Thanks for the reply, I have posted details below
nvidia-settings is a utility for directly manipulating nvidia cards based upon geforce 4 and above GPUs. In our case it provides substantial control of the overscan features provided.
The application is designed to be run as an X-Windows based utility but can also be run from the command line to read a config file and then exit quietly.
The application can be installed by issuing the following command:
apt-get install nvidia-settings
To run the application I normally use the computing option from the media director and select pluto admin website. I then go to a terminal window or use a ssh command prompt to issue the following command:
Using the media director I can now change a whole range of video card settings, and when happy select save settings.
The settings are written to /root/nvidia-settings.rc
I then modify /usr/pluto/bin/Start_IceWM.sh to include the following line before starting the Window Manager:
/usr/bin/nvidia-settings --display=:0 -l
This tells the application to read and apply the settings file and then exit.
It would be easy for your AV Wizard to use this program to allow users to tweak their video card settings as all you need to do is update the nvidia-settings.rc file and then call the application as above, the change is applied immediately.
For earlier geforce cards I use nvtv which has limited controls but I have managed to get excellent results on tv out using the same principle as above.
here is the line that I use with nvtv, even though my TV is PAL-I so it is worth trying the various modes available:
nvtv -t -r 800,600 -s Large -S PAL-M
Hopefully this post will help other users get perfect tv-out displays on nvidia cards