Shader Node: ODT and RRT Color Transforms

When you capture footage with your camera, the image is stored in some color space, let it be sRGB with some non-linear (Kodak-like S-curve) transform to compress high dynamic range into a smaller range of your display.

If you use this photo as a texture in your scene, it is extremely hard to restore original (linear) color - in the render this footage will look very much off. You need it captured in linear color space. Unfortunately, it is not always available.

I suggest a new shader node to convert from texture's color space to Blender's linear by inverting input's Output Device Transform (ODT) and Reference Rendering Transform (RRT) and then applying (if necessary) output RRT and ODT.