[Interest] QMultimedia crashes or doesn't work on recent linux releases

[Thiago Macieira]

Em segunda-feira, 14 de novembro de 2016, às 07:08:41 PST, maitai escreveu:
> Since Ubuntu 16.04, my qt (qt5.7 official release/QWidget-based)
> application cannot play a sound (no crash, but no sound). The very same
> app works fine with Ubuntu 14.04. I get that kind of messages in the
> console when trying to play a sound (.mp3 file) with QMultimedia:
> 
> Warning: "No decoder available for type 'audio/mpeg, mpegversion=(int)1,
> mpegaudioversion=(int)1, layer=(int)3, rate=(int)44100, channels=(int)2,
> parsed=(boolean)true'."
> 
> or (depending on the machine)
> 
> defaultServiceProvider::requestService(): no service found for -
> "org.qt-project.qt.mediaplayer"

This sounds like a mismatch between the compiled GStreamer plugin version and 
the library you have installed. Since it worked on an older version, you 
probably have a plugin for GStreamer 0.10 and your newer distro has GStreamer 
1.0.

>   symbol lookup error: (...)/mediaservice/libgstmediaplayer.so: undefined
> symbol: gst_video_connector_get_type

This is in the #else path for GST_CHECK_VERSION(1,0,0), so it really indicates 
your plugin is linked against GStreamer 0.10 instead of the newer version.

The call to gst_video_connector_get_type failing indicates that the Qt private 
helper library libqgsttools_p.so.1 is corrupted or missing.

> I believe it's gstreamer related, but before I start digging, may be
> someone has some clues about that?

Upgrade your plugin. Use GStreamer 1.0 only.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center