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.

WavPack lossless audio compression. Note that, when converting .wav to this format and back again, the RIFF header is not necessarily preserved losslessly (though the audio is).