Robotic Tools

A workspace of pure-Python tools for working with MCAP files, ROS 1/2 messages, and robotics data — built around a fast, batteries-included CLI.

pymcap-cli

A high-performance Python CLI for slicing, dicing, recovering, and exporting MCAP files. Pure Python, no ROS runtime required.

# Try it without installing
uvx pymcap-cli info data.mcap

# Or add to your project
uv add pymcap-cli

Why pymcap-cli?

• Advanced recovery — repairs corrupt MCAP files via chunk-level recovery and MessageIndex validation
• Smart chunk copying — up to 10× faster filtering by copying compressed chunks without decompressing
• Unified process command — recovery, filtering, and recompression in a single optimized pass
• Precise filtering — regex topics, time ranges, and content-type filters with deferred schema/channel writing
• Broad format coverage — converts ROS 1 .bag and ROS 2 .db3 to MCAP; exports to NDJSON, CSV, Parquet, PCD, GeoJSON / KML / GPX, image folders, and MP4
• Rich terminal output — colored topics, Unicode distribution histograms, tree views, responsive layouts

See the full command reference in pymcap-cli/README.md.

Supporting packages

The workspace also ships the libraries pymcap-cli is built on. Each is usable standalone.

Package	What it does
small-mcap	Lightweight MCAP reader/writer. Zero hard deps, high performance.
mcap-ros2-support-fast	Pure-Python ROS 2 CDR (de)serialization. 30–60× faster than the reference implementation.
ros-parser	Parser for ROS 1 / ROS 2 message definitions and Foxglove message path syntax.
mcap-codec-support	Reusable MCAP encoder/decoder factories for video and point-cloud codecs.
pointcloud2	Helpers for sensor_msgs/PointCloud2 access and conversion.
pureini	Pure-Python implementation of the Cloudini point-cloud compression format.
robo-ws-bridge	Python implementation of the Foxglove WebSocket protocol for streaming robotics data.
websocket-proxy	Proxy in front of Foxglove Bridge with just-in-time message conversion, image compression, and point-cloud compression.

License & credits

These tools draw inspiration from (and aim to interoperate with):

• https://github.com/foxglove/mcap
• https://github.com/foxglove/ros-typescript