slow motion

[boho]

Editing on a PP 22 

I've done a slow motion of a clip at speed 20% with time interpolation in Optical Flow mode.

I've seen and followed the very nice tutorial: 'How to create slow motion effect'. In spite of that my result is not acceptable. 'Outbursts'(?) occur in the edited slow motion version. 

Can anyone help with an explanation and / or a solution? I'm in a bit of a hurry 🙂

(The attached files are just samples from a longer sequence)

Bo

[Mike Dziennik]

Try using Frame Blending, it might actually give you a better result on this clip.

Retiming clips to 20% is no small undertaking, optical flow tries to detect motion in the clip and generate the frames it thinks should be inbetween. It will struggle when you have these soft bands that are merging into each other...it doesn't know what to do. Some much of the success of these techniques depends on the clip your using.

[boho]

You wrote: 'Retiming clips to 20% is no small undertaking' Do you think it would be better if I take the retimming in more smaller steps in stead of doing in one step? or will the problem for the software to mangae the soft bands be the same?  ,

[boho]

Thanks for your reply Mike. I've already tried frame blending (see attached), but then an unfortunate stepwise movement occurs which I want to avoid. I want to keep the continuous fluid motion from the original recording.

bo

[Steve Griffiths]

As Mike has mentioned Optical Flow has a hard time with soft edges - particularly when multiple soft edges cross each other. It's great at smoothly track some stuff but in your case it's just not going to work. Even using Twixtor which is a plugin that you can buy and is more powerful than the built in optical flow in Premiere Pro probably would not do much better.

[boho]

Hi Steve.
Thanks to you and Mike for your quick responses. I must admit that it is not possible to implement the slow motion effect in this way.
I have to go back to the basic footage and build the sequence in a different way.

Thanks for the help to both of you.

Bo

[Ann Bens]

Try 25 percent.

[boho]

Hi Ann

I've tried, but unfortunately it didn't solve the problem. But thank you for your input!

best Bo 

[Steve Griffiths · Accepted solution]

How about blurring the background after applying the optical flow to hide the worst of the optical flow artifacts? I just tried it with your 'slowed 20%' clip - applied a 'Directional Blur' effect and set it to 'Direction 90 degrees' and Blur Length to 126. The background looks different but this hides the artifacts fairly well.

[boho]

Hi Steve

Thank you. In this way it nearly removes all the flow artifacts and solves my problem with this clip.

As mentioned I was in a hurry so I had to start the projection (it's a part of  an art exhibition) and solved it as good as possible by manually defocussing the object. But your suggestion is much much better so I'll reeddit the sequence and replace it on the exhibtion.

So once again: Thank you!

Bo