Editing RealVideo (section)

==Video compression formats and codec versions==
RealVideo files are compressed using several different [[video compression format]]s. Each video compression format is identified by a [[FourCC|four-character code]]. Below is a list of the video compression formats and the version in which each was introduced:

===RV10===
* {{code|rv10}}, {{code|rv13}}: RealVideo 1.0, based on [[H.263]] (included with RealPlayer 5)<ref>{{cite web | url=http://wiki.multimedia.cx/index.php?title=RealVideo | title=RealVideo 1.0 | author=MultimediaWiki | access-date=2009-11-02}}</ref>

===RV20===
* {{code|rv20}}: RealVideo G2 and RealVideo G2+SVT, also based on h.263 (included with RealPlayer 6).<ref>{{cite web | url=http://wiki.multimedia.cx/index.php?title=RealVideo_G2 | title=RealVideo G2 | author=MultimediaWiki | access-date=2009-11-02}}</ref> SVT (Scalable Video Technology) is a feature that allows for decoding at a lower framerate (frame-skipping) on low-end machines.<ref>{{cite web |author1=RealNetworks |title=Chapter 5: Producing Video |url=http://www.jus.unitn.it/services/arc/samples/production/htmfiles/video.htm |website=www.jus.unitn.it |date=1999 |quote=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.}}</ref>

===RV30===
{{anchor|RV30}}
* {{code|rv30}}: RealVideo 8, suspected to be based largely on an early draft of [[H.264]] (included with  RealPlayer 8)<ref>{{cite web | url=http://wiki.multimedia.cx/index.php?title=RealVideo_3 | title=RealVideo 3 | author=MultimediaWiki | access-date=2009-11-02}}</ref>

===RV40===
{{anchor|RV40}}
* {{code|rv40}}: RealVideo 9, suspected to be based on H.264 (included with RealPlayer 9)<ref>{{cite web | url=http://wiki.multimedia.cx/index.php?title=RealVideo_4 | title=RealVideo 4 | author=MultimediaWiki | access-date=2009-11-02}}</ref>
* {{code|rv40}}: RealVideo 10, aka RV9 EHQ (included with RealPlayer 10). This refers to an improved encoder for the RV9 format that is fully backward compatible with RV9 players – the format and decoder did not change, only the encoder did. As a result, it uses the same [[FourCC]].

===RV60===
* {{code|rv60}}: [[RealMedia HD]] (RealVideo 11), suspected to be based on [[HEVC]] (included with RealPlayer 18).<ref>{{cite web | url=https://codecs.multimedia.cx/2017/10/rmhd-a-more-detailed-look/comment-page-1/#comment-216927 | title=RMHD: A More Detailed Look}}</ref> 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.<ref>{{cite web | url=https://medium.com/realnetworks/for-the-right-codec-go-for-the-sum-not-just-the-parts-7683a603f943 | title=For the eight codec, go for the sum - not just for the parts| date=10 April 2018}}</ref>

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.{{cn|date=May 2023}}