Unable to execute the player example after a fresh install

Grynium

Dear all,
I've created a virtual machine with a fresh install of Ubuntu 14.04.5 LTS (Trusty Tahr), then I've installed Qt 5.8. My arch is x64.

When I try to execute the /home/user/Qt/Examples/Qt-5.8/multimediawidgets/player example (simple audio/video player) I've got the following error:

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

I've launched the application with the variable QT_DEBUG_PLUGINS=1 and seen that:

Got keys from plugin meta data ("gstreamermediaplayer")
QFactoryLoader::QFactoryLoader() checking directory path "/home/user/QtWorkspace/bin/mediaservice" ...
Cannot load library /home/user/Qt/5.8/gcc_64/plugins/mediaservice/libgstmediaplayer.so: (/home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libqgsttools_p.so.1: undefined symbol: _gst_value_list_type)
QLibraryPrivate::loadPlugin failed on "/home/user/Qt/5.8/gcc_64/plugins/mediaservice/libgstmediaplayer.so" : "Cannot load library /home/user/Qt/5.8/gcc_64/plugins/mediaservice/libgstmediaplayer.so: (/home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libqgsttools_p.so.1: undefined symbol: _gst_value_list_type)"
defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer"

What is the cause of the "libqgsttools_p.so.1: undefined symbol: _gst_value_list_type" error? Why this mismatch?

Is it possible that am I missing some GStreamer libraries?

Ubuntu 14.04.5 LTS (Trusty Tahr) comes with GStreamer 1.0 installed (1.2.4). Is it possible that QtMultimedia does not support it?

Do I need to install GStreamer 0.1?

How can I fix this problem and run the player example?

Thanks in advance for your time

Best regards,
Fabio

jsulm

@Grynium Yes, you're most probably missing GStreamer libraries.
You can execute

ldd libgstmediaplayer.so

to find out what is missing.

Grynium

It seems that all dependencies are satisfied:

user@user-VirtualBox:~/Qt/5.8/gcc_64/lib$ ldd /home/user/Qt/5.8/gcc_64/plugins/mediaservice/libgstmediaplayer.so
	linux-vdso.so.1 =>  (0x00007fffe09d1000)
	libqgsttools_p.so.1 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libqgsttools_p.so.1 (0x00007f49fb0fd000)
	libQt5MultimediaWidgets.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5MultimediaWidgets.so.5 (0x00007f49faede000)
	libQt5Multimedia.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5Multimedia.so.5 (0x00007f49fabd4000)
	libQt5Widgets.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5Widgets.so.5 (0x00007f49fa3a3000)
	libQt5Gui.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5Gui.so.5 (0x00007f49f9c07000)
	libQt5Network.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5Network.so.5 (0x00007f49f9881000)
	libQt5Core.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5Core.so.5 (0x00007f49f9161000)
	libGL.so.1 => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 (0x00007f49f8ee0000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f49f8cc1000)
	libgstaudio-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstaudio-1.0.so.0 (0x00007f49f8a77000)
	libgstvideo-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstvideo-1.0.so.0 (0x00007f49f8831000)
	libgstpbutils-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstpbutils-1.0.so.0 (0x00007f49f860a000)
	libgstapp-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstapp-1.0.so.0 (0x00007f49f83fd000)
	libgstbase-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstbase-1.0.so.0 (0x00007f49f81a5000)
	libgstreamer-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgstreamer-1.0.so.0 (0x00007f49f7ea0000)
	libgobject-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0 (0x00007f49f7c4f000)
	libpulse-mainloop-glib.so.0 => /usr/lib/x86_64-linux-gnu/libpulse-mainloop-glib.so.0 (0x00007f49f7a4a000)
	libpulse.so.0 => /usr/lib/x86_64-linux-gnu/libpulse.so.0 (0x00007f49f7800000)
	libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f49f74f8000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f49f71f4000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f49f6eed000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f49f6cd7000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f49f6912000)
	libasound.so.2 => /usr/lib/x86_64-linux-gnu/libasound.so.2 (0x00007f49f6621000)
	libQt5OpenGL.so.5 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libQt5OpenGL.so.5 (0x00007f49f63ca000)
	libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f49f61b0000)
	libicui18n.so.56 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libicui18n.so.56 (0x00007f49f5d17000)
	libicuuc.so.56 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libicuuc.so.56 (0x00007f49f595e000)
	libicudata.so.56 => /home/user/Qt/5.8/gcc_64/plugins/mediaservice/../../lib/libicudata.so.56 (0x00007f49f3f7b000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f49f3d77000)
	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f49f3b6e000)
	libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f49f396c000)
	/lib64/ld-linux-x86-64.so.2 (0x000055daf79ac000)
	libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f49f3742000)
	libxcb-dri3.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri3.so.0 (0x00007f49f353e000)
	libxcb-present.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-present.so.0 (0x00007f49f333b000)
	libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007f49f3135000)
	libxshmfence.so.1 => /usr/lib/x86_64-linux-gnu/libxshmfence.so.1 (0x00007f49f2f32000)
	libglapi.so.0 => /usr/lib/x86_64-linux-gnu/libglapi.so.0 (0x00007f49f2d04000)
	libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007f49f2af2000)
	libXdamage.so.1 => /usr/lib/x86_64-linux-gnu/libXdamage.so.1 (0x00007f49f28ee000)
	libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007f49f26e8000)
	libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f49f24e6000)
	libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f49f21b0000)
	libxcb-glx.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-glx.so.0 (0x00007f49f1f99000)
	libxcb-dri2.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri2.so.0 (0x00007f49f1d94000)
	libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f49f1b74000)
	libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007f49f196e000)
	libdrm.so.2 => /usr/lib/x86_64-linux-gnu/libdrm.so.2 (0x00007f49f1760000)
	libgsttag-1.0.so.0 => /usr/lib/x86_64-linux-gnu/libgsttag-1.0.so.0 (0x00007f49f1527000)
	liborc-0.4.so.0 => /usr/lib/x86_64-linux-gnu/liborc-0.4.so.0 (0x00007f49f12a5000)
	libgmodule-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgmodule-2.0.so.0 (0x00007f49f10a0000)
	libffi.so.6 => /usr/lib/x86_64-linux-gnu/libffi.so.6 (0x00007f49f0e98000)
	libpulsecommon-4.0.so => /usr/lib/x86_64-linux-gnu/pulseaudio/libpulsecommon-4.0.so (0x00007f49f0c30000)
	libjson-c.so.2 => /lib/x86_64-linux-gnu/libjson-c.so.2 (0x00007f49f0a25000)
	libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f49f07e0000)
	libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f49f05a1000)
	libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f49f039c000)
	libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f49f0196000)
	libwrap.so.0 => /lib/x86_64-linux-gnu/libwrap.so.0 (0x00007f49eff8b000)
	libsndfile.so.1 => /usr/lib/x86_64-linux-gnu/libsndfile.so.1 (0x00007f49efd23000)
	libasyncns.so.0 => /usr/lib/x86_64-linux-gnu/libasyncns.so.0 (0x00007f49efb1d000)
	libnsl.so.1 => /lib/x86_64-linux-gnu/libnsl.so.1 (0x00007f49ef902000)
	libFLAC.so.8 => /usr/lib/x86_64-linux-gnu/libFLAC.so.8 (0x00007f49ef6d1000)
	libvorbisenc.so.2 => /usr/lib/x86_64-linux-gnu/libvorbisenc.so.2 (0x00007f49ef202000)
	libvorbis.so.0 => /usr/lib/x86_64-linux-gnu/libvorbis.so.0 (0x00007f49eefd4000)
	libogg.so.0 => /usr/lib/x86_64-linux-gnu/libogg.so.0 (0x00007f49eedcb000)
	libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007f49eebb0000)

SGaist

Hi,

I wonder if you are hitting that bug.

rickywong2017

Exactly the same problem!
same os, same qt version, and the same error !

rickywong2017

@Grynium did u solve the problem?

ed_u

@rickywong2017 the same to me ,did u solve this problem?

rickywong2017

@ed_u the sad thing is not, i've changed the qt version to Qt5.6.2 and this error simply just dont happen.

mcallegari79

Solution for Qt 5.8.0 on Ubuntu 14.04

This is basically the error:

Cannot load library /home/massimo/projects/Qt5.8.0/5.8/gcc_64/plugins/mediaservice/libgstmediaplayer.so: (/home/massimo/projects/Qt5.8.0/5.8/gcc_64/plugins/mediaservice/../../lib/libqgsttools_p.so.1: undefined symbol: _gst_value_list_type)

Which means the Qt Multimedia team didn't consider the gstreamer version shipping on Ubuntu 14.04 which is 1.2.3.
To solve you need to update GST with a PPA. Seems 1.6.x is enough to make Qt happy.

sudo add-apt-repository ppa:dan-witt/gstreamer
sudo apt-get update
sudo apt-get upgrade

Footnote: 14.04 is a LTS version and Qt didn't care. This is horrible and bad decision making IMHO.

SGaist

@mcallegari79 If you want LTS everywhere then Qt 5.6 is the current LTS not 5.8.

tamolo

@rickywong2017 Why i still got that error when running the example on 5.6.2 :((
I am newbie. Sorry if my question is noob.
Can anyone tell me how to launched the application with the variable QT_DEBUG_PLUGINS=1

jsulm

@tamolo In the command line:

$ QT_DEBUG_PLUGINS=1
$ ./my_app

Or in QtCreator set this variable in "Projects/Run/Run Environment/Add".

tamolo

thank you so much

tamolo

@Grynium @rickywong2017
This is the way i fixed it.
Step 1: use 'apt-cache search -n gstreamer' to get the list all of the gstreamer and libgstream lib
Step 2: for each of lib in the list. Use 'apt-get install name-of-the-gstreamer-lib' to install it. After install almost the lib in the list my example run. ( i don't know which is the exactly lib i need to install. I just install all of them until my example run)
Step 3: rebuild your example and run.

I hope this help.