---
description: Explore the track.py script for Ultralytics object tracking. Learn how on_predict_start, on_predict_postprocess_end, and register_tracker functions work.
keywords: Ultralytics, YOLO, object tracking, track.py, on_predict_start, on_predict_postprocess_end, register_tracker
---

# Reference for `ultralytics/trackers/track.py`

!!! success "Improvements"

    This page is sourced from [https://github.com/ultralytics/ultralytics/blob/main/ultralytics/trackers/track.py](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/trackers/track.py). Have an improvement or example to add? Open a [Pull Request](https://docs.ultralytics.com/help/contributing/) — thank you! 🙏

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## ::: ultralytics.trackers.track.on_predict_start

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## ::: ultralytics.trackers.track.on_predict_postprocess_end

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## ::: ultralytics.trackers.track.register_tracker

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