RealVideo is a proprietary video format developed by RealNetworks. It was released in 1997 to accompany RealAudio. Both formats can be combined in a RealMedia container, with the .rm file extension. RealMedia is primarily a streaming media format. It is supported on many of platforms, including Windows, Mac, Linux, Solaris, and even some mobile phones. The format has largely been replaced on modern websites with HTML5 video.

To view media using RealNetworks' proprietary formats, you can use the RealPlayerPlugin in K-Meleon.