I've just solved this bug or at least identified the culprit. It's
So what I did:
apt-get install phonon-backend-vlc
dpkg -r phonon-backend-gstreamer:amd64
in systemsettings, the phonon engine was automatically switched to the
only one available, VLC.
And now digikam starts normally.
I believe it's linked to this bug:
and they say that next phonon package update should fix it. In the
meanwhile, using another backend is a good workaround.
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