Optical Flow For Slow-Mo

Hi everyone, I've been trying to do some slow motion and have noticed a few things using Motions Optical Flow. First off, if applying it to a clip that has something fluid occuring in the shot (in this case literally) such as a shot with water in it, Motions Optical Flow makes a very distorted ripple type effect. In addition, I also tried to slow mo a clip of a Lighting Bolt to about 2-5 percent, which also didn't cut the mustard using Op Flow, the frames it creates to accomodate the slow motion make for a strobe like effect and made the lightning look really pulsey. In both of these cases FCP's speed changes with frame blending worked MUCH better. Surprisingly, the lighting shot looks quite good using the frame blend but I'm still looking to make it better.

It would be interesting to know what kind of experiences other users have had using Motions Optical Flow for Slow-Mo, and/or some of the better tools to apply to Slow-Mo and Extreme Slow Mo.

Aloha, Al Werj

i'm pretty sure Twixtor have a demo you can download.
[www.revisionfx.com]

definitely worth having a look.

if you do, please post back your thoughts on Twixtor vs Optical Flow.


cheers,
nick

Slow motion with digital video/non linear systems is never perfects..I think it is just to do with video having two fields. I would love to be able to get great slo mo effects.

nick
i ahven;t used optical flow, and i am still trying to figure out *how* twixtor works, but i gotta say, the shots that i was able to successfully deploy it on look AWESOME
pretty amazing

however, i think it cannot do reverse very weel (at all?) and i am still tryin to figure out the logic behind how it works so that i can use it properly.

but my initial impressions are that it is sweet!
greg

Greg,

Any slow motion algorithm fails on "sliding objects" and on special patterns like small leaves or stone structures or sometimes water.
The way to provide the algorithm with better "details" is to split the source into different layers by rotoscoping/rotopainting.
From there apply the same motion settings to each of the layered "splitted source" and with Twixtor you can also add/keyframe some point or splines to help the plugin to do a better job.

This is a tedious work, but results will be amazing.

Andreas