Blackmagic Forum

This may be a newbie question, but I was using a planar transform (from the planar tracker) to perform a match-move of a title to a background object and I was hoping to be able to smooth the tracking so that the title movement was smooth even though the background object movement was jerky (hand held footage).

This was inspired by a recent update to FCPX object tracking that allows low-pass filtering on the tracking data for exactly this purpose.

Anyone here know how to accomplish this in Fusion?

Thanks!

Not with the Planar Transform. It's easy to do with the standard Tracker, although it's a little confusing since they use 'smooth' to mean two different things.

If you have a Tracker node, you need to first convert the Displacement paths to XY paths by right-clicking in the image Viewer and pointing to Tracker[#]Tracker[#]Path:Polyline > Convert to XY Path... (this step can be skipped if your Preference in Global > Splines > Tracker Path is set to XY Splines). Open the Spline View and select the Tracker's Tracked Center keyframes. Select them all, right-click in the spline view, and choose Smooth Points. (Not simply Smooth, which just changes the interpolation from Linear to Bezier.)

As far as I know, the Planar Transform has no such options to manipulate its data at all. The best you can do is delete individual keyframes, but I'm not entirely sure what the end result of doing that kind of hatchet filtering would be.

You will also get much improved smoothing in the point tracker, if you go into 'Match Move Settings', 'Reference' and select 'Start & end'. Then vary the 'Reference Intermediate Points' slider to suit your taste.

I haven't tried it with this purpose in mind, but there is an option in the planar tracker itself (so not the planar transform) to smooth/stabilize which can be reversed as well, so maybe if you stabilize/smooth, then merge your footage on top of that and reverse then it will work (or it might have the exact opposite effect come to think of it)

Another bit more out of the box option is that you could hack around the planar tracker's intended use.
After you've completed your track, the tracker doesn't actually look at or care about the footage that's going in there, so if you do what I mention above (smooth/stabilize) you could feed your title into that planar tracker and let the tracker smooth out the motion. I don't have any useful planar tracker reference footage available to me so I can't check, but in theory you should be able to do something close to what you're looking for.

@steve: can you share your footage, so I could give it a try? I'm a bit curious right now whether or not it would work.

Thanks to all of you for taking the time to respond. I will have a look at your suggestions when I get a chance.

@Sander - the footage I'm using happens to be from a purchased tutorial from Ripple training so I can't really share it. Any video with jerky motion should work, though.

So far I gave Bryan's suggestion a try and it did pretty much what I was looking for.

Thanks again, guys - I really appreciate the spirit of this forum.

Steve

99% of the time, my answer to questions about the PlanarTracker is "Use the point Tracker instead."

If you have some keyframes that don't work you can't delete them from the Spline window when the node Operation Mode is in "Stabilize".
The best way that I find to resolve this problem is this one:
- Switch the Operation Mode from "Stabilize" to "Track".
- Open the Spline window and delete or smooth the wrong keyframes
- Switch the Operation Mode from "Track" to "Stabilize"
- click "Compute Stabilization"