RMVB, RealMedia Variable Bitrate (.rmvb)
The RMVB Video file format
Unlike the common RealMedia container (which holds streaming media that encodes as a constant bitrate), RMVB files are used for the storage of multimedia content. RMVB (RealMedia Variable Bitrate) is a variable bitrate extension of the RealMedia multimedia container format. Both RealPlayer and Media Player Classic on Windows support RMVB through DirectShow filters or Real Alternative. Linux and related systems use the open-source, reverse-engineered RMVB implementation in FFmpeg to play RMVB files. The well-known VLC media player can also handle these files. They are popular in Asia, especially via the distribution of Chinese television and movies, but not very popular throughout the rest of the world.
Technical details of RMVB files
Compression of RMVB files is similar to the one of MPEG-4 Part 10 encoders. Their incompatibility to work with media players besides RealMedia keeps the file type from becoming popular, yet the constant usage in Asian countries has kept it relevant. This file is often used on file sharing platforms such as torrent programs and other peer-to-peer file sharing programs. Variable bit rate files can change the amount of data in a set time frame. Bitrates can be increased for complex file and decreased for simpler sections. Storage requirements are therefore less with a negligible decrease in quality, requiring a longer encoding process.