rmvb The .rmvb filename extension refers to the RealMedia variable bitrate format which is an extension of the RealMedia multimedia container format. RMVB is a proprietary multimedia digital container developed and maintained by RealNetworks, an internet streaming Media Company. It is different from its closely related format .rm in that it was designed for distribution of complete multimedia content, however it does support real-time media streaming. Video and Audio streams can be encoded and packaged into this format and distributed as single files for later playback on compatible devices and software as opposed to file streaming on high bandwidth networks.
3gp The 3GP file format and its associated filename extension .3gp is an audio, video, and text container developed by the 3rd generation partnership project. The target market for the 3gp file format is 3G enabled UMTS mobile phones through associated UMTS multimedia services. Though mobile devices operating on high speed networks are the intended hardware associated with playing .3gp files, many PC codec packs exist which grant compatibility for .3gp playback. The format has a basic profile in which files of this format do not reference any external media sources and support for audio, video, and text is limited to a single track.