What's With This 24p Stuff, Anyway?
by Charlie White

 

 

 

 

Motion picture film: It has the highest resolution of any media format in common use today. Most film is projected in movie theaters at 24 frames per second. It’s 24p, that is, 24 frames per second, presented progressively. For years, there has been interest in marrying video and film in such a way that they would both use the same frame rates. Seems like that would make lots of things much easier. But until now, neither would budge. Most film had traditionally been shot at 24 frames per second and wasn’t about to change. Video always ran at around 30 (29.97) frames (because of electrical convenience) and also had no reason to change. But now, with digital standards sweeping the world like rolling thunder, it’s fairly easy for video to change -- to finally cave into the 24 fps standard. Until now, film was converted to video by doubling some of the frames on a regular basis, so that it ended up at 30fps. And, even more awkwardly, to be converted to the PAL standard, film was simply sped up 5%, to the 25 frames-per-second that’s required for that format. Neither of these processes is perfect.

So, as video makes a move toward film, film is also making a move toward video as well. Leading the way is the magnificent quality of high definition video. Ever since George Lucas proclaimed a few years ago that he would begin shooting and even projecting his Star Wars Films in video, the tide began to change, pointing toward an all-video future. And, at this year’s NAB, the Oscar-winning Shakespeare in Love was shown to audiences on a high definition video screen that looked just about as good as its film counterpart. I’m here to tell you -- many in that audience who were once doubters are believers now. Video cinema has arrived in a big way. So much so that some are saying that we’re on the cusp of a new art form, where video will supplant film. No more grain, they say. But hey! Some of us actually like grain! Well, maybe we’ve just been conditioned to like grain, and maybe video will finally set us free from that addiction, once and for all.

But film is so much better than video, right? The contrast ratio of film is still many times wider than that of even the highest definition video. And the grain adds a certain physical quality to film that’s hard to match with pure, unenhanced video. However, lots of the feature films we watch today were touched by the digital genie -- computer generated graphics and animation. Many major motion pictures like Star Wars Episode I: The Phantom Menace consist mostly of digitally-generated or enhanced footage. Will we miss the grain when it’s gone? Well, if we love that grainy look, we can always add it back, even if it’s just while we’re being weaned of the stuff. The best part is, this grainless future we face gives producers one more option: How do you like your grain to look?

Enter garden variety television. The plus here is that it’ll be easier for TV to coexist with film if video footage is acquired at 24fps, progressive scan. That’s more easily converted to film if desired. New cameras that shoot video at 24 fps are being introduced as you read this. Or, film can be shot and then transferred to video on a frame-by-frame basis. Another benefit to video: 24 versus 30 frames represents 20% less frames that need to be processed, that need to sit on a disk, that need to be rotoscoped, manipulated and stored. That’s more efficient. But it seems like there must be a bad side effect to this enhanced efficiency. Not really. It’s hard to tell the difference between film’s 24 frames per second and video’s 29.97 frames, especially when the frames are doubled to prevent flickering.  And, with the official video standards not specifying whether home TVs will display progressive or interlaced signals, or 24 or 30 frames per second, the new TVs will be able to display any and all of these formats. Finally, there’s a tremendous need for multiple masters of the same program in different formats. Before, a program’s format was either NTSC and PAL. Now there are more than 18 formats. And let’s not forget that many viewers will be watching video presentations on their computers, representing even more format variations. Three cheers for the flexibility of digital television!

By design, the market will determine the dominant digital video format. Meanwhile, the ground is ripe for this transition to 24p. The industry is rallying around it. It’ll make at least something easier in this confusing, troubled, frustrating and awkward transition we’re all going through right now to all-digital television. Just think: For the industry overall, this transition to digital television is like being hit with a two-by-four. It feels so good when you stop! Won’t you be glad when this great changeover is over?



Charlie White has been writing about digital video editing since it was the laughingstock of the post-production industry. He's an Emmy award-winning producer and director for PBS, and producer of this Web site. Do you have comments or questions? Send Chazz a note at cwhite@digitalmedianet.com.


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