This one is about 3D motion tracking - or how to add or remove objects from a point of view shot.
When you have complex motion - a camera moving in every direction and facing anywhere - it can become hard to do even the most basic of post production. Some effects, such as matting out an object, are easy when you are on a tripod. But when the image is moving everything is much harder.
This test was an effort to put something false into a shot. Again, super easy if this had been a locked off shot.
For you technie fans here was the process...
- Film at 50 fps to get more motion information
- Use "Icarus" to reverse engineer the motion
- Icarus can only use non-HD footage so I give it an downscaled version of my master to work with
- Export that camera movement data and import it into After Effects
- Now the virtual camera in After Effects moves the same as the real camera did
- As Icarus used a downscaled footage I bring in the HD footage again but have to adjust the virtual camera lens angle to compensate. I know my cameras field of view is 59 degrees so I enter that myself.
- Add a 3D layer for the object that is needed in the scene. In this case the big comedy Google Maps arrow
- Put it in the right place in the virtual world
- Render the footage, but back at 25 fps to match other material
The render is quick fast, the Icarus part very slow, perhaps a couple of hours.
I quite like it in the end. I may try and sneak something like it into the feature film.