Is a media data format created by Apple. Named 'Quicktime' and is opened by a program with the same name. This format contains several tracks, each of which can store audio, video or text. Supported by a large number of encodings and in a single file, each element can use its own codec.
As opposed to the more common RealMedia container, which holds streaming media encoded at a constant bitrate (CBR), RMVB is typically used for multimedia content stored locally. Files using this format have the file extension .rmvb.