Glossary
© 2013 Harmonic Inc.
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Ellipse 3000 r.3.0, Rev. B
VPN
Virtual Private Network.
VPS
Video Program System (protocol). A
service (used in some countries in Europe) that
controls the start and stop record times for VPS-capable VCRs. For example, a viewer sets a
VPS-capable VCR to record a program scheduled for 7:00 pm, but the network delays the start
of the program to 7:10 pm because of a news interruption. Rather than recording at 7:00, the
VPS-capable VCR does not begin recording until 7:10 when it receives the VPS signal.
VRN
Video Rich Navigation.
W
WSS
Wide Screen Signaling. WSS is an analog waveform carried in Line 23 of a 625-line (PAL) video
signal. As a type of
signaling, it conveys the aspect ratio of the image, and can be used by
WSS-capable televisions to determine the correct display mode. For example, standard (4:3),
widescreen (16:9), or <letterbox> (16:9 on 4:3). Strictly speaking. It is being obsoleted by
AFD over time.
Y
Y (luminance)
Brightness component of a video signal.
YUV
YUV component signals used by analog composite systems. The Y is the luma component, U
and V are color difference components scaled for proper encoding into the composite signal.
All three components are derived from RGB.