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Hi all, just successfully setup a HTPC using an Asus P5N7A-VM motherboard and following this thread.

However, I have one small query. The TV I'm using is a Sony KDL-40W4500 calibrated using settings from this thread at avforums.com. Now, there are thousands of people thoroughly satisfied with the TV, however to me it appears there are no details in blacks at all.

I tried playing with the settings, and the only way to see the detail in dark scenes is to turn the brightness waaaay up. This makes the rest of the picture look incorrect.

Now surely somebody else would notice this on those forums, but alas everyone just raves how good the picture is. Now I bet most people are using a standard bluray player...

However, I'm using XBMC to play backed-up bluray's over hdmi. Now I don't know too much about color spaces, but I do know when playing the movies on my windows pc (using the appropriate codecs) colors look fine, however blacks aren't 100% black. This is not a problem, in fact I think this is how it's meant to look. It looks as if the video's color space has been adjusted to take into account display on a monitor rather than a TV, the picture looks perfect.

Now back to the XBMC + TV setup. Dark areas of the picture are way to dark, but bright areas look fine. I was thinking whether the TV expects hdmi signals with the color space correct for a tv, but xbmc is outputting a signal with a color space correct for a monitor, and maybe the mismatch between monitor and tv is causing the color problems.

Is there any truth in what I've said? If you've read to here, I thank you, as that was far too long.

The only reason I mention this is because at the moment the picture is unbearable, but surely the 100s of people over at avforums.com don't have this problem, and I bet they are using standard bluray players.

I also remember the XBox having a black level adjustment with the VGA cable, which made a difference depending it was feeding a TV or a monitor.

Thanks for any help, James
Welcome to the forums.

Have you tried bumping the brightness up in the XBMC Video OSD? You weren't entirely clear on WHERE you have tried to make the adjustment already. I assUme your TV since that's what most of the post seemed to be about.
Thank you...

No, I was adjusting the brightness on the TV set, however after raising the brightness in XBMC to ~56, it looks a lot better.

I guess there should be no difference between the TV's and XBMC brightness setting, but XBMC's seems more correct that the TV's.

Thanks for the help, James
Well, although adjusting the brightness in XBMC 'fixed' the problem, it caused another.

The PC (with an intel e8400 3GHz proc.) can't handle the extra maths required to adjust the brightness. This causes frame drops (ranging from 10-50 per minute). Resetting the brightness causes the CPU usage to fall back to normal, and no dropped frames.

Now, can I use the adjustment settings in nvidia's control panel to achieve the same effect, but without any increase in resource usage?

Also, as the TV is connected via HDMI (with a 24Hz modeline), I guess the 'blacker than black' brightness range affects it. This trac bug seems to mention support does exist for this problem. Could this explain why raising brightness on PC (and not the TV) made the dark information return?

Any help would be great, James

EDIT: I just took some screenshots of Iron Man playing, one through XBMC, and one through windows with some DirectShow filters.

The black bars at the top and bottom (in the video, not superimposed) are at RGB level (16,16,16) using the directshow filters, and (0,0,0) through XBMC. As the HDMI standard says video should remain between 16-235, the directshow filter seems correct for display into a TV, XBMC seems correct for a monitor. The link to the trac post earlier mentions this, and I think this is why there was a loss in detail in dark areas originally.

The temporary solution was for me to recalibrate the LCD (using a grey scale chart), to show information below level 16 and above level 235. This has solved the problem, however it would be nice to have a switch for xbmc to fix the problem as mentioned in trac.
I have this problem at least to some degree on my panasonic pz8e plasma. Colors 0-7-9 or so are all black. No matter what settings I put on the TV.

This would be easily solved with recalibrating to 16-235 and using that in XBMC.

I cannot get these blacks to display (as grey) any other way than to possibly fiddle around in my service menu, so this is a very needed fix for me Wink

The issue only appears on my HDMI input, s-video for example is unaffected.
Hi James,

xanium4332 Wrote:The temporary solution was for me to recalibrate the LCD (using a grey scale chart), to show information below level 16 and above level 235. This has solved the problem, however it would be nice to have a switch for xbmc to fix the problem as mentioned in trac.

Just a question as I'm planning to get the exactly same hardware to replace my current setup (sony 40w4500 and Asus motherboard with e8400) Wink Was the recalibrating done using the standard TV menu? Also, did it affect to normal TV SD viewing?

Thanks!
Can say that I'm seeing the same thing here.

Brightness of 55 seems to mask the issue. Worth a dev taking a look?

TheUni
not to dismiss the color space issue, but you can't use the calibration values from another person/set and expect to get optimal results. Ever set is slightly different, every room lighting is different, and every person's sensitivity to light and color is different.
pilluli:

Yes, the setting I used (brightness and contrast) are available under the 'picture' menu. As each input holds it's own complete calibration values, TV was unaffected (I have a Freesat STB feeding over another hdmi port).

I used a greyscale I found on google images to quickly adjust the values, originally the top 2 white and bottom 2 black steps were identical, I checked the RGB values and they fell outside the 16-235 range, as expected.

BTW, the TV is amazing, and I think good value for money (compared to my older, annoying, not quite Full HD, non 1:1 pixel mapping, no 50Hz, LG), and the 24Hz input makes blurays silky smooth.

I was also thinking the issue could be worked around using the gamma settings in nvidia's control panel. Adjusting the 'contrast' slider until everything comes into view (if gamma works the way I think it does, the graph it draws is like a lookup table, so adjust the '0' on the x-axis to '16' on the y-axis should fix the issue). This would also solve the problem for the menu's etc, where I guess modified shaders wouldn't make a difference
theuni Wrote:Can say that I'm seeing the same thing here.

Brightness of 55 seems to mask the issue. Worth a dev taking a look?

TheUni

Yeah, increasing brightness and contrast should fix this problem and with no white crush.
sandos Wrote:Yeah, increasing brightness and contrast should fix this problem and with no white crush.

Contrast should be lower than default.

A 16-235 colorspace option in XBMC should be helpfull.
athloni Wrote:Contrast should be lower than default.

A 16-235 colorspace option in XBMC should be helpfull.

Correct me if I am wrong but I think "enable color studio" option (or something like this) should do the 16-235 colorspace. Only enabled in vdpau though...
pilluli Wrote:Correct me if I am wrong but I think "enable color studio" option (or something like this) should do the 16-235 colorspace. Only enabled in vdpau though...

I searched for but in Confluence beta 2 on windows there is no such settings. Can you confirm that this settings exist under Confluence beta 2 Linux?
I have Nvidia GT220 and on my Panasonic P42V10 plasma the video is washed out Sad.
Windows does not support VDPAU as of today. Enable Studio Color Level is only available for VDPAU, therefore it is certain that this option is not available at Windows.

Ubuntu minimal + XBMC or XBMCLive from CD or install XBMCLive to hard disk will work much better (off load the video to the GPU of your card).

If for some reason you want to stay in windows, you can probably adjust the problem with the control pannel for you nvidia card from the Windos OS, therefore for all application.

Anyhow (and I apologise for being persistent) only linux will give the chance or running full HD - high bitrate without judder (DSPLAYER does not work for me). I assume that if you like the color the way it was designed, you would like the video motion the way it was designed next, and you will need to move to linux. You can save yourself sometime if you move straight away.

Regards,
horserider Wrote:Windows does not support VDPAU as of today. Enable Studio Color Level is only available for VDPAU, therefore it is certain that this option is not available at Windows.

Ubuntu minimal + XBMC or XBMCLive from CD or install XBMCLive to hard disk will work much better (off load the video to the GPU of your card).

If for some reason you want to stay in windows, you can probably adjust the problem with the control pannel for you nvidia card from the Windos OS, therefore for all application.

Anyhow (and I apologise for being persistent) only linux will give the chance or running full HD - high bitrate without judder (DSPLAYER does not work for me). I assume that if you like the color the way it was designed, you would like the video motion the way it was designed next, and you will need to move to linux. You can save yourself sometime if you move straight away.

Regards,

Thank you very much,

I'll try XBMC Live with hope for better pictures with my HTPC and plasma TV.

Regards
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