RealAudio is RealNetworks' proprietary audio format which ranges from low-bitrate to high-fidelity formats depending on the user's needs.
Most notably, .RA, as is its file extension, is used in conjunction with RealMedia and RealVideo streaming content online. In the past it was used for Internet radio stations but has fallen out of favor recently for AAC, MP3 and WMA. RealAudio8 is a popular implementation of ATRAC3 and just one example of many audio formats used in RA.
The format was originally released in 1995 and is now up to version 11.
