Disposition
data class Disposition(val default: Boolean = false, val forced: Boolean = false, val hearingImpaired: Boolean = false, val visualImpaired: Boolean = false, val attachedPicture: Boolean = false)
What a container says a stream is for.
A track menu needs this. Without forced a player cannot mark or auto-select forced subtitles, which is the difference between showing a translation of one foreign line and showing every subtitle in the film. Without attachedPicture album art is treated as a one frame video stream and the player tries to synchronise to it.