Chapter 1. TMDS Video Output Overview

This chapter provides an overview of the DG5-2 with TMDS Video Output (TVO) daughterboard.

Product Description

The TVO daughterboard attaches to a DG5-2 board, which installs in the Onyx2 or Onyx 3000 series graphics module in the same way (and same location) as a standard DG5-2 board. The TVO board provides specialized, high-resolution, digital imagery capabilities for Onyx2 and Onyx 3000 systems. The DG5-2 transmits digital pixel information to the TVO board, which outputs this data via Transition Minimized Differential Signaling (TMDS). When you connect the TVO board to the TMDS connectors on the SGI Video Breakout Box (VBOB), you have a complete High Definition Graphics Video Output ( HD GVO) system. With this system, you can use the Onyx2 or Onyx 3000 to convert graphics data to both High Definition and Standard Definition serial digital video. Two TMDS cables, a BNC timing reference cable, and a 75 ohm terminator are included with the board.

HD GVO provides you with the following capabilities:

  • Real-time graphics-to-video High Definition output of images in the graphics pipe (a subset of ATSC Table 3 - minimally 720p, and 1080i 59.94 Hz).

  • Real-time graphics-to-video Standard Definition output of images in the graphics pipe (CCIR-601 pixels and NTSC or PAL timing).

  • Alpha or key output in both High Definition and Standard Definition video.

  • Genlock capability for multi-pipe operation and synchronized video streaming.


    Note: The TVO board is initially configured by an SGI field installer when the Onyx2 or
    Onyx 3000 system is installed or when it is upgraded. Any reconfiguration should be carefully considered.


Figure 1-1 shows the DG5-2/TVO board assembly and its connectors. For cabling instructions, see Chapter 2, “HD GVO Cabling Configurations”. For software configuration information, see Chapter 3, “HD GVO Software Configuration and Troubleshooting”. For technical questions, see “Product Support”.

Figure 1-1. DG5-2/TVO Board Assembly 


Restrictions and Important Notes

Note the following:

  • The TVO board requires IRIX 6.5.10 (with patch) or later. Early shipments include the required IRIX 6.5.10 patch on a CD. If you are running IRIX 6.5.10, give this CD to your SGI Installer or System Administrator to install the required patch. If you are running later versions of IRIX, do not install this patch.

  • The TVO board option is not compatible with the Onyx2 DDO2 (also called DVP2) option. You can use these two options in the same Onyx2 rack system, but they cannot share the same graphics pipe and you cannot interconnect them.