Why does graphedt hang when I stop a graph using "Generate Still Video"?

Question

I have created this graph in graphedt:

If I start it, then stop it a few seconds later, it often (about half the time) gives me this:

I am running 64-bit Windows 7. Graphedt does not hang if I use a different camera, nor does it hang if I use something other than the "Generate Still Video" filter to feed Input 0 on the VMR9.

I would be very grateful if anyone would tell me if they can repeat this behavior. (Also, if anyone knows what "Hang Signature: 9bc9" means, please pass that along; can't find any reference to it online.)

UPDATE: Turns out that I can get this behavior with a Microsoft camera (a LifeCam HD-5001) and a Chicony camera, and I can get it on 32-bit Windows 7 as well as 64-bit. The key is to stop the graph with the red "stop" button. If I just close the display window (with the "X" button), the graph stops without error and can be restarted. But if I stop it with the stop button, it almost always causes graphedt to hang. Is this just some inherent flaw in the "Generate Still Video" code? I've read a lot about it online, but much of what I've read can't be verified (that it departs from COM standards, isn't really implemented as a filter, and so on).

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Stevens Miller

Answer 1

When/if it freezes, you can take a snapshot with debugger and check threads to see what exactly is locked. The same applies to access violation (crashes) - you can set debugger to break on exception and call stack will give you an idea about faulty module.

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http://alax.info/blog/tag/directshow

Answer 2

Great idea! Thanks. If I can make it work, I'll post here.

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Stevens Miller

Answer 3

Roman, I think I am not following your advice correctly. I started graphedt, then used "Debug/Attach to Process" in VS2010-Express. I checked all exceptions under "Debug/Exceptions" and then ran my graph, which hung graphedt as usual. There is a long list of modules shown under "Debug/Windows/Modules," but nothing in the Breakpoints or Call Stack. The Output window shows this:

'graphedt.exe': Loaded 'C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\graphedt.exe', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ntdll.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\kernel32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\KernelBase.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\advapi32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\msvcrt.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\sechost.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\rpcrt4.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\sspicli.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\cryptbase.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\gdi32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\user32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\lpk.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\usp10.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\mfc42.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ole32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\oleaut32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\odbc32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\comdlg32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\shlwapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\winsxs\x86_microsoft.windows.common-controls_6595b64144ccf1df_5.82.7601.17514_none_ec83dffa859149af\comctl32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\shell32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\version.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\quartz.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\winmm.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\imm32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\msctf.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\odbcint.dll', Binary was not built with debug information.

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\uxtheme.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Program Files (x86)\McAfee\SiteAdvisor\sahook.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\dwmapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\cryptsp.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\rsaenh.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\RpcRtRemote.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\clbcatq.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\winsxs\x86_microsoft.windows.common-controls_6595b64144ccf1df_6.0.7601.17514_none_41e6975e2bd6f2b2\comctl32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Program Files (x86)\Common Files\microsoft shared\ink\tiptsf.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\WindowsCodecs.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\apphelp.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\EhStorShell.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\setupapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\cfgmgr32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\devobj.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\propsys.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ntshrui.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\srvcli.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\cscapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\slc.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ntmarta.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\Wldap32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\SearchFolder.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\xmllite.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\linkinfo.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\profapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\StructuredQuery.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\secur32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\mssprxy.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\thumbcache.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\psapi.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\shdocvw.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ieframe.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\oleacc.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\iertutil.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ksproxy.ax', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\ksuser.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\d3d9.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\d3d8thk.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\wintrust.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\crypt32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\msasn1.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\devenum.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\vidcap.ax', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\Kswdmcap.ax', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\qedit.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\msvfw32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\winsxs\x86_microsoft.windows.gdiplus_6595b64144ccf1df_1.1.7601.17514_none_72d18a4386696c80\GdiPlus.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\lvcodec2.dll', Binary was not built with debug information.

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\igdumd32.dll', Cannot find or open the PDB file

'graphedt.exe': Loaded 'C:\Windows\SysWOW64\dxva2.dll', Cannot find or open the PDB file

The thread 'Win32 Thread' (0x2728) has exited with code 0 (0x0).

'graphedt.exe': Unloaded 'C:\Program Files (x86)\Common Files\microsoft shared\ink\tiptsf.dll'

The thread 'Win32 Thread' (0x2038) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x26ac) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x1368) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x2d48) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x2aa4) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x680) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x2b54) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x1c60) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x1a20) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x214c) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x163c) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x8e0) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x22dc) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x1d28) has exited with code 0 (0x0).

The thread 'Win32 Thread' (0x2270) has exited with code 0 (0x0)

I suspect I am doing this wrong. Can you see where?

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Stevens Miller

Answer 4

Having done this, the application should be still running. Now it is time to runs and stop the graph to eventually make it unresponsive. The application will either throw an exception and the debugger will break on it, or it will freeze and then it's your turn to pause it in debugger and check the state.

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http://alax.info/blog/tag/directshow

Answer 5

It behaves exactly as you described. I run the graph, stop the graph, and graphedt becomes unresponsive. Nothing happens after that. Can you please tell me how to pause it in the debugger? That's a new operation for me.

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Stevens Miller http://www.withoutsupervision.com

Answer 6

Ah! "Debug/Break All" seems to pause it. Here's what I get in the Call Stack:

> user32.dll!772278d7()  
  [Frames below may be incorrect and/or missing, no symbols loaded for user32.dll] 
  user32.dll!772278d7()  
  user32.dll!7722790d()  
  shell32.dll!75709acf()  
  shlwapi.dll!766643c0()  
  kernel32.dll!7732339a()  
  ntdll.dll!77d89ef2()  
  ntdll.dll!77d89ec5()  

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Stevens Miller http://www.withoutsupervision.com

Answer 7

With exception debugger brings you exactly to the point of interest. However when you pause the process manually, it is different: it pops you up a random thread, such as with most recent activity (which might be a system background thread whatsoever). So you need to look around and check other threads too, which have possibly items on stack that indicate the freeze condition.

Keep in mind you can set debugger to download symbol information for Microsoft DLLs and have symbols on call stack, not just addresses.

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http://alax.info/blog/tag/directshow

Answer 8

Right again! I see one main thread and 17 worker threads. Nothing seems to stand out. The call stacks for all but two of those threads end in ntdll.dll. The other two end in user32.dll.

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Stevens Miller http://www.withoutsupervision.com

Answer 9

I downloaded the symbols. Here's the list of threads and where each one is after graphedt hangs and I pause the process:

Unflagged  10960 0 Main Thread Main Thread _NtWaitForSingleObject@12 Normal
Unflagged  848 0 Worker Thread _TppWaiterpThread@4 _ZwWaitForMultipleObjects@20 Normal
Unflagged  10464 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  9172 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  7928 0 RPC Thread RPC Callback Thread CROIDTable::WorkerThreadLoop Normal
Unflagged  12156 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  1520 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  7304 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  9292 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged > 5464 0 Worker Thread WrapperThreadProc _NtUserGetMessage@16 Normal
Unflagged  6872 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  2728 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  11076 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  11200 0 Worker Thread ObjectThread _NtUserGetMessage@16 Normal
Unflagged  6084 0 Worker Thread CBoxNetDoc::NotificationThread _ZwWaitForMultipleObjects@20 Normal
Unflagged  5240 0 Worker Thread DllRefCountSafeThreadThunk _ZwWaitForMultipleObjects@20 Normal
Unflagged  9200 0 Worker Thread VMR9::CVideoMixer::MixerThreadProc _ZwWaitForMultipleObjects@20 Normal
Unflagged  9796 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  11392 0 Worker Thread _TppWorkerThread@4 _NtWaitForWorkViaWorkerFactory@8 Normal
Unflagged  5964 0 Worker Thread CBatchFilterI::LHBatchWorkerThread _NtWaitForSingleObject@12 Normal
Unflagged  4944 0 Worker Thread wmt_CSSEShaderCode::ProcessPositionAndColors _NtWaitForSingleObject@12 Normal
Unflagged  9228 0 Worker Thread wmt_CSSEShaderCode::ProcessPositionAndColors _NtWaitForSingleObject@12 Normal
Unflagged  4412 0 Worker Thread wmt_CSSEShaderCode::ProcessPositionAndColors _NtWaitForSingleObject@12 Normal
Unflagged  2272 0 Worker Thread CBaseReferenceClock::AdviseThreadFunction _NtWaitForSingleObject@12 Time Critical
Unflagged  440 0 Worker Thread CKsClockF::ClockThread _NtWaitForSingleObject@12 Highest
Unflagged  11428 0 Worker Thread CAMThread::InitialThreadProc _NtWaitForSingleObject@12 Normal
Unflagged  4812 0 Worker Thread CAsyncItemHandler::AsyncItemProc _ZwWaitForMultipleObjects@20 Normal

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Stevens Miller http://www.withoutsupervision.com