dmb@wam.umd.edu (David M. Baggett) (03/20/91)
>European TVs work at 50 Hz. We make up for the fewer frames per second by >having more vertical resolution and properly-encoded colours. The only real reason game writers alter the scan rate is so the game play timing won't change. Games run 16.3% faster on U.S. ST's because the scan rate is 60Hz here. This means Joust, e.g., is more difficult in the U.S. than it is in the UK, something I always make clear when comparing high scores with my British competitors. :-) An example of a problem caused by the scan rate difference is the treasure room in Guantlet II. U.S. players will notice that the timer only counts down to about 4 or so, then the level ends. This is because the countdown code stupidly relies on the scan rate being only 50 frames per second (it counts a second by waiting for 50 vblanks to elapse). On U.S. machines 50 vblanks occur in 5/6ths of a second, so the timer counts down too quickly, and you only get 16.6 seconds in the treasure room instead of the normal 20. (Or is it 25?) To avoid the timing problems, some European programmers force U.S. machines into 50Hz mode. (This is accomplished by twiddling a bit in one of the video hardware registers.) Unfortunately, many early ST monitors (those made by GoldStar, I think) just can't handle the switch, and the monitor goes completely off sync. (We're talking "instant headache mode".) It's a shame too, because the GoldStars had better picture quality to my eyes. Many European games and demos are completely unuseable on my machine -- I can only assume that European folks just don't know their stuff doesn't work on a substantial portion of U.S. machines. Thank God Speedball II doesn't change the scan rate... (Hmm, this sounded a bit technical. Followups to c.s.a.s.tech...) Dave Baggett dmb%wam.umd.edu@uunet.uu.net