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Maximum number of output nodes RRS feed

  • Question

  • Is there an undocumented maximum number of output nodes supported in Vista because I am having issues using more than 8 devices.

    I have developed an application using a tee node where I am creating a topology that contain sseveral output nodes. I have a total of 16 usb audio devices (Turtle Beach) using the standard usbaudio driver that I am testing with.

    Now, with up to 8 output nodes, everything works fine but as soon as I want to use a 9th device as output node, the application crashes.

    What is even more weird is that I can reuse the same first 8 devices as output node in other streams. But if I add a stream with a 9th device as output node and or create a new stream with the 9th device as the only output node, it crashes.

    The crash happens immediately after the SetTopology.

    Here is what I see in WinDbg:

    (ca0.364): Access violation - code c0000005 (first chance)
    First chance exceptions are reported before any exception handling.
    This exception may be expected and handled.
    eax=00000000 ebx=06959cf8 ecx=06959cf8 edx=00000364 esi=6a9dd078 edi=6ac500c8
    eip=6aac6da8 esp=05d3f98c ebp=05d3f998 iopl=0         nv up ei pl zr na pe nc
    cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00010246
    MF!CMediaSession::QueueOpCompletionEvent+0x53:
    6aac6da8 ff7008          push    dword ptr [eax+8]    ds:0023:00000008=????????

    I am using Build 5472.

    Thanks,

    Marc
    Friday, August 18, 2006 3:15 PM

Answers

  • After further investigation, I think the error is happening in the Core Audio layer. I found that I could not initialize more than 5 devices per USB hubs. There is also important performance issue when using multiple USB audio devices.

    Here is a link to my post in the Vista Audio-Pro newsgroup:

    http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=649018&SiteID=1


    I hope this is the right place to post it. Please advise if they should be reported on the connect site or somewhere else.

    Friday, August 18, 2006 11:04 PM

All replies

  • After further investigation, I think the error is happening in the Core Audio layer. I found that I could not initialize more than 5 devices per USB hubs. There is also important performance issue when using multiple USB audio devices.

    Here is a link to my post in the Vista Audio-Pro newsgroup:

    http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=649018&SiteID=1


    I hope this is the right place to post it. Please advise if they should be reported on the connect site or somewhere else.

    Friday, August 18, 2006 11:04 PM
  • Hi Marc,

    The crash you're hitting usually indicates some error in resolving the topology. 

    Offhand, I'm not aware of anything that places any limits on how many outputs you can have in a topology (besides the obvious performance issues you'll encouter if you have too much stuff going on).  So here are the steps I would try to narrow down the problem:

    • First off, make sure that your output nodes are all referencing different objects.  You could definitely run into trouble if two output nodes point to the same Stream Sink or something like that.
    • Do your output nodes use different sinks or different media types?  Because if SetTopology works when your topology has {output1, output2, ... , output8}, but not when it has {output1, output2, ..., output9}, I might suggest trying a topology like {output1, output2, ... output7, output9}, i.e. one that has only eight outputs but includes the final one.  It's possible that something about output9 is failing resolution.  Or just try a topology with output9 as its only output.
    • If you find that output9 is the culprit, then take a closer look at it (mediatypes, etc).  If you were so motivated, you might even want to try doing the topology resolution in your own code; at the very least, this might help you see where the trouble happens.

    By the way, we've fixed the fact that some topology errors cause a crash, and you should see the fix in future release versions.

    Monday, August 21, 2006 3:04 PM
  • Ah... race condition :-)

    Seems you found your problem (good job), and I'd say that you posted your question to the right forum.

    Monday, August 21, 2006 3:08 PM