rm RealNetworks, an internet streaming Media Company, is credited as the developers and owners of the proprietary RealMedia multimedia container format. The filename extension .rm refers to this format which is used as an audio and video wrapper to distribute digital media content over the internet. The first version of this container was released in 1997 and has been popularized for its ability to unpack the digital stream while it is being downloaded over computer networks such as the internet. The format is platform agnostic and works equally well on Microsoft Windows as it does on Linux or Mac OS.
ogg The OGG file format and .ogg file extension refer to the open source container format developed and maintained by the Xiph.Org Foundation. The format has been in development since the early 90's and initially was designed as an open format for audio compression. Later iterations has seen the format revised into a full audio and video container format with compression codec support of different standards. OGG can be used both in compressed or uncompressed ways and is compatible with different lossy and lossless codecs both for audio and for video. Text can also be added into OGG files as an overlay, all packaged within a single file.