# CMTimeMultiplyByRatio(_:multiplier:divisor:) Returns the result of multiplying a time by an integer multiplier, and then dividing the result by the divisor. ``` func CMTimeMultiplyByRatio(_ time: CMTime, multiplier: Int32, divisor: Int32) -> CMTime ``` ## Parameters `time` A time value to multiple by a ratio. `multiplier` The value by which to multiply. `divisor` The value by which to divide. ## Return Value A value equal to `(time * multiplier) / divisor`. ## Discussion This method preserves the exact rational value, unless it causes an overflow. If an overflow occurs, the system chooses a new timescale to minimize the rounding error and applies the default rounding method when converting the result to this timescale. If the result’s value still overflows when its timescale is `1`, the system sets the result to positive or negative infinity, depending on the direction of the overflow. If rounding occurs for any reason, the system sets the result’s [`hasBeenRounded`](/documentation/CoreMedia/CMTimeFlags/hasBeenRounded) flag. It also sets this flag if the time argument has its [`hasBeenRounded`](/documentation/CoreMedia/CMTimeFlags/hasBeenRounded) flag set. If the time value or timescale is zero, the result is [`invalid`](/documentation/CoreMedia/CMTime/invalid). If only the timescale is zero, the result is positive or negative infinity, depending on the signs of the other arguments. If time is invalid, the result is [`invalid`](/documentation/CoreMedia/CMTime/invalid). If time is infinite, the result is similarly infinite. If time is indefinite, the result is indefinite. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)