kVTCompressionPropertyKey_PreserveAlphaChannel
A key that specifies whether to encode the alpha channel of input video frames.
Declaration
let kVTCompressionPropertyKey_PreserveAlphaChannel: CFStringDiscussion
Set this property to false in cases where you’re not interested in preserving alpha, or if you know the alpha channel to be fully opaque.
This property isn’t supported by all encoders.