Sorenson codec
From Wikipedia, the free encyclopedia
The Sorenson codec (also known as Sorenson Video Codec, Sorenson Video Quantizer or SVQ) is a proprietary digital video codec devised by the company Sorenson Media Inc. (formerly Sorenson Vision Inc.) It is used in Apple's QuickTime and in Adobe Flash (formerly Macromedia Flash). There are two different proprietary video codecs known as "Sorenson codec": Sorenson Video and Sorenson Spark.
Contents |
[edit] History
The Sorenson Video codec first appeared with the release of QuickTime 3 on March 30, 1998. It was available in two versions: the Basic Edition encoder/decoder built into QuickTime 3 and Developer Edition which enabled advanced encoding features and two-pass variable bitrate.[1] With QuickTime 4, it was given wide exposure for the release of the teaser trailer for Star Wars Episode I: The Phantom Menace on March 11, 1999. Sorenson Video 2 was released in March 1999; however, it mainly included minor improvements and optimizations to the Developer Edition of the encoder, as movies encoded with it were backwards compatible with the Sorenson Video decoder. An improved Sorenson Video 3 codec debuted with the release of QuickTime 5.0.2 on July 1, 2001. It was available exclusively for QuickTime.[2][3] Apple QuickTime later focused on other compression formats and moved Sorenson Video 3 to a separate group called "legacy encoders".[4]
As Apple began to move away from proprietary codecs with its embrace of MPEG-4, Sorenson Media next licensed a new video codec to Macromedia as Sorenson Spark (Sorenson H.263), released with Macromedia Flash 6/MX on March 4, 2002.[5][6] Sorenson Spark is the required video compression format for Flash Player 6 and 7. Macromedia later tried to find a better video codec. Starting with Flash Player 8 (released in September 2005), the preferred video codec is VP6.[7][8] The Sorenson Spark can be still used in the Adobe Flash CS4 Professional (2008) for Flash Video FLV files as one of three video compression formats (alongside H.264 and On2 VP6).[7] Sorenson Spark is an older codec but it is also a widely available and compatible one, when used in Flash Video.[9] It is considered as an incomplete implementation of H.263.[8][10]
The Sorenson Video 3 (SV3) Pro Codec for QuickTime video is offered as a separate software product, but comes standard with the commercial encoding software Sorenson Squeeze.[11] The Sorenson Media, Inc. offers Sorenson Squeeze, which can encode video to proprietary Sorenson formats, but also to standardized video compression formats, such as H.264, MPEG-4 Part 2, MPEG-2 and others.[12] There is also Sorenson H.264 and Sorenson MPEG-4 codec, which are one of many existing implementations of international standards and should not be confused with Sorenson proprietary codecs.
[edit] Technical details
The specifications of the codec were not public, and for a long time the only way to play back Sorenson video was to use Apple's QuickTime player, or the MPlayer for Unix/Linux, which in turn piggy-backed DLL-files extracted from Apple's player for Microsoft Windows.
According to an anonymous developer[13] of FFmpeg, reverse engineering of the SVQ3 codec (Sorenson Video 3) revealed it as a tweaked version of H.264.[14] (It is considered as based on an early H.264 draft.[15]) The same developer also added support for this codec to FFmpeg, making native playback possible on all platforms supported by FFmpeg. FFmpeg supports decoding of "Sorenson Vector Quantizer 3" (fourcc SVQ3) and Sorenson Vector Quantizer 1 (fourcc SVQ1) starting with version 0.4.7, released in 2003.[16] The next version of FFmpeg in 2003 also added encoding/decoding of Sorenson H.263 used in Flash (fourcc FLV1).[17] Encoding of SVQ1 was added in 0.4.9-pre1.[18]
The Sorenson Spark is sometimes defined as "almost H.263" or as "an incomplete implementation of H.263".[8][10] These compression formats differ mostly in header structure and ranges of the coefficients.[14]
[edit] References
- ^ Terran Interactive, Inc. (1998) Codec Central - Sorenson Video, Retrieved on 2009-08-09
- ^ Sorenson Media (2001-07-02) Sorenson Media Announces the Availability of Sorenson Video 3 Exclusively for QuickTime, Retrieved on 2009-08-09
- ^ Apple (2000-10-10) Apple Releases QuickTime 5 and QuickTime Streaming Server 3 Public Previews, Retrieved on 2009-08-09
- ^ Apple Mailing Lists - batch export: where is sorenson ?, Retrieved on 2009-08-09
- ^ Adobe (2002-03-04) Macromedia - Press room : Macromedia and Sorenson Media Bring Video to Macromedia Flash Content and Applications
- ^ Adobe LiveDocs About the Sorenson Spark codec, Retrieved on 2009-08-09
- ^ a b Adobe Flash CS4 Professional Documentation - Digital video and Flash, Retrieved on 2009-08-09
- ^ a b c Kaourantin.net (2005-08-13) The quest for a new video codec in Flash 8, Retrieved on 2009-08-10
- ^ Sorenson Media Difference Between Flash 6 and Flash 8 video, Retrieved on 2009-08-09
- ^ a b "Sorenson Spark". MultimediaWiki. http://wiki.multimedia.cx/index.php?title=Sorenson_Spark. Retrieved 2009-11-03.
- ^ Sorenson Media SV3 Pro Codec, Retrieved on 2009-08-09
- ^ Sorenson Media Squeeze, Retrieved on 2009-08-09
- ^ Deconstructing H.264/AVC on DrunkenBlog, July 28, 2004.
- ^ a b Benjamin Larsson (2009-03-17). "h263-svq3 optimizations". FFmpeg-devel mailing list. http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2009-March/065410.html. Retrieved 2009-08-09.
- ^ MultimediaWiki. "Sorenson Video 3". http://wiki.multimedia.cx/index.php?title=Sorenson_Video_3. Retrieved 2009-11-01.
- ^ FFmpeg Changelog, Retrieved on 2009-08-10
- ^ FFmpeg.org (2003) FFmpeg 0.4.8 Documentation - Video Codecs, Retrieved on 2009-08-10
- ^ FFmpeg.org FFMpeg General Documentation - Video Codecs, Retrieved on 2009-08-09
[edit] External links
- sorensonmedia.com
- Sorenson Video Codec, Version 3 - format description by the Library of Congress
- Sorenson Video 1 - MultimediaWiki
- Sorenson Video 3 - MultimediaWiki
- Sorenson Spark - MultimediaWiki
|
|||||||||||||||||||||||||||||||||||||||||
