FCP X/DSLR Slow Motion Question

[Bill Davis]

Call me crazy, but it seems like you’re recording at 60fps in one raster size (1280×720) then transcoding BOTH the frame size AND the frame rate, then slowing THAT result down? And you’re wondering why things don’t look smooth?

I’m kinda not surprised.

If I read this correctly, you’re interpolating stuff that’s been interpolated then changing the time base of the resulting interpolation.

That’s kinda the digital equivalent of taking a nice photo, crumpling it up into a wad – flattening it out and taking a picture of it – then crumpling the print of THAT picture – then re-photographing it again and wondering why the print doesn’t look very nice.

Pick a frame size. Pick a frame rate. (both as close as humanly possible to what you originally shot – identical if possible.) Do ALL your editing and time re-mapping in that one standard. When it’s all done to your liking, then output the result to your delivery format.

If I’m misreading this sorry, but at that’s my initial impression.

“Before speaking out ask yourself whether your words are true, whether they are respectful and whether they are needed in our civil discussions.”-Justice O’Connor

[Nick Paonessa]

I’m sorry, I’m a total novice and don’t really understand some of the terminology being used. I’m just a beginner trying to learn, so please instruct using layman’s terms. I don’t understand the terms “interpolating” and I don’t understand this:

“Pick a frame size. Pick a frame rate.” (both as close as humanly possible to what you originally shot – identical if possible.)”

The way I’ve been told to get smooth slow motion from my DSLR was shoot at 720p 60, being sure that I double the frame rate while shooting, then conform to 1080p 24 in FCP X when I start a new project — Have I not done that properly? — Per the explanation in my initial post?

“Do ALL your editing and time re-mapping in that one standard.”

I don’t understand “in that one standard.” I thought shooting in one standard then conforming it to another is what made the footage look professional. Keep in mind, I’m shooting a slow mo TEST, it’s simply a shot of my dog sniffing grass.
In FCP X, I’m choosing the clip, slowing it down to 10% and choosing Optical Flow under Video Quality. The result is giving me wavy motion and trails.

When it’s all done to your liking, then output the result to your delivery format.”

I don’t understand this either. The result isn’t to my liking and I do understand how to export the finished product. (if that’s what you mean — “output the result”?) I simply go to the “Share” drop-down window and choose “export media” > H.264 and save it to my external HD.

Please advise.

Any feedback is greatly appreciated.

[Jeremy Garchow]

Nick-

Drop your 60p footage on your 24p timeline and choose “conform speed” from the retiming menu.

This will playback your 60p material at 24p without making new frames (interpolation) and give you about a 60% slow down.

Jeremy

[Nick Paonessa]

Thanks Jeremy,

I didn’t know about “conform speed” from the retiming menu. So I’ve conformed speed and it gave me a 40% slow down automatically, it looks great and even better when I switch to Optical Flow. But when I slow THAT down to 2%, I still get trails and rolling shutter. Is that just because my camera isn’t shooting enough FPS and/or incapable of getting say, the slow motion quality you’d see in a football game/basketball game?

When I see test video online for Plugins like Twixtor or in After Effects, their slow mo quality looks perfect — no trails, no rolling shutter.

Is that because they are shooting like 1,000 FPS or is FCP X incapable of doing this kind of slow motion?

Or is it something that I am doing wrong?

[Jeremy Garchow]

This isn’t magic, Nick.

If you need 1000fps slow motion, you need to shoot it that way.

You shot 60fps slomo. If you need to go slower than that, you can use software to make up new frames of information, but it’s literally making up new information and sometimes, it doesn’t look natural.

Jeremy

[Steve Connor]

Unfortunately you do have to shoot at a much higher frame rate if you want to go down to that low a speed, even Twixtor wouldn’t help

Steve Connor
“FCPX Agitator”
Adrenalin Television

[Craig Seeman]

What you’re doing is very challenging for Optical Flow software in general. Twixtor will give you a lot more tweaks (and therefore may take a lot more experimentation time) but the results may not be that much better.

Basically you’re trying to duplicate what a high speed camera does, like Phantom, costing well over $100,000, with a plugin. Even Twixtor can’t match that in many cases. If software could do it then people wouldn’t be renting Phantoms.

That said, to do it in software really depends very heavily on your subject matter. Optical Flow is trying to create frames that don’t exist by examining the change in motion from frames that do exist. This motion estimation can get things right but it can also (and often) estimate wrong. Twixtor gives you a bit more control over that but difficult subject matter can result in the same problems.

One thing that can help is shooting at much higher shutter speeds. This gives you frames with much less motion blur and therefore, helps the algorithm in making its estimation. Also, when shooting stuff for extreme slow-mo you should avoid complex backgrounds. Especially if there’s ancillary motion. Avoid moving objects that cross paths. Often an object crossing a background with a hard edge in it can create problems as well.

That said, here’s an example of Extreme Slo-motion much like you’re trying to do, down to 1%,
Watch the video very carefully and think about why the subject matter works. If you watch very carefully though you can still see the points where the estimation misses but it may be hard to catch. It seems most obvious as he changes speeds.

https://vimeo.com/25894146

Some contents or functionalities here are not available due to your cookie preferences!

This happens because the functionality/content marked as “Vimeo framework” uses cookies that you choosed to keep disabled. In order to view this content or use this functionality, please enable cookies: click here to open your cookie preferences.

[Nick Paonessa]

I do see where the estimation misses.

Thanks everybody for your help.

I really appreciate it.

[Mitch Ives]

[Nick Paonessa] “I’m having a huge problem trying to capture “true slow motion” in FCPX. When I slow the footage down, even with Optical Flow, I don’t get professional looking slow motion. It’s pretty good at 50% but if I try and slow it down anywhere between 25% and 1% I get the wavy rolling shutter stuff, trails and everything in between. It doesn’t look professional. Can anyone help me understand what I’m doing wrong? Please help.”

We’re having better luck doing it outside of FCPX, using Lock-n-Load…

Mitch Ives
Insight Productions Corp.

“Criticism may not be agreeable, but it is necessary. It fulfills the same function as pain in the human body. It calls attention to an unhealthy state of things.” – Winston Churchill

[James Bayliss-smith]

Hi, further to the questions raised on this thread. If I want to shoot the slowest slo mo possible on a 5DMKii, without using optical flow then I shoud shoot 60p in NTSC mode. Put it on to a 24p time lines and conform speed.

My question concerns NTSC vs PAL. I live and work in PAL land so I know nothing about NTSC. in FCPX there is an option to have a timeline at 23.98 fps or 24 fps. Should I choose 23.98 as I’ve switched the camera to NTSC mode or shall I just leave it at 24fps. Or even 30p. What are the drawback of 24p if my output is for viewing on a computer.

Thanks