Hello all,
(windows xp)
I have had some difficulties with video in Cubase 6 with my ati hd5770 videocard. With a previous Ati Hd5450 card i had the same problem.
I got an error when opening my videoproject that had worked fine with the older drivers. (8.710 and before)
Once i got the latest catalyst control centre installed i couldnt open my Cubase 6 video project. It didnt open the video screen, and on top of that i got the error message to dicard and save my project. Once i install the proper videodrivers everything works fine right away. (same project)
I work with good quality H264 files. So at first i thought to downsize these files to a lower resolution. But that didnt help.
After some reinstalling and finding the right drivers to work with my video in Cubase 6 it is fixed now. But i find it rather strange. Is it Ati or is it steinberg. The latest drivers work fine everywhere.
So here`s my tip to anyone who might encounter the same problem:
Use Ati driver 8.710 and everything will work just fine.
Dont install latest drivers. i.e. 8.861
Dont know what it is, but ill post some more info when i know the core problem.
I hope i can save you some research and time.
Btw in windows 7 , 64 bit everything works fine with latest drivers!
Cheers Stanley
Could this be related to my problem (Virus Ti desktop issues at high sample rate...! - Cubase - Steinberg Forums) ? maybe there is a bug in recent ATI drivers. I have the 8.753 driver version and I admit that I never used the video features in Cubase. Will check to see if the 8.710 is still available somewhere.
Thanks to keep us informed. 
I have an ATI Radeon 5770 and updated the drivers today. Immediately, my Mixer windows (as well as Explorer) shrunk and I started getting crashes on exit - the Windows dialog that offers to look for a solution, not a BSOD or hang. It also switched Steinberg Audio Power off. Edit: I think the resizing and SAP issue are because the Prefs were not fully rewritten before the crash, as I have also lost my Recent Projects.
I seem to have resolved it by rolling back the Radeon drivers (via Device Manager), although it took a reboot or two to get the system fully happy.
Current driver version: 8.850.0.0.0 (dated 2011-04-19) - sorry 
forgot to note down the troublesome driver version…
Cubase 6.0.2 on Win7 HP, both 64-bit.
Hi Again,
Just installed latest Cubase 6.03 update. Improved videosettings! And i suppose video driver fixes.
After that i tried installing latest ati xp32 drivers ati 8.872.0 after previous drivers 8.710. The videodriver issue is now not persisting any longer!
Happy to be able to keep my system updated for latest Ati drivers together with Cubase 6.
Let me know if some new problems arise!
Cheers
Stanley