Optical Flow not working!

[Liam_HiTech]

Hello,

I’ve been using the optical flow since a long time when doing slow-motions, but it has recently « stopped working »..  when I do a slow motion at 24fps and activate the optical flow, it doesn’t fill the missing frames and the clip is laggy (p.ex.: if I slow down a 24fps video by 50%, it won’t fill the missing frames and my clip will be at 12fps).

(P.S.: I do my slow motions in the effect controls panel so I can do progressive slow motions)

Thanks

[jasontcox]

You ARE remembering to Render the clip, correct? It's one of the only effects/techniques in the entire program that simply will not even try and play properly unless you Render it, no matter how powerful your system is!

[Liam_HiTech]

Yes I do! Forgot to mention that before haha

[Ann Bens]

Optical Flow Time Remapping: Tips & Tricks for Best Results | Creative Cloud blog by Adobe

[Liam_HiTech]

It still doesn’t work after doing exactly what it’s said.. It maybe doesn’t work because I use speed ramps?

[pigsalreadyfly]

So when did that become a thing. I remember being able to turn on Optical Flow on an earlier version, and because I have a RTX 2080ti the bar would turn red, but I could preview it without rendering Or am I crazy? (BTW I've used Premiere since 2003 so around version 5, when it crashed every 5 minutes.

[enzom64780351]

Hello,

I have exactlt the same problem where the optical flow works perfectly fine most of the time, but sometimes just won't create the extra images. Have you found a solution ?

Thank You

[ionbattle]

I was having the same issue. It has to do with the frame rate of the footage. My workaround was doing a render and replace of the trouble footage and then applying optical flow and rendering.

Hope that helps!

[unihumi_]

Thank you very much. Re-rendering the file on my timeline (right click on it, then "render and replace") worked perfectly fine. 

[LanglaisPL]

I was having this problem on a project that i'm currently working on, you guys just saved me so much time ! Thank you very much ! 🙂

[A3user]

this solved it! thanks!

[ShantiDasw]

I usually have this problem after applying LUT to video clip on Lumetry->Creative
If remove LUT then Opt.Flow works again

[Lewis5C1F]

I was also having the same issue. Usually when I'd apply optical flow to a clip, I'd get the red line across the top of the timeline indicating it needed rendering, but even this didn't happen. The clip would continue to display the same way as it would with Frame Sampling.

My footage was scaled up quite a lot (it was archival footage that had been digitised some time ago), however I didn't have any other effects applied.

Best work around I found was to go back to the original clip in the source (while playhead is over the clip in timeline, press F key), right-click in source monitor and select "Make Subclip..", right-click on the new Subclip and select "New Sequence from Clip" and apply my time/duration changes in the new sequence, then drag this sequence into my original, and reapply any other scaling/color effects there again.

[enzom64780351]

Thanks for all your answers !

What I figurted out on my own is that the functionning of the optical flow mainly depends on the clip preview:

Sometiemes as I apply my optical flow, the line will turn red and during the short render of the clip either the render will just last 2 or 3 seconds as the pourcentages will go from 27 to 69 to 100
Or the render will actually render each image individually and do something like : 1, 2, 5, 6, 8,10, 12... In which case the optical flow will work!! Each time that the render seemed to go through every images one by one, premiere was capable to create the secondary images to deliver a flawless slow-motion

So even before the end of the render I can already know whether it worked or not.

One might say that this is due to the PC config but I have tried this on 3 different computers with different powers and they all sometilmes made the optical flow work or not... So the issue doesn't seem to come from the computer but from Premiere !

I have tried many of your solutions but they don't seem to work for me... It's been several weeks that I have been trying the figure out the issue - but without success...

If anyone has any more  information on the subject that would be great !

Thanks

[marcosromo]

Hey! I think I have the solution, try to NEST the clip where you want to apply the effect, and then try to reduce the duration and try optical flow with tle clip already nested.

[pigsalreadyfly]

Yep! Doing all your effects first then nesting the clip. THEN adding Optical Flow on top seems to work the best. Same with speedramping. Speedramping does NOT like motion keyframes. NESTS are your friends.

[Arjun8055]

Had this problem

For me it was solved by removing the faussian blur I was using. Guess  for optical flow..no other effect can be used

Cheers

[Jeff Bellune]

For me it was solved by removing the faussian blur I was using. Guess  for optical flow..no other effect can be used

It has more to do with the order that effects are processed than with which effects are used. You can force the order that effects are processed by nesting sequences, as above. It's the same type of thing as pre-composing in After Effects.

[Theo Kooijmans]

I still see this bug with v14.9, optical doesnot work with HD or SD slomotion.

Work arround render that clip in CC2019...

[MOJO_YT]

I am also having the same problem 

I think I have to reinstall the application

[russellk68680847]

Hi Guys, I was having the exact same issue for the past hour, 

You have to right click and "Nest" the clip first , then apply optical flow and it should work out. 

[tamashii5321]

i tried everything they said here and it didnt work for me what i did was i disabled my opacity effect and the red bar showed up top then i tried to render it then the optical flow worked just fine

[MansfieldMedia]

Been having this issue for months. That was the trick!! Thank you sooo freaking much!!