Graphics Programs Reference
In-Depth Information
The YUV color space
The YUV color space is used by the
Phase Alternating Line
(
PAL
),
National Tele-
vision System Committee
(
NTSC
), and
Sequential Color with Memory
(
SECAM
)
composite color video standards for color televisions. Y stands for the luma com-
ponent (the brightness), and U and V are the chrominance (color) components. This
color space was intended to provide luma information for black and white televi-
sion systems and color information for color television systems. Now, YUV is a color
space typically used as part of a color image or CG pipeline to enable developers
and artists to work separately with luminance and color information of an image.
The YCbCr color space
The YCbCr color space was developed as a digital component video standard, which
is a scaled and offset version of the YUV color space. Y is the luma component and
Cb and Cr are the blue-difference and red-difference chroma components. While
YUV is used for analog color encoding in television systems, YCbCr is used for digit-
al color encoding suitable for video and still-image compressions and transmissions,
such as MPEG and JPEG.
Render layers/passes
To optimize render resources and also be able to provide full control at the composit-
ing stage, a CG lighting scene is split into multiple render layers and render passes.
Render layers
A typical lighting scene consists of two to three characters, props, and one set. To
provide an opportunity to re-render only required elements in the scene, each ele-
ment is separated into its own render layer for rendering. All interaction renders are
also separated into render layers. The following list shows a typical render layer clas-
sification.
• Character 1
• Character 2
• Character 3
• Characters cast shadow
• Characters occlusion
