Working with 60p in Apple Final Cut Pro
Dec 7, 2010 12:00 PM, By Jan Ozer
I know, I know, some of you are dying to read the second half of my how to encode a podcast article. Unfortunately, I had a client matter pop up, and I had to get smart on a couple of 60p-related issues, all 720p resolution. I'm writing about it here because I think I've found the best solutions, but I assume that I'll hear about it if I don't. Since there are no comments enabled on this site, just send me a note at firstname.lastname@example.org if you disagree with any of my findings.
Here are the two problems that I was encountering. First, the client a contractor who provides video services to a branch of the U.S. government had a bunch of older 29.97i footage to which they were attempting to add newer 60p footage. They were working on a 29.97i sequence in Apple Final Cut Pro and were concerned that the 720p 60 added to the video didn't look smooth. Second, they were attempting to produce 24p DVDs from 60p source on other projects, and again noticed that the video often appeared jittery.
Let's take a quick look at 60p and then address the issues in order. Let me say this at the start: If you've been working with 60p and you're very familiar with the format, you'll find this article very basic and obvious. On the other hand, if you're new to the format and are frustrated by issues like jerky playback, you may find the 5 minutes or so it takes to read the article worthwhile.
When I first encountered 60p, I was confused by the format because unlike most other acquisition formats, it really doesn't live anywhere else. That is, when I shoot DV or HDV in 29.97i, I know that both formats translate to NTSC-compatible 29.97i that I can display on my TV set or burn to a DVD. When shooting in 24p, I know that I can produce a 24p DVD if I wanted to, or stream at 24fps. In contrast, as far as I know, you can't broadcast 60p and you can't display it on a television setat least not the one in my living room.
After working with the format for awhile, the nickel dropped, and I realized that 60p was primarilyif not exclusivelyan acquisition format. When it's displayed in a 60p timeline in Final Cut Pro, it actually plays 60fps. If you apply the Timecode Generator filter to a 60p clip in a 60p sequence, you can step through the video file and see what you see in Figure 1: a 2;57 timecode that means that three frames later, you'll be at second 3;00 of the video file. Again, each second of video has 60 discrete frames.
For reasons that will become obvious as we go along, if you're just starting to work with 60p video and will be doing lots of format conversions, you might add the timecode to a short 10-second sequence of your own 60p content, and then save off the result as a QuickTime Reference Movie. That way, if you use that clip during your tests, you'll be able to easily tell what's happening to the discrete frames in your content.
Again, looking at Figure 1, the timecode proves the obvious: that a 60p file has 60 discrete frames per second. When you play the video on the timeline, you get a very smooth and crisp 60 discrete frames per second. However, since 60p doesn't live anywhere else in NTSC or DVD-land, you'll probably need to convert 60p to another format to use it, which is where the potential problems start.
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