To find out what the video file name extension (format) is, right-click the file and choose Properties from the drop-down menu.

The video output format is the file name extension (format) you wish to convert the file to. For example, if you wish to convert a .mpg to a .avi you would choose .avi as the 'Output Source Format' in the converter program.

The Output Path is the saving destination of the file, so it does not matter what file name extension (format) the file is in.