[McByte part 1] Add McByte tracker skeleton by tstanczyk95 · Pull Request #388 · roboflow/trackers

tstanczyk95 · 2026-05-01T10:57:39Z

What does this PR do?

Create a skeleton for new tracker, McByte - primarily derived from BoT-SORT, #386.
No mask functionality yet (SAM, Cutie). It serves as the base for the next PRs to build incrementally on top of it.

Type of Change

New feature (non-breaking change that adds functionality)

Testing

I have tested this change locally
I have added/updated tests for this change

Test details:
Import the tracker. Run it (frame setting and calling its update function) on 5 dummy frames.

Checklist

My code follows the style guidelines of this project
I have performed a self-review of my own code
I have commented my code where necessary, particularly in hard-to-understand areas
My changes generate no new warnings or errors
I have updated the documentation accordingly (if applicable)

AlexBodner · 2026-05-04T13:34:12Z

is this the same as in BotSORT? if yes we should think of making it one separate reusable util.

@AlexBodner Yes yes, for the current moment, the CMC in McByte it is exactly the same as the one in BoT-SORT, since this PR is just the very first skeleton.

I am planning to indeed extract the CMC to make it a common util for the trackers, but as I saw, there are still some changes going on with the BoT-SORT PR (from which I derived this branch). I thought about keeping it simple for now and adjust later, in the next PRs, to reduce merge conflicts, avoid the review noise, etc.

Adjusted, using the reusable util from this, already merged, #414.

In general, whole the whole code here adjusted with the released BoT-SORT.

Copilot

Pull request overview

Adds an initial “McByte” tracker implementation under trackers.core.mcbyte, largely mirroring the existing BoT-SORT-style pipeline (predict → optional CMC → high/low confidence association → spawn → prune), plus a basic smoke test to ensure the tracker can run a short CMC-enabled sequence.

Changes:

Introduces McByteTracker with ByteTrack/BoT-SORT-like two-stage association and optional CMC integration.
Adds McByteTracklet with scale-aware KF noise tuning, bbox clamping, and CMC application support.
Adds minimal unit test that instantiates the tracker and runs several updates with sparseOptFlow CMC enabled.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/core/test_mcbyte_tracker.py	Adds a basic smoke test for McByte + CMC-enabled updates.
src/trackers/core/mcbyte/utils.py	Adds tracklet pruning helper and IoU-score fusion helper.
src/trackers/core/mcbyte/tracklet.py	Implements McByte tracklet state/KF behavior, including scale-aware noise + clamping + CMC hook.
src/trackers/core/mcbyte/tracker.py	Implements McByte tracker skeleton (prediction, association stages, spawning, pruning, reset).
src/trackers/core/mcbyte/init.py	Exposes `McByteTracker` from the mcbyte subpackage.

tstanczyk95 · 2026-05-15T14:33:36Z

+class McByteTracker(BaseTracker):
+    tracker_id = "mcbyte"
+


Complete class docstring will be provided when McByte development is finished. Now we are in the phase of building it part by part and adding next features.

The dev/mcbyte-clean branch will be opened and then merged with develop upon completion.

Current version docstring provided in 51874ea.

tstanczyk95 · 2026-05-15T14:40:06Z

+# ------------------------------------------------------------------------
+from .tracker import McByteTracker
+
+__all__ = ["McByteTracker"]


Remark as above with the separate branch to be merged upon the completion at the end.

tstanczyk95 · 2026-05-15T14:54:30Z

+# Licensed under the Apache License, Version 2.0 [see LICENSE for details]
+# ------------------------------------------------------------------------
+
+# tests/core/mcbyte/test_mcbyte_tracker.py


Addressed in 706a6f8.

tstanczyk95 · 2026-05-15T14:54:42Z

+def test_mcbyte_instantiates_sets_frame_and_updates_with_sparse_opt_flow_cmc() -> None:
+    """McByteTracker can run one basic CMC-enabled tracking sequence."""


Applied in 706a6f8.

Borda · 2026-05-19T13:02:40Z

+
+
+class McByteTracker(BaseTracker):
+    tracker_id = "mcbyte"


why this is needed, seem like you couls simply use self.__class__.__name__

This is done in consistency with all the other trackers, e.g. with BoT-SORT: https://github.com/roboflow/trackers/blob/develop/src/trackers/core/botsort/tracker.py#L95

search_space will be considered at later stages.

ok so maybe worth to revisit the patter with all :)

Borda · 2026-05-19T13:04:17Z

+
+class McByteTracker(BaseTracker):
+    tracker_id = "mcbyte"
+


maximum_frames_without_update: int minimum_consecutive_frames: int ...

Could you please clarify on this one?

If you meant class docstring for the McByteTracker class, it has been addressed in the PR from Part 2: #418
https://github.com/roboflow/trackers/pull/418/changes#diff-ac854e39fe30bd0d79d2efce4291889e0415197f4f1ebb48f89c79cab6e21a81R33

we can add it in later PRs

Borda · 2026-05-19T13:05:08Z

+        self.enable_cmc = enable_cmc
+        self.cmc = CMC(CMCConfig(method=cmc_method, downscale=cmc_downscale)) if enable_cmc else None
+
+    def update(


it is getting quite long, can we split it in a few private methods?

It is in consistency with the BoT-SORT tracker, done the same way:
https://github.com/roboflow/trackers/blob/develop/src/trackers/core/botsort/tracker.py#L148

my perspective was to have update composed from a few private methods so the code becomes easier to follow and easier to test as partucular methods can have simple unittests

For now the update() method is also the same style as the other trackers. And exactly the same as BoT-SORT. But if it becomes longer and/or more complex later with the next McByte dev, it might be indeed good to split it into a few private methods!

Borda · 2026-05-19T13:06:14Z

+        self,
+        initial_bbox: np.ndarray,
+        state_estimator_class: type[BaseStateEstimator] = XCYCWHStateEstimator,
+    ) -> None:


lets add dcostring with args

It is done with the consistency with other trackers, e.g BoT-SORT:
https://github.com/roboflow/trackers/blob/develop/src/trackers/core/botsort/tracklet.py#L47

None of the trackers currently has a docstring for the init method.
All of them, including McByte have the class docstring, though:
https://github.com/roboflow/trackers/blob/develop/src/trackers/core/botsort/tracklet.py#L23
https://github.com/roboflow/trackers/pull/388/changes/BASE..970d17cb733d1220f03abd3cfc04342523767bde#diff-4fd50d576fa05b618ccbe713e9bceaf203aa8c6fe4139b4a080f818de957caaeR23

tstanczyk95 requested a review from SkalskiP as a code owner May 1, 2026 10:57

tstanczyk95 requested review from AlexBodner and Borda and removed request for AlexBodner May 1, 2026 10:57

AlexBodner reviewed May 4, 2026

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tstanczyk95 self-assigned this May 6, 2026

tstanczyk95 and others added 2 commits May 14, 2026 23:20

Add McByte tracker skeleton (no masks yet)

a1d2143

fix(pre_commit): 🎨 auto format pre-commit hooks

7fc1af1

tstanczyk95 force-pushed the feat/mcbyte-core-skeleton branch from e4e9b48 to 7fc1af1 Compare May 14, 2026 23:46

fix(pre_commit): 🎨 auto format pre-commit hooks

c696290

tstanczyk95 changed the title ~~Add McByte tracker skeleton~~ [McByte part 1] Add McByte tracker skeleton May 15, 2026

tstanczyk95 requested a review from AlexBodner May 15, 2026 02:07

Borda added the enhancement New feature or request label May 15, 2026

Borda requested a review from Copilot May 15, 2026 07:02

Copilot started reviewing on behalf of Borda May 15, 2026 07:02 View session

Copilot AI reviewed May 15, 2026

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tstanczyk95 and others added 2 commits May 15, 2026 16:51

Address selected review comments for McByte skeleton

706a6f8

fix(pre_commit): 🎨 auto format pre-commit hooks

970d17c

tstanczyk95 changed the base branch from develop to dev/mcbyte-clean May 18, 2026 15:55

tstanczyk95 changed the base branch from dev/mcbyte-clean to develop May 18, 2026 16:03

tstanczyk95 changed the base branch from develop to dev/mcbyte May 19, 2026 12:42

Borda reviewed May 19, 2026

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Borda approved these changes May 20, 2026

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tstanczyk95 merged commit 8cc2ea8 into dev/mcbyte May 20, 2026
18 checks passed

tstanczyk95 deleted the feat/mcbyte-core-skeleton branch May 20, 2026 12:11

		def test_mcbyte_instantiates_sets_frame_and_updates_with_sparse_opt_flow_cmc() -> None:
		"""McByteTracker can run one basic CMC-enabled tracking sequence."""

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tstanczyk95 commented May 1, 2026

What does this PR do?

Type of Change

Testing

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tstanczyk95 May 14, 2026 •

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