RealVideo
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Internet media type |
video/x-pn-realvideo |
---|---|
Developed by | RealNetworks |
Initial release | February 1997 |
Type of format | Video coding format |
Open format? | No |
Free format? | No |
Website | Product Website at the Wayback Machine (archived May 31, 2009) |
RealVideo, or also spelled as Real Video, is a suite of
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.
Technology
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.[2][3][4] 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 H.264-based 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
To facilitate real-time streaming, RealVideo (and RealAudio) normally uses
RealNetworks says that the RealVideo and RealAudio codecs are not available in source code under the RPSL license. Source code is available only under RCSL license for commercial porting to non-supported processors and operating systems. While RealNetworks owns most of the intellectual property for RealVideo and RealAudio, RealNetworks has licensed third party technology for certain aspects of those codecs. RealNetworks claims that it does not have the rights to license that technology under an open source license.[5]
RealVideo Players
The official player for RealVideo is RealNetworks
The latest version of RealPlayer that can run on Windows 9x is RealPlayer 8; but this version can be easily modified to play RealPlayer 9 and 10 files, by the manual addition of just three .dll files (codecs and plugins), from Microsoft's free distribution of RealPlayer 10, that are not included in RealPlayer 8 Basic.
RealNetworks has also developed the open source
RealPlayer does not record RealVideo streams, and RealNetworks has advertised this feature to content owners such as broadcasters, film studios, and music labels, as a means of discouraging users from copying video. However, other software exists which can save the streams to files for later viewing. Such copying, known as
Video compression formats and codecs versions
RealVideo files are compressed using several different
RV10
RV20
rv20
: RealVideo G2 and RealVideo G2+SVT, also based on h.263 (included with RealPlayer 6).[7] SVT (Scalable Video Technology) is a feature that allows for decoding at a lower framerate (frame-skipping) on low-end machines.[8]
RV30
rv30
: RealVideo 8, suspected to based largely on an early draft ofH.264 (included with RealPlayer 8)[9]
RV40
rv40
: RealVideo 9, suspected to be based on H.264 (included with RealPlayer 9)[10]rv40
: RealVideo 10, aka RV9 EHQ (included with RealPlayer 10). This refers to an improved encoder for the RV9 format that is fully backwards compatible with RV9 players – the format and decoder did not change, only the encoder did. As a result, it uses the same FourCC.
RV60
rv60
:HEVC (included with RealPlayer 18).[11] In April 2018, RealNetworks posted test results of encoder speed and compression efficiency. Their tests compared RealMedia HD to HEVC, H.264 and VP9 encoders. Results claimed RealMedia HD provided higher compression than HEVC at higher perceived quality levels. RealMedia HD was also purportedly faster than x265 and VP9 at comparable complexity settings.[12]
The newest version of RealPlayer can play any RealVideo file, as can programs using FFmpeg. Other programs may not support all video compression formats. In addition to decoder code for up to RV50, FFmpeg also contains open-source code for RV10 and RV20 encoders.[citation needed]
See also
Notes
- ^ RealNetworks Products - Codecs Archived 2004-08-04 at the Wayback Machine
- ^ "Iterated Systems And Progressive Networks Announce Strategic Alliance". Press release. RealNetworks China. February 10, 1997. Archived from the original on November 27, 2003. Retrieved August 2, 2013.
- ^ RealVideo Fractal Codec Reference to RealPlayer Fractal Codec installation option
- ^ Terran Interactive, Inc. (1998) Codec Central - ClearVideo, Retrieved on 2009-08-12
- ^ Helix Community, Helix Producer Category FAQ Archived 2011-07-26 at the Wayback Machine, Retrieved on 2009-08-02
- ^ MultimediaWiki. "RealVideo 1.0". Retrieved 2009-11-02.
- ^ MultimediaWiki. "RealVideo G2". Retrieved 2009-11-02.
- ^ RealNetworks (1999). "Chapter 5: Producing Video". www.jus.unitn.it.
RealVideo's Scalable Video Technology (SVT) also allows RealVideo clips to vary in frame rate from 30 fps to 5 fps based on the RealPlayer computer's processor speed. This means you can produce high frame rate RealVideo clips that do not overburden the processors of slow machines during playback.
- ^ MultimediaWiki. "RealVideo 3". Retrieved 2009-11-02.
- ^ MultimediaWiki. "RealVideo 4". Retrieved 2009-11-02.
- ^ "RMHD: A More Detailed Look".
- ^ "For the eight codec, go for the sum - not just for the parts". 10 April 2018.
External links
- RealVideo 10 codec Product Page
- Helix Community the open source project of all media framework of RealNetworks Archived 2011-07-26 at the Wayback Machine
- RealMedia Splitter Gabest(guliverkli, sourceforge.net) to split RV40 etc. in .rmvb, .mkv, .dsm, etc. Decoder is not included.
- Filter for playing RealNetworks audio/video files using Windows Media Player