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jamie hamlin
Optical Flow Slow Motion Q
on Nov 18, 2009 at 3:03:08 am

Hello.

I have attempted several times to round trip a clip from FCP to Motion for optical flow retiming. Once the analysis is done, the clip doesn't look good at all. Its playback is terrible.

It was shot at 24P. Imported as Apple Pro Res.

Any suggestions would be great!

Thanks


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zak peric
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 7:07:51 am

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.


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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 12:55:31 pm

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.


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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 12:09:43 am

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.


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david bogie
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 4:53:08 pm

This might help. might not:

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

bogiesan





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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 5:02:23 pm

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.


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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 6:46:11 pm

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?


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david bogie
Re: Optical Flow Slow Motion Q
on Nov 18, 2009 at 11:32:23 pm

[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



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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 12:58:26 am

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.


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Mikey Bouchereau
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 11:56:58 am

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!

Follow Me On Twitter!


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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 1:37:58 pm

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


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david bogie
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 3:51:33 pm

Now we're getting someplace, buddy, welcome to the family.
Twixtor is a possibility but it's just another expensive hack in terms of post processing.
Cheaper and more efficient to get a different video camera than to keep trying to hack this in post.
You UAV has mass/payload limitations and I suppose you have bandwidth issues for your control channels.
I am not familiar with the state of the craft in aerial platforms and image stability options. My company has entertained several vendors hawking an array of remote controlled flying objects designed for river and riparian zone surveys.

We have the NIFC here in Boise and I attended a demo of one of their aerial photo platforms. Pretty cool, big helicopter, but I would call it "big iron" and I'm sure they've replaced it with more current technologies.

Aerial photography and UAV are huge markets. There must be a BUNCH of forums devoted to the special needs for both hobbyists and professionals.

bogiesan



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jamie hamlin
Re: Optical Flow Slow Motion Q
on Nov 19, 2009 at 10:16:43 pm

Yes, Twixtor does a great job with 24p. About the only option I have found.

Not to change the subject but there are alot of people attempting to get good video off UAVs. Honestly there are only a couple in the US that are capable of actually putting out production quality video.... me being one of them. You probably have seen some at shows. Bet they didnt lift off and show you some footage. Alot of folks have paperweights. I am working with a company who designs UAVs just for this purpose. Gimbal stabed by a KS-2. Footage looks like a boom or crane shot that just keeps going. We do dolly shots but no worries about track. Its just amazing!! I am flying a pre-production helicopter that is WAY ahead of the curve. Hum, might need to post an ad in here.

Thanks to everyone for their help! Let me know if someone wants some amazing footage! Will travel!

Jamie


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Jeffrey Di Lullo
Re: Optical Flow Slow Motion Q
on Nov 26, 2009 at 4:01:20 pm

Check out Kronos from the Foundry

http://www.thefoundry.co.uk/pkg_overview.aspx?ui=FA1927C8-65AB-4463-8997-4F...

It does a fantastic job. I have both Twixtor and Kronos and feel that Kronos does a little better job on busy footage. Though they are both excellent plug-ins. Also the Foundry is running a sale till the end of the month only $150 for the whole furnace plug-in set. GREAT deal.

Truly

Jeffrey Di Lullo



Jeffrey Di Lullo
Jeffedits.com


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Albert OConnor
Re: Optical Flow Slow Motion Q
on Dec 2, 2010 at 5:25:30 pm

I just posted on FCP a 1080 24p (23.976fps) project shot with a Canon EOS still camera where the DP recommended shooting the slo mo scenes at 1080 60p (59.94fps) to be made slo mo in post using FCP.
I trusted what he was telling me but a little voice in the back of my head was screaming at me but I ignored "him".

The scenes shot at 60p are where an actor threw objects into the air, these objects were blurry frame to frame due to the shutter speed the DP used; I have no idea what shutter speed he used, he was relying on frames per second and not shutter speed to create smoother slo mo.

Optical Flow Retiming made slo mo shots smoother but the blurred objects still looked blurred because that's how they were recorded at a moderate shutter speed. So his suggestion of shooting them at 60p sounded good in theory but in practice wasn't what I had hoped for due to whatever shutter angle/speed he used.

So what I'm saying is shooting at 59.94fps isn't going to do it.
I agree with another post that stated shooting at high fps is your best bet for really good slo mo.
But if you're stuck with the camera you have, sure shoot at 59.94fps but use a faster shutter speed to get sharp images on each frame.

Bob


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Stephen Smith
Re: Optical Flow Slow Motion Q
on Dec 2, 2010 at 6:02:39 pm

This is called Over Cranking. If you log and transfer the footage in FCP it will not play in slow mo like you really want it to. To achieve the effect you need to use Cinema Tools to "conform" you 60p footage to 23.98. Hope this helps and best of luck.

Stephen Smith
Utah Video Productions

Check out my Motion Training DVD

Check out my Motion Tutorials


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Albert OConnor
Re: Optical Flow Slow Motion Q
on Dec 2, 2010 at 9:32:16 pm

Stephen,
Thanks for the tip! I gave it a whirl and it works but like I said earlier, the moving objects were blurred from the get-go and even Cinema Tools conform couldn't de-blur the thrown objects. One other thing with the Cinema Tools Conform then Optical Flow process, the objects that were thrown cast shadows on the actor's face which caused some really funky morphing pattern/effect on the actor's face! Hmmmm, keep in mind for future video projects!


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