3D Camera Track Movement: analysis failed

[JoãoSilvaTV--]

So, I'm doing an assignment for university and I'm stuck with 3D Camera Track. So, when I try to track camera it fails and I search about it an nothing helped me.

My footage:

https://drive.google.com/open?id=1XiHo9vdqHp2wJWUScK_0lx7u0pebbdCF

Please, someone help me. What I'm trying to do it's to put polaroids in the air.

[RobShultz]

I'm assuming that the effect doesn't like that you are circling around them.

[JoãoSilvaTV--]

There is any way to fix it? Because in my head this is a really cool idea!

[Rick Gerard]

There is almost no fixed geometry in your scene so there is very little for the camera tracker. Every track point that ends up on a person that is moving must be deleted. The way to fix it is to shoot it again realizing that you need a fair amount of fixed geometry in the scene so that the tracker can analyze the perspective and parallax changes in the shot and figure out where the camera is (Perspective is determined by camera position) and what the angle of view is (focal length determines the angle of view) so you have some decent fixed geometry in the scene with sufficient detail to get a good camera track and camera solution. 

You could try this. Follow the steps closely. If you open AE, change to the Motion Tracking workspace, create a comp from your trimmed footage, then Track Camera and immediately turn on the Advanced Analysis option you'll have the best chance of getting Camera Tracker to work with properly exposed and in focus footage that has sufficient detail in the fixed geometry in the scene. I'm positive that you won't get a camera solution unless you turn on Advanced Analysis, and even then you are going to do a lot of editing on the track points and a lot of testing to get something you can use.

Advanced Analysis did give me a camera solution but there were a bunch of errors and I couldn't get any targets that really looked like they were going to align to any surface. You'll have to try and delete as many tracking points as you can on things that are moving like this actor's face:

Try that several times and you may find something that will give you a decent surface and a camera solution that actually works. After deleting a bunch of points I added a camera and a solid, added a grid to the solid to help me visualize the surfaces and then added a couple more. Things started to look promising. Here's the workflow in a couple of steps:

This was the best looking and biggest surface that I used to start. Then I added a couple more surfaces (solids with grids):

I'm getting closer. Some of the points just didn't produce the results I expected.

After a little more work, removing some more points on surfaces that moved (faces) I came up with this. You are looking at 2 views, top and Active Camera, and several reference solids placed so I have some kind of a chance at getting a Ground Plane (the floor) in the scene and placing 3D elements in the shot so they move correctly. You should be able to right-click on the last image here and open it in a new window or tab to get a good look. 

I spent about an hour fiddling with the shot and got pretty close. I have a lot of experience with camera tracking and I knew immediately which track points needed to go. I deleted trackers about 4 times and let it solve for the camera again before I added the camera and some reference solids. Then I had to delete the camera and all the reference solids and try again twice to get this far. The track is never going to be perfect and getting the 3D layers to stick to the real geometry in the scene is going to be difficult because there is so little fixed geometry in the scene to use to make the calculations. I don't know any 3D camera tracking solution that would give you a really good track of this shot without a bunch of manipulation and a good deal of experience. You might be able to get something that will kind of work for a class, but I'd never use this shot for a paying client. I'd reshoot.

[JoãoSilvaTV--]

Thank you for the help, I'm going to try to do this and in the worst case scenario, I will reshoot. Thank you

[JoãoSilvaTV--]

lso, one thing that I tried it's to cut the video in 5-6s long and put the 3d camera and it works but then I cannot put everything together

[VFXbear]

Several problems :
- Bad lighting, resulting in terrible artifacting and digital noise.
- Terrible compression.
- Black on black without real tracker markers
- A really bad speed ramp effect on every character. 
I'd say in this current condition : the footage is hardly ready to do a reliable Camera Track via After Effect's standard tracking tool.
However, after tweaking the lighting, and throwing the footage to a noise reduction plugin (Neat Video), I did manage to get quite a decent track on the first try.  Check the attached movie ...

Thinking about the scene, you really only need to have an origin point and a stable rotating camera.
The middle of the scene is inbetween the backs of the characters, so I found a frame where all their shoulders were visible, and selected as many track points as possible until the tracking target marker looked like it was horizontal and in the middle. That's where I set my ground plane and origin.  Then I just checked some markers on the faces of the characters  to have a text or plane follow their movement (not necessary, but just wanted to check the movement).

Cleaning up your original footage is key.  Once you get the center ground plane and origin set, the rest is quite ok.

[JoãoSilvaTV--]

Thank you so much, I will do my best to try and do that!

[JoãoSilvaTV--]

If I reshoot it with a light over the camera, it will fix the problem, same location, black background but with a light over the camera.

[Rick Gerard]

You really need some fixed geometry. Tiles on the floor or some kind of pattern. Some other things in the scene. Even chair backs. All of the tracking markers that end up on your actors will foul up the math. You'll have to go and remove all of the markers that are on surfaces that move. The more you remove, the more the accuracy will improve. When you get close enough then the 3D elements you place in the scene will react more realistically with the camera movement. 

You can get close for part of the move, but spinning the full 360 will be a problem unless you get more fixed geometry in your scene.