Transport controls are useful for navigation and for playing media. Each of the Viewer, Compositor, and Program windows has its own transport panel. The controls generally all contain a colored tooltip when you mouse over the control, providing a hint of their function and shortcuts for usage.
The transport panel is controlled by the keyboard as well as the graphical interface. For each of the operations it performs, the starting position is the position of the insertion point in the Program window and the slider in the Compositor and Viewer windows. The ending position is either the end or start of the timeline or the end or start of the selected region if there is one.
The orientation of the end or start depends on the direction of playback. If it is forward the end position is the end of the selected region. If it is backward the end position is the start of the selected region. The insertion point moves to track playback. When playback stops, the insertion point stays where playback stopped. Thus, by playing back you change the position of the insertion point. The keyboard interface of either the numeric pad or alternative keys has more speeds with the addition of Forward Slow(2) and Reverse Slow (5). Hitting any key on the keyboard twice pauses it. The shortcuts section of this manual as well as a Shell Command available from the CINELERRA-GG main window has a listing of each of the keys.
When using frame advance functions the behavior may seem odd. If you frame advance forward and then frame advance backward, the displayed frame does not change. This is because the playback position is not the frame but the time between two frames. The rendered frame is the area that the playback position crosses. When you increment the time between two frames by one and decrement it by one, you cross the same frame both times and so the same frame is displayed. There is an option in Settings → Preferences, Appearance tab to Always show next frame that may help make this clearer for some users.
The transport behavior changes if you hold down Ctrl when issuing any of the transport commands. This causes the starting point to be the In point if playing forward and the Out point if playing backward. If playing forward, the Out point becomes the ending point and if playing backward, the In point becomes the ending point. If no In/Out points are specified, the behavior falls back to using the insertion point and track boundaries as the starting and ending points.
The transport behavior also changes if you hold down the Shift key along with KeyPad 1–6. If normally audio is included in the play, it will be removed and if normally audio is not included in the play, it will be added.
The CINELERRA-GG Community, 2021