Shaky Screen Replace I Thought Simple. Wrong?

So I thought this would be simple. I’ve tried tracking every bit of the hands, different parts of the phone eges / screen / etc., and have worked around reflections but can’t get this one to work. Am I dumb?

Are you replacing the chip or putting something on the phone? It looks like the chip to me. And if that’s the case you are just running out of data to track. However, where the track seems to be going the worst is the end so just use manual track on those last several frames. Manual track is a bit fussy, but really helpful for this kind of thing. You can see an in-depth overview of manual track here, but essentially the workflow is:

  1. Switch to manual track.
  2. Make a keyframe on your last good frame.
  3. Hand animate the last few troublesome frames.

Please let me know if you have any more questions and I will be happy to help you.


HEY MARY! Sorry I should’ve been more clear. I’m actually comping a screen into the phone. Not working with the chip.

I’m finding the reflections, however subtle, are throwing off all of my tracks, and the finger movement and occlusions throw my tracks off and I can’t figure out how to work around them.

OK, I have a similar shot and there’s a few things you can do.

  1. You can make a ton of holdout mattes for fingers and shadows and put them in the layer above the track to help hold out pixel motion that might confuse the track.

  2. Only track the edges, and track slightly outside the edges by a few pixels to help Mocha grab that data. The tracking shape should look like a “C” shape or a picture frame, depending on what works best.

  3. I can see you have some lighting challenges that are probably enough to throw Mocha off, so you can try tracking translation, scale, and rotation only and then using adjust track to hand animate the skew/shear over time. If the track has a hiccup, switch to translation only for that part.

  4. Try tracking a little bit of the fingers on the right hand side of the screen for stabilization in the same shape you are tracking your screen in.

  5. Punch up the contrast and see if you can find the pixel data that is messing the track up and avoid it. Bonus, this gives you crunchier data to have Mocha chew on.

  6. A combination of all of the above.

Shots like this are deceptively hard, you’re missing two corners you’d need for a better track, the contrast is low, the lighting is more dynamic than it looks, and there’s occlusions. This is trackable, but it’s tricky. I think you can get it using some of these techniques though.

Please try that and let me know,

OK wow much better. Thank you Mary O Master of the track.