   MPEGPlay
   ~~~~~~~~
   Purpose:  Play MPEG movies

   Menu:
      Entry                   Action/Meaning
      -----                   --------------
      Run                     Start playing from the start of the movie.
                              (Grey if no movie is loaded.)
      Pause                   Pause the movie if it's running, continue
                              playing if the movie is paused. 
                              (Grey if no movie is running/paused.)
      Stop                    Stop playing a movie. No continue is possible,
                              but it is possible to change dither method. 
      Dither                  Give access to menu with different methods to dither
                              an MPEG-movie.
                              (Grey if a movie is running/paused.)
      Zoom                    An ordinary pixel zoom, e.g., the dither method will
                              use larger pixels not more pixels.
      Save                    An ordinary saveas option. It saves the current
                              picture as a sprite. The sprite is mode 21 for colour
                              dither and mode 18 for monochrome dither.
                              (Grey if no movie is loaded.)
