ectShow
                                   codecs support it).

     maxBFrames        X           For MPEG codecs, gives the max
                                   number of bidirectional frames in a
                                   group of pictures (GOP).

  codecs = videoWriter([],'codecs')
  codecs = videoWriter([],pluginName,'codecs')
  codecs = videoWriter([],'codecs','plugin',pluginName)
    Queries the backend for a list of the valid codecs that may be used
    with the 'codec' plugin 