This issue has now been fixed by a driver update from ati. For more info see the latest article on the issue
There appears to be an incompatibility between the Microsoft codecs in Windows 7 and BBC-HD (and other broadcasters too I understand). This causes some image corruption on all platforms I have tested, but on ATI hardware it results in continuous corruption which renders BBC-HD unwatchable. For anyone looking for a solution to this problem keep an eye on the Microsoft knowledgebase article KB2008334. In the meantime, there is a work-around, as long as you have a sufficiently powerful CPU – disabling GPU accelerated H.264 decoding. To do this requires a registry edit…
- Run regedit
- Browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video
- In video there will be several subkeys. One of these is for your graphics card. To locate it you will have to look through each in turn – each will have a video folder inside it. The “service” value inside the video key is the clue you need – I have several that start RDP which is presumably related to remote desktop so they’re not right. I also have one which is called atikmdag. This is the one!
- When you’ve found the correct subkey of video expand the key 0000 (if you’ve got the wrong one you probably wont be able to expand 0000)
- Expand “UMD” and then “DXVA”
- Create a new string value called VForceUVDH264
- set the value to 0
- Reboot. Test BBC-HD. You will get 5-10 seconds of initial corruption but playback should then become normal and should remain that way thereafter
This tweak will disable gpu acceleration of playback of all H.264 files – so if you have a blu-ray collection you’re going to be decoding with the CPU – expect much higher CPU usage. Any modern dual-core CPU should be plenty capable however.
Once Microsoft issue a fix for this problem simply go back into regedit and delete the key to restore normal functioning.
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