Can't play video on windows xp

LinArcX

An interesting thing that i found is that if i use windeployqt to deploy .dlls to build directory and then run the application, i will get this message and video won't show:

defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer" :45.753 INFO WFS_OPEN_COMPLETE

But if i clean the build directory, and compile the project through qt-creator and run it again, video shows!

Seems qt-creator do a magic behind the scene!

Bonnie

What do you have in your mediaservice plugin folder of the deployed directory?

LinArcX

@Bonnie 3 files:

dsengine.dll
qtmedia_audioengine.dll
wmfengine.dll

Also i tried to compile multimedia module as described here:
https://forum.qt.io/topic/28620/solved-qtmultimedia-defaultserviceprovider-requestservice-no-service-found-for-org-qt-project-qt-mediaplayer/10#

And replace this new mediaservice directory with previous one. But nothing changed

Bonnie

@LinArcX
Hey, since you said when you start from qt-creator, it works, so let's first start with the original dlls from the unmodified .pro file.
Have you tried using environment variable QT_DEBUG_PLUGINS=1 to check from the output about these plugins (dsengine.dll and wmfengine.dll) loaded or not?
Another thing that confuses me, when you start it from qt-creator, is that also on xp? (I remember that xp cannot install msvc2013)
Usually qt-creator's magic is just finding the installed Qt path and using the plugins there.

LinArcX

@Bonnie

This is the log of application when running through qt-creator with QT_DEBUG_PLUGINS=1

when you start it from qt-creator, is that also on xp?

No, i installed qt-creator, msvc2013 on windows7. On XP just installed Visual C++ 2013 Redistributable, since it's a runtime dependency of my app.

Bonnie

@LinArcX
Running through qt-creator works, didn't you say that?
So we don't need the output for that, we need the output when mediaplayer cannot work, that means running the application from your deployed directory .
But there're two different situations:

Running the application without qt-creator on the same machine you have your qt-creator. Does that work?. Even not, I'm sure this will eventually work, as long as it can loaded the right plugins just as running from qt-creator.
Running the application on your xp machine. This would be different with running on windows 7 since the default mediaplayer plugin of msvc builds on vista+ is WMF, but WMF may be not available on xp. So it would also be helpful to see what plugins does it load.

LinArcX

@Bonnie

So we don't need the output for that, we need the output when mediaplayer cannot work...

My mistake. sorry.

Running the application without qt-creator on the same machine you have your qt-creator. Does that work?

Surprisingly yes, I didn't know why this time it worked!

(Also i'v noticed that setting QT_DEBUG_PLUGINS=1 and then run my .exe file doesn't show any debug output info. i don't know why)

Running the application on your xp machine...

I opened cmd.exe in deployed directory and:

SET PATH=QT_DEBUG_PLUGINS=1;%PATH%

And run my application:

MyQtWidgetsTest.exe > output.txt 2>&1

But it didn't generate output.txt file.

Bonnie

@LinArcX
It uses OutputDebugString on windows instead of stdout/stderr, so the output can't be redirected.
One solution is to use DebugView.
(BTW, your above command to set environment variable is not right.)
Open DebugView, then in cmd.exe:

SET QT_DEBUG_PLUGINS=1
MyQtWidgetsTest.exe

The output will be shown in DebugView.

LinArcX

@Bonnie
Here you are:
https://gist.github.com/LinArcX/f124ffb178d4c1d84c84e7e39f37f3a3

Bonnie

@LinArcX
I think the key point is

QLibraryPrivate::loadPlugin failed on "Z:/workspace/c++/qt/build-AtmQtWidgetsTest-Desktop_Qt_5_6_3_MSVC2013_32_bit-Release/release/mediaservice/dsengine.dll" : "Cannot load library Z:\\workspace\\c++\\qt\\build-AtmQtWidgetsTest-Desktop_Qt_5_6_3_MSVC2013_32_bit-Release\\release\\mediaservice\\dsengine.dll: The specified module could not be found.

That usually means there're some dependency dlls missing so the plugin dll cannot be loaded.
Try using DependencyWalker to open dsengine.dll to check the dependencies.
Maybe xp needs to install directx? I'm not sure...

LinArcX

@Bonnie

Hmmm.. Interesing. This is the output of dependency walker on dsengine.dll:

c:\windows\system32\GDI32.DLL
c:\windows\system32\MF.DLL
c:\windows\system32\MFPLAT.DLL
c:\windows\system32\D3D9.DLL
c:\windows\system32\DXVA2.DLL
c:\windows\system32\WINMM.DLL
c:\windows\system32\EVR.DLL
c:\windows\system32\OLE32.DLL
c:\windows\system32\OLEAUT32.DLL
c:\tools\neovim\neovim\bin\QT5WIDGETS.DLL
c:\tools\neovim\neovim\bin\QT5GUI.DLL
c:\tools\neovim\neovim\bin\QT5CORE.DLL
c:\windows\system32\USER32.DLL
c:\windows\system32\MSVCP120.DLL
c:\windows\system32\MSVCR120.DLL
c:\windows\system32\KERNEL32.DLL

So, yes. Seems it depends on D3D9.dll that is parts of DirectX. But I installed DirectX 9 on windows xp and checked that d3d9.dll exists in c:\windows\system32.

Edit: I've noticed that except mf.dll and mfplat.dll other dlls exists in c:\windows\system32.

Bonnie

@LinArcX
Well, this is not how we usually use dependency walker.
In the middle list area, check the yellow icons for missing dlls and red icons for dlls that missing functions.
Some can be ignored referring to https://www.dependencywalker.com/faq.html

Edit: If it depends on mf.dll and mfplat.dll, that can be the problem. Maybe your compiling links newer DX libs that not supporting xp.
Edit2: I've searched on google and others say that if mf.dll and mfplat.dll are lazy loaded, then that can also be ignored.

LinArcX

@Bonnie
Lazy loaded? What that means?

I download them from the internet and copy in system directory.

But nothing changed.

LinArcX

@Bonnie said in Can't play video on windows xp:

In the middle list area, check the yellow icons for missing dlls and red icons for dlls that missing functions.

Bonnie

@LinArcX
Lazy loaded dlls would have a hourglass mark with the icon, like MPR.DLL / IESHIMS.DLL in your picture.
Your MF.DLL and MFPLAT.DLL seems to be direct linked, also your D3D9.dll is red so it may miss functions.
I would guess it is due to the DX lib when you compile Qt, as I said.
I don't have any 5.6.3 dlls on my machine but I have a deployed application of 5.5.1. Checking by dependency walker, the official prebuilt msvc2013 dsengine.dll of 5.5.1 doesn't depend on mf.dll and mfplat.dll directly.

LinArcX

@Bonnie

Maybe your compiling links newer DX libs that not supporting xp. I would guess it is due to the DX lib when you compile Qt, as I said.

You mean i should install Directx9 on my windows7, remove all other DirectX versions and compile qt5.6.3 again?

Bonnie

@LinArcX
You may be able to compile only the dsengine plugin.
But I don't know how to make sure you link the xp supported DX lib, since I don't target xp for at least 5 years...

LinArcX

@Bonnie
What aboot this:

https://forum.qt.io/topic/59838/building-qt-from-source-on-windows/7

hskoglund

Hi, one other thing I saw in the dependency walker's output, it wants the Qt files from another Qt directory on your XP machine:
c:\tools\neovim\neovim\bin

Make sure that this other version exists and is also Qt 5.6.3 Release for MSVC 2013.

LinArcX

@hskoglund
Hello. I have some questions:

Why application loads these .dlls from that weird directory instead of current directory of my application? (I used windeployqt)
Lets say, i fixed it. Do it fix main issue?(Showing video)