RealVideo
| Developed by | RealNetworks |
|---|---|
| Initial release | February 1997 |
| Website | Product Website at the Wayback Machine (archived 2009-05-31) |
RealVideo is a suite of proprietary video compression formats developed by RealNetworks – the specific format changes with the version. It was first released in 1997 and as of 2008[update] is at version 10. 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 (.rm) container. RealMedia is suitable for use as a streaming media format, that is one which is viewed while it is being sent over the network. Streaming video can be used to watch live television, since it does not require downloading the entire video in advance. Compression and decompression software for each version are called "codecs".
The first version of RealVideo was announced in 1997 and was based on the H.263 format. At the time, RealNetworks issued a press release saying they had licensed Iterated Systems' ClearVideo technology and were including it as the RealVideo Fractal Codec. However, support for ClearVideo quietly disappeared in the next version of RealVideo.
RealVideo continued to use H.263 until RealVideo 8, when the company switched to a proprietary video format. RealVideo codecs are identified by four-character codes. RV10 and RV20 are the H.263-based codecs. RV30 and RV40 are RealNetworks' proprietary codecs. These identifiers have been the source of some confusion, as people may assume that RV10 is RealVideo version 10, when it is actually the first version of RealVideo. RealVideo 10 uses RV40.
RealVideo can be played from a RealMedia file or streamed over the network using the (RTSP), a standard protocol for streaming media developed by the IETF. However, RealNetworks uses RTSP only to set up and manage the connection. The actual video data is sent with their own proprietary Real Data Transport (RDT) protocol. This tactic has drawn criticism because it made it difficult to use RealVideo with other player and server software. However, the open source MPlayer project has now developed software capable of playing the RDT streams.
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