CMTimeMakeWithSeconds explained
CMTime is structure which has two main components, timeScale and value. CMTIME = VALUE / TIMESCALE where, TimeScale = fraction of a second each unit in numerator occupies. CMTIME = Value / TimeScale 1) public func CMTimeMake( _ value: Int64 , _ timescale: Int32 ) -> CMTime CMTimeMake ( 6000 , 10 ) Means, there are 6000 units , each unit occupies 1/10 of a second 2) public func CMTimeMakeWithSeconds( _ seconds: Float64 , _ preferredTimescale: Int32 ) -> CMTime CMTimeMakeWithSeconds(10.0,500) 10.0 = VALUE /500 Therefore VALUE = 5000 So, there are 5000 units, each occupy 1/500 of a second