> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/cvat-ai/cvat/llms.txt
> Use this file to discover all available pages before exploring further.

# Frequently Asked Questions

> Common questions and answers about using CVAT

Find answers to common questions about CVAT installation, usage, troubleshooting, and features.

## General Questions

### What is CVAT?

CVAT (Computer Vision Annotation Tool) is an open-source, interactive tool for annotating images and videos for computer vision applications. It's used by tens of thousands of users worldwide to create high-quality training datasets for machine learning models.

### Is CVAT free?

Yes! CVAT is open-source and released under the MIT License. You can:

* Use [cvat.ai](https://cvat.ai) for free with limitations (10 tasks, 500MB storage)
* Self-host CVAT for unlimited usage
* Subscribe to [CVAT Cloud](https://www.cvat.ai/pricing/cloud) for additional features
* Get [Enterprise support](https://www.cvat.ai/pricing/on-prem) for self-hosted deployments

### What annotation types does CVAT support?

CVAT supports:

* **Bounding boxes** (rectangles)
* **Rotated bounding boxes**
* **Polygons**
* **Polylines**
* **Points**
* **Ellipses**
* **Cuboids** (3D boxes)
* **Skeletons** (keypoints)
* **Masks** (segmentation)
* **Tags** (image-level labels)

### What file formats does CVAT support?

CVAT supports 30+ annotation formats including:

* CVAT (XML)
* COCO (JSON)
* YOLO / Ultralytics YOLO
* Pascal VOC
* KITTI
* Cityscapes
* LabelMe
* Datumaro
* TFRecord
* And many more!

See the [full format list](https://docs.cvat.ai/docs/manual/advanced/formats/).

## Installation

### What are the system requirements?

Minimum requirements:

* **RAM**: 8GB (16GB recommended)
* **CPU**: 4 cores (8 cores recommended)
* **Storage**: 20GB+ depending on data size
* **Docker**: 20.10.0+
* **Docker Compose**: 1.29.0+

For production:

* **RAM**: 32GB+
* **CPU**: 16+ cores
* **Storage**: SSD with sufficient space for your datasets

### How do I install CVAT?

For local installation:

```bash theme={null}
git clone https://github.com/cvat-ai/cvat
cd cvat
docker compose up -d
```

Access at [http://localhost:8080](http://localhost:8080)

See the [installation guide](https://docs.cvat.ai/docs/administration/basics/installation/) for detailed instructions.

### Can I use CVAT without Docker?

While it's technically possible, Docker is strongly recommended because:

* CVAT has many dependencies (PostgreSQL, Redis, ClickHouse, etc.)
* Docker ensures consistent environments
* Manual setup is complex and error-prone

For cloud deployment, consider using Kubernetes/Helm.

### How do I update CVAT?

For Docker Compose installations:

```bash theme={null}
cd cvat
git pull origin develop
docker compose down
docker compose pull
docker compose up -d
```

**Important**: Always backup your data before updating!

### Can I install CVAT on Windows?

Yes, using:

* **WSL2** (Windows Subsystem for Linux) - Recommended
* **Docker Desktop for Windows**

Follow the [Windows installation guide](https://docs.cvat.ai/docs/administration/basics/installation/) for details.

## Usage

### How do I create my first annotation task?

1. Go to **Tasks** → **Create new task**
2. Enter a task name
3. Add labels (e.g., "car", "person", "dog")
4. Upload images or videos
5. Click **Submit**
6. Wait for processing to complete
7. Click **Open** to start annotating

### What's the difference between a Task, Job, and Project?

* **Project**: Container for related tasks with shared labels
* **Task**: A set of media files to annotate
* **Job**: A subset of a task's frames, assigned to an annotator

Example: Project "Autonomous Driving" → Task "Highway Videos" → Job "Frames 1-1000"

### How do I import existing annotations?

1. Open your task
2. Go to **Actions** → **Upload annotations**
3. Select format (COCO, YOLO, etc.)
4. Upload your annotation file
5. Click **Submit**

CVAT will import and validate your annotations.

### How do I export annotations?

1. Open your task
2. Go to **Actions** → **Export task dataset**
3. Select export format
4. Choose whether to save images
5. Click **Export**
6. Download when ready

### Can I use CVAT for video annotation?

Yes! CVAT has excellent video support:

* Track objects across frames
* Interpolation between keyframes
* Video chapter navigation
* Frame-by-frame control
* High-performance frame caching

### How does tracking work?

1. Create a **Track** annotation (not a shape)
2. Draw the object on the first frame
3. Navigate to a later frame
4. Adjust the annotation position
5. CVAT automatically interpolates between frames

You can also use AI-powered tracking with serverless functions.

### Can multiple people annotate the same task?

Yes! Split your task into jobs:

1. When creating a task, set **Job overlap** and **Segment size**
2. CVAT creates multiple jobs automatically
3. Assign different jobs to different annotators
4. Each annotator works on their assigned frames

### What are serverless functions?

Serverless functions enable:

* **Auto-annotation**: Automatic annotation using AI models
* **Interactive annotation**: AI-assisted annotation tools (e.g., Segment Anything)
* **Tracking**: Object tracking across frames

CVAT supports models like:

* Segment Anything (SAM)
* YOLOv7
* Mask R-CNN
* Custom models via Nuclio

See the [serverless functions guide](https://docs.cvat.ai/docs/administration/advanced/installation_automatic_annotation/).

## Troubleshooting

### CVAT is slow or unresponsive

Common causes:

* **Insufficient RAM**: Increase Docker memory limit
* **Large images**: Use smaller images or enable compression
* **Too many objects**: Split task into smaller jobs
* **Slow storage**: Use SSD instead of HDD

Optimizations:

* Enable frame caching
* Use compressed chunks
* Reduce chunk size
* Close unused browser tabs

### I can't upload large videos

For large files:

* Increase Traefik's upload size limit
* Use cloud storage integration (AWS S3, Azure, Google Cloud)
* Split video into smaller segments
* Use mounted file shares

Edit `docker-compose.yml`:

```yaml theme={null}
traefik:
  command:
    - --entrypoints.web.http.middlewares=cvat-request-body-limit
```

### Annotations disappeared or weren't saved

Check:

* Click **Save** (Ctrl+S) regularly
* Check browser console for errors
* Verify permissions (can you write to the job?)
* Check server logs: `docker logs cvat_server`

Recover:

* Check **Actions** → **Export job dataset** to see if data exists
* Contact admin if data is critical

### Docker containers fail to start

Common issues:

**Port conflicts:**

```bash theme={null}
docker ps -a  # Check running containers
sudo lsof -i :8080  # Check port usage
```

**Insufficient memory:**

* Increase Docker memory limit (Docker Desktop → Settings → Resources)
* Kill unnecessary processes

**Permission issues:**

```bash theme={null}
sudo usermod -aG docker $USER  # Add user to docker group
# Log out and back in
```

### How do I check logs?

```bash theme={null}
# All services
docker compose logs

# Specific service
docker logs cvat_server
docker logs cvat_worker_import

# Follow logs
docker logs -f cvat_server
```

### Database is corrupted

To reset (WARNING: This deletes all data!):

```bash theme={null}
docker compose down -v  # Remove volumes
docker compose up -d    # Recreate
```

To backup before resetting:

```bash theme={null}
docker exec cvat_db pg_dump -U root cvat > backup.sql
```

### CVAT shows "502 Bad Gateway"

This usually means backend isn't ready:

```bash theme={null}
docker logs cvat_server  # Check for errors
docker compose restart cvat_server  # Restart backend
```

If persists, check:

* Database is running: `docker ps | grep db`
* Redis is running: `docker ps | grep redis`
* Migrations completed: `docker exec cvat_server python manage.py showmigrations`

## Features

### Can I use CVAT offline?

Yes, if self-hosted! Once installed:

* No internet connection required for annotation
* Internet needed for:
  * Auto-annotation (if using cloud models)
  * Cloud storage integration
  * Updates and new models

### Does CVAT support 3D annotation?

Yes! CVAT supports:

* **Point cloud annotation** (.pcd files)
* **3D cuboids** with rotation
* **Multiple camera views**
* **Related images** (synchronized 2D images)

### Can I customize CVAT?

Yes! CVAT is highly customizable:

* **UI plugins**: Add custom UI components
* **Server plugins**: Extend backend functionality
* **Custom annotation formats**: Add import/export formats
* **Serverless functions**: Deploy custom AI models
* **Webhooks**: Integrate with external systems

### Does CVAT have an API?

Yes! CVAT provides:

* **REST API**: Full-featured HTTP API
* **Python SDK**: `pip install cvat-sdk`
* **CLI**: `pip install cvat-cli`
* **OpenAPI schema**: [https://app.cvat.ai/api/docs](https://app.cvat.ai/api/docs)

See the [API documentation](https://docs.cvat.ai/docs/api_sdk/api/).

### Can I integrate CVAT with my ML pipeline?

Yes! Common integrations:

* **FiftyOne**: Dataset management and visualization
* **Roboflow**: Model training and deployment
* **HuggingFace**: Model integration
* **Custom scripts**: Using SDK/CLI
* **Webhooks**: Real-time notifications

Example workflow:

1. Train model
2. Use model for auto-annotation in CVAT
3. Manually correct predictions
4. Export improved dataset
5. Retrain model
6. Repeat

### What about annotation quality control?

CVAT includes:

* **Quality reports**: Compare annotations between annotators
* **Consensus**: Merge annotations from multiple annotators
* **Honeypot frames**: Ground truth frames for validation
* **Review mode**: Accept/reject annotations with comments
* **Inter-annotator agreement**: Calculate agreement metrics

### Does CVAT support SSO/LDAP?

Yes, in Enterprise version:

* **LDAP/Active Directory**
* **SAML 2.0**
* **OAuth 2.0**

Contact [sales@cvat.ai](mailto:sales@cvat.ai) for enterprise features.

### Can I run CVAT in production?

Yes! For production:

* Use **Kubernetes/Helm** for orchestration
* Set up **SSL/TLS** (HTTPS)
* Configure **backups** (database and media)
* Use **cloud storage** (S3, Azure, GCS)
* Set up **monitoring** (Prometheus, Grafana)
* Consider **Enterprise support**

See the [administration guide](https://docs.cvat.ai/docs/administration/).

## Getting Help

### Where can I get help?

* **Documentation**: [https://docs.cvat.ai/](https://docs.cvat.ai/)
* **GitHub Issues**: [https://github.com/cvat-ai/cvat/issues](https://github.com/cvat-ai/cvat/issues)
* **Gitter Chat**: [https://gitter.im/opencv-cvat/public](https://gitter.im/opencv-cvat/public)
* **Discord**: [https://discord.gg/fNR3eXfk6C](https://discord.gg/fNR3eXfk6C)
* **Stack Overflow**: Tag questions with `#cvat`
* **Email**: [contact@cvat.ai](mailto:contact@cvat.ai)

### How do I report a bug?

1. Check if already reported: [GitHub Issues](https://github.com/cvat-ai/cvat/issues)
2. Create new issue with:
   * CVAT version
   * Steps to reproduce
   * Expected vs actual behavior
   * Screenshots/videos if applicable
   * Browser console errors
   * Server logs if relevant

### How do I request a feature?

1. Check [existing requests](https://github.com/cvat-ai/cvat/issues?q=is%3Aissue+is%3Aopen+label%3Aenhancement)
2. Create new issue:
   * Describe the feature
   * Explain use case
   * Provide examples if possible
3. Discuss with maintainers
4. Consider contributing!

### Can I contribute to CVAT?

Absolutely! Contributions welcome:

* **Code**: Fix bugs, add features
* **Documentation**: Improve guides and docs
* **Testing**: Report bugs, test new features
* **Community**: Answer questions, help others

See the [contributing guide](/contributing/getting-started).

## More Resources

* **Website**: [https://www.cvat.ai/](https://www.cvat.ai/)
* **Documentation**: [https://docs.cvat.ai/](https://docs.cvat.ai/)
* **GitHub**: [https://github.com/cvat-ai/cvat](https://github.com/cvat-ai/cvat)
* **YouTube**: [https://www.youtube.com/@cvat-ai](https://www.youtube.com/@cvat-ai)
* **LinkedIn**: [https://www.linkedin.com/company/cvat-ai/](https://www.linkedin.com/company/cvat-ai/)
* **Blog**: [https://www.cvat.ai/post](https://www.cvat.ai/post)

## Still Have Questions?

If your question isn't answered here:

* Check the [full documentation](https://docs.cvat.ai/)
* Ask on [Gitter](https://gitter.im/opencv-cvat/public) or [Discord](https://discord.gg/fNR3eXfk6C)
* Open a [GitHub Issue](https://github.com/cvat-ai/cvat/issues)
* Contact us at [contact@cvat.ai](mailto:contact@cvat.ai)