AVVideoCleanApertureKey
A key that defines the region within the video dimension displayed during playback.
Declaration
let AVVideoCleanApertureKey: StringDiscussion
The value for this key is an instance of NSDictionary containing one or more of the following keys: AVVideoCleanApertureWidthKey, AVVideoCleanApertureHeightKey, AVVideoCleanApertureHorizontalOffsetKey, or AVVideoCleanApertureVerticalOffsetKey. If no clean aperture region is specified, the playback displays the entire frame.