set_running_time
Description:
Adjust the start/stop and base values of this such that the next valid buffer will be one with 
        running_time.
Parameters:
| this | 
           a Segment structure.  | 
      
| format | 
           the format of the segment.  | 
      
| running_time | 
           the running_time in the segment  | 
      
Returns:
| 
           true if the segment could be updated successfully. If false is 
            returned,   |