Re: Fwd: Sorenson Spark question

Benjamin Larsson <[email protected]>
Newsgroups gmane.comp.video.xine.codec.devel
Message-ID <[email protected]>
Michael Roitzsch wrote:

>Hi codec experts,
>
>My codec knowledge is too limited to answer the question I got. Does 
>anyone know anything about this?
>
>Michael
>
>  
>
http://livedocs.macromedia.com/flash/mx2004/main/10_vide3.htm
http://www.cvalley.com/product/Sorenson/squeeze_flash.html

--Snip--

Sorenson Spark is an interframe codec. Sorenson Spark’s efficient 
interframe compression, among other features, distinguishes it from 
other compression technologies, requiring a much lower data rate than 
most other codecs to produce good-quality video. Many other codecs use 
intraframe compression; for example, JPEG is an intraframe codec.

However, interframe codecs also use intraframes. The intraframes are 
used as the reference frames (keyframes) for the interframes. Sorenson 
Spark always begins with a keyframe. Each keyframe becomes the main 
reference frame for the following interframes. Whenever the next frame 
is significantly different from the previous frame, the codec compresses 
a new keyframe.

--Snap--


Nothing revolutionary new as it seams. And this link

http://www.macobserver.com/article/2002/07/21.1.shtml

uses the name other versions of Spark video codec. So I would assume 
that Sorenson just "sold" Macromedia an updated version of the codec 
they licensed to Apple. And that would mean that it is a modified 
version of H.263 (that's what svq3 is if IIRC). And I havn't seen an 
open source svq3 encoder so I would guess that there aren't any for Spark.

MvH
Benjamin



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