You manipulate offline trial data with time and synchronization characteristics in the time bar.
The time bar is available at the bottom of all types of view pane when you play back data from a saved trial. It is displayed only when the system is in Offline mode (click the Go Offline button), and contains the following controls:
- Play/Stop button
Play forward continuously through trial. When clicked, the button switches to its Stop setting.
- Jump to Previous Event button
Play backward one event (when in Event Identification Mode).
Switch between modes in which you can manipulate data based on time (button off) or events (button on). For details on manipulating data, see Add events to trials in the Vicon Nexus User Guide. Enter Event identification mode button
- Jump to the next event button
Play forward one event (when in Event Identification Mode).
Display a context menu from which you can select the following options to manipulate trial data (you also can display the context menu by right-clicking anywhere on the time bar):
- Zoom to Trial Reset the ruler to the full trial timescale after zooming in or out.
- Zoom to Region-of-Interest Reset the ruler to the range of frames identified by the Start Range Frame indicator and the End Range Frame indicator (for details on these indicators, see below).
- Set Current Frame Opens the Go to Frame dialog box, in which you can specify the required frame. When you click OK, the current time indicator moves to the specified frame.
- Set Region-of-Interest Opens the Set Region of Interest dialog box, in which you can specify the start and end frames for the region of interest.
- Play Every Frame When selected, the datastream ships all frames. (Rendering is unaffected.) Select this option only if you want to perform calculations on the datastream data.
- Replay Speed Specify the playback speed relative to real time by selecting one of the following sub options: 1/10, 1/4, 1/2, 1, 2, or Other. The Other option displays a dialog box in which you can set a specific value.
- Trajectory Tails Specify the length of tails for selected trajectories, as a value in frames before and after every gap by selecting one of the following from the displayed context menu: 0 frames, 25 frames, 50 frames, 100 frames, 200 frames, or Other. The Other option displays the Trajectory Tails dialog box in which you can set a specific value.
Default: 100 frames
- Clear All Events Clear all marked events from the ruler. Note that you can also use the Delete Timebar Events pipeline operation to delete events from a specified range of frames.
- You can also manage data playback using the keyboard. For example, you can use keys and mouse actions to manage the timescale displayed in the timeline, the time bar data displayed in the workspace, and event identification mode. For more information see Hot keys and shortcuts in the Vicon Nexus User Guide.
You identify or manipulate trial data based either on time or event, depending on the whether the Enter Event Identification Mode button is on or off with the following areas of the time bar.
The overall time span and the range of frames currently viewable in the workspace. The timeline is split into default contexts:
- Left The top rule on the timeline contains markers for any events specified for the left context.
- Right The middle rule on the timeline contains markers for any events specified for the right context.
- General The bottom rule on the timeline contains markers for any events specified for the general context.
- Selected frame The number of the currently selected frame is displayed at the bottom of the timeline.
Displays the overall span of time for the range of frames that can currently be selected. The current frame of trial data is displayed in the label on the left side of the scale at the bottom of the timeline. You can move the visible portion of the timescale or zoom in or out of it (for details, see Shortcuts for working with the time bar in the Vicon Nexus User Guide).
Indicate a selected characteristic of the trial data for playback. You can move the indicators along the timeline to manually move the data playback forward or backward and display the desired frame in the view pane. Indicators are displayed when appropriate for the playback operation:
- Current time indicator
Indicates the current time of the data playback along the timeline. This vertical bar spans the entire height of the timeline. In Event Identification Mode, the current time indicator follows the mouse cursor. You can click and drag the mouse for slow-motion playback. When you release the mouse button, the event context menu is displayed.
- Start of range indicator
Indicates the frame specified as the start of the range of trial data to play back or process. This blue triangle is initially positioned on the first frame at the top of the timeline.
- End of range indicator
Indicates the frame specified as the end of the range of trial data to play back. This blue triangle is initially positioned on the last frame at the top of the timeline.
- Current time indicator
- Event markers
Indicate a specific event to be applied or displayed in the currently selected frame of the trial data:
- Foot Strike The point at which the trial subject's foot contacts the ground.
- Foot Off The point at which the trial subject's foot leaves the ground.
- General A point at which the trial subject performs a user-defined event.
- Custom A point at which the trial subject performs a user-defined event that can be named.
- Delete Event <Type> Deletes the selected event.
- Delete All Events at Frame x Deletes all events previously set for the current frame.
- Clear All Events Deletes all events previously set for the entire trial.