Описание тега cmtime

CMTime structs are non-opaque mutable structs representing times (either timestamps or durations). A CMTime is represented as a rational number, with a numerator (an int64_t value), and a denominator (an int32_t timescale). A flags field allows various non-numeric values to be stored (+infinity, -infinity, indefinite, invalid). There is also a flag to mark whether or not the time is completely precise, or had to be rounded at some point in its past.

CMTime structs are non-opaque mutable structs representing times (either timestamps or durations).

A CMTime is represented as a rational number, with a numerator (an int64_t value), and a denominator (an int32_t timescale). A flags field allows various non-numeric values to be stored (+infinity, -infinity, indefinite, invalid). There is also a flag to mark whether or not the time is completely precise, or had to be rounded at some point in its past.

CMTimes contain an epoch number, which is usually set to 0, but can be used to distinguish unrelated timelines: for example, it could be incremented each time through a presentation loop, to differentiate between time N in loop 0 from time N in loop 1.

Click here for Apple Documentaion of CMTime class.