code: private void convertSup(int index, int displayNum, int displayMax)
  			throws CoreException {
  		convertSup(index, displayNum, displayMax, false);
  	}
docs: Convert source subpicture image to target subpicture image.
  
  @param index
  Index of subtitle to convert
  @param displayNum
  Subtitle number to display (needed for forced subs)
  @param displayMax
  Maximum subtitle number to display (needed for forced subs)
  @throws CoreException