GVO(7)GVO(7)NAMEgvo - Serial digital video option for Onyx InfiniteReality graphics
DESCRIPTION
GVO is a video option for the Onyx2 workstation equipped with
InfiniteReality graphics. It provides a broadcast quality serial
component digital video output, compliant with ITU-R BT601-4 and SMPTE
259M. Two links are supplied per SMPTE RP-125, to allow the alpha planes
of graphics to be used as a matte or key signal.
The GVO is configured via the ircombine(1G) command and the setmon(3G)
command. Parameters may be controlled from user software via the
XSGIvc(3) X extension.
Modes of Operation
There are two modes of operation of the GVO:
Low-bandwidth mode
In this mode, the GVO will output a portion of the video that is
being sent to some other monitor. In this way, it will consume no
additional system bandwidth. The cursor will appear in both the GVO
output and the main monitor output. To select this mode, select the
channel to shadow using ircombine.
Low-latency mode
In this mode, the GVO will make its own requests from the
framebuffer. This requires additional system bandwidth; however, it
has two advantages: the GVO can output from a section of the
framebuffer that is not being sent to any other output; and the GVO
video output will have the lowest latency possible. (In fact, in
this mode, the GVO will introduce no latency at all). The cursor
will appear in the GVO output or the main window output, but not
both at the same time. To select this mode, select 'None' on the
ircombine window for GVO under 'Source Channel'. This is the mode
for professional installations that require compatability with a
house sync.
Gamma
GVO has its own gamma tables that can be configured through
ircombine(1G). or XSGIvc(3) and are independent of the DG5 gamma tables.
NOTES
In low-latency mode, a suitable genlock signal must be supplied, or the
GVO will not function correctly.
in low-bandwidth mode, the source channel must have a frame rate that is
faster than the GVO field rate (59.94 frames/sec NTSC, 50.00 frames/sec
PAL)
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GVO(7)GVO(7)SEE ALSOircombine(1G), setmon(1G), XSGIvc(3)
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