My older nVidia card was not supported by the TVOverScan option in the XF86Config-4 config file or in NvidiaSetup (I think this refers to GeForce2? and GeForce3? cards: Greg Frost). I had a 1 inch black border around the screen. Running the following command in xterm would solve it

/usr/bin/nvtv -r 768,576 -s Large# -t -S NTSC

In order to get this to run every time x11 start I did the following:

1. apt-get install nvtv (Note: nvtv is installed by default on the R5 Alphas)

2. nano /etc/gdm/PreSession/Default (Note: the appropriate place to put X-Session startup commands in the R5 Alphas is /home/mythtv/.fluxbox/apps - the format should be obvious)

insert the following two lines after the PATH command (use your own best parameters)

/usr/bin/nvtv -r 768,576 -s Large# -m -S NTSC
/usr/bin/nvtv -r 768,576 -s Large# -t -S NTSC

3. /etc/init.d/gdm restart

The window should be set properly every time X starts now.

The nvtv command also works with i810 graphics chips. The commands that worked best for me in Step 2 above are:

/usr/bin/nvtv -r 800,600 -s Huge# -m -S NTSC
/usr/bin/nvtv -r 800,600 -s Huge# -t -S NTSC

If you really want to get serious about getting the overscan setup just right, nvtv has what is effectively a modeline calculator GUI. This allows you to compute and implement the various combinations of vertical and horizontal overscan percentages that your card is capable of generating. Unfortunately the version of nvtv that comes with the R5 Alphas is built from source and when it was configured it disabled the GUI because it could not detect the required version of the GTK libraries.

To enable the gui part of nvtv, you will need toi rebuild it and disable the part where configure builds a gtk test program:

tar xvfz nvtv-0.4.7.tar.gz
cd nvtv-0.4.7
./configure --prefix=/usr --disable-gtktest
make all install

(Note: This still isn't right. I just tried this on R5A16 and still couln't get the gui. In the end, I installed atk, pango and gtk+ from source and I was finally able to configure nvtv so that it built the GUI)

You can use the TestPattern generator to help you select the optimum overscan percentages using the BT/CX Calc tab and the horizontal and vertical offsets using the nv regs tab. You can get nvtv to print the parameters for that setup. You then need to modify the source code so that your optimum setup can be invoked from the command line using a command similar to those shown above. I have attached a patch that I used to get my Geforce2 MX400 setup ideally on my television with 800x576 and 768x576 resolutions. (Click on the Attachments link at the bottom of this page).

• Note by rarefluid - To change the horizontal offset i.e. for building your own mode you can also change the "HSynchStart?" parameter of the appropriate mode structure in "data_nv.c". If you want to have a vertical offset you need to change the "VSynchStart?" in "data_nv.c" and recompile. You may need to copy nvtv AND nvtvd to the right directories. For me (linux n00b) they are: for the superuser: nvtv goes to "/usr/bin/", nvtvd to "/usr/sbin/" and for others: nvtv goes to "/usr/local/bin/", nvtvd to "/usr/bin/"

After patching and building nvtv, I can use the following command in /home/mythtv/.fluxbox/apps to get it to configure my display each time X starts (pay heed to Luca's note below):

nvtv -S PAL -t -r 800,576 -s Medium --set Saturation:-30 --set Contrast#:10

Hope this is of help to someone else

Greg Frost

• Note by Luca - I found reference (http://mysettopbox.tv/phpBB2/viewtopic.php?p=8810&;) stating that in order to run nvtv as an unprivileged user you need to have nvtvd running.

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If you're having trouble with PAL and no colours (only black and white) with S-Video, besides of bying a better cable you should try this:
nvtv -S PAL -t -r 800,600 -s Large -C CONVERT
and Option "TVOutFormat" "COMPOSITE" in XF86Config-4.
Kai (kwbolte) gymnastics leotards

My GeForce2? MX400 required

/usr/local/bin/nvtv -r 800,600 -s Large# -t -S NTSC --set Colorfix:1

This set up the overscan and fixed the brightness and flicker problems I was seeing. nvtv version:

ii nvtv 0.4.7-1 NVTV 0.4.7 w/ patch. Graham

For a regular Geforce2 MX, the Large# mode won't necessarily be recognized. Normal works fine, however, so try: /usr/bin/nvtv -S NTSC -t -r 800,600 -s Normal

I had to use the above command on a Currnet R5D1 with a geforce 4 4400

(knoppmyth has nvtv in /usr/bin, not /usr/local/bin) PHP Web Development

You can also substitute 720,480 and Normal if that fits your screen better. Benjamin Bradford

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