Motion Tracking help!

[_joe]

Hi All!

I'm putting together a little video for my friends who are holding an event on their college campus about their experiences in Uganda, and one of the things I planned to do was a little trailer for their website to drum up interest in the event.

One of the shots includes putting a television in the middle of the city, out of context, where the television would be playing shots of both their interviews and footage from their trip. hitting on the idea that there's a disconnect between what we can watch on TV and disconnect that from our daily lives.

In planning things out, we thought it would be best to put cardboard in the middle of the screen, paint it green, and composite the video on top in after effects...only I've suddenly realized that the AE I have ISN'T the pro version and does not have tracking controls. D'oh.

I was planning on putting a spot/cross in the screen so I can later make a null layer or similar to hand track motion in the footage and just hand make the layer, but I thought it'd be worth asking all you bright folks for advice before undertaking!

Has anyone done something similar? advice on how I should handle this?

Thanks in advance :-B

 

[grahamdunn]

I would try to upgrade AE if possible or get Mocha for AE from Imagineer (it comes with AE CS4 now). You can track in the screen simply using the shape of the TV and generally avoid tracking markers onscreen, giving you a cleaner key you still plan to stick a sheet of green paper on the glass. It's not hard to use your track to mask out the glass though, and then you could avoid doing anything to the screen during production.

 

[oneinfiniteloop]

This is pretty easy by hand. Put a colored dot in each corner of the screen and then use the Corner Pin effect to track the shot into the TV. You may need to lower the opacity to 0% to see the dots and move the corner pin points accordingly. This is what the built-in tracker does, it takes the four tracking points and translates them to the Corner Pin effect.

The colored dots are optional, you can easily do it to the corners of the screen, but with the dots you are always going to the same point each time. For total accuracy, you can put a cross in the middle of each dot so that you get it perfect, but that's nitpicky. It also depends on the complexity of your camera move. I wouldn't use any markers until there is a sever shift in parallax and/or angle in the shot.