AndrewVK

Not 100% sure that this will help, maybe I forgot something.
I used this method for UE+Pftrack+Houdini:

Export few object from UE scene as a hint (floor, wall, table….etc.)
Import fbx to Houdini !!!!BUT!!!!! Uncheck “Convert to Y-up Coordinate System” checkbox
Import camera from Pftrack.
Use camera`s parent null to fit camera animation to the scene (scale,rotate,translate)
Duplicate the camera to keep the same Focal Length, Aperture, but break the connection from parent for this camera.
Create CHOP network:

Object import chop (Target Object: your camera from Pftrack……Compute: Full Transform)
|
Export chop (Channels: tx ty tz rx ry rz Node: duplicated camera Path: tx ty tz rx ry rz)

Turn on export flag.
Make sure that both cameras are aligned.
Export ONLY duplicated camera to fbx (Souce Objects Export:/obj/Camera1Copy)
Import this fbx to sequencer.

Thanks for detailed explanation!
BTW is there any solution for “import camera from UE to houdini”?

It works with an animated “focal” parameter, but does not take into account animated “aperture”
To fix this, find the line:

if (objType == ‘cam’) and (len(obj.parm('focal').keyframes()) != 0):

and replace with:

if (objType == ‘cam’) and (len(obj.parm('focal').keyframes()) != 0) or (len(obj.parm('aperture').keyframes()) != 0):