Short version: get SP1. There is a bug fix in SP1 that goes with a bug fix currently in the released Nvidia GPU drivers.

Long version: In Vista RTM there was a bug in many video drivers and a bug in Vista such that the GPU drivers ignored any requests having to do with nominal range (video vs. pc black-level handling during color space conversion) and Vista improperly set the nominal range on the video renderer as well. These two bugs together resulted in Media Center actually doing the right thing on most video cards. Vista did the wrong thing, and the GPU drivers ignored it. Fine for VMC but not for Media Player, which requested a different behavior but did not get it.

In the 169.25 driver drop from Nvidia this bug is fixed. But the Vista side fix is in SP1 which most people don't have yet.

So, if you upgraded your video drivers and the "moving x" test pattern for brightness that is included in the product results in an "X" that is barely visible no matter how high you crank the brightness this may be the issue you're running into. Roll back your driver, or get SP1.

Be advised, on many desktop displays the "brightness" adjustment merely changes the back-light so this test pattern is really only intended for consumer grade non-data displays where the "brightness" adjustment actually changes the way the display handles black levels.

-Ian

Thanks for the update.  Can you let us ATI owners know where we'll stand too?  The black level expansion bug is well documented and has been an issue for about a year.  Will SP1 change the way Media Center handles black levels?  I have my Bravia calibrated for video levels currently.  Will I need to change it post SP1 to PC levels?

It would be nice to get a definitive answer on this for both ATI and nVidia.  I'm tired of having to resort to registry tweaks to get SD and HD black levels the same.

Thanks.

Thats great news Ian!

If you recall, we discussed this with HT Slider in a different thread. Glad there is a solution and you have sorted out which part that is correct vs incorrect...

/Henrik

MrNorth:

Thats great news Ian!

If you recall, we discussed this with HT Slider in a different thread. Glad there is a solution and you have sorted out which part that is correct vs incorrect...

/Henrik

The question now is where best to get SP1. 

My grey levels are now all messed up (too dark) with HD Recorded TV content in Media Center as well as videos are still too bright with Media Player.  This is with an ATI card and I'm hoping SP1 will fix the issues.  The "too dark" in Media Center with HD content is a new "feature" that seems to have arrived at the same time as upgrading from Catalyst 7.10 to 8.1 and at the same time installing PowerDVD Ultra and configuring Media Center to use it through My Movies 2.42 (I don't know what actually messed it up...).

Another issue that I hope is fixed with SP1 is the random crashes we are seeing with our low bitrate 1080i digitally recorded dvr-ms files.  These are the same files that are too dark that also cause Media Center to crash.  I'm also hoping that SP1 might fix the inability for Media Center to play our low bitrate 480i digitally recorded dvr-ms files (maybe Ian can comment - I sent him some samples that won't play in Vista Media Center, but will play everywhere else, including Media Player).

I managed to download a copy of SP1 RTM from the winvistaforums main blog page, but they eventually ran out of bandwidth and are no longer hosting it.  I haven't tried it yet, because I was hoping to get some information on which drivers were not compatible with SP1 before going for it.

I've also read that you can enable Windows Update to install SP1 by executing the following from an elevated command prompt:

reg add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr entVersion\WindowsUpdate\VistaSp1 /v Beta1 /t REG_SZ /d dcf99ef8-d784-414e-b411-81a910d2761d /f

After this and checking for updates, windows update will install a few patches to get your system ready for SP1 and then about 10 minutes later, checking for updates again it will offer SP1.

This setting enables you to access the beta program for SP1, but since everyone on the beta program has now been offered the full RTM, this now apparently installs the actual SP1 RTM on your system.

If anyone wants to try it, please back up your system first and then let us know if you get the actual RTM...

I think I'll install the SP1 RTM that I got from the winvistaforums blog site (after seeing if there are any known issues with drivers for Intel P35 based motherboards - so far I haven't really heard of any real issues with SP1 and drivers...).

>> My grey levels are now all messed up (too dark) with HD Recorded TV content in Media Center

Yup, same here.  SP1 doesn't fix it and neither does Catalyst 8.2 (just now available for download, btw).  I just finished testing this on a clean install.  This is exactly why I asked Ian what the default behavior should be.  I think it's a driver bug with ATI but I can't get MSFT or ATI to even acknowledge the problem.  At least "use btc601csc" reg hack used in combination with brightness and contrast controls in CCC still fixes it but I'm growing very tired of reg hacks and catalyst tweaks.

The novice user will have absolutely no idea how to fix something like this.  They'll just be frustrated because their HD material looks too dark.

fdisker:

SP1 doesn't fix it and neither does Catalyst 8.2 (just now available for download, btw).  I just finished testing this on a clean install.  This is exactly why I asked Ian what the default behavior should be.  I think it's a driver bug with ATI but I can't get MSFT or ATI to even acknowledge the problem.  At least "use btc601csc" reg hack used in combination with brightness and contrast controls in CCC still fixes it but I'm growing very tired of reg hacks and catalyst tweaks.

The novice user will have absolutely no idea how to fix something like this.  They'll just be frustrated because their HD material looks too dark.

That is annoying.

I thought the usebtc601csc didn't work with EVR though.

I've tried playing with brightness and contrast to get the HD right, but I end up with SD content too bright and looking washed out.

How exactly did you get your grey levels correct?  Is it a certain set of brightness and contrast controls that you use (video vs overall output)?

>> Is it a certain set of brightness and contrast controls that you use (video vs overall output)?

Yes, it's a combination of a single registry tweak and a change to the brightness and contrast settings in Catalyst Control Center.  Arfster's definitive post explains each of the registry tweaks but the one you want is "UseBT601CSC = 1".  The trick is getting it in the right place in the registry.  Again, arfster explains how to find the correct registry keys better than I can.

Once you get the registry updated just open up Catalyst Control Center and go to the "Avivo Video -> Basic Color"  section (use Advanced View as these settings aren't exposed in the Basic View).  Uncheck "Use application settings" and move the Brightness slider to +16 and the Contrast slider to -86.

That's it.  All your video within Media Center should now be at Video black levels.

I find the process a giant pain in the behind and I wish ATI would get their act together and fix this bug so none of this would be necessary.

I just spent some time experimenting with UseBT601CSC, setting it to 1 and 0 and erasing it, including rebooting between each change.  On my system it doesn't seem to affect Media Center nor Media Player at all with Catalyst 8.1 installed (and I didn't notice any change when I tried it with 7.9 or 7.8 a while ago either).

What I did find is there are some VERY strange brightness changes going on with the latest video driver.

With 7.10 I set the overall (color in CCC) brightness to +22 and contrast to 85 along with the gamma to somewhere between 1.25 and 1.3 and our system would pass all of the grey level tests, including the Media Center black (moving X) and white level (shirt) tests.  With 7.10 however, Media Player was far too bright.

With 8.1 I left the settings as above and now HD is far to dark, SD is also a little to dark and Media Player is also now too dark.

I was unable to get the brightness levels to pass the black nor white levels within Media Center, nor could I get them to pass in Media Player by using the overall (color) settings within CCC.  No matter how far I went, darks were too dark and whites were saturated (white shirt had no detail).

In order to get it to pass the tests I had to play with both the overall (color) settings as well as basic color in AVIVO.  Now I have:

overall (color):  brightness +20, contrast 75, gamma 1.3

basic color (AVIVO): brightness +8, contrast 88

I don't understand what is going on, but I had to really crank up the brightness and really turn down the contrast.  I haven't touched the HDTV settings and it is calibrated with our hardware DVD player. The image does finally look good, but I'm concerned there may be a significant amount of crush going on.  Note that the settings above essentially combine so this works out to something like +28 for brightness and 66% overall contrast, leaving me with a roughly a theoretical 38% worth of the available grey scale bandwidth (doesn't sound good at all!!).

To my surprise with these settings HD and SD is has correct grey levels in Media Center as well as everything played back in Media Player.  I do not have Vista SP1 installed yet and it sounds like it won't help me (based on posts above).

HT Slider: Do you use the "moving cross" video within media center to verify your black levels?

Because as I recall, it looked fine in Media Center, but when playing the wmv file in media player, it looked extremly black... no details at all.

But this was with the older catalyst drivers? Im really afraid to install new drivers, because they seem rather instable.

/Henrik

>> I just spent some time experimenting with UseBT601CSC, setting it to 1 and 0 and erasing it, including rebooting between each change.  On my system it doesn't seem to affect Media Center nor Media Player at all with Catalyst 8.1 installed

You may not be entering the key in the right place.  The key definitely has an effect on HD material in the Media Center application.

MrNorth:

HT Slider: Do you use the "moving cross" video within media center to verify your black levels?

Because as I recall, it looked fine in Media Center, but when playing the wmv file in media player, it looked extremly black... no details at all.

But this was with the older catalyst drivers? Im really afraid to install new drivers, because they seem rather instable.

/Henrik

Recently I have been using the moving cross.  I used to use the Avia TV calibration DVD.

You recall correctly, but Media Player being too dark has been fixed somewhere between 7.10 and 8.1.

8.1 has been a very big improvement on our system as far as image quality too.  All of the jittering of solid reds and blues is gone, plus the deinterlacing is improved, plus the artifacts that used to show up in low light video is also gone.  We haven't had a single (new) issue with 8.1 except for the grey level.

After posting my previous post I decided to recalibrate my HDTV for Media Center, instead of calibrating my Media Center to match the HDTV that was calibrated with a hardware DVD player (that was a mouthful...).

So what I did was:

1. Downloaded a couple of reference grey level images, one 4-bit and one 8-bit.
2. In order to ensure I was using the maximum number of grey levels output from the Media Center, I cranked up the brightness all the way up on the HDTV (and that wasn't enough so I got into the service menu and kept on cranking it up).
3. Turned down the contrast on the HDTV (same reason as 2).
4. I then calibrated the overall color levels at the Media Center through CCC right to the edge of clipping on the white and clipping on the black.  It turned out that I needed to use +15 for brightness and 85% for contrast.  This is with gamma at the default of 1.0.  Any less on the brightness and I'd loose some black levels, any more on the contrast and I'd loose some white levels.
5. I then calibrated the AVIVO color levels for video playback at the Media Center using the Media Center black (moving X) and white level videos (white shirt).  To make it so the X "just" could be seen and so the shirt looked good I needed to use brightness of +2 and contrast of 85% (again - strange that I needed to turn down the contrast so much since 100% is default).
6. Finally I calibrated the brightness on the HDTV so the Media Center black test (moving X) "just" couldn't be seen with typical ambient lighting and I adjusted the contrast to a reasonable level (it turned out the shirt looked good all the way to 80% contrast, but I settled on 50% since there was a clearer image).

This method really worked quite well for our system.  The are visibly much more grey levels than before and this actually makes colors provide much smoother transitions.  Another benefit is I am now running the video card's gamma at 1.0 (default) and I think this also helps with a more natural look (previously I couldn't get enough brightness with darks without increasing the gamma).

One thing I noticed with our HDTV is the DVI port produces much darker images than if we use component out (even component out with the hardware DVD player is much brighter).  I suspect there is something not quite right with the DVI port's brightness calibration, but I could only find a single brightness control in the service menu).

So now we have an excellent image on our HDTV from our Media Center, but all other video sources (ExpressVu STB direct, hardware DVD player, & C-band STB), will be far too bright.  I figured we are now using Media Center for virtually all TV watching so this is a better compromise for us than living with so much compression/crush in the grey levels.

fdisker:

>> I just spent some time experimenting with UseBT601CSC, setting it to 1 and 0 and erasing it, including rebooting between each change.  On my system it doesn't seem to affect Media Center nor Media Player at all with Catalyst 8.1 installed

You may not be entering the key in the right place.  The key definitely has an effect on HD material in the Media Center application.

After recalibrating the entire system (see above), for some reason all SD and HD Recorded TV now seems to have decent grey levels, including if it is played with Media Player.  I haven't tried PowerDVD yet (I'll try to give it a go with an HD-DVD and Blue-ray DVD tonight).

I am certain I have the UseBT601CSC in the location specified by arfster over on avsforums.  I also have TRDenoise set to 0 here and TRDenoise makes a huge difference.  For some reason UseBT601CSC does absolutely nothing with our hardware/HDTV and Catalyst 8.1.  I even tried it again, after calibrating the grey levels right on the edge (so it would be very noticable) and it still didn't do anything on my system.

I wonder if UseBT601CSC only affects certain HDTVs or something.  Is it possible that the EDID tells the video driver if the HDTV supports PC or TV levels and some HDTVs are missing this entry or something like that?

>> Is it possible that the EDID tells the video driver if the HDTV supports PC or TV levels and some HDTVs are missing this entry or something like that?

Thats a good question.  Hopefully Ian will stop by the thread again and answer.  I hear SP1 gives us a new MPEG2 decoder.  It'd be great to know what changes were included.