.RM is a video format that stands for ‘Real Media’. You can open and play RM format audio or video files using a special software. You can use official Real media player to play RM audio / videos files. However, this player is heavy and makes system slow. Also, this software is laden with lot of unnecessary stuff.
Another free, quick and eay alternative for RM files is VLC player. You can use this player to open RM and many other video format files without downloading any addition software or plugins. So, use VLC Player to play .RM (Real Media) video files.