RealVideo is a suite of proprietary video compression formats developed by RealNetworks and first 1997. RealVideo is supported on many platforms, including Windows, Mac, Linux, Solaris, and several mobile phones. RealVideo is usually paired with RealAudio and packaged in a RealMedia container, which can also include metadata including subtitles and closed captioning, with the file extension .rm. RealMedia is suitable for use as a streaming media format. Streaming video can be used to watch live television, since it does not require downloading the entire video in advance. The official player for RealVideo is RealNetworks RealPlayer SP, which is available for various platforms including Windows, Macintosh and Linux.
To facilitate real-time streaming, RealVideo and RealAudio use constant bitrate encoding, sending the same amount of data over the network each second. RealMedia Variable Bitrate (RMVAB) allows for better video quality but is less suited for streaming because it is difficult to predict how much network capacity a certain video stream will need. Video with fast motion or rapidly changing scenes requires a higher bitrate.
RealPlayer, formerly RealOne Player is cross-platform adware created by RealNetworks and primarily used for the playing of recorded media. The media player is compatible with numerous formats within the multimedia realm, including MP3, MPEG-4, QuickTime, Windows Media, and multiple versions of the proprietary RealAudio and RealVideo formats. RealPlayer is also available for on Macintosh, and Linux, Unix, Palm OS, Windows Mobile and Symbian versions have been released. The software is powered by an underlying open-source media engine called Helix.
The first version of RealPlayer was introduced in April 1995 as RealAudio Player and was one of the first media players capable of streaming media over the Internet. RealPlayer was initially accessed by many users as a plug-in to watch streaming video or listen to streaming audio but has since been overtaken in popularity by Adobe Flash.
Features of RealPlayer include a web browser, graphical animations, equalizer and video controls including cross-fade and gapless playback, recording audio, LivePause which pauses streaming video clips, CD ripping, and a media converter which allows converting to proper format and transferring video to iPods, cell phones, Xbox, PS3 and other devices. This allows for convenient file sharing of filmed material for such uses as editing, archiving and transcription. Users of RealPlayer can also post videos to Facebook and Twitter directly from the software.
RealPlayer SP for Windows includes audio CD burning capabilities, DVR-style playback buffering, multimedia search, Internet radio, a jukebox-style file library, an embedded web browser using Microsoft Internet Explorer, and the ability to convert and transfer media to a wide range of devices.