DVD Pal Speedup

[Gandalf]

Anyone have a link for a technical explaination of the PAL speedup situation.

Thanks,

Paul.

[SimonI]

No link, but it's very simple: films run at 24 frames per second (fps), PAL TV runs at 50 Hz, so to get the two to match up the film is speeded up to 25 fps (one frame every two screen refreshes).

What a shame though that the DVD spec doesn't include some way of outputing the fim at 48 Hz - after all, modern TVs can cope with PAL at 50 Hz and NTSC at 60 Hz, so a 48 Hz option seems feasible...

[Hernster]

Isn't there a simple calculation that you can work out a films running time in either Pal or Ntsc?

Pal to Ntsc / Ntsc to Pal etc.

Isn't there a simple calculation that will enable you to work out a running time in Pal from it's Ntsc running time, and vice versa?

[Michael Brooke]

It’s needlessly confusing if you throw NTSC into the mix, as conversions from PAL to NTSC and vice versa don’t involve any speeding up at all (which is why some PAL DVDs have the same running time as their NTSC counterparts, because they were sourced from NTSC video as opposed to 24fps film).

But if you want to convert from theatrical running time to PAL, the formula is:

Theatrical RT x 24 / 25 = PAL DVD RT

…and if you want to work out what a PAL DVD’s theatrical (and reference book) running time should be, the formula is:

PAL DVD RT x 25 / 24 = Theatrical RT

And if you’re dealing with nice round numbers, a 100-minute film runs 96 minutes on PAL DVD, a 120-minute film runs 115 mins, and so on.

[Confucius]

NTSC to PAL: multiply NTSC runtime by 0.96 (ie 24/25)

PAL to NTSC: divide runtime by 0.96

(Assuming you're referring to movie based material)

An NTSC version of a movie runs at the correct speed, a PAL version does not.

I don't know why this (or at least one to the title page) LINK! (http://www.dvddemystified.com/dvdfaq.html#3.4) isn't more prominantly displayed as a 'sticky', it answers so many questions.....