Stabilizing a Jib Shot

[gpjcole]

Hello,
I have a shot on a movie I'm doing post for that is causing me some headaches. We have a jib shot that is incredibly unstable and wavy. After tracking the shot and smoothing it out the best I could I came up with this (Note: I have yet to scale the shot - we're contemplating adding bars to the movie to tighten the frame):

http://www.vimeo.com/4414724

While it is generally smooth around a quarter of the way through the shot you can see a strange warping effect. I have no idea where or how it has appeared into the footage, there isn't any motion blur on the layer, and all I have done is smooth out tracked keyframes. Does anyone know how this has formed, and if it is possible to fix?

Thanks

 

[CaptainMench]

You used AE to track that? It looks like a SHAKE smoothCAM node with all the warping.

First, I'd LOCK OFF the first part until the JIB actually starts the pull. As for the tracking... what technique did you use? One point? Two point?

Any chance you can post that clip somewhere? I'd love to take a look at trying it.

CaptM

 

[Matt Grunau]

Far and again the best results I have had so far, and this was with footage so shaky it looked like the person holding the camera was literally having a seizure and tripping at the same time, was to use frames where more of the shot is in view, use those to rebuild and expand the entire background plate in the composition. Then do a normal stabilization and simply lay the new parts of the frame on top of the stabilized footage, covering any newly formed visible frame edges and emptiness.

The biggest problem after that is not the footage moving, but the motion blur caused by the camera. You can remove that with pretty good success via the blur removal tools in Photoshop and lay it back in, but that can be tedious. The better way is to assemble the finished (and slightly larger) new back plate, motion track the original, and apply that track data via null to only one dimension of the position of the back plate, divide the total movement by half with expressions or slider, and then apply a motion blur to the plate.

The results are startlingly good, and with that little bit of added motion blur, it really covers any errors.


You can also use multiple frames to create a much larger plate "cover", assembled in Photoshop like a panoramic, and after stabilizing, do a motion track and apply it to scale. Then apply that data to the cover.

 

[gpjcole]

You used AE to track that? It looks like a SHAKE smoothCAM node with all the warping.

First, I'd LOCK OFF the first part until the JIB actually starts the pull. As for the tracking... what technique did you use? One point? Two point?

Any chance you can post that clip somewhere? I'd love to take a look at trying it.

CaptM

Yeah I used Mocha to track the shot, and then took the shot into AE, applied the track, and used 'The Smoother' to smooth the keyframes. Considering how bad the original shot was, this is tremendously better.

I'll be able to post the original footage when I get back to my computer.

Far and again the best results I have had so far, and this was with footage so shaky it looked like the person holding the camera was literally having a seizure and tripping at the same time, was to use frames where more of the shot is in view, use those to rebuild and expand the entire background plate in the composition. Then do a normal stabilization and simply lay the new parts of the frame on top of the stabilized footage, covering any newly formed visible frame edges and emptiness.

The biggest problem after that is not the footage moving, but the motion blur caused by the camera. You can remove that with pretty good success via the blur removal tools in Photoshop and lay it back in, but that can be tedious. The better way is to assemble the finished (and slightly larger) new back plate, motion track the original, and apply that track data via null to only one dimension of the position of the back plate, divide the total movement by half with expressions or slider, and then apply a motion blur to the plate.

The results are startlingly good, and with that little bit of added motion blur, it really covers any errors.


You can also use multiple frames to create a much larger plate "cover", assembled in Photoshop like a panoramic, and after stabilizing, do a motion track and apply it to scale. Then apply that data to the cover.

Would this option still be able to be executed even with a large change in perspective? Not only does the camera raise, but it dolly's back and angles down.

 

[Matt Grunau]

Would this option still be able to be executed even with a large change in perspective? Not only does the camera raise, but it dolly's back and angles down.

Yup. If you use the Motion tracker for corner pin it will. You can even use Optics Compensation in reverse to simulate barrel distortion.