Audio/Video Compression

[Charles Steinkuehler]

Jason Clinton wrote:
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> At the meeting-after-the-meeting last night, some of us were discussing the
> benefits of certain compression algorithims over others. For those interested,
> here's an article on how wavelet compression works such as that that is used in
> MPEG4 (DivX) and JPEG2000. Many a geek will find this interesting.
> 
> <http://www.beyonddiscovery.org/content/view.article.asp?a=1952>

A very good article that makes easy reading of a fairly complex subject.

Interstingly, one of the digital animations mentioned in the article 
that used wavelet technology in their rendering, also used wavelet 
technology for display (Toy Story 2).  This film is also unique in being 
the first ever 100% digital movie release.

For release on digital cinema screens around the country (including the 
AMC studio 30 in Olathe), the original CGI images for Toy Story 2 were 
digitally copied via ethernet to a QuBIT image recorder (which uses 
wavelet based compression).  The digital master was then copied and 
distributed to theaters digitally (via sattelite, DVD-ROM, and/or 
magnetic tape), and ultimately played back through a TI DLP based projector.

For those unfamiliar with the TI DLP devices, they are "digital" devices 
that produce varying light intensity by rapidly switching an array of 
micro-mirrors between the "on" and "off" state at a very high speed. 
With the interface between the QuBIT and the DLP projector being 
digital, and the DLP controller and output being inherently digital, if 
you watched Toy Story 2 at a digital cinema, the first time the content 
*EVER* hits the analog domain is when the rods and cones in your 
eyeballs integrate the pulsed light being reflected off the screen to 
create an average brightness.  Kind of wierd/spooky if you think about it...

-- 
Charles Steinkuehler
charles at steinkuehler.net