File Extension RM
File extension RM is most commonly associated with a RealMedia multimedia file, which is a container format developed by RealNetworks. RM files contain audio and video streams compressed in a proprietary format, and are used primarily for the streaming of media over the Internet, though can also be downloaded and played on compatible standalone media players.
RM files are a multimedia container format which can carry audio and video streams encoded using RealNetwork's proprietary RealAudio and RealVideo codecs. RM files are similar to other container formats developed primarily for streaming video over the Internet such as MPEG4 in that both the video and audio streams can be heavily compressed to ensure smooth playback over most Internet connections. However, RM files only contain streams encoded using RealNetwork's proprietary codecs, whereas formats such as MPEG4 allow different streams to utilise different formats which allow for greater control over the quality of both audio and video.
An RM file may contain either audio tracks or video clips, and whilst they are more frequently used to stream media, can also be downloaded and played on a standalone media player. They are commonly used by Internet applications such as online radio, as they are a widely supported format and the high compression ratio make them suitable for streaming media over the majority of Internet connections. Though MPEG4 can provide superior quality at similar file sizes, RM files continue to be widely used.
RM files can be opened using RealNetwork's standalone media playing software, RealPlayer. They can also be opened in an Internet browser such as Microsoft Internet Explorer or Mozilla FireFox with the RealPlayer plug-in. As RM is a proprietary format, support via other applications is limited. Other applications such as VideoLAN VLC Player can open some RM files, though the format is only partially supported and the file is not guaranteed to play correctly.