The Select New Duration dialog allows you to change the duration of a clip in the sequence while in the Sequence Style of Storyboard. Click the ruler button of any clip on the storyboard to open the Select New Duration dialog.
To change the duration in the dialog, enter a new duration in seconds into the field, then click the OK button to save. If a shorter duration has been entered, the time will be taken off the end of the lcip. If a longer duration has been entered, any time remaining after the clip’s current out point will be added back on, up to the total duration of the clip. A clip cannot be made longer than its original length using this method.
Note that this method of editing clip lengths is best when precise lengths have been predetermined. If you prefer to line your in and out points up to visual cues on the clip, use the clip navigation buttons in the Selected Clip Preview area to cue up the precise moment of the in or out point, then use the red and blue flags to mark the in or out point.