RMVB files: It is a proprietary file format developed by RealNetworks Inc. RMVB stand for RealMedia Variable Bitrate (RMVB) & is a variable bitrate extension of the RealMedia multimedia container format. This file format is which is optimized for the content of the video & it is a newer variation of the standard Real Media (.RM) file format that allows for more efficient compression. Note: RMVB files have become a popular format for Anime and Asian movie titles because they have smaller file sizes and lower bitrates with better quality compared to DivX (.DVX) files.