问题
I'm using the official Qt 5.6 SDK on Ubuntu 16.04 and when I try to play an mp3 file I just get:
defaultServiceProvider::requestService(): no service found for - "org.qt-project.qt.mediaplayer"
The code is as simple as it gets:
mMediaPlayer->setMedia(QUrl::fromLocalFile(myMp3File));
mMediaPlayer->play();
This works on Android and it worked on my Ubuntu 14.04 machine before. What am I missing? All the required gstreamer (by documentation) stuff seems to be installed already by default, but it still doesn't work:
$ dpkg -l | grep gstream
ii gir1.2-gstreamer-1.0 1.8.2-1~ubuntu1 amd64 GObject introspection data for the GStreamer library
ii gstreamer1.0-alsa:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugin for ALSA
ii gstreamer1.0-clutter-3.0 3.0.18-1 amd64 Clutter PLugin for GStreamer 1.0
ii gstreamer1.0-fluendo-mp3:amd64 0.10.32.debian-1 amd64 Fluendo mp3 decoder GStreamer 1.0 plugin
ii gstreamer1.0-libav:amd64 1.8.2-1~ubuntu1 amd64 libav plugin for GStreamer
ii gstreamer1.0-plugins-bad:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins from the "bad" set
ii gstreamer1.0-plugins-bad-faad:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer faad plugin from the "bad" set
ii gstreamer1.0-plugins-bad-videoparsers:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer videoparsers plugin from the "bad" set
ii gstreamer1.0-plugins-base:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins from the "base" set
ii gstreamer1.0-plugins-base-apps 1.8.2-1ubuntu0.1 amd64 GStreamer helper programs from the "base" set
ii gstreamer1.0-plugins-good:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins from the "good" set
ii gstreamer1.0-plugins-ugly:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins from the "ugly" set
ii gstreamer1.0-plugins-ugly-amr:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins from the "ugly" set
ii gstreamer1.0-pulseaudio:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugin for PulseAudio
ii gstreamer1.0-tools 1.8.2-1~ubuntu1 amd64 Tools for use with GStreamer
ii gstreamer1.0-x:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer plugins for X11 and Pango
ii libgstreamer-plugins-bad1.0-0:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer development files for libraries from the "bad" set
ii libgstreamer-plugins-base1.0-0:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer libraries from the "base" set
ii libgstreamer-plugins-good1.0-0:amd64 1.8.2-1ubuntu0.1 amd64 GStreamer development files for libraries from the "good" set
ii libgstreamer1.0-0:amd64 1.8.2-1~ubuntu1 amd64 Core GStreamer libraries and elements
ii libreoffice-avmedia-backend-gstreamer 1:5.1.4-0ubuntu1 amd64 GStreamer backend for LibreOffice
...and of course my sounds work otherwise perfectly.
回答1:
First, run your application with QT_DEBUG_PLUGINS=1 to see plugin errors.
If you see errors about "libgstaudio-0.10.so.0", it's a GStreamer version problem. The official Qt binaries seems to need GStreamer 0.10.
Solutions I found :
- Use the libqt shipped with your distribution, using your package manager : It's the best solution I found, since it's built with the right GStreamer version. I use different chroot to make packages for distributions that embed different GStreamer versions.
- Compile Qt from source to enable Gstreamer 1.0 : Not tested
- Install Gstreamer 0.10 : I don't recommend this option, or use a chroot with an older distribution if you need it.
来源：https://stackoverflow.com/questions/39563308/qmediaplayer-doesnt-play-anything-on-ubuntu-16-04-qt-5-6