What is a RM file?
RealMedia streaming format (legacy)
RM files are multimedia files made specifically for the audio/video playback and streaming program called RealPlayer. Mostly, files with the .rm file extension are used for streaming content over the Internet (video and internet radio). RM files were developed by RealNetworks as a multimedia container optimized for internet streaming. Most RM files are played with RealPlayer, but other media players such as VLC do have partial support for RM files.