Vicon Tracker 4 banner

As you work through your Tracker session, it's important to understand these fundamental aspects of Tracker's behavior:

Device synchronization session

When you connect Tracker to a live system of cameras and/or Vicon connectivity devices, a new device synchronization session is created. To identify the current device synchronization session, look in the timebar at the bottom of the Workspace for the value in brackets [ ]. 

When you start Tracker, the device synchronization session starts at 1 and the Frame and Seconds displayed are relative to the start of that session. 

The device synchronization session enables the system to synchronize all devices. As such, a new system session starts when:

  • The hardware is rebooted
  • A device is added to the system
  • The frame rate changes

Being aware of the device synchronization session, and the time or frame relative to its start, can be useful when:

Live Review

When Tracker is live, the system's pause buffer is a feature that enables data to be stored to memory for Live Review (see Review live data). The maximum amount of data that can be stored is controlled by the Pause Buffer Size, which you can configure in the Processing panel (see Configure system processing parameters). The Pause Buffer Size specifies the duration of the pause buffer, and thus the amount of data that is always accessible.

The data types stored in the pause buffer are identical to the data types that are saved when capturing data. This includes data such as, but not limited to, centroids in each camera view, object pose, analog devices, and system performance metrics such as latency. For more information on the data types that are stored in a capture, see Capture live data.

The pause buffer influences the behavior and workflow of multiple aspects of the software including:

  • Object creation and manipulation
  • Reviewing recent live data
  • Graph Plots
  • CSV exports


With Tracker started, its default behavior is to save all settings automatically according to the Auto-save interval setting (see Preferences options), which is the duration of time between each save operation. Autosaved settings do not affect any of the saved system settings.

All autosaved files are located within this folder:


Autosave files are only updated if there have been changes since the last autosave.

As you work in Tracker, files populate into the above folder according to the temporary filenames listed in the following table. When you close Tracker properly, the temporary filenames are converted and saved as normal filenames.

Temporary filenameNormal filename

If Tracker terminates abnormally (including closing the process from Windows Task Manager), the temporary filename is not converted to its normal filename and thus is left in the LastRun folder.

When you restart Tracker, if any of the autosave files are detected, you are prompted to confirm which files you wish to load:

  • To load the most recent (autosaved) settings, click Yes.
  • To load settings from the last successfully closed session, click No.

This feature prevents you from losing your settings if Tracker closes abnormally, for example, due to process termination, machine reboot, etc.

To control the autosave settings, select Settings > Preferences > User:

  • To disable autosave, clear Enable auto-save. The default is selected.
  • To change the autosave interval, enter a value (in seconds) for the Auto-save interval. The default is 60 seconds.

If you have system settings that you are likely to re-use, we recommend that you save them, rather than relying on the autosave feature. For more information, see Save system settings.