[vlc-devel] [PATCH]: fix a CoInitializeEx() issue on Windows

[erwan.tulou at gmail.com]

Yes, sorry

On 12/07/2019 16:46, Hugo Beauzée-Luyssen wrote:
> I think you're missing the mailing list in CC :)
>
> On Fri, Jul 12, 2019, at 4:42 PM, erwan.tulou at gmail.com wrote:
>> On 12/07/2019 15:34, Hugo Beauzée-Luyssen wrote:
>>>> Anyway it seems correct. The CoInitializeEx() calls in our Qt code uses
>>>> COINIT_APARTMENTTHREADED.
>>>>
>>> AFAIU, a thread doesn't belong to anything (with regard to the COM object concurrency mode) before the first call to CoInitializeEx. After that call, the thread is bound to that mode.
>>>
>>> If this is to be called from the UI thread, then it needs to match what's done in the UI, or the UI changed the other way around, but I think Qt mandates APARTMENTTHREADED (which would match this remark from MSDN: «The multi-threaded apartment is intended for use by non-GUI threads. Threads in multi-threaded apartments should not perform UI actions.»)
>>>
>>> However it seems CommonChangeThumbnailClip might still be called from the vout thread, and I fear that changing the object concurrency mode for the vout thread won't play well with SAPI, which is using MTA. I didn't find any requirement for SAPI to use COINIT_MULTITHREADED, so I suppose SAPI should be changed as well (unless I missed such a requirement, in which case I'm really not sure what to do here)
>> Yes, CommonChangeThumbnailCli() is called twice in a row from two
>> different threads, one with no previous concurrency mode setup and the
>> GUI thread that demands APARTMENTTHREADED. I guess this function is
>> called multiple times because it was placed in CommonPlacePicture()
>> which is a more general multi purpose function, which is a bit
>> unfortunate. How and where the function is called needs to be reworked.
>> The function just needs
>>
>> to know that the video size/position has changed and update the tasklist
>> thumbernail accordingly. This is GUI stuff and therefore the GUI thread
>> doing the job directly via vout_window_ReportResize() seems a good
>> thing. Another thread also doing the job seems a side effect which was
>> not intended and should be regarded as a bug.
>>
>> Rgds
>>
>>
>> ---
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>> https://www.avast.com/antivirus
>>
>>


---
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