SphericalProjection

The six faces of a cube in a 3 by 2 layout: right, left and up in the top row, down, front and back in the bottom one, the only layout FFmpeg reads. The front, left, right and back faces stand upright, the top of the up face is toward the front and the top of the down face is toward the back. padding is the number of pixels of padding at the edges of each face.

The whole sphere: longitude across the width, from -180 degrees at the left edge to 180 at the right, and latitude down the height, from 90 degrees at the top to -90 at the bottom.

A part of an Equirectangular picture. Each bound is the share of the whole picture's width or height that lies beyond this part's edge on that side, from 0 to 1, so the whole picture is this one's width divided by 1 - left - right and its height divided by 1 - top - bottom. The container stores each as 0.32 fixed point, and each is that number over 2^32, exactly.

Apple's fisheye projection.

Half the sphere, 180 degrees across, as an equirectangular picture.

Apple's parametric immersive projection.

A flat picture, which Apple's video extension box can state outright.