mmunication overhead.

   vw = videoWriter(url, ..., param,arg,...)
     Allows the user to pass extra configuration arguments to plugin.
     At present, all parameter names are case sensitive (but in the
     future they may become case-insensitive).  

     The following parameters are supported by current plugins:

                        Plugin 
     Parameter      ffmpeg* DShow  Implementation Notes
     ---------      ------- -----  -----------------------------
     width             X  