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Hello,I have read recently that typical films (24 fps) are transferred to PAL (50 half-frames per second) simply... INCREASING SPEED ABOUT A 4%! This has me floored. They say that a 4% is not an issue... is this a joke? I am specially concerned about any films with musical content. A 4% speed increase will certainly alter pitch, even the whole "musical message"... I have checked all the operas I have here, and thanks god it seems they are shot in PAL or NTSC. But what about all those musicals or operas shot in film? I even suspect that a plain talking voice changes noticeably with a 4% speed increase. Please tell me I am just mistaken... I thought this technology had reached higher levels... :-(
Follow Ups:
It is all in the way how real film is projested and how TV samples signals.
If real film is projected 24fps, and PAL has 50 half-frames/s, then you are just fine as long as TV f/s is bigger than real film/s.
How is this?
Film presents one picture for certain amount of time and then switches to another picture, and cycle goes on. So you get a continious movement.
TV is sampled different. One picture is sampled continiuously for certain amount of time, and the another picture comes continuously again.
Film samples picture by picture in separate times, while TV samples continiously picture by picture without separation. There is blank pulse (signal) betwean TV pictures but that is way shorter than film.
So what happens ?
You DO NOT sync fps to PAL's half pic by increasing the speed, where did you get this crazy idea?
You just lose 4% of any 50-th picture or you lose (24/25)/2 of any single frame from the film.
You lose the same on NTSC + resolution that is worse.
Pitch is not altered AT ALL.Movie that is 1h on film will last 1h on PAL and NTSC as well.
Audio is not altered, and it is same for PAL and NTSC.
Although 1h video tape for PAL is longer than 1h for NTSC. But that's another story.
PAL transfers of movies *are* speeded up by the difference between 24fps and 25fps. Compared with what happens in an NTSC transfer, it's not crazy at all. There's a 1:1 mapping between film frames and PAL frames...what could be simpler?
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.
...or do anything drastic. But yes, it's true. Sorta.The mastering of *film* sources to PAL video results in a slight speed up. It's the reult of the frame rate, yes, but a difference in pitch is not really noticeable. A three hour plus film like LOTR is 4 minutes shorter on PAL. But Gandalf is not turned into a soprano.
This will only make you crazy if you have perfect pitch. Think of it as a very slight (and I do mean slight) transposition up. Concert and opera material will sound fine. (BTW, much of that is sourced from video, as a lot of it was produced for European TV, so there is no "speed up" at all.)
For details - head over to avsforum.com
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