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efraim orlower/upper field
by on Aug 24, 2009 at 11:37:40 am

Hi everybody.
I'm trying to use RevisionFX Twixtor to get really slow 'slow motion' effect.
therefor, I tuned the 'speed' to 5%.
there problem is, I keep getting strange lines and "rub" at the places where the most motion, why?

is it got something to do with the lower/upper field? its just the I have no idea what lower/upper field dialog means.
right now its one NONE at the footage setting and none on the Twixtor.

any help guys? I'm starting to give up on it.


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Todd KoprivaRe: lower/upper field
by on Aug 24, 2009 at 3:02:38 pm

Is your source footage interlaced? Did you separate video fields when you imported your footage?


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Ben HeusnerRe: lower/upper field
by on Aug 24, 2009 at 6:03:30 pm

I'd also add a quick RTFM for Twixtor too. Starting with the fields and see if that solves it.

All the best,
Ben

Curious Turtle Pro Video
Training | Editing | Support


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efraim orRe: lower/upper field
by on Aug 24, 2009 at 6:40:09 pm

thanks Todd and Ben. I'll start working on it right now.
I'll let you guys know if its working.


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efraim orRe: lower/upper field
by on Aug 24, 2009 at 10:19:00 pm

nothing guys.
chose upper field to the footage and in the render setting, AND in the Twixtor.
still looks stammer and unstable. why cant I make it smooth slow motion?


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efraim orRe: lower/upper field
by on Aug 24, 2009 at 10:56:48 pm

ok, just rendered out example:





please help...I cant get slow motion without this annoying side-effect.


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Ben HeusnerRe: lower/upper field
by on Aug 25, 2009 at 4:51:38 am

It looks like it's picking up the black edges from your source video. Try scaling the footage up a small amount, pre-composing the layer and then applying your Twixtor effect.

Remember to check off "Move all Attributes to the New Composition" when precomping.

Hope that helps,
Ben

Curious Turtle Pro Video
Training | Editing | Support


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ben rollasonRe: lower/upper field
by on Aug 25, 2009 at 10:25:28 am

I don't think it's a fields issue. The artefacts in your video look to me like the perfectly normal side effects of trying to slow down a piece of video 20 times. Twixtor is very clever - as are the built in frame interpolation methods in After Effects - but these technologies can't perform miracles.If you've slowed down your footage 20 times, the software is having to create 19 frames out of thin air for every one that you shot. The interpolation between frames is linear, which is why you get this strange cadence.

The more you slow footage down, the more obvious the artefacts become.

In my experience, using these effects are no match for shooting with a high speed camera and we can't really expect the results to look the same.

As a rule of thumb, reduce the shutter time as you shoot by the same factor as you wish to slow the footage down. i.e 4x slow-mo, shutter time = 1/200th. This will make the motion blur match correctly. Apart from that, it's simply a matter of tweaking the settings until you get it as good as you can.



http://www.benrollason.com


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efraim orRe: lower/upper field
by on Aug 25, 2009 at 1:46:12 pm

ok... I tried it all, nothing works.
seems like you were right, its the crappy camera...hehe.
I used my 5M Pixel phone camera...guess its time to buy a new one?

thank you guys for trying to help anyway..good day.


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Ben HeusnerRe: lower/upper field
by on Aug 25, 2009 at 1:56:04 pm

I was looking at the wrong problem apparently! :o)

The other Ben was completely right when he said that 5% is an extreme amount of speed change. You're trying to get the equivalent of shooting about 500fps just using software. With the best will in the world, that's not going to happen.

Hope you find another creative solution for your project.

Cheers,
Ben

Curious Turtle Pro Video
Training | Editing | Support


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efraim orRe: lower/upper field
by on Aug 25, 2009 at 2:00:48 pm

Ben.H, lets say I want to make it 5% slow motion.
is it possible with a good professional camera? (unlike the 5M Pixel phone camera I used.. hehe)
and if it is possible, maybe you can show me any camera that CAN do it?


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Ben HeusnerRe: lower/upper field
by on Aug 25, 2009 at 2:33:28 pm

A 5% slo-mo from any source footage is a big thing to ask. As Ben R said, you're creating 95% of the movie from nothing. There are some very smart alogrithms at work in Twixtor and other optical flow slo-mo filters, but they don't have a great deal of information to work with at 5% speed.

There's tweaking you can do to the filters, which can reduce some of the effect, but I wouldn't think it would be good enough.

If you're after that super-crisp super-slo-mo effect you have to shoot at higher frame rates. The Red One, for example, can shoot up to 120fps. That will give you a bit more lattitude in post.

Cheers,
Ben



Curious Turtle Pro Video
Training | Editing | Support


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efraim orRe: lower/upper field
by on Aug 25, 2009 at 3:14:31 pm

are you crazy? this camera costs $17,500 body only (@#%@#%@$#^!@!!!!)
when I said "good professional camera" I meant HOME camera for a beginner camera man... that CAN give good results and quality image.
something smooth to work with in AE.

anything like that mate?

btw:
how come in Hollywood's movies they can make some shots even 2% speed, and it still looks smooth?


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Dave LaRondeRe: lower/upper field
by on Aug 25, 2009 at 3:56:57 pm

[efraim or] "...when I said "good professional camera" I meant HOME camera for a beginner camera man... that CAN give good results and quality image...."

Then you should have SAID "home camera" instead of "professional camera". Why do you think the Red One costs so much? Because it can do things that a pea-shooter Handicam can't do, that's why. And if there were such a camera as you write about above, don't you think everybody would have one? Apparently, you've got champagne tastes on a beer budget, pal.


[efraim or] "how come in Hollywood's movies they can make some shots even 2% speed, and it still looks smooth?"

Because in Hollywood, they go out and get the right camera for the job no matter what it costs, which is something that that your budget won't allow, I guess.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Ben HeusnerRe: lower/upper field
by on Aug 25, 2009 at 4:04:54 pm

What Dave said.

[efraim or] "how come in Hollywood's movies they can make some shots even 2% speed, and it still looks smooth?"

That'll be the overcranking not the software interpolating 2%.


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efraim orRe: lower/upper field
by on Aug 25, 2009 at 4:11:31 pm

I see, thanks for the info Dave and Ben.
found a solution btw, found 2 frames that the change between them VERY little, and the 5% slow motion works great...very little frams for AE to fill.

anyway, you guys helped a lot so thanks mates.
have a nice day.


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Todd KoprivaRe: lower/upper field
by on Aug 25, 2009 at 4:11:15 pm

To add to what Dave said:

The important thing about the specialized cameras used for filming action for slow motion is that you can shoot at extremely high frame rates. That way, when you slow the footage down to 24fps (or whatever), you have all of the information from full frames---rather than have to interpolate (make up) image data for some of the frames.

Software like Twixtor or Timewarp is good for slowing down some, but a factor of 50 really relies on having _shot_ at a high frame rate.

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