Getting Back to Mocha Pro-Can't See Matte

As usual, I go many months between Mocha sessions and tend to forget a lot of stuff. I need to replace a phone screen with a web site, so tracking and corner pining is what I’m looking for.

I’m running Mocha Pro 5.6 AE Plugin version inside After Effects 16 (latest October release). I’ve tracked my phone screen, made the roto, linked to track layer and tweaked from there. Back in AE, I can’t get it to show the mask I’ve made. If I hit View Matte, my screen turns black. If I hit Apply Matte, the entire screen is transparent. BUT, if I hit Create AE Masks, I do get a mask for my screen.

I noticed when I go back into Mocha, I can no longer turn on the Process cog for this layer. Not sure how that happened.

I’m also struggling to remember the corner pin workflow inside the plugin. I’ll keep looking for tutorials.



Out of nowhere, the mask is now visible. I didn’t change anything. Oh well. OK, I’m getting smarter now. I realized the Process cog can’t be turned on because I have it linked to the track layer.

My issue with getting my replacement layer corner pinned is still there though.

If you’re using the new Mocha AE CC you might find these videos useful: Boris FX | Mocha AE CC in Adobe After Effects 2019

Here’s the export workflow: Boris FX | Quick Tip: Mocha AE 2019 Export Workflow for Adobe After Effects

These helped and I got very close. The only thing that’s not working for me is when I hit the Apply Export button, and target my Null layer, it isn’t lined up with the phone. In other words, it seems like the Perspective or Shear is slightly off, buy the main motion is good. Here are a couple of images if that helps.

Since the footage had a graphic that was moved around by the finger, I used the trick of only tracking the outer edges.
My Mocha Setup:

I targeted the Null layer, which will then have my iPhone Search comp Parented to the Null.
My AE Setup:

At least the pattern on the screen makes it easy to see the problem.
Perspective Off:

Here’s another shot showing how the alignment is off. I’ve done this type of job with Mocha several times before and never had this problem. The Planar Surface is aligned throughout the clip on the Roto layer. This is correct?

You might want to make the screen layer 3D so you can tilt it to make it line up. I’ve had great success using after effects 3D camera tracking to track the screen, then create a 3D null object to group the screen graphics to, then using mocha to make the mask for the screen so the edges blend into the screen properly.

Appreciate the tips.

Errant posting.

Don’t use a null for screen replacements, use a corner pin.

Since this screen is very tall as the actor scrolls up, how would I do the corner pin since the new content is not the same proportion as the screen?

Make the insert into a precomp and animate it.

I get that concept, but I’m struggling to remember how not to have my insert content get smooshed into the screen.

Well, there’s a few ways to do it. But as long as the aspect ratio matches the screen aspect ratio, you can simply “fit to comp width” inside the precomp, animate is scrolling upwards, and use that as your insert layer. Or you can animate it properly in place on one frame, in a precomp the proper aspect ratio for the phone screen, animate that scrolling inside the precomp, and then use align surface to make it fit properly.

I watched the video a few times and I understand those techniques. The part I’m struggling with from your reply is the “animate it properly in place on one frame.” Not sure what you mean by that honestly. When I go to my the first frame in Mocha and use the Align to Surface button, then apply that to my graphic, it’s WAAAAAY off. Obviously, that first step is critical.

I did make a comp the same size/ratio as the phone in the shot and placed my taller graphic inside that and I’m clear how to animate to match the finger. Perfect.

That first step though…

OK, what I mean by that is align the insert on the first frame or another frame you like, animate it properly, precomp it, use align surface in Mocha on the frame you made it work on, and it should track to the rest when you copy and paste the corner pin back into AE or apply the data. You will still need to use roto to trim it to the screen so it animates correctly, I would do that with a track matte.