MCAP Viewer

Custom editor for exploring ROS 2 oriented .mcap logs inside VS Code.

This extension is aimed at robot data inspection workflows where camera streams and joint signals need to be reviewed together step-by-step.

Features

• Open .mcap directly from Explorer
• Render sensor_msgs/msg/CompressedImage topics as synchronized camera panels
• Use sensor_msgs/msg/JointState as the main timeline when available
• Merge trajectory_msgs/msg/JointTrajectory topics into an action view
• Show step-by-step state/action signals beside the camera frames
• Show nearest-frame lag and persist per-camera visibility/focus state
• Package as a VS Code custom editor for direct file opening

Development

npm install
npm run compile
npm test
npm run smoke -- ../mcap-example/20260416_150442_961284/20260416_150442_961284_0.mcap
npm run package:vsix

Then open this folder in VS Code and press F5 to launch an Extension Development Host.

Supported topics

• sensor_msgs/msg/CompressedImage
• sensor_msgs/msg/JointState
• trajectory_msgs/msg/JointTrajectory

The webview currently picks the nearest camera frame for each timeline step.

Controls

• Space: play/pause
• Left Arrow: previous step
• Right Arrow: next step
• Camera chips: hide, restore, focus a single stream

Packaging Notes

• Optimized for ROS 2 MCAP logs with cdr message encoding.
• Currently focused on CompressedImage, JointState, and JointTrajectory.
• Validated against the sample log in ../mcap-example/20260416_150442_961284/.
• Treat 0.1.x as a pre-release line unless it has been tested against your specific MCAP variants.