# CMTime A structure that represents time. ## Discussion Core Media represents time as a rational value, with a time value as the numerator and timescale as the denominator. The structure can represent a specific numeric time in the media timeline, and can also represent nonnumeric values like invalid and indefinite times or positive and negative infinity. ## Topics ### Creating a Time [`CMTimeMake`](/documentation/CoreMedia/CMTimeMake(value:timescale:)) Creates a time with a value and timescale. [`CMTimeMakeWithEpoch`](/documentation/CoreMedia/CMTimeMakeWithEpoch(value:timescale:epoch:)) Creates a time with a value, timescale, and epoch. [`CMTimeMakeWithSeconds`](/documentation/CoreMedia/CMTimeMakeWithSeconds(_:preferredTimescale:)) Creates a time that represents a number of seconds in a preferred timescale. [`CMTimeMakeFromDictionary`](/documentation/CoreMedia/CMTimeMakeFromDictionary(_:)) Creates a time from a dictionary representation of its fields. ### Inspecting a Time [`CMTimeGetSeconds`](/documentation/CoreMedia/CMTimeGetSeconds(_:)) Returns a representation of the time in seconds. [`CMTimeAbsoluteValue`](/documentation/CoreMedia/CMTimeAbsoluteValue(_:)) Returns the absolute value of a time. [`CMTIME_IS_VALID(_:)`](/documentation/CoreMedia/CMTIME_IS_VALID(_:)) Returns a Boolean value that indicates whether a given time is valid. [`CMTIME_IS_INVALID(_:)`](/documentation/CoreMedia/CMTIME_IS_INVALID(_:)) Returns a Boolean value that indicates whether a given time is invalid. [`CMTIME_IS_POSITIVEINFINITY(_:)`](/documentation/CoreMedia/CMTIME_IS_POSITIVEINFINITY(_:)) Returns a Boolean value that indicates whether a given time is positive infinity. [`CMTIME_IS_NEGATIVEINFINITY(_:)`](/documentation/CoreMedia/CMTIME_IS_NEGATIVEINFINITY(_:)) Returns a Boolean value that indicates whether a given time is negative infinity. [`CMTIME_IS_INDEFINITE(_:)`](/documentation/CoreMedia/CMTIME_IS_INDEFINITE(_:)) Returns a Boolean value that indicates whether a given time is indefinite. [`CMTIME_IS_NUMERIC(_:)`](/documentation/CoreMedia/CMTIME_IS_NUMERIC(_:)) Returns a Boolean value that indicates whether a given time is numeric. [`CMTIME_HAS_BEEN_ROUNDED(_:)`](/documentation/CoreMedia/CMTIME_HAS_BEEN_ROUNDED(_:)) Returns a Boolean value that indicates whether the system rounded the time value. [`CMTIME_IS_VALID`](/documentation/CoreMedia/CMTIME_IS_VALID) Returns a Boolean value that indicates whether a time is valid. [`CMTIME_IS_INVALID`](/documentation/CoreMedia/CMTIME_IS_INVALID) Returns a Boolean value that indicates whether a time is invalid. [`CMTIME_IS_POSITIVE_INFINITY`](/documentation/CoreMedia/CMTIME_IS_POSITIVE_INFINITY) Returns a Boolean value that indicates whether a time is positive infinity. [`CMTIME_IS_NEGATIVE_INFINITY`](/documentation/CoreMedia/CMTIME_IS_NEGATIVE_INFINITY) Returns a Boolean value that indicates whether a time is negative infinity. [`CMTIME_IS_INDEFINITE`](/documentation/CoreMedia/CMTIME_IS_INDEFINITE) Returns a Boolean value that indicates whether a time is indefinite. [`CMTIME_IS_NUMERIC`](/documentation/CoreMedia/CMTIME_IS_NUMERIC) Returns a Boolean value that indicates whether a time is numeric. [`CMTIME_HAS_BEEN_ROUNDED`](/documentation/CoreMedia/CMTIME_HAS_BEEN_ROUNDED) Returns a Boolean value that indicates whether the system rounded the time. ### Performing Time Calculations [`CMTimeAdd`](/documentation/CoreMedia/CMTimeAdd(_:_:)) Returns the sum of two times. [`CMTimeSubtract`](/documentation/CoreMedia/CMTimeSubtract(_:_:)) Returns the difference between two times. [`CMTimeMultiply`](/documentation/CoreMedia/CMTimeMultiply(_:multiplier:)) Returns the result of multiplying a time by an integer multiplier. [`CMTimeMultiplyByFloat64`](/documentation/CoreMedia/CMTimeMultiplyByFloat64(_:multiplier:)) Returns the result of multiplying a time by a floating-point multiplier. [`CMTimeMultiplyByRatio`](/documentation/CoreMedia/CMTimeMultiplyByRatio(_:multiplier:divisor:)) Returns the result of multiplying a time by an integer multiplier, and then dividing the result by the divisor. ### Changing the Timescale [`CMTimeConvertScale`](/documentation/CoreMedia/CMTimeConvertScale(_:timescale:method:)) Converts the source time to a new timescale using the specified rounding method. [`CMTimeRoundingMethod`](/documentation/CoreMedia/CMTimeRoundingMethod) An enumeration of rounding methods to use when performing time calculations. ### Comparing Times [`CMTIME_COMPARE_INLINE`](/documentation/CoreMedia/CMTIME_COMPARE_INLINE) Returns a Boolean value that indicates whether the specified comparison is true. [`CMTimeCompare`](/documentation/CoreMedia/CMTimeCompare(_:_:)) Returns the numerical relationship of two times. [`CMTimeMaximum`](/documentation/CoreMedia/CMTimeMaximum(_:_:)) Returns the greater of two time values. [`CMTimeMinimum`](/documentation/CoreMedia/CMTimeMinimum(_:_:)) Returns the lesser of two time values. ### Representing Times [`CMTimeShow`](/documentation/CoreMedia/CMTimeShow(_:)) Prints a description of the time to the console. [`CMTimeCopyDescription`](/documentation/CoreMedia/CMTimeCopyDescription(allocator:time:)) Creates a string representation of the time. [`CMTimeCopyAsDictionary`](/documentation/CoreMedia/CMTimeCopyAsDictionary(_:allocator:)) Creates a dictionary representation of the time. ### Data Types [`CMTime`](/documentation/CoreMedia/CMTime) A structure that represents time. [`CMTimeValue`](/documentation/CoreMedia/CMTimeValue) An integer time value. [`CMTimeScale`](/documentation/CoreMedia/CMTimeScale) An integer timescale. [`CMTimeEpoch`](/documentation/CoreMedia/CMTimeEpoch) An epoch for a time. [`CMTimeFlags`](/documentation/CoreMedia/CMTimeFlags) A structure that defines the flags for a time value. ### Constants [Time](/documentation/CoreMedia/cmtime-time) Defined time values. [Timescale](/documentation/CoreMedia/cmtime-timescale) Defined timescale values. [Dictionary Keys](/documentation/CoreMedia/cmtime-dictionary-keys) Keys to use when working with dictionary representations of time. --- Copyright © 2026 Apple Inc. 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