How to add flying birds to my footage

Question

Hello guys,
I have some cool aerial footage of a river and I would love to add a group of birds flying over it with tracking feature of AE, I need some 3d animation of birds flying but have no idea if it exists and where to find it, any suggestion ? Seagulls or pigeons... or something white...
Thanks

Answer 1

Think about what you are trying to do for a moment... That's the most important part of any compositing or VFX project. There are two possible workflows. The first is your suggestion of using stock footage.
First, you need some footage of birds that has an alpha channel or a way to make an alpha channel so you end up with birds and no background. You'll have to check stock footage libraries for this kind of footage.
Second, the camera angle must match the camera angle of your 'cool aerial footage' close enough so you can match the perspective.
Third, you will have to track the river footage and the bird footage, stabilize (remove all camera movement) from both clips, line them up, and then redo the camera movement in the river footage and parent the stabilized bird footage to the camera footage and then animate the position of the bird footage to give them some movement...
I've been doing AE and Visual Effects for more than 20 years and that's not the way I would go about it. There are just too many variables. The only way to reduce the variables to a manageable number would be to pick the bird footage first and then fly the river shot with camera angles and speed to match.
A more reasonable option would be to create your own flock of birds in a 3D app or a particle system.
I'd set up a 3D camera track in AE, set a ground plane and origin, and export the scene to Cinema 4D. Inside Cinema 4D I'd create my flock of flying birds. (very hard to do in the light version) or I'd create a flock of flying birds in Blender (open source and free) and then composite my birds into the scene.
The potential pitfalls are that your 3D camera solution must be accurate and if the footage was shot by something like a GoPro carried by a quadcopter, you are going to have all kinds of lens distortion and tracking issues unless the shot is very stable and the lens distortion is removed before tracking. Once you get a good track and a good camera solution it's just a matter of animating the birds in a 3D app and having them fly through the scene. There are a few tutorials out there about creating a flock or swarm of birds.
You could also create your birds in a particle system like Trapcode Particular using some sprites or textured polygons and composite that into your scene. There's actually a bunch Particular tutorials out there for creating a flock of birds. Part 2 is here.
The last part of your project would be color and light matching the flock of birds. Blender's camera tracker will do a very good job of setting up some illumination for a scene and there is some support for Blender to AE so if you're on a budget and have a bunch of time to learn about Blender's camera tracker and animation tools (give it a week of solid study) you can try that.
I hope this helps. Some things are not as easy as you think until you change your approach.