Optical Flow Slow Motion Q

[Zak Peric]

Optical Flow has tendencies to create artifacts on a footage, but I have not heard that your playback suffers. Am I correct in saying that you are talking about playback of your video.

[Jamie Hamlin]

Yes, preview in Motion and when it gets back to FCP. Thought that it just needed to be rendered but even after that it looks bad. Its glitchy and doesn’t play the whole clip. Watched several tutorials trying to find what I’m doing wrong. Seems pretty cut and dry.

[David Bogie]

This might help. might not:

https://www.kenstone.net/fcp_homepage/fcp_7_smooth_cam_stone.html

bogiesan

[Jamie Hamlin]

Thanks but Im all set using smoothcam. I actually use Boris Optical stab. This footage was smoothed prior to sending to Motion. Does that matter?

Here is what Im doing-

Send clip to Motion, select optical flow and decrease timing to 20%. This starts the background process. After its over, I view in Motion and clip is unusable. Saved and sent to FCP, rendered and clip is still unusable.

[Jamie Hamlin]

Well, thought that I found something in yet another tutorial but ddnt work. It was changing the properties in motion to double the frames. Same result. Going frame to frame, it looks like every other frame is distorted. I would assume those are the frames Motion generates? What would cause that?

[David Bogie]

[jamie hamlin] “Thanks but Im all set using smoothcam. I actually use Boris Optical stab. This footage was smoothed prior to sending to Motion. Does that matter? “

SmoothCam uses Apple’s Optical Flow, it runs the same analysis. You might have mentioned the whole Boris thing much earlier. Never heard of it myself but it’s obvious you need to talk to BorisFX.

bogiesan

[Jamie Hamlin]

Um okay, I will. Sorry, I\’m a firefighter/paramedic, not an editor. I\’m teaching myself and thought slo-mo would be simple using FCP suite. Guess not.

[Jamie Hamlin]

Um okay, I will. Sorry, I\’m a firefighter/paramedic, not an editor. I\’m teaching myself and thought slo-mo would be simple using FCP suite. Guess not. Didnt intentionally not tell anyone about the Boris plug-in. Footage looks fine after stab. Frame by frame looks great. Dont know why Motion would have a problem with it. Maybe Ill just slow it in FCP but wanted to get the best result possible.

[Mikey Bouchereau]

FCP/Motion offer 3 types of slow motion/retiming. Optical flow is great but it is not perfect. If your clip has lots of background detail, or lots of little detail. Optical flow just won’t work it always looks like garbage. (Example: a river, or a shot of a moving object with a background full if people.) you can always do a speed change in fcp and try turning off blened frames. I think this looks best for small speed changes. Or maybe it’s a fast paced clip. Then frame blending may be your best choice.

The truth is trying to fix everything in post isn’t always (and when I say isn’t always I really mean it never is) your best solution. For the best slowmotion over crank the camera and shoot at a higher FPS.

Hopefully that helps.

…..
Please forgive any typos or run on sentences this was posted from my iPhone.

Mikey B!

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[Jamie Hamlin]

I’m shooting with a Panasonic SD-9 which does give me the option of shooting 60i but my platform doesn’t do well with interlaced footage. I shoot from the nose of a large rotary UAV and interlacing looks bad with that much motion. Yes its a cheap camera but works great for my platform. Just requires some smoothing in post but gets footage that no one has been able to get before.

After reading last night, I came to the conclusion that you just said. 60 fps then decrease to 24 or you can buy Twixtor. It does a great job with 24P. Tried it out last night and every frame looks just like the one prior.

I will try out the FCP non-frame blending tech.

Thanks,
Jamie