Is a recording format, designed for use in movie theaters. Who is a direct competitor of Dolby Digital. It is used to accompany the film with the movie, as well as on optical video discs. It supports two modes of audio: 5.1 and 7.1, allows full bit rate in high end home theaters.

RA is an audio format developed by RealNetworks to use in its RealPlayer for streaming audio which means that it can be played while downloading. It uses several audio codecs, they range from the ones for delivering high-fidelity sound to those for recording low bitrate audio data. Although, the format was pretty popular and was used by many radio station to stream online, now it is technically inferior to other newer formats.