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Discussion Starter · #1 ·
Quick question to any HTPC owners using nVidia solutions and Vista and connected to their HDTV via HDMI...


How many of your are getting consistent black levels between SD DVDs and HD Blu-ray Discs without having to switch the nVidia control panel between 0-255 and 16-235 or fiddle with brightness and contrast settings on your display or driver?


I've built an HTPC around a Gigabyte E7AUM-DS2H motherboard - IGP nVidia 9400 graphics and an Intel E7300 Core 2 Duo CPU. I am almost happy with it - except for one major issue - which appears to be an inherent failing.


Within Vista Media Center, Power DVD and Total Media Theater I consistently have different black levels between SD DVDs (and SD TV) and HD Blu-ray discs... I have confirmed this with PLUGE from the DVE Essentials DVD and BD discs - I either get set-up blacks on DVDs and OK BD blacks, OR crushed blacks on BDs and OK DVD blacks.


For some reason SD and HD (or is it protected path HD?) content is being treated differently.


My HDMI display is correctly calibrated for 16-235 ITU 601/709 black levels, and other sources switched to the HDMI input on my Sony 40W4000 Bravia display (Full 1080 24/50/60Hz compatible) are correctly displayed (Sky HD set top box, Toshiba HD-DVD player, Sony PS3 etc.)


However when running my nVidia drivers in 16-235 dynamic range only HD Blu-ray content is displayed correctly, SD DVDs are displayed with set-up black levels (black is grey, and thus saturation is decreased and colours washed out). Switching the control panel to 0-255 displays SD DVDs correctly, but then displays HD Blu-ray Discs incorrectly, with crushed blacks and clipped whites (and thus over-saturation).


I don't want to try hacking EDIDs and using DVI/HDMI dongles - as I need full HD multichannel PCM audio from my HTPC - that was the reason I bought an nVidia motherboard with on-board HDMI after all. It shouldn't be this difficult to get decent quality HDMI video from a £500 HTPC when you can get it from a £99 HD satellite receiver or a £150 Blu-ray player - should it?


Ignoring blacker than black and whiter than white issues - I don't seem to be able to find a single control panel setting that displays DVDs and Blu-rays with correct black levels (and white levels).


SO :


1. Does anyone with nVidia graphics have a Vista set-up feeding a standard HDMI TV where SD DVDs and HD BDs display correctly - if so, what are your driver settings? Did you have to use a registry fix to achieve this etc.? (I had the same issues with ATI graphics - but their BT601CSC registry fix sorted this) Or are people just putting up with less than ideal video on SD or HD sources?


2. If others have the same problem I do - could you let me know?


I've opened a support ticket with Gigabyte (who made my motherboard) and they say I'm the first person to raise this as an issue - and that nVidia say black levels are subjective - which is a total fob-off... (Rubbish - HDMI and 601/709 are non-subjective standards - and my nVidia solution is not correctly outputting 601 or 709 consistently via HDMI - not a subjective observation, but a FACT) They also claim not to be able to replicate the issue in their labs - but they don't seem to have much decent test gear - and hadn't heard of PLUGE (so I'm not convinced that they really understand the issues involved)


It would be good to be able to have an idea of the number of people who have this issue. I believe it may be due to a SNAFU in Vista's EVR (caused by an incomplete understanding of video levels probably - PC people often get confused between 0 and 16 representation of black AND the NTSC composite/S-video +7.5IRE set-up black/blanking level differential - which is a red-herring in component video as it doesn't exist...) however if ATI can fix it (albeit with a non-publicised registry hack - which may actually make the drivers non-MS compliant BUT work properly!), surely nVidia can?


If others are having this problem it would be good to approach nVidia en-masse. I can't believe MS/nVidia appear to have dropped the ball in such an amazing and ridiculous manner on this.


Thanks for listening!
 

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I totally agree! this is a major issue!


Ive recently been playing around with a 4350 connected to my pioneer 9gen television. Ati recently included a pixelformat option allowing you to the set the outputformat. The cool thing about the television is that it allows you to manually change the input mode(dig componen 444/422 and RGB 0-255/16-235) for the hdmi socket. Thus, im able to see excatly what type of signal my pc is sending.


With the tv direclty connected i was able to elucidate that Ycbcr444 does not work from my 4350 using catalyst 8.12, it outputs limited RGB instead. Totally messed up. In addition, blacker than black was always cut no matter the output mode using conventonal mpeg decoders(powerdvd, windvd) in zoomplayer(EVR). However, changing dvd decoding to ffdshow and outputting RGB32 (output full range), setting my tv for RGB 16-235 btb finnaly appered in PLUGE.


Performing the EDID override to get HD audio through my reciver changed the situtation. Now nothing else works except for ycbcr444 (CCC reports its sending for example RGB 0-255 but its ycbcr 444 in reality)! strange to say the least.



Are you having trouble seing btb in SD DVD(pluge) with the 9400? Ati, as far as I can see in ycbcr444, do infact have consistent black level in both HD and SD. However, btb is cut in both SD and HD.


Maybe u should try using ffdshow in RGB32 mode. This bypasses the graphics driver. Its easy to create profiles in ffdshow for SD and HD depending on horizontal resoultion with the correct bt601/709 output. Last thing, to get the fullrange of video including btb, you must use the fullrange 0-255 setting.
 

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Yes it's 100% a bug in the driver.


It only effects native HDMI out, not DVI->HDMI adapters and only in vista (maybe win7 too).


The symptom of the bug is the blu-ray played back in commercial players is exactly one compression step darker than SD video.


The cause is that via native HDMI out the desktop itself is compressed to video levels. Most video then works relative to the desktop setting so expanded then means video black is output at desktop black, which now is at 16, but limited levels 16-235 are now output above video black (roughly 29). Blu-ray (and other Protected Path content) goes down Protected path and still uses an absolute expaneded or limited, so in limited mode it's black is still at 16, and in expanded mode it's black is at 0, below desktop black.



Nvidia should be able to fix this, I've documented it and sent it in again and again.
 

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Quote:
Originally Posted by sotti /forum/post/15545948


Yes it's 100% a bug in the driver.


It only effects native HDMI out, not DVI->HDMI adapters and only in vista (maybe win7 too).


The symptom of the bug is the blu-ray played back in commercial players is exactly one compression step darker than SD video.


The cause is that via native HDMI out the desktop itself is compressed to video levels. Most video then works relative to the desktop setting so expanded then means video black is output at desktop black, which now is at 16, but limited levels 16-235 are now output above video black (roughly 29). Blu-ray (and other Protected Path content) goes down Protected path and still uses an absolute expaneded or limited, so in limited mode it's black is still at 16, and in expanded mode it's black is at 0, below desktop black.



Nvidia should be able to fix this, I've documented it and sent it in again and again.

I can send it in too if you'd like


Where do you send it?


CFC
 

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Quote:
Originally Posted by sotti /forum/post/15545948


Yes it's 100% a bug in the driver.


It only effects native HDMI out, not DVI->HDMI adapters and only in vista (maybe win7 too).


The symptom of the bug is the blu-ray played back in commercial players is exactly one compression step darker than SD video.


The cause is that via native HDMI out the desktop itself is compressed to video levels. Most video then works relative to the desktop setting so expanded then means video black is output at desktop black, which now is at 16, but limited levels 16-235 are now output above video black (roughly 29). Blu-ray (and other Protected Path content) goes down Protected path and still uses an absolute expaneded or limited, so in limited mode it's black is still at 16, and in expanded mode it's black is at 0, below desktop black.



Nvidia should be able to fix this, I've documented it and sent it in again and again.

+1!


Great work documenting this issue Sotti!
 

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Quote:
Originally Posted by sotti /forum/post/15545948


Yes it's 100% a bug in the driver.


It only effects native HDMI out, not DVI->HDMI adapters and only in vista (maybe win7 too).


The symptom of the bug is the blu-ray played back in commercial players is exactly one compression step darker than SD video.


The cause is that via native HDMI out the desktop itself is compressed to video levels. Most video then works relative to the desktop setting so expanded then means video black is output at desktop black, which now is at 16, but limited levels 16-235 are now output above video black (roughly 29). Blu-ray (and other Protected Path content) goes down Protected path and still uses an absolute expaneded or limited, so in limited mode it's black is still at 16, and in expanded mode it's black is at 0, below desktop black.



Nvidia should be able to fix this, I've documented it and sent it in again and again.

Can you explain why this is not the same for DV->HDMI adapters? I have the 4670 and that comes with a DVI->HDMI dongle. Are you saying this does not have the same problem?
 

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Quote:
Originally Posted by rmmeli /forum/post/15548077


Can you explain why this is not the same for DV->HDMI adapters? I have the 4670 and that comes with a DVI->HDMI dongle. Are you saying this does not have the same problem?

It is only an nvidia issue. I saw in a post at the green button from an MS guy that the nvidia drivers when using HDMI natively in order to comply with HDMI licensing compress the desktop to 16.

http://thegreenbutton.com/forums/per...ad.aspx#314362


So because they want to call the output "HDMI" they have to adhere to the HDMI spec. But if you just use a DVI->HDMI adapter well then no such restriction.
 

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Quote:
Originally Posted by sotti /forum/post/15549615


It is only an nvidia issue. I saw in a post at the green button from an MS guy that the nvidia drivers when using HDMI natively in order to comply with HDMI licensing compress the desktop to 16.

http://thegreenbutton.com/forums/per...ad.aspx#314362


So because they want to call the output "HDMI" they have to adhere to the HDMI spec. But if you just use a DVI->HDMI adapter well then no such restriction.

Thanks for that but what is the difference between DVI and HDMI then? I thought they were the same and the dongle didn't really do much of anything.
 

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Quote:
Originally Posted by rmmeli /forum/post/15550960


Thanks for that but what is the difference between DVI and HDMI then? I thought they were the same and the dongle didn't really do much of anything.

I don't mean to sound rude, but like I said above, and the MS guy said in his post, it is a licensing thing to include "HDMI" on the packaging an a physical HDMI port natievly on the card.. Electronically they aren't different, but the card would know it has an HDMI port on it if it was manufactured that way.


Like I said in my original post, it only happens with native HDMI out, DVI->HDMI adapters do not reproduce the issue.
 

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I have an nVidia 8500GT. It has both a DVI and HDMI out. Are you saying that if I switch to DVI out using a DVI to HDMI adapter and set the nVidia CP to 0-255 then I won't have a difference between SD via VMC and blu-ray content via PowerDVD8?


It seems like the $12 invested for the adapter would be well worth it if that is so.
 

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Quote:
Originally Posted by JMGNYC /forum/post/15553545


I have an nVidia 8500GT. It has both a DVI and HDMI out. Are you saying that if I switch to DVI out using a DVI to HDMI adapter and set the nVidia CP to 0-255 then I won't have a difference between SD via VMC and blu-ray content via PowerDVD8?


It seems like the $12 invested for the adapter would be well worth it if that is so.

That's exactly what I'm saying.


Or you can use 16-235 and calibrate your TV for that, but either way the black level will be consistent between SD and blu-ray.
 

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Quote:
Originally Posted by sotti /forum/post/15555744


That's exactly what I'm saying.


Or you can use 16-235 and calibrate your TV for that, but either way the black level will be consistent between SD and blu-ray.

Cool, I'm going to try the DVI to HDMI connector. Since I watch both SD and blu-ray I think consistency will be the thing to go for. Thanks.
 

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Quote:
Originally Posted by bonzichrille /forum/post/15540990


Performing the EDID override to get HD audio through my reciver changed the situtation. Now nothing else works except for ycbcr444 (CCC reports its sending for example RGB 0-255 but its ycbcr 444 in reality)! strange to say the least.

There is a setting in the second EDID block (audio block) which impacts colorspace. Can I look at the before and after for you?
 

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Quote:
There is a setting in the second EDID block (audio block) which impacts colorspace. Can I look at the before and after for you?

In the situtation when everything worked except ycbcr444 I was connecting the tv to my graphics card directly. The reciever was connected through toslink.


Just got one EDID for the reciever (only reciever to the hdmi output on 4350, no tv connected), nothing before and after. Or can you somehow look at the edid from the television and compare that to the values from the harman kardon 255? Deduce which values should be changed to give me colorspace control?


Would be very greatful if you could help me in anyway...
 

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Yes, sorry, I was unclear. What was the EDID for the TV alone vs TV + receiver. I can't guarantee anything (your receiver may refuse to pass something, even if your TV might accept it), but if there's a difference it might be enough to just override the EDID again.
 

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Discussion Starter · #18 ·

Quote:
Originally Posted by sotti /forum/post/15555744


That's exactly what I'm saying.


Or you can use 16-235 and calibrate your TV for that, but either way the black level will be consistent between SD and blu-ray.

This blocks HDMI audio though right - even though it can be electrically carried on a DVI connector (it is on the same pins as the video but at different times)?
 

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Discussion Starter · #19 ·

Quote:
Originally Posted by bonzichrille /forum/post/15540990


Are you having trouble seing btb in SD DVD(pluge) with the 9400? Ati, as far as I can see in ycbcr444, do infact have consistent black level in both HD and SD. However, btb is cut in both SD and HD.

I get BTB and WTW - confirmed with PLUGE - when in 0-255 mode, which appears to pass source 16-235 as output 16-235 - so I get BTB and WTW.


BTB is of no real importance to me - other than as an aid to aligning my display so I DON'T see it... (That is the only reason to have it - no decent broadcast or pre-recorded source should have picture information in sub-black, and if you can see it your display is set-up. It is important to pass it further up the broadcast chain - to preserve over/undershoots on transitions that if clipped could cause ringing in the analogue domain)


I also don't use FFDShow at the moment - I figured getting this sorted with just the stock Vista codecs + Power DVD or Total Media Theater would leave fewer possibilities for questioning my set-up causing the problem and not the driver implementation.


The fact that nVidia and ATI both exhibit an SD/HD black level issue (but that ATI have a registry fix for) suggests that there are either multiple issues causing the same results, or a fault in the "official" spec for something.


In an ideal world the full 1-254 (no 0 or 255 as these are reserved for EAV/SAV etc signalling in 601/709) of a 16-235 signal would be passed for both HD and SD via HDMI - with the desktop remaining 16-235 (remapped from 0-255) - but failing that consistent support for 16-235 with no BTB and WTW would be better than nothing...
 

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Quote:
Originally Posted by sotti /forum/post/15555744


That's exactly what I'm saying.


Or you can use 16-235 and calibrate your TV for that, but either way the black level will be consistent between SD and blu-ray.

Sotti,


I'm fairly sure I see the same issue when using either a native HDMI output from a 9400/730i system or DVI output from a discrete 8600GTS when connecting to an HDMI device (HDMI>HDMI or DVI>HDMI respectively)


In both cases the NVIDIA control panel recognises the connection as HDMI because the HDMI device advertises an EDID extension block that satisfies the HDMI spec.


I think the workaround you've discussed in other posts (which breaks HDMI audio) basically does away with the EDID extension block and fools the system into thinking it's connected to a DVI device (connection seen as DVI in the NVIDIA control panel) and therefore the system no longer compresses output to conform to HDMI standards.


Still testing but that's what I've seen so far.


Are you in a position to test this too?


Wo0zy


Edit: I should add that the 8600 card in question is one of those models with SPDIF passthrough support and claimed to be "HDMI Certified" ( http://www.asus.com/products.aspx?l1...12&modelmenu=1 ). Perhaps these cards behave differently to other "non-audio/ HDMI" discrete cards as per the reason you've cited?
 
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