# PlaybackSession

Source: https://www.nianticspatial.com/docs/api/swift/NSDK.class-PlaybackSession/

PlaybackSession
> inherits from ARKit.ARSession

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## Declaration

class PlaybackSession

## Summary

Drives playback. **Subclasses ARSession** so it can be assigned to `ARView.session` and the app can use
the same delegate pattern. Runs a loop on a background queue, builds **PlaybackFrame** per frame from
the PlaybackDataset, dispatches to the main queue, and notifies the delegate and **PlaybackRenderer**.
Relation to Apple AR: **Replaces** the behavior of ARSession (no real device frames); API-compatible so
ARView and delegate code don't need to know it's playback.

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## Constructors

init(dataset: PlaybackDataset)

#### Summary

Initializes a new playback session with an existing dataset.

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## Properties

| Name | Type | Summary |
| --- | --- | --- |
| var compassTimestampBase | ClockBase | Clock the played-back dataset's compass timestamps are on. |
| var currentPlaybackFrame | PlaybackFrame | The most recently delivered playback frame. Set on the main queue when each frame is delivered.Use this to get camera or frame data outside the delegate (e.g. in a render loop). |
| weak var playbackDelegate | ( PlaybackSessionDelegate)? | Delegate that receives frame updates during playback |
| var playbackRenderer | PlaybackRenderer? | - |

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## Methods

| Name | Type | Summary |
| --- | --- | --- |
| hasDepth | Bool | Returns whether the dataset contains LiDAR depth (depthSource == "lidar"). Used by NSDKView.hasDepth and feature checks. |
| override pause | void | Stops playback. The loop exits on its next iteration; the current frame index is preserved so a later `run()` resumes from the same frame. |
| override run | void | Starts playback. The playback loop runs asynchronously on a background queue; frames are delivered on the main queue.Configuration and options are ignored (playback uses the dataset's frame rate and content). Call `pause()` to stop. |

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## Relationships

conforms to:  Swift.Sendable 

conforms to:  ObjectiveC.NSObjectProtocol

conforms to:  Swift.Equatable 

conforms to:  Swift.Hashable 

conforms to:  Swift.CVarArg 

conforms to:  Swift.CustomStringConvertible 

conforms to:  Swift.CustomDebugStringConvertible 

conforms to:  Swift.SendableMetatype