# Metric event types ## Topics ### HTTP Live Streaming [`class AVMetricMediaResourceRequestEvent`](/documentation/AVFoundation/AVMetricMediaResourceRequestEvent) An event that represents a media resource request. [`class AVMetricContentKeyRequestEvent`](/documentation/AVFoundation/AVMetricContentKeyRequestEvent) An event that represents a live streaming content key resource request. [`class AVMetricHLSMediaSegmentRequestEvent`](/documentation/AVFoundation/AVMetricHLSMediaSegmentRequestEvent) An event that represents a live streaming media segment resource request. [`class AVMetricHLSPlaylistRequestEvent`](/documentation/AVFoundation/AVMetricHLSPlaylistRequestEvent) An event that represents a live streaming playlist resource request. [`class AVMetricPlayerItemVariantSwitchStartEvent`](/documentation/AVFoundation/AVMetricPlayerItemVariantSwitchStartEvent) An event that represents when the player attempts a variant switch. [`class AVMetricPlayerItemVariantSwitchEvent`](/documentation/AVFoundation/AVMetricPlayerItemVariantSwitchEvent) An event that represents when the player completes a variant switch. [`class AVMetricMediaRendition`](/documentation/AVFoundation/AVMetricMediaRendition) ### Buffering [`class AVMetricPlayerItemStallEvent`](/documentation/AVFoundation/AVMetricPlayerItemStallEvent) An event that represents when playback stalls. [`class AVMetricPlayerItemLikelyToKeepUpEvent`](/documentation/AVFoundation/AVMetricPlayerItemLikelyToKeepUpEvent) An event that represents when playback is likely to continue without stalling. [`class AVMetricPlayerItemInitialLikelyToKeepUpEvent`](/documentation/AVFoundation/AVMetricPlayerItemInitialLikelyToKeepUpEvent) An event that represents the initial state for whether playback is likely to continue without stalling. ### Transport control [`class AVMetricPlayerItemPlaybackSummaryEvent`](/documentation/AVFoundation/AVMetricPlayerItemPlaybackSummaryEvent) An event that represents the combined metrics for the entire playback session. [`class AVMetricPlayerItemRateChangeEvent`](/documentation/AVFoundation/AVMetricPlayerItemRateChangeEvent) An event that represents when the playback rate changes. [`class AVMetricPlayerItemSeekDidCompleteEvent`](/documentation/AVFoundation/AVMetricPlayerItemSeekDidCompleteEvent) An event that represents when the playback seek completes. [`class AVMetricPlayerItemSeekEvent`](/documentation/AVFoundation/AVMetricPlayerItemSeekEvent) An event that represents when a playback seek occurs. ### Playback mode [`enum AVMetricPlaybackMode`](/documentation/AVFoundation/AVMetricPlaybackMode) These constants are the possible playback modes returned by the property “mode” on AVMetricPlaybackModeSwitchEvent [`class AVMetricPlaybackModeSwitchEvent`](/documentation/AVFoundation/AVMetricPlaybackModeSwitchEvent) Represents a change in playback state, entering one of AVMetricPlaybackMode ### Summary [`class AVMetricPlayerItemPlaybackSummaryEvent`](/documentation/AVFoundation/AVMetricPlayerItemPlaybackSummaryEvent) An event that represents the combined metrics for the entire playback session. [`class AVMetricDownloadSummaryEvent`](/documentation/AVFoundation/AVMetricDownloadSummaryEvent) Represents a summary metric event with aggregated metrics for the entire download task. --- 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)