query_duration
  
  Description:
  public bool query_duration (
Format format, 
out int64 duration)
  
 
  
    Queries a pad for the total stream duration.
    Parameters:
    
      
        | this | a Pad to invoke the duration query on. | 
      
        | format | the Format requested | 
      
        | duration | a location in which to store the total  duration, or null. | 
    
    Returns:
    
      
        | true if the query could be performed. |