Screen capture, Aero Glass and dwm.exe


  • We are writing a screen-capture applications (~VNC...) that captures the desktop about 20 times per second. This works fine when Aero Glass is turned off. However when Aero Glass is turned on, the memory used by the Windows process dwm.exe starts rising very fast until it reaches 1.5GB and stops. Windows then gives a message about 'You're computer's performance is slow' and restarts the process dwm.exe. It does this a few times and then switches off Aero Glass alltogether.

    I use the classic method of BitBlt from the 'DISPLAY' DC. I'm pretty sure I don't have any memory leaks in my code. It seems as though dwm.exe allocates memory each time BitBlt is called and doesn't free it until much later. When I stop capturing, the memory goes down in a matter of seconds.

    I saw on the Net that other screencapture tools (VNC, SplashTop...) experience the same problems. But I haven't seen a solution to this issue anywhere.

    Is there anything I could do to avoid this problem (except to turn off Aero Glass myself when I start capturing)?

    Any hints are welcome!



    Monday, June 11, 2012 6:48 AM

All replies

  • Did you think so it would be related to some version video cards or its drivers? Since I remembered that there's a man's dwm.exe costs too much memory and more than 1g, but the problem just disappear when he replace a different version video card.

    I cannot have any thinking about this issue, this is my only thinking.

    I will try to involve others senior engineer to see if they have any idea and reply to you.

    Best wishes,

    Mike Zhang[MSFT]
    MSDN Community Support | Feedback to us

    Tuesday, June 12, 2012 8:12 AM
  • Thanks for your answer. I did a test with two Dell Precision M6600 laptops, one with an ATI card and one with a NVidia card. Only the one with the ATI card gives the problem. Also the thread on the SplashTop forum seems to indicate that the problem is ATI related.I will try with other laptops as I can find them.

    I would still appreciate it a lot if you could involve that senior engineer as they have more capabilities than me to check this out with ATI. Desktop streaming becomes more and more common, so it would be sad if a large part of the customer base would have to disable Aero Glass for that purpose.

    Best regards,

    Tuesday, June 12, 2012 3:10 PM
  • You're welcome!

    I involved them, they will reply to you once they have any idea for you.

    Best wishes,

    Mike Zhang[MSFT]
    MSDN Community Support | Feedback to us

    Wednesday, June 13, 2012 4:19 AM
  • Based on your test result, this issue is related to ATI card. Suggest you to get contact with ATI support team.

    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

    Jacky Wu
    Microsoft Online Community Support

    Thursday, June 14, 2012 4:03 AM