---
description: Learn how to register custom event-tracking and track predictions with Ultralytics YOLO via on_predict_start and register_tracker methods.
keywords: Ultralytics YOLO, tracker registration, on_predict_start, object detection
---

# on_predict_start
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:::ultralytics.tracker.track.on_predict_start
<br><br>

# on_predict_postprocess_end
---
:::ultralytics.tracker.track.on_predict_postprocess_end
<br><br>

# register_tracker
---
:::ultralytics.tracker.track.register_tracker
<br><br>