[Development] QtMultimedia && QML - hard performance regressions on Windows

[Denis Shienkov]

I'm currently have checked it with the Qt 5.5 and have no this 
problem... So, the regression was introduced in Qt 5.6...

So, Qt-developers, do you checks your code of QtMultimedia on 
regressions when you accept a patches, and before releasing? I do not 
understand, how is it possible to introduce this epic regression??? How 
is it possible to work for a salary and to make such bugs (and, please 
do not say that it is open source)?


27.04.2016 16:44, Massimo Callegari via Development пишет:
> ________________________________
> Da: Mitch Curtis <mitch.curtis at qt.io>
> A: Massimo Callegari <massimocallegari at yahoo.it>; "development at qt-project.org" <development at qt-project.org>
> Inviato: Mercoledì 27 Aprile 2016 14:56
> Oggetto: RE: [Development] QtMultimedia && QML - hard performance regressions on    Windows
>
>
>
>> I didn't look at the other bugs, but QTBUG-37004 seems like it would pretty easy to contribute a fix yourself.
> I don't believe it is pretty easy, especially on Linux.
> OSX already returns a user friendly list of devices.
> Windows cuts the devices names to 31 characters, cause it use APIs coming directly from the 90s.
> Linux is the worst case instead, cause every possible ALSA device is returned, so if you have 2 sound cards it will return like 20 devices, most of which don't even work.
> I believe users expect to see a list like what KDE/Gnome expose, so 4-5 devices total.
> Plus I should be looking at the pulseaudio implementation as well, which I know nothing about.
> In any case, it would require an internal change of the logic, most likely breaking backward compatibility, which is not something that I can decide.
>
>> Why waste your time and energy being outraged when you could be fixing it? Seems like a far more effective way of getting things fixed in an open source project.
> Well, I believe reporting an issue is already a contribution to fixing it and while a "pretty easy" issue would take me 1 hour to be fixed, the overall effort to get it approved would be 100 hours. I already went through the process for a QtSerialPort method, and it was a hell of a journey. Especially working with Gerrit. Please excuse my limited GIT knowledge :(
>
>> As said in the bug report, higher priority issues are being worked on.
> Which one ?
> And also...since 1-2 years ? Right...
>
>
> I would rather appreciate much more if the Qt Company could start a sort of "bounty program", where users can place a few bucks for the resolution of specific issues.
> There are more and more examples of this mechanism, like Kickstarter, Bountysource or even Stackoverflow.
> I would be happy to participate to it for the most urgent issues affecting my projects.
> I'm pretty sure there are a lot of open source projects raising donations, and small companies willing to spend some money on issues that are a priority for them.
>
> Instead, it seems to me (and it's purely my mere assumption) that big bucks come from big companies and they have the full attention of the Qt developments.
> Attention that don't go to all the rest of minor developers/projects/companies that are actually the largest user base of the Qt libraries.
> If this is really the truth, it is pretty sad. Again, just my opinion.
>
>> ________________________________
>> Da: Denis Shienkov <denis.shienkov at gmail.com>
>> A: "development at qt-project.org" <development at qt-project.org>
>> Inviato: Mercoledì 27 Aprile 2016 11:37
>> Oggetto: [Development] QtMultimedia && QML - hard performance regressions
>> on    Windows
>>
>>
>>
>> Hi developers.
>>
>> I faced with a big problem with the video playback performance, when I
>> try to open the mp4 video file from any of QML video examples. I have a
>> high CPU loading (~40%) and the video is freezing and jerks. But the C++
>> media player works satisfactory, more or less tolerably (on point 3 from
>> the 1-5 points)...
>>
>> It is impossible to use at all in QML, I face more and more with the
>> surprises of QtMultimedia, and disappointed more and more...
>>
>> WTF ? What sense in QtMultimedia if it does not work as expected?
>>
>> PS: I have created a bug: https://bugreports.qt.io/browse/QTBUG-53019
>>
>> BR,
>> Denis
>>
>>
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