Silicon Imaging SI-2K User Manual page 51


Keyer Module
The Keyer mode in the IRIDAS color correction panel is a special mode that
allows users to preview keys on-set in the context of the subject they are shoot-
ing. Keys can be set on either green or blue-screen using a real-time RGB
difference keyer, and backgrounds can be composited behinds subjects to
give the shooter an indication of how a final key and composite in post will
look. „Problem Areas" and other green or bluescreen issues can be quickly
diagnosed and solved on-set rather than waiting to defer decisions to post
where mistakes can cost time and money, especially if re-shoots or extensive
rotoscoping is required.
Another important aspect of the keyer module is that the settings are saved
inside the .look XML, so when the user recalls the .look and applies it to the
same clip inside another IRIDAS compatible application, the keyer settings are
transmitted intact, and the same key is applied to the footage in post as was
visualized on-set, giving a WYSIWYG keying experience from set-to-post. The
distinction though needs to be made between the keyer and other color meta-
data information that also travels with the .look file. The keyer itself is a filter,
and is therefore not a part of the 3D LUT that the user is creating when making
color-corrections in the IRIDAS control panel. Therefore when the user opens
up a clip they have recorded in post in an NLE or other media player, the keyer
information will not be applied to the clip by the CineForm codec engine, which
is only applying the 3D LUT portion of the .look file to the clip in real-time. In
order for the keyer settings to be re-applied to a clip in-post as they were in
the camera, the .look must be applied to the clip in an IRIDAS compatible ap-
plication, so that the same filter-graph that the IRIDAS engine is creating in the
camera to preview the live green or bluescreen can be correctly accessed and
reproduced in post.
The keyer is downstream of the color-correction filter path of the IRIDAS pipe-
line, therefore modifications in the color-corrector portion of the control panel
will affect the quality and other aspects of the key. This can be especially effec-
tive in allowing the user to color-correcting the image for the optimal key.
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LookControl
SI 2K Manual