Static kVTCompressionPropertyKey_SourceFrameCount 

pub unsafe static kVTCompressionPropertyKey_SourceFrameCount: &'static CFString

Available on crate feature VTCompressionProperties only.

Indicates the number of source frames, if known.

This property allows a client to give the video encoder advance guidance as to how many frames will be encoded. If nonzero, this should be the exact number of times that the client calls VTCompressionSessionEncodeFrame in each pass. The default is 0, which indicates that the number of source frames is not known.

See also Apple’s documentation