A black triangle represents the marker of the current time stamp on the timeline. Moving the current time marker will stop all selected players and jump to the timestamp of the marker.

A dotted blue line indicates the current point of time of a selected camera view on the timeline of the camera. This marker is dynamic. It moves forward when a video is playing.

The current time marker (triangle) can be moved by clicking and dragging it with the mouse. If you click anywhere on the timeline, the marker will jump to this position.

Moving the marker sets the selected camera(s) back to play mode. The players follow the marker time. The blue dotted lines follow the current time marker as well. The replay speed of the selected camera(s) will be set to the replay speed configured in the properties dialog.

Moving the marker also updates the time in the time picker. If you want the selected camera(s) to jump to the specified time in the time picker, the jump icon must be clicked.