Mopidy: No audio found in file.

Since I installed mopidy on a fresh raspian jessie image I can neither play locally stored m4a nor mp3 files.
It has a HiFiBerry DAC+ - RCA sound card installed (worked before) and mopidy runs as a service BUT SINCE REINSTALLATION the command sudo mopidyctl local scan results in errors for all found files.

EXAMPLE:

**WARNING Failed local:track:DJ%20Wigs/Loungin%27/01%20Titel%2001.m4a: No audio found in file.**

mopidy deps says:

$ mopidy deps
**libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast**
Executable: /usr/bin/mopidy
Platform: Linux-4.1.19+-armv6l-with-debian-8.0
Python: CPython 2.7.9 from /usr/lib/python2.7
Mopidy: 2.0.0 from /usr/lib/python2.7/dist-packages
Pykka>=1.1: 1.2.1 from /usr/lib/python2.7/dist-packages
requests>=2.0: 2.4.3 from /usr/lib/python2.7/dist-packages
tornado>=2.3: 3.2.2 from /usr/lib/python2.7/dist-packages
GStreamer: 1.4.4.0 from /usr/lib/python2.7/dist-packages/gi
Detailed information: 
Python wrapper: python-gi 3.14.0
Relevant elements:
Found:
uridecodebin
souphttpsrc
appsrc
alsasink
osssink
oss4sink
pulsesink
flump3dec
id3demux
id3v2mux
mad
mpegaudioparse
mpg123audiodec
vorbisdec
vorbisenc
vorbisparse
oggdemux
oggmux
oggparse
flacdec
flacparse
shout2send
Not found:
lamemp3enc

And the actual config looks like this:

$ sudo mopidyctl config
Running "/usr/bin/mopidy --config /usr/share/mopidy/conf.d:/etc/mopidy/mopidy.conf config" as user mopidy
[core]
cache_dir = /var/cache/mopidy
config_dir = /etc/mopidy
data_dir = /var/lib/mopidy
max_tracklist_length = 10000

[logging]
color = true
console_format = %(levelname)-8s %(message)s
debug_format = %(levelname)-8s %(asctime)s [%(process)d:%(threadName)s] %(name)s\n %(message)s
debug_file = /var/log/mopidy/mopidy-debug.log
config_file = /etc/mopidy/logging.conf

[audio]
mixer = software
mixer_volume = 
output = autoaudiosink
buffer_time =

[proxy]
scheme = 
hostname = 
port = 
username = 
password =

[mpd]
enabled = true
hostname = 127.0.0.1
port = 6600
password = 
max_connections = 20
connection_timeout = 60
zeroconf = Mopidy MPD server on $hostname
command_blacklist = 
listall
listallinfo
default_playlist_scheme = m3u

[http]
enabled = true
hostname = 127.0.0.1
port = 6680
static_dir =
zeroconf = Mopidy HTTP server on $hostname

[stream]
enabled = true
protocols = 
http
https
mms
rtmp
rtmps
rtsp
metadata_blacklist = 
timeout = 5000

[m3u]
enabled = true
base_dir =
default_encoding = latin-1
default_extension = .m3u8
playlists_dir = /var/lib/mopidy/playlists

[softwaremixer]
enabled = true

[file]
enabled = true
media_dirs = 
$XDG_MUSIC_DIR|Music
~/|Home
show_dotfiles = false
follow_symlinks = false
metadata_timeout = 1000

[local]
enabled = true
library = json
media_dir = /media/usb1/iTunes Music
scan_timeout = 1000
scan_flush_threshold = 100
scan_follow_symlinks = false
excluded_file_extensions = 
.directory
.html
.jpeg
.jpg
.log
.nfo
.png

The music files did play well on the old installation and the file permission to all of them is set like this:

$ ls -l /media/usb1/iTunes\ Music/DJ\ Wigs/Loungin\'/
total 155992
-rwxr-xr-x 1 mopidy audio 31944754 Mar 7 2011 01 Titel 01.m4a
-rwxr-xr-x 1 mopidy audio 44805884 Mar 7 2011 02 Titel 02.m4a
-rwxr-xr-x 1 mopidy audio 42822626 Mar 7 2011 03 Titel 03.m4a
-rwxr-xr-x 1 mopidy audio 40156581 Mar 7 2011 04 Titel 04.m4a

Could anyone point me in the right direction with my question as to how to solve this? If necessary I could provide further information.