um, fpsDenom pair.
     framesPerSecond_denom
                       X      X

     bitRateTolerance  X           For supporting codecs, the actual
                                   bit rate is allowed to vary by +/-
                                   this value. 

     showCompressionDialog    X    If true (a non-zero number), a dialog
                                   box is presented to the user allowing
                                   precise manual selection of the codec
               