---
description: Learn how to register custom event-tracking and track predictions with Ultralytics YOLO via on_predict_start and register_tracker methods.
# on_predict_start
:::ultralytics.tracker.track.on_predict_start
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# on_predict_postprocess_end
:::ultralytics.tracker.track.on_predict_postprocess_end
# register_tracker
:::ultralytics.tracker.track.register_tracker