The timestamp in nanoseconds of the frame the givenTrackDatawas recorded on.
If frames are skipped during playback, the played back external track data may be attached to a later frame. This timestamp is equal to the result ofUnityEngine.XR.ARSubsystems.XRCameraFrame.timestampNson the frame during which track data was written.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-14 UTC."],[[["\u003cp\u003e\u003ccode\u003eTrackData\u003c/code\u003e stores externally recorded data associated with an AR Track, retrieved using \u003ccode\u003eARPlaybackManager.GetUpdatedTrackData\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eIt includes the raw byte data (\u003ccode\u003eData\u003c/code\u003e) recorded using \u003ccode\u003eARRecordingManager.RecordTrackData\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eIt also provides the frame timestamp (\u003ccode\u003eFrameTimestamp\u003c/code\u003e) indicating when the data was recorded, potentially subject to playback adjustments.\u003c/p\u003e\n"]]],["`TrackData`, recorded externally, is accessible via `ARPlaybackManager.GetUpdatedTrackData`. It contains two key attributes: `Data`, a byte array recorded through `ARRecordingManager.RecordTrackData`, and `FrameTimestamp`, the nanosecond timestamp of the frame when the `TrackData` was recorded. If frames are skipped, track data might be associated with a later frame; the timestamp aligns with `XRCameraFrame.timestampNs` of the recording frame.\n"],null,["# TrackData Struct Reference\n\nTrackData\n=========\n\nData that was recorded to an external [Track](/ar/reference/unity-arf/struct/Google/XR/ARCoreExtensions/Track#structGoogle_1_1XR_1_1ARCoreExtensions_1_1Track).\n\nObtained by [ARPlaybackManager.GetUpdatedTrackData(System.Guid)](/ar/reference/unity-arf/class/Google/XR/ARCoreExtensions/ARPlaybackManager#getupdatedtrackdata).\n\nSummary\n-------\n\n| ### Public attributes ||\n|-----------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| [Data](#data) | `byte[]` The byte data array that was recorded via [ARRecordingManager.RecordTrackData(Guid, byte[])](/ar/reference/unity-arf/class/Google/XR/ARCoreExtensions/ARRecordingManager#recordtrackdata). |\n| [FrameTimestamp](#frametimestamp) | `long` The timestamp in nanoseconds of the frame the given [TrackData](/ar/reference/unity-arf/struct/Google/XR/ARCoreExtensions/TrackData#structGoogle_1_1XR_1_1ARCoreExtensions_1_1TrackData) was recorded on. |\n\nPublic attributes\n-----------------\n\n### Data\n\n```c#\nbyte[] Google::XR::ARCoreExtensions::TrackData::Data\n``` \nThe byte data array that was recorded via [ARRecordingManager.RecordTrackData(Guid, byte[])](/ar/reference/unity-arf/class/Google/XR/ARCoreExtensions/ARRecordingManager#recordtrackdata). \n\n### FrameTimestamp\n\n```c#\nlong Google::XR::ARCoreExtensions::TrackData::FrameTimestamp\n``` \nThe timestamp in nanoseconds of the frame the given [TrackData](/ar/reference/unity-arf/struct/Google/XR/ARCoreExtensions/TrackData#structGoogle_1_1XR_1_1ARCoreExtensions_1_1TrackData) was recorded on.\n\nIf frames are skipped during playback, the played back external track data may be attached to a later frame. This timestamp is equal to the result of [UnityEngine.XR.ARSubsystems.XRCameraFrame.timestampNs](https://docs.unity3d.com/Packages/com.unity.xr.arsubsystems@4.2/api/UnityEngine.XR.ARSubsystems.XRCameraFrame.html#UnityEngine_XR_ARSubsystems_XRCameraFrame_timestampNs) on the frame during which track data was written."]]
