# step(byPresentationTime:wasPinned:) Moves the cursor by a given delta time on the presentation timeline. ``` func step(byPresentationTime deltaPresentationTime: CMTime, wasPinned outWasPinned: UnsafeMutablePointer?) -> CMTime ``` ## Parameters `deltaPresentationTime` The amount of time to move in the presentation timeline. `outWasPinned` The system sets the value of this pointer to if the cursor reaches the beginning or the end of the sample sequence before it reaches the requested time. You may specify `nil` if you’re not interested in this information. ## Return Value The amount of time the cursor was moved along the presentation timeline. Because sample cursors snap to sample boundaries when stepped, this value may not be equal to the specified time delta even if the cursor was not pinned. ## Discussion --- 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)