RM is an extension characteristic of RealPlayer. It is a tool that allows you to watch multimedia content transmitted in real time, most often via the Internet. These are both audio and video content.

RM are files that are used to store compensated data containing audio or video material. Sometimes they may contain links to media files. Data compression in an RM file is performed with the RealAudio or RealVideo codecs. All of these solutions were developed by RealNetworks, Inc. In addition to RealPlayer, some other players also offer partial RM support.