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Topic: Hopefully someone here is familiar with video
Replies: 13   Last Post: Jun 16, 2012 5:18 AM

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 Tim Little Posts: 1,793 Registered: 2/7/09
Re: Hopefully someone here is familiar with video
Posted: Jun 6, 2012 10:15 PM

On 2012-06-06, Industrial One <industrial_one@hotmail.com> wrote:
> 29.97 and 50 is an even better example. The LCM is 149,850 fps. Damn.

If you capture at 150 fps, almost all the frames will be of almost
perfectly the correct length. The 50 fps frames will be perfect,
while the 29.97 frames will be 33.33 ms instead of 33.37 ms. However,
a tiny fraction (about 1 frame per 30 seconds) will be 40 ms instead -
a deviation of 6.6 ms.

However, suppose you had sampled at 130 fps instead. Then the 50 fps
frames will be of lengths 15.4 ms and 23.1 ms, while the others will
be 30.8 and 38.5 ms. The maximum error is now only 5.1 ms instead of
6.6 ms.

So a question arises as to what you want to optimise. Do you consider
the first better than the second, or worse?

--
Tim