CalMAN Pattern Generator test w/nvidia GeForce8400M G

[lcaillo]

These are some results that I posted on the CalMAN forum after some tests of the pattern generator in their latest Beta (build 95) of v3.

This is really more of a test of the video adapter than the pattern generator. The machine is the ASUS A8 notebook running a T7250 core2 duo processor, 2.00ghz, 2 gig ram, vista OS.

These are camparisons between my Accupel HDG-3000 and the nvidia using component output into a Sencore SC3100 scope. The levels were compared on a 100% white full field Y output. Pb and Pr readings were both about 1 microvolt higher on the nvidia and had similar stability to the Accupel.

Y level black to white
Accupel .713 +.001, -.001 vpp
nVidia .717 +.005, -.002 vpp

Y level black to + sync
Accupel .300 +.002, -.001 vpp
nVidia .304 +.002, -.003 vpp

Y level black to -sync
Accupel .307 +.001, -.001 vpp
nVidia .310 +.005, -.005 vpp

Y level -sync to white
Accupel 1.025 +.001, -.001 vpp
nVidia 1.048 +.003, -.001 vpp

Sync was very similar on both devices, with the nVidia adapter actually a little cleaner on transitions. Both units have a similar very slight overshoot on the Y for the first few lines.

Using the PC, the levels and variability were essentially identical with hard drive activity and without and on battery vs ac adapter.

The big result here is about a 23 millivolt increase in y level from the nvidia adapter relative to the Accupel. The variability in the levels were also greater on the Y than the color difference channels, which were very stable. This could have significant impact on a calibration. Other video cards may behave differently, and there should be no difference on digital outputs. Calibration measures using the DVI output on both the PC and the Accupel are within the variance of my probe (EyeOne Pro).

[Bear5K]

Leonard - If you have the time, I'd love to see how this tracks at various signal levels vs. the DVI standard, e.g., a 235 white signal ought to be XXXmV, the PC was at YYYmV and Accupel was at ZZZmV.

We are planning on releasing this program as marketing-ware once it is finalized and we get v3 out the door. Until v3 is finalized, only our beta testers get to play with it.

Bill

[lcaillo]

I'll work on it. I just got a USB scope for my PC that I want to validate as well, so I will do it all at the same time. Of course, it will only be meaningful for this system. Obviously, the video card and any software fiddling with the signals are going to be the point of variance in most cases.