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Re: FPS versus ko/sec

At 10:02 AM -0400 6/6/03, Alain Boisvert wrote:

I am exporting different movies at a 12 fps, keyframe 24 and 180 ko/sec.

Is kilobyte really abbreviated to ko in Canada? It can get confusing, kb might be kilobit or kilobyte, so I usually say kbyte or kilobit, etc.

Any, assuming you mean kilobytes per second, what you would use depends on the machines you want it to be viewed on, and on how much time you want to fit into how much space (either for CD-ROM budget reasons, or for download time).

Going from 12 to 24 fps will affect the quality of the video, and might make it harder to play on the slowest machines. Likewise, making it larger will affect the quality and number of machines that can play it. If you really want to give slower machines a hard time, setting the data rate to a high figure will cause them a lot of grief. If you want the playback experience to be very choppy on slower machines, setting the key frame spacing to be wide will ruin the experience.

Very wide key frame spacing won't improve the quality so much. With certain kinds of footage it might allow you to lower the data rate a bit, but for most video it won't help quality, and it will upset users of slower machines.

Whether to use 12 or 24 fps is also affected by what the material is. For talking head tutorial stuff, I'm not sure you need 24 fps. For virtually all cartoon work you can use 12 fps, because that's what it's animated at. Features films might appreciate 24 fps, but I did the CD-ROM version of A Hard Day's Night, and the 12 fps I used was ok for the job. I also did This Is Spinal Tap and The Day After Trinity (and many, many other QuickTime based CD-ROMs), and the gain in quality for doing 12 fps was well worth living with the less smooth motion.
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 >FPS versus ko/sec (From: Alain Boisvert <email@hidden>)



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