RM (Real Media) is a multimedia format developed by RealNetworks. It features a .rm filename extension and is typically multiplexed with RealAudio and RealVideo when streaming content online. The stream is usually in constant bitrate (CBR), although a file container for variable bitrate (VBR) is now available, called Real Media Variable Bitrate (RMVB).
RealNetworks RealPlayer Coud Final Media Player Media Monkey RealTrimmer
FLV (Flash Video) is a video container format developed by Adobe Systems and comes with a .flv filename format. FLV is primarily used to stream audio, video, and text data such as subtitles. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player
VLC Media Player