the best of both worlds, because we can use NTSC carts as desired - but NTSC people are generally stuck to NTSC cartridges only, or to viewing in black and white only.

 

Sometimes, I guess, being American sucks.

 

Cheers

A

[Atari2600.com]

Just to reiterate your conclusions:

_

PAL Game + NTSC Console + PAL TV= proper game screen, no color

NTSC Game + PAL Console + PAL TV= screen roll, in color

NTSC Game + NTSC Console + PAL TV= screen roll, no color

PAL Game + PAL Console + PAL TV= Happy Aussie

_

Have you any experience with a NTSC/PAL Video converter? I'd imagine this would clear up the loss of color problem you've described when Using a NTSC console on a PAL TV.

 

JC

[+Mitch]

NTSC Game + PAL Console + PAL TV= screen roll, in color

 

Also note that the colors in this instance will be wrong.

 

Mitch

[Andrew Davie]

Just to reiterate your conclusions:

_

PAL Game + NTSC Console + PAL TV= proper game screen, no color

NTSC Game + PAL Console + PAL TV= screen roll, in color

NTSC Game + NTSC Console + PAL TV= screen roll, no color

PAL Game + PAL Console + PAL TV= Happy Aussie  

_

Have you any experience with a NTSC/PAL Video converter?  I'd imagine this would clear up the loss of color problem you've described when Using a NTSC console on a PAL TV.

 

JC

 

 

If you mix NTSC/PAL TV and console, your ability to see the screen non-rolling depends on your TV. And when you DO see it, your screen will be shrunk or stretched vertically - basically because the TV is adjusted to show the correct number of lines full-screen.

 

In essence, if you send a NTSC (262) line picture to a PAL (312) line TV (we're talking one field here, let's not nitpick), then the image you see will be squashed to rougly 84% of 'normal' vertical size. And if you send a PAL picture to a NTSC screen, it will be 120% of 'normal' vertical size (probably some of it will be off the tube boundary). So another way that PAL users are lucky, and NTSC users are shafted

 

It is typical for video recorders here to have inbuilt NTSC->PAL conversion (producing a hybrid signal called PAL60 in some case - which is a PAL-format picture with colour information in the correct place for PAL, but sent at 60Hz - the NTSC frame rate). I've used this method (plugging a NTSC console into my video recorder, letting it do the colour conversion to PAL, and feeding a PAL60 signal to my TV) on occasion. I've not had experience with other gadgets.

 

Cheers

A

[Thomas Jentzsch]

NTSC Game + PAL Console + PAL TV= screen roll, in color  

 

Also note that the colors in this instance will be wrong.

Yup. And as Andrew said, the screen roll can be avoided (60Hz compatible TV or VCR).

 

But - due to the alternate line color encoding - the colors won't show at all if the NTSC game produces an odd number of scanlines. Most quality games produce an even number, maybe sometimes having a single frame with an odd number. Cheap or pirated carts and (early) protoypes often don't care for constant scanlines and therefore you will often either not see any colors or the colors will go on and off (quite annoying).

[Mayhem]

NTSC Game + PAL Console + PAL TV= screen roll, in color

 

I disagree here. Not every NTSC 2600 game I have playing on my PAL 2600 and PAL TV freaks like that. Some work fine, or have good picture with crapped out color. It really depends...