JTrackers

A multi-object tracking library for Swift, powered by a Rust-based tracking engine.

Provides three tracking algorithms:

• ByteTracker — Two-stage matching using high and low-confidence detections
• BoostTracker — IoU + Mahalanobis distance + shape similarity (supports BoostTrack+/++ modes)
• OCSort — Observation-centric online smoothing with velocity direction consistency

Requirements

• macOS 12+
• iOS 15+
• Swift 5.9+

Installation (Swift Package Manager)

Add the following to your Package.swift:

dependencies: [
    .package(url: "https://github.com/mprg-smilab/JTrackers.git", from: "0.4.1"),
],
targets: [
    .target(
        name: "YourTarget",
        dependencies: ["JTrackers"]
    ),
]

In Xcode, go to File → Add Package Dependencies... and enter the repository URL above.

Usage

Basic Flow

1. Initialize a tracker
2. Pass detections ([TrackedObject]) to update() for each frame
3. Use the returned trackId to track each object across frames

import JTrackers

// 1. Create a tracker
let tracker = ByteTracker()

// 2. Create detections (e.g. output from an object detection model)
let detections = [
    TrackedObject(x: 10, y: 20, width: 100, height: 200, prob: 0.9),
    TrackedObject(x: 300, y: 400, width: 80, height: 160, prob: 0.8),
]

// 3. Update the tracker and get track IDs
let results = try tracker.update(detections).get()

for obj in results {
    print("Track ID: \(obj.trackId ?? -1), bbox: (\(obj.x), \(obj.y), \(obj.width), \(obj.height))")
}

ByteTracker

let tracker = ByteTracker(
    frameRate: 30,
    trackBuffer: 30,
    trackThresh: 0.5,
    highThresh: 0.6,
    matchThresh: 0.8
)

BoostTracker

let tracker = BoostTracker(
    detThresh: 0.5,
    iouThreshold: 0.3,
    maxAge: 30,
    minHits: 3
)

// Enable BoostTrack++ mode
let tracker = BoostTracker(enableBoostPlusPlus: true)

OCSort

let tracker = OCSort(
    detThresh: 0.5,
    maxAge: 30,
    minHits: 3,
    iouThreshold: 0.3,
    deltaT: 3,
    inertia: 0.2,
    useByte: false
)

Documentation

Full API documentation is available at: https://kadu-v.github.io/JTrackers/documentation/jtrackers/

License

See LICENSE for details.