[vlc-devel] commit: FIX: DSHOW "none" device open (#2201). Some cleaning (basos g )

xxcv xxcv07 at gmail.com
Wed Mar 18 10:32:20 CET 2009

xxcv wrote:
> Hello,
> I just noticed there's something wrong with my build currently,
> when I test the NB today from buildbot it doesn't crash.
> This issue might be caused by qt 4.5.0 which I'm experimenting
> with vlc-1.0.0-git.
> [0xc4c3384] dshow demux error: no video capture device was detected
> [0xc4c3384] dshow demux error: can't open video device
> ---
> Crashed here...
> ---
> QObject::killTimers: timers cannot be stopped from another thread
> ^^^ noticed this
> So, I'm in the process of switching back to qt 4.4.3 and retest.
> Regards.
>> basos g wrote:
>>> Sorry, you are not helping me. I would like to understand the state of
>>> dshow plugin. For example is an audio device opened ? If not then
>>> Common Close will be called else it will print just an error for video
>>> and start capturing audio. And this might lead to clues about what is
>>> deallocated ..
>>> Anyway i might found something about the destruction order (i don't
>>> think there is race condition. CoInitialize is an atomic operation).
>>>  Could you please try with the attached patch ?
Once again my retests concludes my vlc-dshow issue isn't related to
updating to Qt4.5.0.

Anyways, FYI, I'm using gcc-3 to build vlc.
However the race condition, heap free bug is still in the dshow.cpp code.
(Introduced in the commit by your patch 

I recommend someone to look at the code, and fix up some
ancient mistakes, like missing parameter for an interaction
function, which lived through the dark ages of invisibility been
pass through developer's very eyes six times..., while been through some
very useless commits like removing trailing spaces and tabs.

One way to find it is, to use a Windows XP machine with VIVO and
put vlc to run inside GDB and under qt4, Open Capture dialog, might
trigger this bug.

Below is attached debugging log file and result is from running
NB buildbot's binary, on a Windows XP machine with VIVO.

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