gvo(7)

NAME
     gvo - 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)
SEE ALSO
     ircombine(1G), setmon(1G), XSGIvc(3)