ATI 5450 brightness issue

[phoneguyinpgh]

Both of my HTPCs are using ATI 5450 cards.  When I got my Ceton card netoworked to them I noticed on the living room PC on certain channels the brightness seemed to pulse up and down randomly durring commercials and on a few cable channels.

I just recently updated the drivers for both machines and now the brighness seems to be pulsing on many more channels and even on my ripped DVDs (in MPEG). 

The dynamic contrast is off on both.  CCC is set to use it’s video settings and not the “program settings”.  The levels were adjusted using the procedure and test pattern files noted in the display calibration guide.

 

Has any one else had an issue like this??  Is there is a fix or work-around??

 

Thanks in advance.

[mikinho]

If you don’t have it set already, try the below registry key

 

[HKEY_LOCAL_MACHINESOFTWAREDebugehPresenter.dll]

“NominalRange”=dword:1 

[phoneguyinpgh]

[quote=mikinho]

If you don’t have it set already, try the below registry key

 

[HKEY_LOCAL_MACHINESOFTWAREDebugehPresenter.dll]

 

“NominalRange”=dword:1 

 

[/quote]

 

Thanks Mike.  Can you give me a quick description of what that registry entry does??

[mikinho]

See the below for the explanation.

 

This will enable a more efficient scaling path in the AV pipeline. On some GPUs it may result in a sharper image, on some it may get funky:
Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINESOFTWAREDebugehPresenter.dll]
“BoundByNativeSize”=dword:0

This will set your nominal range to video levels, the current defualt for MCE. Use with properly calibrated consumer displays and projectors. IE: devices set for 7.5IRE blacks.
Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINESOFTWAREDebugehPresenter.dll]
“NominalRange”=dword:2

This will set your nominal rante to 0-255 (PC levels) essentially doing “expanded blacks” use this with a typical PC monitor calibrated for blacks==0.
Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINESOFTWAREDebugehPresenter.dll]
“NominalRange”=dword:1

They were provided by Ian Kennedy – Microsoft via http://thegreenbutton.com/forums/p/59322/276662.aspx#276662

[phoneguyinpgh]

Many thanks.

[phoneguyinpgh]

Michael,

You’re great.  That did the trick.  It even fixed my issue of WMP being adjusted perfectly while TMT3 was too dark.  Everything, ripped DVD’s, recorded TV, live TV and BlueRays (TMT3) all look as close to perfect as I can get without $$$ test equipment.

Thanks again.

[mikinho]

Glad I could help!

[phoneguyinpgh]

Mike,

My brightness pulsing issue has returned.  It is only on certain channels, most notably the Discovery channel during programing and commercials.  On other channels it only seems to occur on commercials and not the main program.  I have my nominal range registry entry set to 1, dynamic contrast is off, dynamic range is set to full.  My CC for my 5450 is up to date.  Is there anything else I should try?

[mpatnode]

Sure sounds like the ATI Dynamic Contrast issue, even though you say it’s disabled.    When I had a 5450, I noticed that it would mysteriously get switched back on sometimes.  

 

[phoneguyinpgh]

Every time I notice the brightness flashing I get out of MC and check CC and the dynamic contrast is still off.  What is throwing me is it is only certain channels and some programs on those channels flash more than other programs.

I noticed it quite allot on the Discovery channel this weekend, particularly during Storm Chasers while watching in my living room.  I recoded the program with my bedroom HTPC and it flashes when viewing the recorded program on the Living room but not the bedroom HTPC. Both with 5450s but the bedroom is using CC 11.2 while the Living room is using CC 11.8.  Should I uninstall 11.8 and try 11.2???

[mikinho]

Next time you notice it hit 4-1-1 + INFO on your remote (or 4-1-1- <Ctrl-D> on a keyboard) to bring up the Live TV debug screens within Windows Media Center.  When up keep hitting right until you see the Live TV frame rate.  See if it fluctuates between 29 and 59.  If so, that could cause it.  ATIAMD handles it very poorly.

[phoneguyinpgh]

Michael,

I removed CCC 11.8 and installed 11.9, no joy.  I removed CCC 11.9 and installed 11.2, still no joy.  For both changes I uninstalled CCC and uninstalled the driver from device manager and started over w/ no “quality” driver installed.  Also, once the ATI driver was installed, I did a re-calibration w/ the video calibration files to set the black, white clipping and color clipping levels. 

I didn’t read your post until I did all the driver changes, but once I was on 11.2 I checked the frame rate. The frame rate is occasionally, and very briefly, changing from 59.9401 to 29.97.  The brightness flashes seemed to be occurring at the same time as the frame rate changes.  Is this coming from the network as part of the video signal?  Is it improper deinterlacing?  Or is it a hardware issue that I will just have to live with?? 

Also one other thing I noticed while installing various CCC versions and setting up the display again, I could not obtain correct pixel mapping unless the pixel format was set to RGB 4:4:4.  I don’t know if that might have something to do with it, but it was peculiar that the pixel format needed to be RGB on my TV (it’s a cheap Insignia from Big Box).

Update:  I checked the frame rate on the bedroom HTPC and it also changes from 59 to 29 but no flashing brightness.  The bedroom TV is an LG.  Could it be the cheaper TV in the living room that is the issue??

[mpatnode]

Oooh.  One of the more infamous and heated threads from TGB back in the day, but given the different behavior between the two systems, I would try the older CCC driver as well.

On the otherhand, I’m just put a used 1GB Zotac GT 430 on Amazon.   I thought it was bad so replaced it with a Asus trying to solve a BSOD problem.    Turned out to be the system memory.

In general, I’m much happier with the NVidia driver than AMD.   Also, the GT 430 seemed to perform the best on the 23.976Hz tests.

[mikinho]

For some background on the issue see http://www.cetoncorp.com/support/index.php?/Knowledgebase/Article/View/20/3/hbo-and-other-channels-rapid-framerate-changing—stuttering

Basically it is an incompatibility issue between Media Center’s decoder and the channels MPEG steam encoder.  The incompatibility in Windows Media Center is when it receives video which does not properly indicate its framerate.

JohnW248 knows more about the issue than anyone should have to so hopefully he will chime in but in my experience ATIAMD handles it very poor and NVIDIA tends to handle it the best.

[phoneguyinpgh]

Thanks Michael. 

One more question if I may, and I don’t mean to put you on the spot, but what would you recommend?  Going with a NIVIDIA adapter?  Strange that the Bedroom HTPC doesn’t flicker, but I should do some more comparing the settings between units.

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