[PD] Gem texturing panoramic video to a hemisphere

[Alex]

I have some panoramic video that I want to use to texture a hemisphere
[or rather, the bottom half of a sphere].

I cannot simply texture the sphere with the video because the warping
is not correct.. it seems that I need some sort of non-rectangular
warping of the image before I texture the object, or a non-rectangular
mapping of the texture onto the sphere.

Any ideas or advice?  Does anyone else have experience working with
panoramic video in Gem?

-Alex