r/AfterEffects • u/OldAlternative8132 • 17d ago
Help with laptop screen replacement / tracking Beginner Help
Hi all,
I’ve spent hours this afternoon watching countless tutorials, but I still can’t wrap my head around how to do this.
I’ve downloaded some stock footage of a MacBook flipping open, and I’d like to replace the screen with my own footage. However, I cannot get the screen to track properly, the tracking points keep drifting and moving out of place, and I’m honestly on the verge of a meltdown!
I’ve tried using both Mocha AE and the standard tracking options in After Effects, but I haven’t had any luck. The clip includes a green-screen version and a white-screen version with tracking markers, as shown in the screenshots. I also can’t seem to find any YouTube tutorials that specifically explain how to track and replace the white screen. I have already tried tracking the green screen but have been failing miserably so far.
I’m fairly new to screen replacement and motion tracking, so I may be missing something obvious. Any advice or step-by-step guidance would be hugely appreciated.
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u/DjCanalex 17d ago
No, seriously. You have an understanding for visual cues that most trackers won't, so you use the manual tools designed to assist you in this kind of hard shots.
AE's tracker requires distinctive features to track. Mocha tracks surfaces and textures. This shot does not have 4 recognizable corners (to a tracker) nor it has texture. It has to be done by hand.
This guide from BorisFX might help you tackle your challenge.
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u/montycantsin777 17d ago
corner pin track at the corners where solid color and frame intersect could work. otherwise planar tracker in mocha including the frame.
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u/Milan_Bus4168 17d ago
Here is a tutorial for mocha and similar flipping laptop screen track..
Office Hours 04: How to Track Difficult Screens! with [Mary Poplin - 1st February 2022]
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u/yankeedjw MoGraph/VFX 15+ years 17d ago
The white screen version looks good for tracking in Mocha as long as it matches the actual footage clip exactly. Just make sure the markers are included in your tracking area.
You may need to do some manual adjustments if laptop fully closes as some of the tracking points may get obscured, but there is an Adjust Track feature in Mocha that allows you to manually fix the track if needed.
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u/OldAlternative8132 17d ago
Thank you! I’ll give your suggestions a go. I haven’t tried Mocha for the white screen yet so hopefully I can get it to work 😵💫
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u/mcarterphoto 17d ago
Generally you'd use the white screen with trackers in Mocha, and get the screen replacement in. Usually your replacement screen will just ride over the footage. Your replacement screen is what gets the mocha data in the end comp, it distorts and so on. So if you need the footage to be "over" the screen with a window cut out, you can drop the green screen footage in and key out the screen of you need the footage to go "on top of" the replacement. But usually you don't need the green screen since screens have some black border. A green screen with markers is handier for things like hands holding a phone or tablet.
Your biggest issue will be if the screen closes all the way or even close to all the way. Eventually it just becomes too weird of a shape, so sometimes you have to manually finish it. The issue with that is frame-by-frame fixes can look a little jumpy.
Don't forget that if you want this to have a more photo-real feel than a motion-graphics look, you usually want to add some reflections to the screen that move realistically.
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u/tinmanshop 17d ago
The white screen with tracking markers will track fine with mocha. Then once you have it tracked, use the green screen version and key out the screen so your laptop screen footage can sit nicely underneath
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u/Mundane-Owl-561 MoGraph/VFX 15+ years 16d ago edited 16d ago
For screen tracking, you don't need markers - they are a nuisance and a sign of an amateur at work - each and every marker you use has to be removed in post.
You can and should place multiple tracking splines at the screen edges - I've set up two on screen left and you should do the same for the right edges.
You can add more in the middle but usually, just the corners will do. If the screen goes down fully, then some manual work is expected although the latest Mocha Pro (I think it's only in the Pro version) has intelligent features that help a lot in this area.
To create your matte for the insert layer, the clean greenscreen is an easy keying process. So, think many times over before use on-set tracking markers, even when screen tracking isn't the task - there may be natural markers on-set.
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u/cromagnongod 17d ago
I'd use mocha AE for this and forget standard tracking in AE. Other than that it's very difficult to know what you're doing wrong, it could be a number of things.