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#1 2008-01-24 14:33:22

lost eden
Member
Registered: 2008-01-01
Posts: 62

TV-out too big for screen?

I've successfully gotten TV-output from my nvidia graphics card, however the image is too large for the screen (e.g. the top, bottom, left & right are off the screen, so when I maximise a window the title bar is cut off, when I full-screen a video I lose the edges of the image, etc.). Changing the resolution doesn't make a difference either; there's as much missing at 320*240 as there is at 1024*768. I've been told that dropping the resolution from 60Hz to 50Hz (which I want to do anyway) might reduce the size of the image to fit, but I don't know the syntax for this? (nvidia-settings won't let me choose any refresh but 60Hz, at any resolution.)

Anybody help me with dropping the refresh, or have any other ideas how to solve the problem?

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#2 2008-01-24 17:31:50

ianegg
Member
Registered: 2007-06-18
Posts: 38

Re: TV-out too big for screen?

TVs do this by design, it's called overscan and nvidia-settings lets you compensate for it in the same place you adjust digital vibrance, flicker filter etc. (The section is labelled something like "TV-0 (TV-0)" usually.) You can also set the overscan in xorg.conf, but I can't remember the option name off the top of my head.

You also need to set the TV standard to PAL in xorg.conf for 50Hz. I just need to ssh into my mum's computer and I'll paste the relevent section.

Section "device"
        Option "TVOutFormat" "composite" #or s-video
        Option "TVStandard" "PAL-I" # default is NTSC
        Option "TVOverScan" "0.65"
EndSection

The values for overscan differ in xorg.conf and nvidia settings (0.00-1.00 and 0-20 respectively) so in my case nvidia-settings shows 13 which lines up perfectly on my mother's tv. You'll just have to experiment.

On an aside, if you're not using cloned output then 720x576 (PAL TV native resolution) with full overscan gives the sharpest image. (But with quite a bit of the picture missing depending on the TV.)

Last edited by ianegg (2008-01-24 17:44:41)

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#3 2008-01-24 17:46:42

lost eden
Member
Registered: 2008-01-01
Posts: 62

Re: TV-out too big for screen?

I already have it set as PAL-I (Hong Kong & the United Kingdom) because I'm from the UK; it is still at 60Hz though, not 50Hz.

I also looked at overscan before but the nvidia readme says that it is disabled by default (0.0) so if I was to enable it all I could do would be make it EVEN larger, not smaller as it has to be in teh range 0.0 to 1.0 (unless you know something I don't?)

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#4 2008-01-24 18:03:52

ianegg
Member
Registered: 2007-06-18
Posts: 38

Re: TV-out too big for screen?

Setting to PAL is the only way to set 50Hz as far as I know (the driver has built in modes and won't let you set your own.) Are you sure it's outputting at 60Hz? I can't access the PC physically at the moment, but I have a feeling nvidia-settings just reports 60Hz regardless of what it's outputting. Maybe setting to NTSC would help.

Have you explicitly set the overscan to 0 and/or played with the slider? I get pretty big black borders with less than 0.65. It could be that your card and TV just don't like each other very much.

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#5 2008-01-24 18:29:47

lost eden
Member
Registered: 2008-01-01
Posts: 62

Re: TV-out too big for screen?

Well, I can't actually tell whether the TV is running at 50Hz or 60Hz, as it has no form of OSD that reports such figures. I'm not sure what dialogue to trust on the PC end, as I know for a fact that KDE's display config lies.

My version of nvidia-settings doesn't seem to have an overscan slider anywhere, but I have tried putting the overscan option into the config file manually & there is absolutely no difference whatsoever between 0.0 & 1.0, which seems somewhat strange. The exact syntax I am using is thus;

Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "Unknown"
    ModelName      "TV-0"
    Option      "TVStandard" "PAL-I"
    Option      "TVOutFormat"   "COMPOSITE"
    Option      "TVOverScan"    "1.0"
EndSection

Replacing "1.0" with various other values such as "0.0", "0.25", "0.75", etc.

I'm beginning to wonder if it may be the TV & card not getting along together; the designers of the nvidia 8xxx series cards probably didn't expect them to be connected to many 2 decade old TVs.

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#6 2008-01-24 19:47:17

ianegg
Member
Registered: 2007-06-18
Posts: 38

Re: TV-out too big for screen?

If you're not getting the slider in nvidia-settings and the overscan option has no effect, it makes me suspect it's a driver or card problem. Could be the TV out on 8x00 series is just not fully implimented on linux yet.

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