RMVB (RealMedia Variable Bitrate) is a digital variable bitrate extension for the RM (RealMedia) container format. Unlike the standard RM format that streams content in CBR (Contant Bitrate), the RMVB, as the name suggests, streams local media in VBR (Variable Bitrate). This file format uses a .rmvb filename extension.
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F4V is a filename extension for Flash Video (FLV) container format. It supports H.264 (MPEG-4 AVC) video codec compression standard, which is known to offer significant compression. FLV videos come in multiple formats apart from F4V, including F4P, F4A, and F4B. Also, it opens on Adobe Flash Player 6 or later and Windows Media Player.
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