Sorenson codec may refer to any of three
proprietary video codecs:
Sorenson Video Two versions of Sorenson Video were released, both using
SVQ1 as their
FourCC. Version one first appeared with the release of QuickTime 3 on March 30, 1998. The backward-compatible version two was released with QuickTime 4 on March 11, 1999, which mainly included minor improvements and optimizations to the Developer Edition of the encoder, so encoded movies would be backwards compatible with the QuickTime 3 release. Changes for version two were only made to the encoder, not to the compression format. This format uses a
YCbCr 4:1:0
chroma subsampling, which means every block of eight pixels share the same color components, which can cause
color bleeding across pixels. This was solved in version 3 and the Spark version which both use the more common YCbCr 4:2:0 subsampling.
FFmpeg supports decoding of Sorenson Video since 2002, encoding of SVQ1 was added in 2004 for 0.4.9-pre1. Version two was given wide exposure from the release of the teaser trailer for
Star Wars: Episode I – The Phantom Menace on March 11, 1999. The official specifications of the codec are not public. For a long time the only way to play back Sorenson Video was to use Apple's QuickTime or
MPlayer, which used
DLL files extracted from QuickTime for Windows.
Sorenson Video 3 This incompatible version of Sorenson Video uses
SVQ3 as its
FourCC. This version was released with QuickTime 5.0.2 on July 1, 2001. It was available exclusively for QuickTime. Apple QuickTime later focused on other compression formats and moved Sorenson Video 3 to a separate group called "legacy encoders". According to an anonymous developer of
FFmpeg,
reverse engineering of the SVQ3 codec (Sorenson Video 3) revealed it as a tweaked version of
H.264. The same developer added support for this codec to 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. Sorenson Video 3 comes with
Sorenson Squeeze.
Sorenson Spark Sorenson Spark is an implementation of
H.263 for use in
Flash Video and
Adobe Flash files.
FFmpeg uses
FLV1 FourCC and Adobe frame identifiers of 0x21, 0x22 and 0x23. As Apple began to use
MPEG-4 and move away from other proprietary codecs, Sorenson Media licensed Sorenson Spark (Sorenson H.263) to
Macromedia, which was included with
Macromedia Flash MX v6 on March 4, 2002. 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 became
VP6. Sorenson Spark can be still used in the
Adobe Flash CS4 Professional (2008) for Flash Video files (alongside
H.264 and VP6). According to Adobe engineer Tinic Uro, Sorenson Spark is an incomplete implementation of H.263. It differs mostly in header structure and ranges of the coefficients. == See also ==