Building a video signal generator with a (Dell) laptop and NVIDIA video card

rpjday · 01-04-09, 04:05 PM

I'm interested in building as much of a video signal generator as I can with (most likely) a Dell laptop and an NVIDIA video card running some distro of Linux.

As a concrete example, I was handed a new WUXGA (1920x1200) Dell Latitude E6500 with an NVIDIA Quadro NVS 160M and one of the new "display port" ports. I wanted to pump the display image out the port to a WUXGA Samsung monitor, so I first had to download the appropriate NVIDIA driver (177.80) to even get display port support, which worked just fine with that system running Fedora 10. Now I want to get ambitious, and I wonder if anyone else has tried this.

I want to be able to tweak really low-level properties of the video signal being generated out the display port -- things like gamma colour correction, video timings and so on -- because I want to use the laptop as a simple video signal generator to drive a signal into various pieces of video equipment to see how well they work.

Ideally, I'd like to be able to modify things like the vertical refresh rate to test whether a piece of video equipment is capable of adjusting to that. And things like blanking, front porch, back porch and other video attributes.

Has anyone done something like this? Obviously, what I'll be able to do will depend on the quality and features of the video card, but I want this to be available on a laptop since I want to be able to carry it around. And Dells would be the corporate choice -- I can't imagine choosing a different vendor would make lot of difference since it's really the video card that's the issue here.

Thoughts? I'm just starting out on this project so I haven't got much further than writing out what I'm trying to do. Thanks.

rday

xianthax · 01-04-09, 06:17 PM

if the parameters you wish to tweak are exposed by the driver, then your set, just write the program. If they are not then you'll have better luck with intel or ATI graphics chips as they release hardware specifications and have more mature open source drivers for you to muck around with.

There is a reverse engineered open source nvidia driver tho that you may have luck with: http://nouveau.freedesktop.org/wiki/

all comes down to exactly what it is you wanna tweak....gamma and refresh rate are simple and adjustable in a GUI as is.

cheers,

x

rpjday · 01-05-09, 05:58 AM

Which GUI (or GUIs) would you recommend for the basic tweaking? I can use either Fedora or OpenSUSE if anything is distro-dependent? Thanks.

rday

**AaronP** · 01-05-09, 12:31 PM

Chapter 9 in the README covers configuring your own mode timings. You may need to set the ExactModeTimingsDVI option to get it to actually drive your flat panel using the timings in the mode instead of the panel's native backend timings. I believe this option applies to DisplayPort as well. There are various old HOWTOs floating around the web that discuss exactly what the various parts of a ModeLine mean and how to compute them.

Note that DisplayPort is just a high bandwidth unidirectional bitstream that transmits the video data, among other things, at one of two possible bandwidths (1.62 Gbps and 2.70 Gbps), so the "timings" are more of a guideline for the monitor than anything the GPU actually puts out. If you really want low-level control of timings signals coming out of the GPU, you need to use VGA.

As xianthax mentioned, you can adjust the gamma settings in the nvidia-settings display configuration page.

01-04-09, 04:05 PM	#1
rpjday Registered User Join Date: Jan 2009 Posts: 2	Building a video signal generator with a (Dell) laptop and NVIDIA video card I'm interested in building as much of a video signal generator as I can with (most likely) a Dell laptop and an NVIDIA video card running some distro of Linux. As a concrete example, I was handed a new WUXGA (1920x1200) Dell Latitude E6500 with an NVIDIA Quadro NVS 160M and one of the new "display port" ports. I wanted to pump the display image out the port to a WUXGA Samsung monitor, so I first had to download the appropriate NVIDIA driver (177.80) to even get display port support, which worked just fine with that system running Fedora 10. Now I want to get ambitious, and I wonder if anyone else has tried this. I want to be able to tweak really low-level properties of the video signal being generated out the display port -- things like gamma colour correction, video timings and so on -- because I want to use the laptop as a simple video signal generator to drive a signal into various pieces of video equipment to see how well they work. Ideally, I'd like to be able to modify things like the vertical refresh rate to test whether a piece of video equipment is capable of adjusting to that. And things like blanking, front porch, back porch and other video attributes. Has anyone done something like this? Obviously, what I'll be able to do will depend on the quality and features of the video card, but I want this to be available on a laptop since I want to be able to carry it around. And Dells would be the corporate choice -- I can't imagine choosing a different vendor would make lot of difference since it's really the video card that's the issue here. Thoughts? I'm just starting out on this project so I haven't got much further than writing out what I'm trying to do. Thanks. rday

01-04-09, 06:17 PM	#2
xianthax Registered User Join Date: Dec 2008 Posts: 38	Re: Building a video signal generator with a (Dell) laptop and NVIDIA video card if the parameters you wish to tweak are exposed by the driver, then your set, just write the program. If they are not then you'll have better luck with intel or ATI graphics chips as they release hardware specifications and have more mature open source drivers for you to muck around with. There is a reverse engineered open source nvidia driver tho that you may have luck with: http://nouveau.freedesktop.org/wiki/ all comes down to exactly what it is you wanna tweak....gamma and refresh rate are simple and adjustable in a GUI as is. cheers, x

01-05-09, 05:58 AM	#3
rpjday Registered User Join Date: Jan 2009 Posts: 2	Re: Building a video signal generator with a (Dell) laptop and NVIDIA video card Which GUI (or GUIs) would you recommend for the basic tweaking? I can use either Fedora or OpenSUSE if anything is distro-dependent? Thanks. rday

01-05-09, 12:31 PM	#4
AaronP NVIDIA Corporation Join Date: Mar 2005 Posts: 2,487	Re: Building a video signal generator with a (Dell) laptop and NVIDIA video card Chapter 9 in the README covers configuring your own mode timings. You may need to set the ExactModeTimingsDVI option to get it to actually drive your flat panel using the timings in the mode instead of the panel's native backend timings. I believe this option applies to DisplayPort as well. There are various old HOWTOs floating around the web that discuss exactly what the various parts of a ModeLine mean and how to compute them. Note that DisplayPort is just a high bandwidth unidirectional bitstream that transmits the video data, among other things, at one of two possible bandwidths (1.62 Gbps and 2.70 Gbps), so the "timings" are more of a guideline for the monitor than anything the GPU actually puts out. If you really want low-level control of timings signals coming out of the GPU, you need to use VGA. As xianthax mentioned, you can adjust the gamma settings in the nvidia-settings display configuration page.