yowo 1.0.2

Production YOLO inference and export library for edge and cloud deployment

yowo

Production YOLO inference and export — hardware-aware, multi-backend, edge-ready.

yowo implements native YOLO11 and YOLO26 architectures for inference and export, adding what production deployments need: automatic hardware detection, transparent backend selection, graceful degradation, and stream resilience.

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Install

# Core (PyTorch backend, CPU inference)
pip install yowo

# ONNX Runtime — CPU inference (ARM, x86)
pip install yowo[onnx]

# ONNX Runtime — CUDA inference (NVIDIA GPU)
pip install yowo[onnx-gpu]

# OpenVINO — Intel CPU/iGPU
pip install yowo[openvino]

# Everything (ONNX GPU + OpenVINO)
pip install yowo[all]

# TensorRT — requires Linux + NVIDIA GPU (manual step)
pip install tensorrt>=10.0 --extra-index-url https://pypi.nvidia.com

Requirements: Python >=3.11, Linux (production) / macOS (development)

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Quick Start

CLI

# Auto-detect hardware and run inference
yowo detect image.jpg

# Use a specific model
yowo detect video.mp4 --model yolo26n

# Use a local weights file (skips download)
yowo detect image.jpg --model yolo26n --weights /path/to/YOLO26.pt

# RTSP stream
yowo detect rtsp://camera-ip:554/stream --model yolo26n --confidence 0.4

# Save detections to JSON
yowo detect ./images/ --model yolo11s --output detections.json

# Show hardware and installed backends
yowo info

# List all registered model variants
yowo models

Python API

from yowo import InferenceEngine, ModelSpec, ModelFamily, ModelSize, open_source

# Minimal: auto-select everything
spec = ModelSpec(ModelFamily.YOLO26, ModelSize.NANO)
with InferenceEngine(spec) as engine:
    for detection in engine.stream(open_source("image.jpg")):
        for box in detection.boxes:
            print(f"{box.class_name}: {box.confidence:.2f} @ {box.as_xyxy()}")

---

Example

yowo detect "input.jpg" \
  --model yolo26n \
  --weights "yolo26n.pt" \
  --backend pytorch \
  --confidence 0.25 \
  --output detections.json

The full JSON output per detection:

{
  "frame_index": 0,
  "source_id": "input.jpg",
  "inference_time_ms": 582.2,
  "backend": "pytorch",
  "model": "yolo26n",
  "boxes": [
    {
      "x1": 387.0, "y1": 422.0, "x2": 622.0, "y2": 537.0,
      "confidence": 0.888,
      "class_id": 2,
      "class_name": "car"
    },
    ....
  ]
}

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Models

Name	Alias	Notes
yolo11n/s/m/l/x	YOLO11	Stable, best production baseline
yolo26n/s/m/l/x	YOLO26	NMS-free, best CPU and INT8 speed

Weights are downloaded automatically to ~/.cache/yowo/weights/ on first use.

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Backends

yowo selects the best available backend automatically. You can override.

Backend	Format	When used
TensorRT	.engine	NVIDIA GPU + TensorRT installed
ONNX Runtime (CUDA)	.onnx	NVIDIA GPU + onnxruntime-gpu
OpenVINO	_openvino_model/	Intel CPU/iGPU + openvino
ONNX Runtime (CPU)	.onnx	Any CPU + onnxruntime
PyTorch	.pt	Universal fallback

Priority chain: TensorRT → ONNX (CUDA) → OpenVINO → ONNX (CPU) → PyTorch

If a backend fails to load, yowo falls back to the next in chain and logs a warning — it never crashes.

---

Detect

Single image

from yowo import InferenceEngine, ModelSpec, ModelFamily, ModelSize, open_source

spec = ModelSpec(ModelFamily.YOLO11, ModelSize.SMALL)
with InferenceEngine(spec, confidence=0.3) as engine:
    src = open_source("photo.jpg")
    for detection in engine.stream(src):
        print(f"{detection.num_boxes} objects in {detection.inference_time_ms:.1f}ms")
        for box in detection.boxes:
            print(f"  {box.class_name}: {box.confidence:.2f}")

Video file

with InferenceEngine(spec, batch_size=4) as engine:
    src = open_source("recording.mp4")
    for detection in engine.stream(src):
        # detection.frame.frame_index is the video frame number
        pass

RTSP stream (auto-reconnect)

with InferenceEngine(spec) as engine:
    src = open_source("rtsp://192.168.1.10:554/live")
    for detection in engine.stream(src):
        # Reconnects automatically on disconnect
        pass

Batch of frames

from yowo import InferenceEngine, ModelSpec, ModelFamily, ModelSize

spec = ModelSpec(ModelFamily.YOLO26, ModelSize.NANO)
engine = InferenceEngine(spec, batch_size=8)
engine.load()

import cv2, numpy as np
from yowo.types import Frame

frames = [
    Frame(data=cv2.imread(f"frame_{i:04d}.jpg"), frame_index=i)
    for i in range(8)
]
detections = engine.detect(frames)
engine.close()

Override backend and precision

from yowo import BackendType, Precision

with InferenceEngine(spec, backend=BackendType.ONNX, precision=Precision.FP16) as engine:
    ...

---

Export

Export .pt weights to an optimized format for your target hardware.

CLI

# Export to ONNX (FP16) — downloads weights automatically
yowo export yolo11n --format onnx --precision fp16

# Export using a local weights file (skips download)
yowo export yolo26n --weights /path/to/YOLO26.pt --format onnx --precision fp32

# Export to TensorRT engine (FP16)
yowo export yolo26s --format tensorrt --precision fp16 --output-dir ./engines/

# Export to ONNX with INT8 quantization (requires calibration images)
yowo export yolo11m --format onnx --precision int8 --calibration-data ./cal_images/

# Export with dynamic batch support
yowo export yolo11n --format onnx --dynamic-batch --imgsz 1280

Python API

from yowo import export_model, ModelSpec, ModelFamily, ModelSize, ExportFormat, Precision
from pathlib import Path

meta = export_model(
    ModelSpec(ModelFamily.YOLO26, ModelSize.NANO),
    ExportFormat.ONNX,
    output_dir=Path("./exported/"),
    precision=Precision.FP16,
)

print(meta.file_path)          # Path to exported model file
print(meta.file_size_bytes)    # Size in bytes
print(meta.export_duration_sec)  # How long it took

Each export produces a .yowo.json sidecar file recording the model family, precision, export date, and hardware used.

INT8 quantization

INT8 requires a calibration dataset of at least 300 representative images.

yowo export yolo26n --format tensorrt --precision int8 \
    --calibration-data /datasets/coco_val/images/

meta = export_model(
    spec, ExportFormat.TENSORRT, Path("./engines/"),
    precision=Precision.INT8,
    calibration_data="/datasets/coco_val/images/",
)

---

Hardware Info

yowo info

Output example:

=== Hardware ===
CPU: Device(type=cpu, name=AMD EPYC 7763, cpu_arch=x86_64)
GPU 0: Device(type=cuda, index=0, name=NVIDIA A100, arch=ampere)
CPU features: avx2

=== Libraries ===
torch:        2.3.0+cu121
cuda:         12.1
tensorrt:     10.0.1
onnxruntime:  1.18.0 (CUDA)
openvino:     not installed

---

Configuration

Via Python

from yowo import InferenceConfig, InferenceEngine

cfg = InferenceConfig(
    confidence=0.35,
    iou_threshold=0.5,
    batch_size=4,
    max_det=100,
)
with InferenceEngine(spec, **cfg.__dict__) as engine:
    ...

Via YAML file

# yowo.yaml
confidence: 0.35
iou_threshold: 0.50
batch_size: 4
max_det: 100

from yowo import load_config
cfg = load_config("yowo.yaml")

Via environment variables

export YOWO_CONFIDENCE=0.35
export YOWO_BATCH_SIZE=4
export YOWO_IOU_THRESHOLD=0.5

Precedence: environment variables > YAML file > defaults.

---

Error Handling

All exceptions inherit from yowo.YowoError.

from yowo import (
    YowoError,
    DependencyError,   # SDK not installed
    BackendLoadError,  # Model file corrupt / wrong format
    InferenceError,    # Runtime inference failure
    SourceError,       # Input stream unreachable
    ConfigError,       # Invalid configuration values
)

try:
    with InferenceEngine(spec) as engine:
        ...
except DependencyError as e:
    print(f"Missing package: {e.package}")
    print(f"Install with: {e.install_cmd}")
except BackendLoadError as e:
    print(f"Backend failed: {e}")
    # Engine already tried all fallback backends before raising
except YowoError as e:
    print(f"yowo error: {e}")

---

Platform Notes

Platform	Backend	Notes
NVIDIA GPU (server)	TensorRT or ONNX (CUDA)	Install yowo[onnx-gpu]; TensorRT is manual
NVIDIA Jetson	TensorRT	JetPack >= 5.0; CUDA and TensorRT pre-installed
Intel CPU/iGPU	OpenVINO	Install yowo[openvino]
x86 CPU (Linux)	ONNX	Install yowo[onnx]; AVX2 gives ~2x speedup
ARM CPU (Raspberry Pi, Graviton)	ONNX	Install yowo[onnx]

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Architecture

Module	Path	Responsibility
core	src/yowo/	InferenceEngine, public API surface, engine.py, config.py, types.py, errors.py
arch	src/yowo/arch/	Native YOLO11 and YOLO26 PyTorch — backbone, FPN-PAN neck, detection head, scaling, weight loading
backends	src/yowo/backends/	Inference backend implementations (TensorRT, ONNX, OpenVINO, PyTorch) and automatic priority-chain selection
cli	src/yowo/cli/	Click-based CLI — detect, export, info, models commands
export	src/yowo/export/	Export .pt weights to ONNX / TensorRT / OpenVINO with calibration, metadata sidecar, and output validation
hardware	src/yowo/hardware/	One-time hardware detection (GPU, CPU arch, installed libs), cached for session lifetime
io	src/yowo/io/	Frame sources (image, video, RTSP, directory), batch preprocessing, output sinks
models	src/yowo/models/	Model family / size registry, weight download, and ~/.cache/yowo/weights/ cache management
postprocess	src/yowo/postprocess/	Decode raw backend tensors into Detection objects; NMS for backends that return raw proposals

---

Development

# Clone and install with dev deps
git clone https://github.com/your-org/yowo
cd yowo
uv sync --group dev

# Quality gates (run before every commit)
uv run ruff check src/ tests/
uv run pyright src/yowo/
uv run pytest tests/unit/ --cov=yowo --cov-report=term-missing

# CLI from source
uv run yowo info

Architecture and module contracts are documented in:

• CONTEXT.md — project scope, principles, dependency graph
• src/yowo/README.md — library architecture overview
• src/yowo/arch/README.md — native YOLO backbone/neck/head, scaling, weight loading
• Each module directory has its own README.md

Experiments

Report	Summary
Vehicle Detection Benchmark — YOLO11s vs YOLO26m	PyTorch FP32 vs ONNX FP32/FP16/INT8 on Apple M4 Pro. YOLO11s ONNX FP16 achieves 18.1 FPS (2.62× PyTorch). YOLO26m ONNX FP32 achieves 6.9 FPS.
Native Architecture Inference Optimization — all 10 variants	DFL buffer, in-place sigmoid, stride flag, anchor cache applied to arch/. YOLO26 family 10–17% faster than ultralytics baseline; YOLO11 family 1–4% faster. Box IoU vs ultralytics: 0.967–0.995. 9/10 variants faster, avg 1.07×.

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License

Apache-2.0 — see LICENSE.