So I'm working on a shot which requires some screen replacement and I'm definitely running into an issue with the tracking and possibly making mistakes elsewhere. I've provided a couple of screenshots to give some context.
The shot starts at 'Screenshot 1' and ends at 'Screenshot 2'. As you can see the screen starts off out of frame and out of focus then comes fully into frame and in focus. I've tried tracking with the "Position" and "Rotation" boxes ticked with a "Transform" track type and tried tracking with the "Perspective Corner Pin". The tracking seems to work fine when it's all on screen but the second one of the tracking points goes off screen, it starts failing. When it starts going out of focus, it really starts going all over the place. I've wanted to try using Mocha but it doesn't seem to recognise the file format of the footage. Is there a way to make sure the tracking points stays where it's meant to?
I'll describe what I'm doing the rest of the time just in case I'm messing up elsewhere or could be doing it in a way that makes it easier. "Screenshot 3" shows what's happening when I attempt to put all the elements together.
After the tracking I'll then create a Null Object, then select it in the "Edit Target" menu and hit apply. Then I add the footage that's meant to be on the screen, use the Corner Pin to match it up with the screen, create a pre-composition then parent the footage with the Null object.
I haven't got as far as blurring the footage to match with the "out of focus" aspect as there's no point (again, "Screenshot 3). I am aware that there is a green screen however I've since learned that it's not really needed unless if something is passing in front of it, so I've just not bothered with the keying as that needlessly creates another element I need to take into account.
... and when the TV goes out of focus, you can track another point which is in focus at that point in time -- perhaps the remote control -- from there on forward, then parent one null (TV logo) to the second null (remote control) so that it keeps going even when out of frame.
Thanks for your responses. Firstly, using a single tracking point on the frame rather than trying to use two on the screen has made it so much better! Didn't realise it could be tracked to anything, thought it had to be on the screen. There's still some moments where it slightly shifts away but I think a bit of frame by frame position/corner pinning adjustments could solve that.
In the interest of what you recommended Kalleheikki, just incase that also helps, could you elaborate on the specific steps a bit more please? When I tried it, the footage that's meant to be on screen would shift away from the it whenever the second tracking point started.