# MCAP Format

Each input segment produces one MCAP containing:

- One compressed-video image topic and one camera-information topic per
  discovered camera.
- `/imu/devN` messages using the published [`imu.proto`](../imu.proto) schema.
- An embedded `metadata.json` attachment describing the session and streams.
- A flat `robocap` MCAP metadata record.

Camera packet times are anchored to:

```text
session_start_utc + MP4 format.tags.comment device_clock_us + packet DTS
```

IMU samples use their device-clock nanosecond timestamp with the same session
UTC base. The converter validates timestamp synchronization between video and
IMU streams before writing.