F4V is a Flash Video format supported by Adobe Flash Player software and all browsers with flash video playback. The container uses boxes for data storage and it is compatible with h.264 video and AAC audio compression standards. F4V files provide better quality than FLV but need a newer version of Flash (9.0.115 or higher) and a faster processor.

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.