Video Black Level

I was checking out the video black level on my new build to see if it was OK. The HTPC has an ECS H61 mobo and Intel G620 CPU & is connected to a Sony HDTV via HDMI.

I used the THX Opimizer setup that was on a standard DVD & could not display the THX drop down shadow or more than 7 shades of gray/black no matter how I set the HDTV's black level / brightness. I went into the Intel Graphics properties & changed the Quantization Range from Limited to Full but it made no difference.

I used the same DVD on my Blu-ray player connected to the same HDMI connection on the HDTV and I can adjust the HDTV to display all 10 blocks of shades of black & the drop shadow. And IIRC my standard DVD player also would allow blacker-than-black.

The only variable is the HTPC. The 7 shades of black from the HTPC appear to match the 7 shades of black from the Blu-ray player with the HDTV properly adjusted. IOW I'm not losing anything from the HTPC.

But I am curious why the HTPC is not even able to output a B-T-B signal.
Is there another setting which controls that?

I do have an Avia calibration DVD & do not have a problem displaying B-T-B with either of my two DVD players or the Blu-ray player. I don't recall the exact setting names & don't have the manuals in front of me at the moment, but all the players are setup to output the proper NTSC levels. They can all output B-T-B, but of course I don't have the HDTV calibrated for that. The HDTV is calibrated for the proper black level, at least as best as can be done with the calibration disc & other test patterns.

I do not want to display B-T-B with the HTPC, but am wondering why it cannot output such a signal. I an using the integrated Intel HD Graphics and am trying to find out what setting controls this.

That's probably it, but how do I control this?

My secondary concern is what happens when I display jpeg photos. Will the HTPC change the 0-255 to 16-235, and what happens to the photo black levels when this happens?

I can plug an SD card into my Blu-ray player & look at photos.
Is their color space being changed to TV's safe 16-235 colors?
Is this the correct process for viewing on an HDTV because it is expecting 16-235?

I think I'll put a few jpeg test patterns on an SD card & view them on the HDTV using the HTPC and Blu-ray player and see what the blacks look like.