Remove tool and training

We have the Mocha Plug-in for our Avid Media Composer. I have spent a lot of time watching online tutorials and reading through links on using this software. After a few dozen tries I have been unable to have any of my removes work and I have no idea why.

I think most of it involves none of the training really explains what to do when things fail, nor do they really explain some of the finesse and fine tuning required.

Apart from hiring someone for training, does anyone have any suggestions?

Make sure that you have a tracked BG and that the BG shape is larger than the object you are trying to remove. Make sure your background track is rock solid. And make sure that you are removing over a planar Background. You can’t remove over a whole scene with people walking through it or fractal waving water and grass. If you have shadows going over the area you need to remove, you are better off doing that as a patch. Without seeing your shot, those are my most common troubleshooting techniques.

Thanks for the tips. I have made sure the BG shape is larger than the object I am removing and have run the tracker on the BG. I turn the grid tool and surface tool on, but I really don’t understand how I am supposed to use these items and what they are telling me.

The shot I was working on today, I tried to remove a blue artifact on a shot from a lens flare. The artifact did not move in the shot, but a person’s leg swung through. The results looked like poor use of a clone tool where it was included information that it shouldn’t have.

Another time was a drone that was in the shot. The drone didn’t move, it was simply hovering against the sky. Again, the results looked like a bad clone or patch tool job where the sky gradation wasn’t even close.

I can upload a still if you like, but I’m more curious about what options exist for training as this is fairly complex software.

I use Mocha in Vegas Pro. And I’m also learning. And so far I’ve learnt a most fundamental concept, that when I want to remove an object it depends on WHETHER it is moving, then it’s motion tracking against a tracked BG, OR if there is no motion then use a Clean Plate where that clean plate is created in a photo editor, here that would be your stationary Drone.

For motion tracking MOCHA can only replace that which had been ceanly tracked and can REPLACE on, say, a panned motion. On the other hand MOCHA can’t Track a BG that doesn’t move and I need to produce my own clean plate in a Graphics editor. This was when the penny dropped for me. I had watched many of the Tutorials and it wasn’t until I had this most fundamental of concepts under my belt could I go forward. Thank you Mary.

So far I’ve removed a person walking through a stationary shot and I’ve removed an ugly power outlet to one side of a Talking Head.

I hope this helps?

It sounds like you are getting a bad track and not understanding the fundamentals of planar tracking in the first place.

In order to get a good remove you must have a good background track. The way you get a good background track is by drawing a shape around a single plane. Break your shot mentally into a low poly model, each “poly” is a plane. That’s what you need to track, and you can’t track more than one “poly” at a time. You align your grid and surface tool to the plane and see if it follows the plane exactly, if it does, you know your track is solid. If it does not move along with the plane as if it was glued in place, it is not a suitable track for a remove. The remove tool is only really useful for removing over one or two planes at a time, with the exception of some complex removes over very geometrically planar backgrounds.

Removing an artifact from a lens flare will work as long as your track behind it is a single plane, but often it’s a complex organic background. You might have better luck rotoscoping and color correcting that section if the background behind the flare is complex.

To remove a drone, is the sky moving behind it? If not, you need a cleanplate, and for a lock off shot you’re better off with a simple patch. If the sky is moving, you need a good track on the sky. Often, the better solution for something like this is rotopaint though. It’s way faster for the sky, which is very forgiving and can be feathered. If it’s clouds though, the remove tool is your best bet. Just make sure you track the clouds well.

Cheers,
Mary