On Wed, 29 Aug 2001 18:20:39 -0400, "Nick Fox-Gieg" wrote:

>I've noticed that when I compare renders created on a ProMax-codec Mac and a
>Canopus-codec PC, there's a significant difference in the way each handles
>darkest black (0, 0, 0 in RGB); the ProMax is noticeably brighter than the
>Canopus. I've heard that this is because the ProMax codec "clamps" the
>luma, allowing no RGB values lower than 16, 16, 16, and the Canopus codec
>doesn't.
>
>Now I'm starting a new project, using a G4 with Quicktime 5. We'll be
>making DVDs that feed four video projectors, and the projectors will overlap
>each other, so it's important that we start with as dark a black as possible
>to keep from making gray in the spaces where they cross.
>
>Does the much-praised new Quicktime 5 DV codec clamp luma or not? And if it
>does, is there a way to stop it? I've heard of ProMax's DV Toolkit
>software, but I'm not sure whether it works with DVD Studio Pro.

It would seem to me that the codec should duplicate
whatever characteristics the unrendered video material
has, otherwise rendered stretches of video will not match
unrendered stretches (actually, a common problem, and
the Canopus codec is one of the few that changes the
rendered footage characteristics very little). On my
web page is a sample of 10-generation forced renderings
with the Canopus codec, and a URL for tests of others
(look for the video articles under "I babble"). As
others pointed out, though, "black" is a relative thing
in video - but as you point out, "super black" can be
useful...;-)