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Re: Flame/Inferno Coloring



>
>Dave Corbitt Wrote:
>
>The image displayed on the Inferno or Flame hi-res monitor will
>most likely have display errors of colorimetry as well as absolute levels
>of black, gamma, and highlight brightness, all due to the monitor itself.
>
>This will effect the perceived appearance of the images greatly.  It is
>also my experience that the lighting in an Infoerno or Flame room is
>oftentimes not controlled as it is in telecine rooms for color temperature
>and illumination level.  This will also effect the way the display is
>perceived.  Make sure that when doing "color correction" in these rooms you
>are not "correcting" for the monitor and the room ambient lighting.
>
>

Which is why in almost every Flame/Inferno suite there is a broadcast
monitor connected to the output of the video card. Thus the path is:

- color corrected pixels go to graphics card (RGB 4:4:4)
- pixels are transfered from graphics card frame buffer to
  video card, converted from 4:4:4 RGB to 4:2:2 YUV,
  and then sent to broadcast monitor

On Onyx, the broadcast monitor is driven by the same Sirius video
board as it used to output to tape.

On the Onyx2, the InfiniteReality graphics pipe has a direct 601 output
(the GVO option) which uses the same hardware for RGB->YUV conversion
as the DIVO video card to make sure that what is sent to the
broadcast monitor from the frame buffer is the same as what will
be output to tape via the DIVO video board.

Although I don't have any experience as an operator, I would imagine
that color correction decisions would be based on how it looks like
on the broadcast monitor, not on the SGI display, since this is what
is going to end up on your tape.

Of course, this doesn't address the issue of lighting or calibration
of the broadcast monitor in the Flame/Inferno suite, which in theory
should be given as much attention as in the telecine suite if
correct color correction is to be done.

JF


Jean-Francois Panisset                                panisset at discreet.com
Software Engineer
Discreet Logic 


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