Typed view of the mdhd Media Header Box. Exposes timescale/duration
(and creation/modification times); the trailing language + pre_defined fields
are preserved in rest.
Summary
Types
@type t() :: %ISOMedia.Boxes.MediaHeader{ creation_time: non_neg_integer(), duration: non_neg_integer(), flags: <<_::24>>, modification_time: non_neg_integer(), rest: binary(), timescale: non_neg_integer(), version: non_neg_integer() }