# Buffer Trigger Conditions The trigger conditions the framework supports. ## Topics ### Constants [`var kCMBufferQueueTrigger_WhenDurationBecomesLessThan: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDurationBecomesLessThan) Trigger fires when queue duration becomes less than the specified duration. [`var kCMBufferQueueTrigger_WhenDurationBecomesLessThanOrEqualTo: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDurationBecomesLessThanOrEqualTo) Trigger fires when queue duration becomes less than or equal to the specified duration. [`var kCMBufferQueueTrigger_WhenDurationBecomesGreaterThan: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDurationBecomesGreaterThan) Trigger fires when queue duration becomes greater than the specified duration. [`var kCMBufferQueueTrigger_WhenDurationBecomesGreaterThanOrEqualTo: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDurationBecomesGreaterThanOrEqualTo) Trigger fires when queue duration becomes greater than or equal to the specified duration. [`var kCMBufferQueueTrigger_WhenMinPresentationTimeStampChanges: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenMinPresentationTimeStampChanges) Trigger fires when the minimum presentation timestamp changes (triggerDuration is ignored). [`var kCMBufferQueueTrigger_WhenMaxPresentationTimeStampChanges: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenMaxPresentationTimeStampChanges) Trigger fires when the maximum presentation timestamp changes (triggerDuration is ignored). [`var kCMBufferQueueTrigger_WhenDataBecomesReady: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDataBecomesReady) Trigger fires when next dequeueable buffer becomes ready (that is, [`CMBufferQueueDequeueIfDataReady(_:)`](/documentation/CoreMedia/CMBufferQueueDequeueIfDataReady(_:)) will now succeed). (triggerDuration is ignored.) [`var kCMBufferQueueTrigger_WhenEndOfDataReached: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenEndOfDataReached) Trigger fires when CMBufferQueueIsAtEndOfData’s condition becomes true. (triggerDuration is ignored.) [`var kCMBufferQueueTrigger_WhenReset: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenReset) Trigger fires when CMBufferQueueReset called. (triggerDuration is ignored.) [`var kCMBufferQueueTrigger_WhenBufferCountBecomesLessThan: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenBufferCountBecomesLessThan) Trigger fires when buffer count becomes less than the specified threshold number. [`var kCMBufferQueueTrigger_WhenBufferCountBecomesGreaterThan: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenBufferCountBecomesGreaterThan) Trigger fires when buffer count becomes > the specified threshold number. [`var kCMBufferQueueTrigger_WhenDurationBecomesGreaterThanOrEqualToAndBufferCountBecomesGreaterThan: CMBufferQueueTriggerCondition`](/documentation/CoreMedia/kCMBufferQueueTrigger_WhenDurationBecomesGreaterThanOrEqualToAndBufferCountBecomesGreaterThan) --- 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)