Screen Tracking & Replacement in AE

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*********WITH THE RELEASE OF TRACKERVIZ, THIS TUTORIAL IS OUTDATED. TRACKERVIZ PRESENTS A MUCH EASIER WAY TO ROTOTRACK.**********
***********TRACKERVIZ LINK viewtopic.php?f=31&t=5477 **************
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Ok, I made another one. it's half an hour long, downloadable as an EXE file, but, as usual with me, it doesn't install anything on your computer, it just has to be an EXE because it comes with it's own self-extractor.

This one covers something I've done on almost every movie I've ever worked on, TV screen and computer monitor replacement. But, this technique could also be used for TONS of other things, like putting posters on walls, pinning a matte painting to an area, changing book and magazine covers, etc, etc... The applications are almost limitless. The entire tutorial is for After Effects only, no 3D, even though it's a handheld, perspective changing camera move.

If you want to use every technique I use in the tutorial, you'll need this AE script (which is absolutely amazing!):

http://www.aenhancers.com/viewtopic.php?t=329

Here's the before and after:

http://www.mackdadd.com/tutorials/monit ... ore_01.mov
http://www.mackdadd.com/tutorials/monit ... nal_01.mov

And here's the files you'll need:

This is the tutorial, 215Megs:
http://www.mackdadd.com/tutorials/monit ... torial.exe

This is the field-blended footage, uncompressed, maybe 140Megs:
http://www.mackdadd.com/tutorials/lapto ... r_1_DI.mov

This is the picture I used, but you can use anything you want:
http://www.mackdadd.com/tutorials/simpl ... een_01.jpg

This tutorial does NOT cover putting a reflection back over top of the image, since there was no reflection in my laptop screen footage. If anyone really wants to know how to do that perfectly, I can make a supplemental tutorial on how to do it (it's more for TV screens than computer monitors).

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*********WITH THE RELEASE OF TRACKERVIZ, THIS TUTORIAL IS OUTDATED. TRACKERVIZ PRESENTS A MUCH EASIER WAY TO ROTOTRACK.**********
***********TRACKERVIZ LINK viewtopic.php?f=31&t=5477 **************
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yep, quinn, put it where zach said.

(I also keep a seperate folder on another hard drive that has all my 3rd party AE and Max scripts in it, because someimtes, if I have to reformat or reinstall, I always forget to back that kind of stuff up, then I have to scour the net looking for it again. so it might be a good idea to have a copy somewhere else besides the script folder)

yeah, zach, scripting in AE can be just as powerful as scripting in a 3D program, which I think I clearly demonstrate in this tutorial (even though i don't write scripts). This script is amazing! i think you use shake alot, right? shake probably has built in mask point tracking capabilities, doesn't it? fusion does, i think, and R&H's proprietary stuff does (kind of). Combustion and Commotion (not made anymore) do, as well. Silhouette Roto for AE is still the straight-up, hands-down BEST rotoscoping tools anywhere on earth, but it's kind of expensive for something that you never want to do anyway! hahaha... But this script I demonstrate in this tutorial is REALLY amazing, and every AE user should have it!

and yeah, i think the tracker is a little better in 7. i noticed it got a little better from 6 to 6.5, too. I think they're always making little tweaks on it.

I'm still looking online for a script for AE that will allow you to select 2 layers with position keyframes and average them together to create a new layer with the averaged keyframes applied. This is exactly what the script I have from work does, and I can't live without it, but I also can't post it for everyone to use since it's a proprietary thing i didn't write. But i'm dying to show everyone the power of track averaging!

YAY!!!! I can't wait to get started on more of your tutorials Hype! I have to wait till Chrismas so that I have time, but your tutes make me really excited to learn about compositing!

I've noticed that in making of featurettes, that computer screens and tv screens always have green screen on them. Is that because they don't want the reflection of the camera in it? Or because it allows them flexibility to change the image later if they want?

Oh, and I'm interested in learning about reflections too... I was asking you about that earlier, I think. I'd love to see tips on having the reflection blend into the window, mirror, tv, etc.

COOL!!!!!
~Mechis

amazing find, mechis! that's exactly what i've been looking for! i'll try it out and do a tutorial with it - it's something everyone should have!

iest - yep, all AE.

Hey man, Ive been doing your tutorial today with my own footage. The tracking part where you lock track 1-4 to each corner messes up. It follows the corner for a while then goes all over the place >_< do I have to mannualy move every fram into the right spot or any easier way to fix this? The track slides ALL over the ouside edge, and doesnt stay in the corner. Everythings been done the exact same way as you r clip. Any way to fix this, any help would be huge man. Thanks for taking the time to help us.

Cheers

Fantastic Hype, thanks! Will pass these around to my English speaking compositor friends

thanks guys, for liking it!

quinn, i'm running to dinner right now, when i get back i'll suggest a million things to help your track! like, maybe an hour from now...

heh... just seen the demo vids. Dude, you have so many candles... are you into ritual sacrafice? The way the camera pans on that it looked pretty ominous... I mean... If I was that laptop I'd be kinda scared!

...um... don't mind me, I think the morning coffee has just kicked in!

globes, hahaha... actually, the lit candle is a yummy frosted cranberry smelling candle, and its awesome! the ones behind my laptop are holders that my old roommate left here when she moved out, i need to give that stuff away. (anyone want them? hahaha)

quinn... i'd need to see the footage to really give a proper suggestion, but some things you might want to try would include:

- in the options setting in the tracker panel, there's a pulldown menu that says something like "continue tracking" if accurracy is less than 80%. try changing that percentage to something like 70 or 65 (i wouldn't go much lower than that, though, but try it if you want), or change the pulldown part to say "adapt feature". you could also click on the "adapt feature on every frame" check box. although, when this is checked, it may stay on the area for the entire duration, but you may notice it drifts over the course of the track. it would be slight, but it would be enough to make the track not accurrate. but try it.

- the reason it worked so good on the footage i provided is because the contrast on the areas i tracked was huge. if your footage doesn't have that much contrast in the area you're tracking, take a look at the color channels. if one of the channels has a pretty decent contrast, you can set it to track the RGB or the saturation instead of the luminance (in the options panel).

- another thing you could try is to pre-comp your footage, and in that pre-comp, apply a levels effect to the footage and CRANK the contrast WAY up. then track the pre-comp composition in a different composition. even throw on a hue/saturation and make it greyscale, then crank the levels to get contrast up. totally mess with the footage however you have to to make the area you want to track contrasty, or easy to pick out. then, once you have the track done, you can just get rid of all those effects and use the track like normal.

- or, you could manually move the tracker box on every frame. which sucks, but is sometimes neccessary. be careful with this though, because depending on where you click to grab the box to move it, it does different things. If I ever do a tutorial called "everything you ever wanted to know about tracking", i'd cover this. if you click in the box when the cursor is a black arrow, when you move the tracker box, your track will actually shift at that point in your finished track. if you click directly on the edge of the tracker box, when the arrow turns white, you will change the actual area the tracker is tracking, but the center point will continue on from it's current position. If you click on the little plus sign in the middle, you're only changing the center point, or where it pins the track when it's done, not the area it's searching for. that's all kind of confusing, which is why it would work much better as a video tutorial than a written explanation. and this doesn't even cover what to do when your tracking feature leaves the frame and comes back on later.

i don't if that helps. maybe i'll do the "everything you ever wanted to know about 2D tracking" tutorial.

Just my two cents, If you change your footage to just the R, G or B channel, (whichever has the most luminance contrast.) and then blur it, precomp that layer, and then track it, you might get a better result.

The reason this works is because the tracker works based on contrast values per pixel, and if you have your pixels blurred, then neighboring pixels dance back and forth less, making them more of a stable color for the tracker to see. (hopefully that makes sense) This almost always provides me with a good solid track when working with DV especially.


-Z

Cool cheers man, ill try all these new things tomorrow morning. Thanks for the help.

you can tell AE to pre-blur the footage for you in the options panel of the tracker, but i usually find that makes the track slowly drift over the course of the track. but, yeah, its certainly worth a try!

Hey man its nothing to do with this, but do you know how to keep camera in same place, film yourself like 4 times and have all 4 shot together as one so looks like all four of you are doing something? Cause I really wanna learn that. Such a cool effect.

yep, it's actually pretty easy, as long as you know you're in for quite the rotoscoping adventure. unless you have a bluescreen handy.

it's super super easy if you don't cross in front of yourself at any point.

do you want to know how to do it, like, a detailed explanation?

Yea, and if you cross in front of yourself, all you need to do is decide which is going to be in front and delete the other.

Well CHEERS Hype, I got it all working. I successfully turned my microwave into a computer ^__^ I love this technique. Cheers man.

excellent! glad to hear it, quinn! you gonna post your work? i'd love to see it!

Hey Quinn-- what did you end up doing to get your track to work better?

Thanks!
~Mechis

When adding the track I increased the area around the corner from which it gets its information. Right before you play the track. You know when you set the inside and outside box around the point. Played with those so it had more info to read and work from. Thats how I fixed my problem, and found it helps to work on something that stands out ALOT.

ok, I'm on the "Multiple You" tutorial. Gimme a couple days. Maybe I'll recruit one of the kids in my Apt building to be in it, since more than one of me would be a bad, bad thing...

Sean,

I just added a comment to the section of After Effect CS3 Help on the Web, pointing to your great tutorials about tracking that you've posted here. Keep up the good work.

Cool, thanks, Todd!

There will be another coming soon, demonstrating a tracking tool that Nab is making for me over at AEnhancers!

Thanks for this wonderful information guys. I appreciate it. I also have my own screen tracking tools and it works perfectly for me. I never have had a problem with it.