Vertical banding in dvd video

[TekViper]

I am noticing some very odd vertical "banding" during dvd playback. I only noticed after upgrading my monitor so i thought the monitor was at fault, but i was able to capture a screenshot of the occurence;

http://img683.imageshack.us/f/linesi.jpg

Zoom the image if it doesn't come up fullsize, and look in the dark regions. You can see some vertical bands. While the dvd is being played back they move around and it is pretty apparent. I tried both WMP and PowerDVD10, same result in both. Also happens in dark movie files that I have downloaded. Dark still images on screen do not appear to be affected, only movies.

Any ideas? I am stumped. Currently running windows7 with an ati 4850 and a core2duo with latest drivers. I tried dvd playback in linux but the result is a completely garbled image, i think that is a seperate issue though.

Thanks for any ideas!

 

[ViRGE]

WMP and PowerDVD both use DXVA by default, so it's actually your card doing the decoding. I'd start by using a software decoder, either by disabling DXVA on PowerDVD or using something like VLC.

My assumption is that the banding is a product of the video card, so this would confirm that theory if the banding goes away.

 

[TekViper]

You were right! I tried VLC and the banding is not present. I also disabled hardware acceleration in PowerDVD10 (they call it ATI Avivo) and the banding isn't present. Any ideas why this is happening? I updated to the latest video drivers and its still there. Could the card be faulty or is this something to do with settings?

 

[ViRGE]

It probably has something to do with your settings. Go through AMD's control panel and disable things like dynamic contrast and see if that improves the situation for you.

 

[TekViper]

Dude you are two for two. I disabled Dynamic Contrast and its exactly what is causing the problem. Did a quick google search for ati dynamic contrast and it appears to be a common issue, heres one link i found; http://forum.doom9.org/archive/index.php/t-153394.html

Glad its gone though (for now) and I hope ATI fixes that in the next driver release.

Thanks ViRGE