Comment 92 for bug 823155

On pc Debian x86-64 with master sources updated today, I could reproduce the problem indicated in initial description but I noticed these logs:
warn:avmedia:24225:1:avmedia/source/viewer/mediawindow_impl.cxx:248: failed to create media player service com.sun.star.comp.avmedia.Manager_VLC
warn:avmedia:24225:1:avmedia/source/gstreamer/gstplayer.cxx:446: gstreamer error: 'Resource not found.' debug: 'gstfilesrc.c(515): gst_file_src_start (): /GstPlayBin:playbin3/GstURIDecodeBin:uridecodebin3/GstFileSrc:source:
No such file "/home/julien/usr/lib/libreoffice/basis3.3/share/gallery/sounds/apert.wav"'
warn:avmedia:24225:1:avmedia/source/gstreamer/gstplayer.cxx:446: gstreamer error: 'Resource not found.' debug: 'gstfilesrc.c(515): gst_file_src_start (): /GstPlayBin:playbin3/GstURIDecodeBin:uridecodebin3/GstFileSrc:source:
No such file "/home/julien/usr/lib/libreoffice/basis3.3/share/gallery/sounds/apert.wav"'
warn:avmedia:24225:1:avmedia/source/gstreamer/gstplayer.cxx:446: gstreamer error: 'No URI set' debug: 'gstplaybin2.c(5426): setup_next_source (): /GstPlayBin:playbin3'
warn:avmedia:24225:1:avmedia/source/gstreamer/gstplayer.cxx:446: gstreamer error: 'No URI set' debug: 'gstplaybin2.c(5426): setup_next_source (): /GstPlayBin:playbi

Unzipping odp file, I see this in content.xml:
<anim:audio xlink:href="../../../../usr/lib/libreoffice/basis3.3/share/gallery/sounds/apert.wav" />
Taking a look at where could be apert.wav, I found it there:
/usr/lib/libreoffice/share/gallery/sounds

So first attachment can't work. An enhancement could be to indicate the file is not found and propose to modify the sound.