About Illegal RGB Levels
Most video formats are recorded, edited, and transmitted in Y´C
B
C
R
(component) color
space. Although you may never intentionally convert your footage to RGB color space,
it is fairly certain that it will become RGB at some point—most likely during display on
a television or monitor. Video is almost always converted to RGB color space within
display devices.
When you work in Y´C
B
C
R
color space, levels are either described in their native color
space or they are referred to as RGB-equivalent values, meaning the values of your
Y´C
B
C
R
video signal when it is eventually converted to RGB.
Illegal RGB levels are generally caused when certain combinations of luma and chroma
levels (in Y´C
B
C
R
color space) are converted to RGB color space. Even if both luma and
chroma levels are legal in Y´C
B
C
R
color space, the combination of these two may cause
illegal RGB levels.
∏
Tip: The RGB Parade scope in the Video Scopes tab is useful for viewing RGB levels
when working in Y´C
B
C
R
color space. For more information, see “
Learning to Read the
RGB Parade Scope
” on page 518.
Legal RGB levels are usually defined as 0 percent to 100 percent, where 0 percent is the
lowest legal value and 100 percent is the highest. When Y´C
B
C
R
footage is converted to RGB,
RGB levels can be illegal in two ways: if they are below 0 percent or above 100 percent.
Note: If your video originated using a codec that is already in RGB color space (such as
the Animation codec), it is unlikely that the RGB levels are illegal.
532
Part III
Color Correction and Video Quality Control