Tab 3 — Recording

Synchronised recording across the selected cameras, with automatic download and audio synchronisation.

🚧 TODO: screenshot.

Recording a trial

1. Enter a trial name and select the cameras.
2. Start — then perform two loud hand claps within the first 3 seconds. (Two claps enable a consistency check; one clap works, but without cross-validation.)
3. Perform the movement, then Stop.
4. Files are downloaded from each camera into [project]/sessions/[session]/[trial]/video/, and audio synchronisation runs automatically — synced files appear in video/synced/.

A session/trial tree view at the bottom shows all recorded trials.

Sync outputs (per trial)

• Trimmed MP4s in synced/ — start-aligned and end-trimmed to identical duration. Originals are never modified.
• sync_onsets.png — detected clap onsets on each camera's audio envelope.
• stitched_videos.mp4 — a 2×2 grid preview for quick visual verification of sync.
• A WARN status means the two clap offsets disagree by more than one frame — consider re-recording with clearer claps.

Sound source position (speed-of-sound compensation)

At high frame rates, differences in camera-to-clap distance cause sub-frame sync errors (~3 m ≈ 8.8 ms). Set Sound source X / Y / Z (metres, in the calibration coordinate system); with a calibration loaded, sync automatically subtracts the differential propagation delay. Values persist in go2kin_config.json. Not applied during extrinsic calibration or Set Origin.

🚧 TODO: when to bother (e.g. ≥100 fps with metres of distance difference) and how to measure the source position.