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The multi-sensor viewer provides a unified timeline that keeps all panels synchronized as you navigate through your recording. Whether you are scrubbing through an hour-long drive log or stepping frame-by-frame to verify a single annotation, the timeline controls give you precise access to every moment in the data.

Playback Controls

The timeline bar runs across the bottom of the viewer. It displays the full duration of the recording and indicates the current playback position.

Play and Pause

Press Space or click the play button to start continuous playback. All panels advance in sync at the selected playback speed. Press Space again to pause.

Playback Speed

Adjust the playback rate to slow down or speed up the recording:
SpeedUse Case
0.25xInspect fast-moving objects or rapid state changes
0.5xDetailed review of sensor data at reduced speed
1xReal-time playback at the original recording rate
2xQuickly scan through long recordings
4xFast-forward to find specific events or scenes
Click the speed indicator next to the play button to cycle through available rates.
Use 0.25x or 0.5x playback when reviewing annotations on fast-moving objects. At full speed, it is easy to miss misaligned cuboids or drifting bounding boxes.

Frame-by-Frame Navigation

For precise inspection, step through the recording one frame at a time.
ShortcutAction
Left ArrowStep back one frame
Right ArrowStep forward one frame
Shift + Left ArrowSkip back 10 frames
Shift + Right ArrowSkip forward 10 frames
HomeJump to the start of the recording
EndJump to the end of the recording
Each frame step moves all panels to the next message timestamp in the recording. Panels with different publishing rates display the closest message to the current time.
Frame stepping uses the message timestamps in your recording, not a fixed time interval. If your LiDAR publishes at 10 Hz and cameras at 30 Hz, stepping forward advances to the next available message across all active topics.

Timestamp Seeking

Scrubbing

Click and drag anywhere on the timeline bar to scrub through the recording. All panels update continuously as you drag, giving you a visual preview of the data at each position.

Jump to Timestamp

To navigate to a specific time:
1

Click the timestamp display

The current timestamp is shown in the timeline bar. Click it to open the timestamp input field.
2

Enter the target time

Type the desired timestamp in HH:MM:SS.mmm format (hours, minutes, seconds, milliseconds).
3

Press Enter

All panels jump to the specified time. The viewer displays the closest available message to the requested timestamp.

Panel Synchronization

All panels in the viewer are locked to the same timeline position. When you perform any navigation action — play, pause, step, scrub, or seek — every panel updates simultaneously. This synchronization works across panels with different data rates:
PanelExample RateBehavior on Frame Step
Camera30 HzShows the frame at or immediately before the current timestamp
LiDAR10 HzShows the scan at or immediately before the current timestamp
IMU200 HzShows the reading closest to the current timestamp
GPS1 HzShows the most recent fix at or before the current timestamp
The viewer uses message timestamps (not wall-clock time) for synchronization. This means panels stay aligned even if sensors were recorded with different clocks, as long as the timestamps in the MCAP file are consistent.
If sensors in your recording have significant clock skew (timestamps that differ by more than a few milliseconds for the same real-world moment), panels may appear out of sync. Ensure your recording pipeline synchronizes sensor clocks before capture. See Recording Best Practices for guidance.

Keyboard Shortcuts Reference

ShortcutAction
SpacePlay / Pause
Left ArrowPrevious frame
Right ArrowNext frame
Shift + Left ArrowSkip back 10 frames
Shift + Right ArrowSkip forward 10 frames
HomeJump to start
EndJump to end
+ / -Zoom in / out (on individual panels)
0Reset zoom
FToggle fullscreen

Next Steps