With HD, I think it's ATSC and, and yes, the only difference is the frame rate ( the power lines in PAL country are different that we have in America, and so the frame rates have to work with what works in the respective countries ).

Please correct me if I'm incorrect here or if I've left something out.

Dave

You are basically correct about the power lines. Power in Europe is 50Hz and in the us 60Hz. Older electronic equipment would use the power frequency for a lot of things, which is, for example, why your alarm clock will go off if you move it across the pond (assuming you did alter the voltage).

This is the historical reason for the 30fps and 25fps difference. Since modern electronic equipment doesn't use the power frequency for anything much when it comes to timing, this should no longer be an issue, but I assume most European countries and their broadcasters didn't want the hassle of moving to 30fps given archival footage and the same for the US, so even when it doesn't make any reals sense, we still have two different formats.

On the other hand, having just moved back to Europe, I have so far not found a single HD TV that didn't fully support PAL and NTSC both. Wish that was also the case in the US.

You're correct.
The reason the different frame rates survive is because of problems with flicker from lighting which isn't as much of a problem as it used to be now that more and more ballasts are high frequency.
As the terms PAL and NTSC don't make sense in HD generally now people use the term Region 50 or Region 60.

Bob.

Older TV-sets (especially tube sets) had quite lousy power supplies. The mains frequency ripple was very dominant in the deflection circuitry, and if the frame rate frequency would have deviated too much from the mains frequency, you would have seen the beat frequency (difference between framerate and the mains frequency) modulating the picture geometry...lots of wobble...

50i is better compared to 60i in that respect that the lower framerate gives more bits for the actual encoding (assuming both use same max bitrate for encoding as they normally do), so PAL has lower spatial frequency, but slightly better preserved detail, even if there are more lines to encode.

Christian

Another difference between PAL and NTSC

PAL 50i is actualy 50 field per secnd, 40ms per frame.
NSC 60i is "almost" 60 fields per second (59.94)

24 and 25 are converted using simple 4% speed difference.
24 and 30 are converted using complex pooldowns

PAL's editors life are simpler.

Udi