video: refactor HDR implementation

List of changes:

1. Kill nom_peak, since it's a pointless non-field that stores nothing
   of value and is _always_ derived from ref_white anyway.

2. Kill ref_white/--target-brightness, because the only case it really
   existed for (PQ) actually doesn't need to be this general: According
   to ITU-R BT.2100, PQ *always* assumes a reference monitor with a
   white point of 100 cd/m².

3. Improve documentation and comments surrounding this stuff.
4. Clean up some of the code in general. Move stuff where it belongs.

0 files changed, 0 insertions, 0 deletions