The RMVB file extension is a RealMedia Variable Bit Rate File and is used by RealVideo from RealNetworks Inc. The variable bit rate means its optimized for the content of the video. It is a newer variation of the .RM file format that allows better compression and thus a smaller file size. The RMVB format has become popular for Anime and Asian movie titles because of lower bitrates with better quality than DIVX and smaller file sizes.
Mime type: application/vnd.rn-realmedia-vbr