You can add a subtitle to a clip using a common video converter. You can use an application like Freemake Video Converter. They even have a small tutorial to teach you how to do it. It's placed on the download page.
Download page: http://www.freemake.com/how_to/how_to_add_subtitles_to_a_movie
Recommendation: While installing the software you will be offered with other products. Read carefully and deny any installation until you reach the actual program's installation.