Prototyping video processing

I got a prototype of my 360 video project done in Quartz Composer using a custom Core Image filter.     I am in love with Quartz Composer and core graphics because it is such a nice prototyping environment and because I can stay in 2D for the video.   Here is the whole program:

 

A cool thing is I can use an image for debugging where I can stick in whatever calibration points I want to in Photoshop.   Then I just connect the video part and no changes are needed-- the Core Image Filter takes and image or video equally happily and Billboard displays the same.

The Filter is pretty simple and is approximately GLSL     

One thing to be careful on is the return range of atan (GLSL atan is the atan2 we know and love).

I need to test this with some higer-res equirectangular video.    Preferably with fixes viewpoint and with unmodified time.   If anyone can point me to some I would appreciate it.