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.
avi The AVI file format is one of the most widely used multimedia containers ever devised. AVI, which stands for audio video interleaved, was first introduced to the public by Microsoft in 1992 as part of their 'video for windows' multimedia framework. Being a container format, an AVI file with the .avi filename extension can exist with both video and audio content synchronized for playback. The format can thus be used by authors to edit and encode audio video sequences or just video sequences. The Digital video AVI format exists in two forms, Type 1 and Type 2.