RealAudio is a proprietary audio format developed by RealNetworks. It was used by the once-common RealPlayerPlugin.

RealAudio files originally had the extension .ra (for Real Audio). In 1997 RealNetworks introduced a video format called RealVideo. The combination of the audio and video formats was called RealMedia and used the file extension .rm. Files with the extension .rv were video files (with or without audio), while .rmvb stood for VBR video files. Other RealPlayer formats inlcuded .ram (Real Audio Metadata) and .smil (Synchronized Multimedia Integration Language). These two are text files containing a link to the audio stream.