Video Asylum

Posted by Some Guy on November 03, 2003 at 05:44:06

In Reply to: PAL transfers speed increased from film´s original? posted by Joaquin on October 29, 2003 at 13:59:48:

Just to quibble, PAL is 25 frames per second OR 50 FIELDS per second... I don't think I've ever heard the term half-frames before. And yes, many PAL transfers are done frame by frame, but I believe some are also adjusted to maintain time. More on that process later...

The PAL system has a lot of advantages over NTSC, not least of which is the simpler frame rate. Speeding up the visual source by 4% isn't that big of a deal... not like the jump there was in viewing most early silent films (shot at 16fps) on equipment built for 24fps - you're talking about a 50% jump in speed! Visually, you probably won't notice the slight increase in speed, but audibly you might notice it...

If it weren't for brilliant technology that lets you shift the pitch. This equipment has been around since at least the 1960s (probably closer to the 50s, honestly) and, quite simply, it allows you to drop or raise the pitch of the signal in situations where you have to speed up or slow down the source. Eventide pretty much built their business around this technology. I've used this before when I used to do dialogue edits for interviews on 1/4" tape with a razor blade... first you'd go through and cut out all the "ums", "errs", pauses, and coughs to make it shorter. Then you'd figure out the actual length of the interview, compare it to the desired length, then run it with the speed control of the source deck ganged to the pitch adjustment of the Eventide. The result: a shorter interview at the same pitch. The great thing about those units is they didn't have all the whistling and artifacts of many of today's software based time compression plug-ins.

But don't let that worry you... NTSC is 29.97fps. Wha?!?!! Try dropping 24fps source down to that! Now you're talking about time base correctors and a slew of whosits, whatsits, and idontknowsits... AND you're messing with the picture. Somehow, though, they managed to do it just fine.

So don't worry so much... I'm fairly positive that anything that made it to commercial release from film was properly pitch corrected. ESPECIALLY music source.