phonon_backend gstreamer could not be loaded

[BestSteve]

Binary package hint: phonon-backend-gstreamer

I use 8.10 development branches.
phonon-backend-gstreamer version is 4:4.2~svn820171+4.1.83-0ubuntu2

When I compiled sources from a example at http://doc.trolltech.com/4.4/phonon-musicplayer.html , It could not play any file.
It says:

$./musicplayer
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded
Phonon::createPath: Cannot connect Phonon::MediaObject(no objectName) to Phonon::AudioOutput(no objectName).
WARNING: bool Phonon::FactoryPrivate::createBackend() phonon backend plugin could not be loaded

but I've installed phonon-backend-gstreamer.

$aptitude search phonon
i libphonon-dev - development files for the Phonon multimedia framework
i A libphonon4 - Phonon multimedia framework for Qt 4
i A phonon - metapackage for Phonon multimedia framework
v phonon-backend -
i A phonon-backend-gstreamer - Phonon GStreamer 0.10.x backend
p phonon-backend-null - Phonon null backend (no real backend)
p phonon-backend-xine - Phonon Xine 1.1.x backend
p phonon-dbg - Phonon debugging symbols

After some tries, I made a workround:

sudo ln -s /usr/lib/kde4/plugins/phonon_backend /usr/lib/qt4/plugins/phonon_backend

And the player will work after that.

$./musicplayer
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)
alsasink2: snd_pcm_open(default)

[Mkeeler (mjkeeler7)]

I have gotten the same warnings along with it not working. This is due to the fact that the devs have added most of the phonon stuff in at the wrong locations.

libphonon-dev should install phonon headers to /usr/include/qt4/phonon
phonon-backend-gstreamer should install the plugin to /usr/lib/qt4/plugins/phonon_backend

Currently phonon is broken in intrepid due to the files being put into the improper locations. They seem to think it doesnt belong with the rest of QT even though it is a standard part of QT4.4.

All phonon related files need to be put into qt4 directories instead of kde or other non-qt4 related directories. Hopefully this will be fixed soon

[Jonathan Thomas (echidnaman)]

Fixed in Karmic. Phonon is installed so that pure-Qt apps can use phonon.

[Ahmad Amr (aamr)]

So? Won't I be able to use this application in Jaunty?? Seems unlogical to me not to be able to run an application on the already-available Jaunty and I have to wait to install Karmic in order to run it?? Why was a version produced for Jaunty from the beginning???

[Eric Seigne (eric-seigne)]

Hello Ahmad,
here is a solution for poor users such me :)

apt-get install phonon-backend-gstreamer
ln -s /usr/lib/kde4/plugins/phonon_backend /usr/bin

really, it works !

Éric

[piXel (pi88el)]

There is no explicit folder there you have to copy/link the backend.
Try to run your app with strace and look for the path, where it try to open the backend. Usually, first it look in the folder there you compiled/installed qt (like: /usr/lib/qt/plugins/phonon_backend) and second in the folder of the application.

Pete