How important is a certain fps?

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How important is a certain fps?

Postby Yogurtron » Wed Sep 11, 2002 1:25 am

I've read a few quides talking about framerate, and I've wondered about an "error" I have heard about. I've heard that Adobe Premiere is incapable of 23.976 fps videos. I've noticed that It can export 23.98 and 24 fps videos. I'm wondering, what exactly is the difference between these framerates. Why is 23.976 so popular/good (other than because it is film framerate and that most videos on DVD are encoded as such). Is there something wrong about encoding my video as a 24fps or 23.98fps video as opposed to a 23.976fps video?
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Postby klinky » Wed Sep 11, 2002 1:54 am

What I believe happens here is that original FILM is shot @ 24fps. NTSC TVs display @ 59.94 FIELDS per second, technically 29.97 "frames per second". Do to electronics mumbo jumbo the NTSC standard is %1 slower then 30FRAMES PER SECOND. So what they do is they take the 24fps video, slow it down %1 and then do telecining, which is the process of meshing together fields to produce whole frames to increase the frame rate from to 29.97 frames per second.

So if you import 23.976 / 23.98fps video into Premiere, but you have a 24fps timeline then you're going to have some slight timing issues :| . The cure I guess is to speed up teh video and audio by %1 and then edit it in Premiere. Then you can slow it back down :| Or you can just leave it be and see if it causes much of a problem :\


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Postby Yogurtron » Wed Sep 11, 2002 2:08 am

It appears that before I had fully read and processed the guides like ErMac's and AbsoluteDestiny's, I had set my video's timebase to 29.97. Is it best that I just leave it that way and just create a music video with 29.97fps? Since my music video is, for the most part, finished, I would prefer to not reset the timecode and retime the video.

(BTW, the timebase for the project is 29.97, but my source video is about 23.98 (or 23.976 (since it's from DVD), but premiere only displays it as 23.98)
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Postby klinky » Wed Sep 11, 2002 2:10 am

Well if it looks okay then I would leave it :| Adjusting the timebase could screw something up. :| In the future choose the closest one to your source footage :\


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Postby Yogurtron » Wed Sep 11, 2002 6:35 am

Well, I'm going through and redoing the timebase, it's looking better. I'm not going to do the changing of the song though (AD suggests speeding up the song 1% when editting in in 24fps, and then using the source with normal speed when final rendering). THat would take much too long. The 24FPS conversion didn't hurt the all that much, especially since much of my timing could be acceptable 1-3 frames away from the point I originally took. So I'm fixing those minor problems as I fix some other annoying problems I have. Thank You Again Klink ^_^

I do have one other question though. On my Evangelion DVDs, there is a line of black on the right side of my source footage. Is there any way to get rid of that (other than shifting every single one of my clips so many points to the right)?
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Postby Zarxrax » Wed Sep 11, 2002 8:24 am

On adjusting the song, do you have any idea how this affects the audio quality? I'm sure it would cause some decrease in overall quality wouldn't it? Would it be noticable? Especially if yor source was an mp3, would this cause the reencoding process to be of lower quality?
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Postby Yogurtron » Wed Sep 11, 2002 8:35 am

As far as i know, the quality drop would be minimal, if any. But the timing would be much farther off if I were to use that method, which is why I don't want to until my next music video.
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