RA (RealAudio) is an audio format released in 1995 by RealNetworks. It uses multiple audio codecs, including high-fidelity music formats and low-bitrate formats. Since its introduction, the RA format has been mainly used by radio stations to stream audio online. Also, up until 2009, the BBC has been using it to stream sounds online.
RealNetworks RealPlayer Cloud VLC Media Player Wensites with the RealPlayer Plugin
M4V is a digital video container format developed by Apple Inc. It is pretty similar to the popular MP4 in terms of structure, but M4V files can sometimes be DRM protected. Today, M4V is the primary video format for iTunes Store videos and can multiplex together multiple audio and video data.
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