Tracking a Zoomed shot

[Filip Vandueren]

If you can’t get a better track:

I would just disable the effect, but keep it selected so the 4 points of the corner pin are still visible in the editor,
then go through it frame by frame and tweak so those points line up to the source-photo.

Also take a look at the values 1 by 1 in thecurve editor, and see if there are spikes there, since it looks like a perfectly fluid zoom, the points should move fluidly, so the lines in the curve editor should be nice curves, not noisy squiggles.

not sure what you want from an expression ?

[Alan Tonn]

Hello Filip

Sorry, I didn’t explain that part did I?

I was thinking that if I used and expression to create a smooth mathematical path maybe that would work if I could get the timing right. Can’t expressions be used that way?

I guess I will just have to hand track it. :/

[Chris Buttacoli]

Does the zoom have to bee that slow? Much easier would be to artificially zoom, by scaling the newspaper layer with the video insert parented to it. Motion blur would hide any scale artifacts.

Otherwise, how about using a script to average out multiple instances of tracking data?

[Alan Tonn]

Hello Chris

Unfortunately there is no opportunity to reshoot the shot. The newspaper is long gone, the actor is gone, and the deadline is coming up quick. And to figure out how to script a average of the tracking data, and since I have really no knowledge of scripting (except maybe wiggle(5,5) 🙂 ), I dont think that is a good option.

I was thinking of drawing a path, and then making it a motion path for a null and then using the null anchor as the corner pin position. The only thing left would be to make the positions exact and then I might as well as go back to hand tracking. Better get cracking… 🙁

Thanks for the suggestions.

[Peter O’connell]

Hi, did you use the adjust track tab in Mocha? Also, track the whole plane in Mocha not just the area where the image is.
Pete

roguekeyframe.com

[Alan Tonn]

Hello Pete

Yeah I tracked the whole plane. Question, does the amount of points on a spline matter? Additionally the footage as you can see isn’t terrible, but as it is zooming in there are frames where all the text of the newspaper is blurred into pixels and the edges of the picture “bleeds” into bars of pixels. I think this is due to the zoom and the frame rate it was shot at. I am wondering if this is what is throwing Mocha off.

It gets worse as the image zooms.

How would the adjust track tab differ from adjusting the corner pins in After Effects?

[Bartek Skorupa]

You will have to use all the above suggestions, but probably you won’t get the required result just like that.
I have seen zillions of tutorials about tracking and was very surprised that the authors find the right spot or area in a second, hit “track” and have the perfect result.
After some time I realised that I can’t believe what I see in tutorials.
The footage that tracks perfectly is something unusual. I have tracked hundreds of videos. Maybe 5% of them tracked perfectly. The majority required more or less tweaking.
The “track” is not the goal. The “track” is the means. The goal is to fool the eye, so that the viewer believes, that the attached object is a part of the video.
In your case you could try the following:
Make a few trials with the tracks. If you don’t find the right one – use what you have.
The right side looks good, so focus on the left side.
Take the keyframes for the top left corner, delete all but the first and the last one, and see what it looks like. It won’t look good, so try to use easy ease keyframes. It won’t probably look good eithes, so go to the middle, and tweak the position manualy. Add few more keyframes, but not too many. You should end up with 3 or 4 keyframes max. Finally you will get the result.
Than do the same with the bottom left corner.
Additionally activate the motion blur. Try to feather the edges a bit.
Combine all those things, and when you think that’s all you can do – let somebody who is not working on this project see it, but don’t tell him what you are doing. If he doesn’t see any mistake, tell him what you are doing, and let him watch it once again.

Don’t believe too much that the tracks or scripts will do everything for you.

Bartek Skorupa
Warszawa, Poland

[Alan Tonn]

Hello Bartek

Wow. Thanks. That first idea, the beginning and the end key frames and then work from the middle, hadn’t occurred to me.

Yeah, I have learned the same thing. Tutorials are always the “best case scenario”. I still think that some shots can happen better. This newspaper shouldn’t be this difficult. I had a better track on my actor’s hands in another scene.

I am still learning some of the in’s and out’s but I think that this should be a little easier now with your suggestion.

Thanks again.

[Chris Buttacoli]

I had the same problem as you in this shot, and ended up artificially zooming. No need to reshoot. The exact instant prior to the zoom, I froze the magazine shot and scaled the layer. The parented insert of the girl came along for the ride. No need to track.

Take a look.
https://shorts.creativecow.net/film/example-artificial-zoom

[Alan Tonn]

Hello

Actually I retracked it and got the results I needed. It was also a combination of that and a mistake in the placement of the surface and a quirk between the interpretation of frame rates between Mocha and AE. I added a frame at the end of my comp before I pasted into AE and the tracking data hit the marks. It seems that 29.97 frames per second turns out differently between Mocha and AE. Somehow they look at it different, by adding an extra frame at the end of my comp it worked out. I did the same thing in some other shots I was having trouble in and have been doing that ever since and every track has worked on the first try.

Thanks for the help and suggestions.