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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