Motion Tracker issue

[Julian Sixx]

Hi

thanks for your reply Dave.

[Dave LaRonde] “but I’m pretty sure there’s a Perspective Corner Pin tracking choice which will solve your problem quickly and easily.”

i wish there would be one

[Steve Roberts]

Not under Track Type in the Tracker controls?

[Julian Sixx]

Hi
[Steve Roberts] “Not under Track Type in the Tracker controls?”

what do you mean?As i wrote in the first post i’ m already using Perspektive Corner pin as track type.
Don’t tell me that this is not doable with the AE tracker.

[Julian Sixx]

[Dave LaRonde] “all four track points are following the corners of the frame, right?”

Yes

[Dave LaRonde] “And you are of course applying that tracking information to a different layer, right?”

Yes

I’m appliying the tracking information to the copy of the footage.

[Julian Sixx]

Hi
[Dave LaRonde] “So then your footage is growing bigger as the frame gets closer to the camera, yes?”

Yes,that is the problem!!!

[Julian Sixx]

is it a task for a 3d tracker plug in?

[Steve Roberts]

Oh, I get it! You want the objects in the footage to stay the same size, but you want the outer edges of the footage to follow the tracked frame? In essence, where the frame acts as an expanding mask for the footage?

If so, then apply the tracking to a solid, then use that solid as a track matte for the footage layer…?

[Julian Sixx]

Hi
here is a screen capture of my issue
https://rapidshare.com/files/6662611/Tracker_2.wmv.html

click on free(bottom right)>enter shown code>open

Steve i’ll try your way tomorrow it’s getting a bit late here.

[Julian Sixx]

hi

a new day and no improvement yet!

[Steve Roberts]

I see your problem: the tracked layer scales up by X pixels and Y pixels, and we expect the masked version to scale up by the same number of pixels … but it won’t, so we see a border around the masked area. It doesn’t match the frame.

Here’s why: imagine a white 640×480 layer with a black 320×240 rectangle inside. If you scale the white layer to 648×486, you’ll be adding 3 pixels top and bottom, and 4 pixels left and right. But will those same pixels be added to the 320×240? No — it will be scaled up to 324×243, not 328×246. The smaller portion gets scaled up by a smaller amount of pixels, but its scaled-up percentage stays the same as the big one. In your case, the big layer got scaled up, and its center portion got scaled up by the same percentage, but by a smaller number of pixels, since it had to, being an inseparable part of the big layer.

In other words, I believe that you shouldn’t have tracked a big layer then masked it down. You should track the corners of a layer that is roughly the same size as the small frame. If you are concerned about losing resolution by using a small layer and scaling it up, start at the other end, where the object is big, and track backwards.