how to enable TV output from an nVidia card

These are instructions on how to add a TV as an extra (or standalone) screen to your PC with an nVidia card having a TV-out option.

connecting the graphics card and audio to the TV

If you have a GeForce4 Ti4200 like me, then the card does TV output and input, and it comes with an S-video/composite adapter cable, like this:

(to see what type of card you have, type: lspci | grep VGA)

European TVs often have a SCART ("Euroconnector") input/output, so the next thing to get is a SCART to composite video (and audio) adapter cable, like this one:

You can also get ones with a switch on the SCART connector that switches the composite plugs between input and output, or ones with 6 composite plugs, 3 for input, and 3 for output. For playing a PC image on a TV, we need one with at least 3 plugs, where the composite plugs are for input. These cables typically cost 12 euros and up, depending on the quality. Of course if your TV has composite input, then you just need a straight composite to composite cable (3 plugs at each end).

The standard color coding for composite cables is: yellow = video, white = left audio, red = right audio.

For the audio, you need an adapter cable from the PC's audio output (which takes a 3.5 mm jack plug), to the composite plugs of the cable above (so for this cable, the composite plugs need to be of the "female" type).

I found that the S-video output produces a slightly better image, so I'm using another adapter cable, one that goes from S-video to composite.

To avoid having to plug and unplug cables all the time when switching between TV and PC output (especially for the audio), I got a simple switchbox that takes three triples of composite plugs, and connects the middle three either to the left ("A") or the right ("B") three:

configuring X, one monitor and one TV

First the configuration for a single monitor and a TV, shown in this xorg.conf file (the Xorg version of XF86Config of XFree86).

For details on TV formats, see this appendix on configuring TV out from nVidia.

Note this line:
Option "MetaModes" "1680x1050, 800x600; NULL, 800x600"
The 1680x1050 is the resolution of your PC monitor (could also be 1280x1024, for example). The second part NULL, 800x600 allows you to switch to a mode with just the TV (press Ctrl-Alt-+ for this). Then when you use mplayer in fullscreen mode, for example, it will fill the TV screen exactly.

configuring X, two monitors and one TV

I haven't been able to get two monitors and one TV all going at the same time. It is possible though to define two "layouts" in the xorg.conf, one for two monitors, and one for one monitor and one TV (as above), and switch between the two using the startx command. Here is the modified xorg.conf file with the two layouts. To start X using two monitors, you can still use startx (if you're not logging in in text mode, see this tip).

To start X using one monitor and the TV, use:
startx -- -layout TwinViewTV

For some more TwinView info, see this TwinView page.