I think this would go under Generic directives/plugins syntax about general directives.
Personally think we should explicitly say if it’s a video or not. Makes parsing a heck of a lot more easier to do e.g.
!video[ title ]( url ){ size=10 }
!audio[ title ]( url ){ size=10 duration=10 cycle=forever }
!youtube[ title ]( url ){ size=10 cycle=forever }
This is since I think ![]()
is by default considered to be an image.