Optical Flow

I have purchased Final Cut Pro X and i'm really intreged in the Optical Flow option for slowing down motion in my videos. But i noticed i don't have a lot of control over it. I just say i want it to be optimized for optical flow, then i slow the video down, and it does it's magic on making my 60fps video look like it was shot in 1000fps or something crazy like that!
but i get all these artifacts in my video that warp and move around a lot. i want to get rid of that.
i was curious if Motion 5 has optical flow in it, and if it has any better control over it. or if motion 5 does have optical flow in it, if it's just a matter of saying 'i want this to have optical flow and to slow down to 5%', or if there's more to it than what you can do in final cut pro x?

GFXZen wrote:
http://www.fxguide.com/featured/art_of_optical_flow/
Hopefully this will help you ...
AWESOME article, thank you VERY much for sharing this, GFXZen!
.... probably way beyond my amateur skills, but very, very, very interesting.
in my humble hobbyist's observation, too much 'changing' from frame #1 to #2 (I was told the tech term angular speed is of importance here…) creates wobble, and the Oflow in M5 has some probs with rotation (=I'm doing a lot of soccer stuff).
my simple rules:
shooting with high shutter speed (=avoiding natural motion blurr)
no close ups
cam on tripod
= good results.
… and that fits to the 9 rules mentioned in that article.
5 stars, GFXZen!

Similar Messages

Optical Flow and setting Offset make Not an Image

Hi all,
What I'm trying to accomplish is taking only a few hundred rows from a camera sensor to improve frame rate and moving the offset around based on movement in the image.
I am utilizing configure grab and grab in a loop to improve refresh rate.
I set up a test where the offset in Y was just incremented each loop and displayed the image. This is no problem. I have the incrementor as a remainder output and it will loop all day without error, and the image 'scrolls' across the available sensor space.
When I use optical flow (or point LK algorithm), with no incrementation, and just moving the camera around, optical flow has no problem. It will run all day. Also, the output is correct when I take care to set up the algorthim.
However, when I put the incrementation of the offset and the optical flow together, there is a problem. I expect the optical flow to return a vector similar to my incrementation. Instead, the program exits with a 'Not an Image' in the input of the optical flow block. Indeed, if I put a probe down the image does not appear.
The weird thing is this: for some increments it runs no problem. If I increment 10 rows at a time, no problem. If 8 or 9 or 1 for example, it crashes with 'Not An Image'. If I feedback the output of the optical flow vector into the offset change, the program will run until the distance of the vector in one of the X or Y directions happens to be one of these 'unhappy' numbers.
I also don't understand why 'Grab.vi' is returning an empty image when connected to optical flow, but with an image output without optical flow the image is never empty.

Hi,
Please share your code if possible. This would be helpful to better understand your code flow and make recommendations accordingly.
Also for your reference, here is also a link to a forum regarding optical flow:
http://forums.ni.com/t5/Machine-Vision/Displaying-Optical-Flow-from-AVI-file/m-p/2738890
Luis S
Application Engineer
National Instruments

Check settings combinations to achieve good Optical Flow HDV 50i -ProRes422

Hi Guys
RE: Motion 3, HDV 50i, standard ProRes 422, optical flow
I'm trying to decide which combination of settings I should choose in order to ensure the highest possible standard of optical flow-treated video for a video clip which just features live people - no graphics.
So far my results haven't been as 'smooth' as I would have liked. Below I have detailed my steps taken - if you could recommend which combination of 'lighting', 'field rendering', 'motion blur' or 'frame blending' I should choose I'd appreciate it.
1. I captured my Canon XHA1 HDV 50i video via HDV - standard Prores 422
2. I edited in FCP6 with standard Prores 422
3. I sent a video clip to Motion 3, new project and chose Broadcast HD 1920 x 1080 25 fps field order Top (Upper First)
4. I treated the video clip with optical flow to slow it down.
5. Export as standard Apple ProRes 422 movie.
Prior to exporting which of 'lighting', 'field rendering', 'motion blur' or 'frame blending' would anyone recommend please?
For reference, in this forum David Bogie kindly stated the difference between the choices. I have included his post below. However I just want to be sure I'm making the correct choices, as I'm a bit confused about the '50i' (interlaced) aspect of my video footage.
Here is David's post:
"lighting
field rendering
motion blur
frame blending"
These are options you need to use when you know why you want to use them.
If you have lights on in your scene, you want to render them. If you have no lights (and no camera) you do not need to activate lights. why does the switch exist at all? I render without lights for preview purposes.
Fields are necessary for interlaced formats. You must know if your production format is progressive or interlaced.
Motion blur enhances the illusion of movement by simulating image smear caused by an open shutter. You get the illusion at the expense of rendering time.
Frame blending is only necessary if you have video clips in your scene and even then you don't need it unless you've changed the speed of the clip. Sort of. "
Zak Peric also kindly posted, although I think his post relates more to graphics as opposed to interlaced video footage. Nonethless, here is his post:
"Just use animation codec + alpha if you have alpha channel if not use animation codec millions of colours. This is the best codec for best quality. Also 4444 is a very good codec to use as it supports alpha channel but gives you smaller file sizes. Use always BEST from the render window, if you want additional motion blur then switch it on in render view. Be advised it takes much longer to render with motion blur on."
Any tips would be really appreciated.
Warm regards
Peter

Hi Mark
Thanks for your kind prompt feedback.
"You say you sent a clip to Motion, but then you say you chose project settings - I don't understand this. If you really "sent' a clip to Motion using Final Cut Pro's "Send to Motion" command, you don't need to set project settings - Motion automatically creates a project with settings that match the FCP sequence. "
Okay I understand - sorry for any confusion caused - I had already used "Send to Motion" and applied Optical Flow to a clip which I then exported from Motion 3 as a Quicktime file. I was planning to repeat this process afresh, but am interested in which settings you could recommend from 'field rendering', 'motion blur' etc that might be applicable to my Optical Flow-analysed footage prior to exporting it as a Quicktime file.
As regards exporting my Motion work as a separate Quicktime file, I prefer to do this so as to avoid the waiting for it to render in FCP.
The already-optical-flow-analysed footage is actually pretty good (the original clips from FCP6 have already been stripped down to short durations to suit Optical Flow), but want to to double-check which of the 'field rendering', 'motion blur' etc combinations I should ideally choose to obtain best results, just in case I'm neglecting something that could otherwise make the quality even better?
Once I finish this video project I'm on I'll definitely be going for a clean install of SL and FCS3.
So, based on these choices...
lighting
field rendering
motion blur
frame blending
...I'm thinking that for my optical flow-treated video I won't need lighting, as it's mostly applicable to graphics.
I don't have any graphics in these optical-flow video clips. It's just moving video footage of people.
Am not sure about whether to choose Field Rendering (interlaced PAL 50i HDV - ProRes422 video).
Am not sure whether to choose Motion Blur.
Am not sure whether to choose Frame Blending.
Any tips would be really appreciated, and thanks again for your valuable feedback.
Peter

Can't get Optical Flow to render

I've read a couple of posts about other people having this problem, but they don't seem to apply as I can't find a workaround. I'm running FC 10.0.8.
If I render my timeline (about 15 minutes), the entire timeline renders, except for about five seconds that are in slow motion. The orange bar remains above that section even after the entire timeline is rendered.
After reading the other posts, I know the following might be relevant: I'm editing optimized AVCHD footage. There is no speed ramp. It's just a clip at slowed to 50%. The clip is completely separate (it's not just a selected range--in another post, somebody said just selecting a range was their problem).
I also tried creating a new project, bringing in a short clip (and nothing else), slowing it to 25%, and rendering all. The percentage display counted up to 100% like the clip was being rendered, but, at the end, the timeline still showed orange above the retimed clip.
I should say that I don't know if the clips are actually rendered properly in Optical Flow. I'm not sure I'd be able to tell the difference. All I know is that the timeline is still showing orange above them, so I'm presuming they aren't.

Russ--
Funny thing. I decided to test this by taking the same very brief clip and putting it into a timeline three times in a row. Then I made each slow motion 25%. Then I left the first normal, made the second frame blending, and the third optical flow. Then I exported the master file.
I guess I can see a difference, but the optical flow section actually looks kind of blurry to me.
Then I went back to the timeline and chose Modify> Render All. And FCX rendered the entire timeline, with no orange above any portion (not even the Optical Flow portion).
So I don't know what to think now. I don't know what the problem was, or if optical flow is any better than normal or frame blending. Maybe I need to try it with some different footage?

Optical flow retime not working

i am using a backup library and event for a project and now the projects retimes with optical flow with 24p photage are really stuttery, they where not this way in the original project ... any idea why? Ive tried different thinks but i am still getting the same results.

This problem has also crippled my normal workflow for the past few months, but thankfully I think it's been fixed. I ran the latest OSX software update 3 or 4 days ago (I think it's at 10.8.2 now), but was relulcant to check if optical flow was fixed because the notes about the update mentioned nothing about it. Yesterday, however, I dared to try using Optical flow on a clip just to humour myself, but it worked! Try running Software Update and see if that works for you.
I'm still a little upset though that thoughout the past few months where FCPX users on Mountain Lion complained about this problem, Apple never said a word about acknowledging the issue, that a fix was on the way, or announced that the issue was fixed. I for one sent about 5 feedback bug reports every 2 weeks about the problem and never received a single response.

Optical flow equivalent for slo-mo?

Hi all...
I have been very interested in discussions about really amazing slo-mo footage, and I did post here recently about my 60fps 7-d footage and how to work with it. I did a test and it worked out well.
Here is my query;
Instead of paying thousands for a Phantom camera... ---amazing really... you should check out Tom Guilmettes new site and see his "locked in a hotel room with a phantom' video.. awsome results-- I have seen that with a Final Cut Pro plugin called 'Optical Flow' I saw 7-d footage slowed down to 1% of original speed!!!! and it looked great!!!
Admittedly, that is far too slow for any useable purpose (for me) but it would open up all kinds of great possibilities.. without the humoungous expense of these pro cameras..
Is there a similar plugin like Optical flow for Premiere pro6? Or any other workflows (programs) to get my slow-mo's down as if I had shot at say 120FPS instead of only the maximum 60 FPS of my 7-D?
Thanks all...
Ray
Miami Beach

Timewarp in after effects is almost as good as twixtor (it's got few tweaks for difficult scenes but does pretty well). Unfortunately you do have to drop in to After Effects to use it
I was rather hoping it was going to be in CS6 like Warp Stablizer is, because those were the two effects I used most.

Optical Flow from AVI file

Hi,
I am trying to calculate and display the optical flow field from a .AVI file. I am working from the example Optical Flow.vi, however I cannot get it to work and am getting a 'IMAQ Vision: Incompatible image size error' on the optical flow function box. As far as I can see the 2 image inputs to the optical flow function are both in 8-bit greyscale format as they should be.
I am using my own greyscale conversion sub vi but this is again taken from one of the examples. I've included both the vi's as well as the .avi file im using. Hopefully someone can point out where I've gone wrong.
Thanks,
Oscar.
Attachments:
optical_flow_1.png ‏214 KB
convert_greyscale.png ‏20 KB

Hi Oscar,
I've had a quick look at your code and although I can't identify the exact reason why it's not working I have spotted a few things.
If I scroll the image I see the vectors appear briefly, so I think the image might be getting ovewritten somehow after the motion flow overlay is drawn
Also, I'm not sure a dedicated Grayscale conversion sub VI is needed, and yours creates a new image reference every time it runs which isn't ideal as it will continue to allocate more memory.
I think maybe a more linear flow of code may help combat your issues, I've written a quick VI that implements motion flow from an AVI, it seems to work fine with the AVI files I tested, so hopefully this might help:
Regards,
Adam Brown
Applications Engineer
National Instruments UK

What is it best to feed Motion for good slow motion with optical flow?

What I mean is: what type of footage does the retiming work with best? I shot some footage in 1920x1080p using a shutter speed of 1/1000 under the assuption that having each frame as sharp as possible (little to no motion blur) would improve the vector analysis of optical flow. Unfortunately, the resulting slowdown isn't very smooth. (50% slowdown is decent but not great and anything slower looks choppy). I don't know if this was due to the shutter speed and progressive frames or simply the nature of the material (A swimmer doing the butterfly stroke, i.e a lot of splashing water) My first test for opticalflow retiming was 1920x1080i at 1/60 shutter (pouring water in a glass). Results were a bit blurry but a lot smoother. Any tips? (interlaced or progressive? slow or fast shutter?) Thanks.

http://panasonic.co.jp/pavc/global/videocamera/hd/global/products/hdc-sd9/
Thanks for tip David. I work at a middle school, we shoot a lot of district functions with three cameras then use the multiclip function of FCP. If I bought three of these cameras do you think they will work well in that environment? here is our workflow:
1. Sync cameras with a clapper at the start of show.
2. Import into FCP
3. Mark inpoint at the sound of the clapper
4. Create the multiclip sequence and edit
We have done 50 or so shows like this with 14 year olds as the editors and the results are very nice. I would like to move to the hard drive based camera. Being in education we are on a tight budget. Think three of these camerass would work in this environment?
Thanks so much for your expert advice.

Optical Flow - Work Flow for Project Tips?

Hello, I have a 45 second sequence in FC and all of the clips are in Slow motion.
I sent one clip to Motion to add the optical flow to get the super smooth slow motion. The clip looks 100 times more professional.
But I have several clips. How can I do them all at once while away from my computer?
Do I export the movie as self contained, then import into Motion or is there a better way with exporting.

Andy, so I finally got it rendered on a Dual Core. I did as you said and selected the clips I wanted to send to Motion. I analyzed and when it went back into FCP it was all one long clip instead of individual clips and between two different shots there was 10 frames or so of black throwing off my time line and timing to the beat. Does anyone know what step I may have skipped??
Also,
I'm trying to render this simple triple stacked text with a light ray keying from left to right in V1 via filters tab.
[IMG]http://i42.tinypic.com/33a9u2w.png[/IMG]
But my comp gives this message: "The effect"Light Rays" failed to render: Your hardware cannot render at the requested size and depth"
REALLY???
Just plane confused. Is it a preference thang?
Thanks.
Message was edited by: thedirtyduo

Does motion 5 have optical flow for slow mo?

Hey
Does motion 5 have the optical flow option to create a slow motion effect ?
Cheers

Thanks for the help,
I am also wondering can you apply this in motion 5, then render/export the clip to be edited in imovie '11 or do I also need FCP X ?

Optical Flow produces only a still frame

Weird bug; hoping there's a workaround...
When I choose a clip and select Video Quality >> Optical Flow, it analyzes it and renders a still frame for the duration of the clip. (The thumbnail indicates shows motion throughout the clip, but indeed it's just a single frame.)
Any help is much appreciated.

As far as I can tell, this may only occur when the clip is set to a reverse direction (-100% speed, for example).

Batch Processing Optical Flow shots

Any one know if it's possible to batch process a lot of shots with optical flow somehow? I have over 20 clips that require various speed ramps and would rather batch them up versus having to come back every time. Any help of ideas would be great. Thanks!

Specifically, 8 bytes per pixel.
So - a 720x480 frame takes 720x480x8 or about 2.8 megabytes per frame. Times 30 frames per second, times 10 seconds and you're getting close to a gigabyte. Multiply that by 20 clips and you can see how you might start filling up your drive pretty fast. AND remember, the ENTIRE clip is analyzed, even if you only use 10 seconds.
So - make sure your clips are limited to the material you are ACTUALLY going to use.
make sense?
Patrick

Optical flow has bulged wave slow motion effect

Trying to slow down hd clips with optical flow, but it shows waving bulged effect, sometimes around the edge, sometimes the whole image. Using 2011 Mac book pro 2.3 g with 8 g memory and thunderbolt raid hard drive. No way to get smooth slow mo effect, any idea? Thanks.
Z.M

Thanks Tom, I uploaded a clip on youtube, it is a time lapse, actually, it doesn't matter what file, same bad effect. Don't remember in the old DV days time change is this difficult.
I chose time change, here 50%, then quality, chose optical flow.
http://www.youtube.com/my_videos_edit?ns=1&video_id=AMWaoh5jmwA
Z.M

Optical flow rendering clip, computer logged out, missing files

I was creating a video, where some of the clips were on the iMac harddrive and some of them were on an external SeaGate harddrive. I was waiting for an optical flow rendering of one of the clips and walked away from the computer. Unfortunately, the computer screen saver came on and logged me out. When I logged back in, and opened Final Cut, the only clips showing available in the library are those on the iMac. The SeaGate files briefly appear in the event library only while final cut is loading, but once it completely loads it disappears (and can't be accessed), and all of the clips from there are showing as red "missing file." Therefore, my video is not there. Any suggestions on how to get back to where I was before the computer logged out? Or why the SeaGate is not available anymore?

this is what shows in the event library as fcp is loading.
once loaded it changes to this:
Here is the finder showing the seagate drive and one of the clips I used:
i ran disk utility, verify disk, both drives are working properly... all green.

Optical Flow in 10.0.6

Optical flow will not render when using speed ramp or Hold Frame. The orange render line never moves and the dashboard timer doesn't indicate any activity. A normal speedup or slowdown seems to be fine. Anyone seen this?

Kind of interesting result. For adding slomo to clips that had no retiming optical works fine in 10.0.7. But for clips previously retimed using normal, optical doesn't seem to work when you try to change from normal to optical flow.

No optical flow going from FCPX to Compressor

Using Compressor 4.1.3 and FCPX 10.1.4. When I export a project from FCPX to Compressor, and the project has some clips with Optical Flow, Compressor does not render those clips using Optical Flow. Using "Apple Devices HD (Best Quality)" setting.
I searched for similar questions, both here and in the FCPX forum, and didn't find any similar questions, which leads me to believe that either I don't know how to search properly, or I must be missing something obvious.
Any help is appreciated. Thanks.

Your experience matches what others have reported. Alternatively you could export a master file and bring that into Compressor to apply your settings. In other words, skip the Send to Compressor workflow altogether. Or export directly with ATV settings from FCP X
Russ

Optical Flow

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