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Re: White Compression



Rob Lingelbach:
>We had, when I worked at Action Video, a beautiful capability called
>"White Compression", which allowed individual control of R G & B clip,
>it was wonderful and I miss it greatly.  Dave Tosh was (partly or
>mostly?) responsible for its design.  Dave, is that circuit outmoded
>today, or available?  Or can we even talk about it (patent ugliness)?
   The circuit was an analog "hack" suggested by Sam Holtz and implemented
by me. Glenn Gundlach absolutly hated the implementation of it and I think
it prompted him to do some of the research that is now found in his shading
kit (Carnival available soon from Sprocket Digital.) Sam had me document
the development of the negative white compression so that we could prove
prior art should anyone claim a patent later in the game. To do the circuit
in an URSA, it would need to be integrated into the afterglow - A/D
conversion area where there is a very great dynamic range. Digital video
quantized at 10 bits or less wouldn't have enough dynamic range (in my
opinion) to do subtle compression and clipping. That said, anyone want to
do some design on a replacement afterglow and A/D board set for the URSA?

--- David Tosh  dlt at earthlink.net  (CIS 72167,1376)
--- Video Engineer, Complete Post, Hollywood