Atari VCS/2600 NTSC/PAL scanline list

 

 

100% standard compatible NTSC games display 262 lines per frame at 60Hz

100% standard compatible PAL games display 312 lines at 50Hz

These are the ideal specs that Atari adhered to.

 

NOTES:
Different television standards in different parts of the world are the main obstacle to the international distribution of Atari products. The U.S., Canada and a few other countries use the National Television Systems Committee (NTSC) scheme, which is geared to the use of 6OHz of electricity and 525 horizontal scan lines. In Europe, two Systems have emerged. One, called SECAM (Sequential with Memory), is the standard in France, while PAL (Phase Alternate by Line) is standard in Germany, England and many other countries. Both SECAM and PAL typically use 50 Hz of electricity and 625 scan lines. Complicating matters, all three standards use different systems for coding the red, green and blue color components of a TV picture, resulting in many subsets (PAL-M, PAL-N, etc.)

 

Having an odd # of scan lines will result in color loss on PAL TVs, or with problems recording with a VCR.  There are however a lot of games which don't match the standard exactly. For known NTSC games you can find values from 248 to 286, and for PAL from 284 to 342. So it's not easy to tell for games around 280-290 lines whether they are PAL or NTSC. The more the value is off the standard value, the more TVs get sync problems.  Often these games may be stable enough to run on both NTSC and PAL systems.

Games in both versions will be off about the same (NTSC will be ~10% faster and PAL ~7% slower).  Most companies developed games in NTSC and later converted them to PAL.  Since programmers were mainly concerned with having a stable image and acceptable colors, no time was spent on adjusting gameplay so that it ran identical to the NTSC version. 

A few companies (Atari, Activision, CBS, Apollo?  Spectravision?) made SECAM-specific carts.  Most were simply PAL carts with different labels or “S” stickers on them (http://www.digitpress.com/faq/vcs_label_variations/vcs_label_variations.htm#format) but some were actually a bit different code-wise, with adjustments for color. Below is a list of known SECAM titles:

Decathlon
Ghostbusters
Gorf
HERO
Keystone Kapers
River Raid
Smurf: Rescue in Gargamel’s Castle
Space Invaders
Space Shuttle

SECAM systems have the color/b&w switch hardwired to b&w, which means it reads the PAL b&w values and assigns them a fixed color to each lum of b&w, according to the following table:

 

LUM	COLOR
0	black
2	blue
4	red
6	magenta
8	green
A	cyan
C	yellow
E	white

 

PAL sounds work fine on SECAM with one exception: when a sound is to be turned off, it must be done by setting AUDV0/AUDV1 to 0, NOT by setting AUDC0/AUDC1 to 0.  If you don’t, you’ll get an obnoxious background sound!

To see how many scanlines a game produces with the Z26 emulator, press Alt + 9; for Stella users, press Alt + L.

 

 

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