CMTime

Overview

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(value:timescale:)
• CMTimeMakeWithEpoch(value:timescale:epoch:)
• CMTimeMakeWithSeconds(_:preferredTimescale:)
• CMTimeMakeFromDictionary(_:)

Inspecting a Time

• CMTimeGetSeconds(_:)
• CMTimeAbsoluteValue(_:)
• CMTIME_IS_VALID(_:)
• CMTIME_IS_INVALID(_:)
• CMTIME_IS_POSITIVEINFINITY(_:)
• CMTIME_IS_NEGATIVEINFINITY(_:)
• CMTIME_IS_INDEFINITE(_:)
• CMTIME_IS_NUMERIC(_:)
• CMTIME_HAS_BEEN_ROUNDED(_:)

Performing Time Calculations

• CMTimeAdd(_:_:)
• CMTimeSubtract(_:_:)
• CMTimeMultiply(_:multiplier:)
• CMTimeMultiplyByFloat64(_:multiplier:)
• CMTimeMultiplyByRatio(_:multiplier:divisor:)

Changing the Timescale

• CMTimeConvertScale(_:timescale:method:)
• CMTimeRoundingMethod

Comparing Times

• CMTimeCompare(_:_:)
• CMTimeMaximum(_:_:)
• CMTimeMinimum(_:_:)

Representing Times

• CMTimeShow(_:)
• CMTimeCopyDescription(allocator:time:)
• CMTimeCopyAsDictionary(_:allocator:)

Data Types

• CMTime
• CMTimeValue
• CMTimeScale
• CMTimeEpoch
• CMTimeFlags

Constants

• Time
• Timescale
• Dictionary Keys

See Also

Time Representation

• CMTimeRange
• CMTimeMapping