diff --git a/TODO b/TODO
index 55ea8b4e..1a37b681 100644
--- a/TODO
+++ b/TODO
@@ -2,6 +2,9 @@
 [Book]
 - Make the feature?
 
+[Build]
+- Makefile per directory. Use the include flags only where needed?
+
 [Cover]
 - Handle preferred cover file names ("front.xxx", "cover.xxx", ...)
 - Implement a cache and a grabber from some web service (mandatory for artists?)
diff --git a/src/Makefile.am b/src/Makefile.am
index 18a8bcbc..22f5e246 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,6 +7,7 @@ lms_SOURCES = \
 	$(srcdir)/cover/CoverArtGrabber.cpp			\
 	$(srcdir)/database/Artist.cpp				\
 	$(srcdir)/database/DatabaseHandler.cpp			\
+	$(srcdir)/database/DatabaseUpdater.cpp			\
 	$(srcdir)/database/MediaDirectory.cpp			\
 	$(srcdir)/database/Playlist.cpp				\
 	$(srcdir)/database/Release.cpp				\
@@ -15,13 +16,9 @@ lms_SOURCES = \
 	$(srcdir)/database/Track.cpp				\
 	$(srcdir)/database/User.cpp				\
 	$(srcdir)/database/Video.cpp				\
-	$(srcdir)/database-updater/DatabaseUpdater.cpp		\
-	$(srcdir)/database-updater/Checksum.cpp			\
 	$(srcdir)/image/Image.cpp				\
 	$(srcdir)/logger/Logger.cpp				\
 	$(srcdir)/metadata/AvFormat.cpp				\
-	$(srcdir)/service/ServiceManager.cpp			\
-	$(srcdir)/service/DatabaseUpdateService.cpp		\
 	$(srcdir)/ui/LmsApplication.cpp				\
 	$(srcdir)/ui/auth/LmsAuth.cpp				\
 	$(srcdir)/ui/audio/AudioPlayer.cpp			\
@@ -57,6 +54,7 @@ lms_SOURCES = \
 	$(srcdir)/ui/settings/SettingsMediaDirectoryFormView.cpp	\
 	$(srcdir)/ui/settings/SettingsUserFormView.cpp		\
 	$(srcdir)/ui/settings/SettingsUsers.cpp			\
+	$(srcdir)/utils/Checksum.cpp				\
 	$(srcdir)/utils/Utils.cpp
 
 if VIDEO
diff --git a/src/database/DatabaseHandler.cpp b/src/database/DatabaseHandler.cpp
index b44588ea..1a6307dd 100644
--- a/src/database/DatabaseHandler.cpp
+++ b/src/database/DatabaseHandler.cpp
@@ -83,6 +83,8 @@ Handler::Handler(Wt::Dbo::SqlConnectionPool& connectionPool)
 	_session.mapClass<Database::Artist>("artist");
 	_session.mapClass<Database::Genre>("genre");
 	_session.mapClass<Database::Track>("track");
+	_session.mapClass<Database::Classification>("classification");
+	_session.mapClass<Database::ClassificationData>("classification_data");
 	_session.mapClass<Database::Playlist>("playlist");
 	_session.mapClass<Database::PlaylistEntry>("playlist_entry");
 	_session.mapClass<Database::Release>("release");
diff --git a/src/database-updater/DatabaseUpdater.cpp b/src/database/DatabaseUpdater.cpp
similarity index 86%
rename from src/database-updater/DatabaseUpdater.cpp
rename to src/database/DatabaseUpdater.cpp
index 872f8478..d1420d89 100644
--- a/src/database-updater/DatabaseUpdater.cpp
+++ b/src/database/DatabaseUpdater.cpp
@@ -17,19 +17,19 @@
  * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdexcept>
 
 #include <boost/filesystem.hpp>
 #include <boost/thread.hpp>
 #include <boost/asio/placeholders.hpp>
 
 #include "logger/Logger.hpp"
-#include "utils/Utils.hpp"
-
-#include "database/Types.hpp"
-
-#include "Checksum.hpp"
-#include "DatabaseUpdater.hpp"
 #include "cover/CoverArtGrabber.hpp"
+#include "utils/Utils.hpp"
+#include "utils/Checksum.hpp"
+
+#include "Types.hpp"
+#include "DatabaseUpdater.hpp"
 
 namespace {
 
@@ -115,23 +115,40 @@ isPathInParentPath(const boost::filesystem::path& path, const boost::filesystem:
 } // namespace
 
 
-namespace DatabaseUpdater {
+namespace Database {
 
-using namespace Database;
+Updater& Updater::instance(void)
+{
+	static Updater updater;
+	return updater;
+}
 
-
-Updater::Updater(Wt::Dbo::SqlConnectionPool &connectionPool, MetaData::Parser& parser)
+Updater::Updater()
  : _running(false),
-_scheduleTimer(_ioService),
-_db(connectionPool),
-_metadataParser(parser)
+_scheduleTimer(_ioService)
 {
 	_ioService.setThreadCount(1);
 }
 
+void
+Updater::setConnectionPool(Wt::Dbo::SqlConnectionPool& connectionPool)
+{
+	_db = new Database::Handler(connectionPool);
+}
+
+void
+Updater::restart(void)
+{
+	stop();
+	start();
+}
+
 void
 Updater::start(void)
 {
+	if (_db == nullptr)
+		throw std::logic_error("uninitialized db!");
+
 	_running = true;
 
 	// post some jobs in the io_service
@@ -154,9 +171,9 @@ Updater::stop(void)
 void
 Updater::processNextJob(void)
 {
-	Wt::Dbo::Transaction transaction(_db.getSession());
+	Wt::Dbo::Transaction transaction(_db->getSession());
 
-	MediaDirectorySettings::pointer settings = MediaDirectorySettings::get(_db.getSession());
+	MediaDirectorySettings::pointer settings = MediaDirectorySettings::get(_db->getSession());
 
 	if (settings->getManualScanRequested()) {
 		LMS_LOG(DBUPDATER, INFO) << "Manual scan requested!";
@@ -229,9 +246,9 @@ Updater::process(boost::system::error_code err)
 
 		std::vector<RootDirectory> rootDirectories;
 		{
-			Wt::Dbo::Transaction transaction(_db.getSession());
+			Wt::Dbo::Transaction transaction(_db->getSession());
 
-			for (MediaDirectory::pointer directory : MediaDirectory::getAll(_db.getSession()))
+			for (MediaDirectory::pointer directory : MediaDirectory::getAll(_db->getSession()))
 				rootDirectories.push_back( RootDirectory( directory->getType(), directory->getPath() ));
 		}
 
@@ -253,9 +270,9 @@ Updater::process(boost::system::error_code err)
 		// Update database stats
 		boost::posix_time::ptime now = boost::posix_time::second_clock::local_time();
 		{
-			Wt::Dbo::Transaction transaction(_db.getSession());
+			Wt::Dbo::Transaction transaction(_db->getSession());
 
-			Database::MediaDirectorySettings::pointer settings = Database::MediaDirectorySettings::get(_db.getSession());
+			Database::MediaDirectorySettings::pointer settings = Database::MediaDirectorySettings::get(_db->getSession());
 
 			if (stats.nbChanges() > 0)
 				settings.modify()->setLastUpdate(now);
@@ -279,10 +296,10 @@ Updater::process(boost::system::error_code err)
 void
 Updater::updateFileExtensions()
 {
-	Wt::Dbo::Transaction transaction(_db.getSession());
+	Wt::Dbo::Transaction transaction(_db->getSession());
 
-	_audioFileExtensions = MediaDirectorySettings::get(_db.getSession())->getAudioFileExtensions();
-	_videoFileExtensions = MediaDirectorySettings::get(_db.getSession())->getVideoFileExtensions();
+	_audioFileExtensions = MediaDirectorySettings::get(_db->getSession())->getAudioFileExtensions();
+	_videoFileExtensions = MediaDirectorySettings::get(_db->getSession())->getVideoFileExtensions();
 }
 
 Artist::pointer
@@ -293,9 +310,9 @@ Updater::getArtist( const boost::filesystem::path& file, const std::string& name
 	// First try to get by MBID
 	if (!mbid.empty())
 	{
-		artist = Artist::getByMBID( _db.getSession(), mbid );
+		artist = Artist::getByMBID( _db->getSession(), mbid );
 		if (!artist)
-			artist = Artist::create( _db.getSession(), name, mbid);
+			artist = Artist::create( _db->getSession(), name, mbid);
 
 		return artist;
 	}
@@ -303,7 +320,7 @@ Updater::getArtist( const boost::filesystem::path& file, const std::string& name
 	// Fall back on artist name (collisions may occur)
 	if (!name.empty())
 	{
-		for (Artist::pointer sameNamedArtist : Artist::getByName( _db.getSession(), name ))
+		for (Artist::pointer sameNamedArtist : Artist::getByName( _db->getSession(), name ))
 		{
 			if (sameNamedArtist->getMBID().empty())
 			{
@@ -314,12 +331,12 @@ Updater::getArtist( const boost::filesystem::path& file, const std::string& name
 
 		// No Artist found with the same name and without MBID -> creating
 		if (!artist)
-			artist = Artist::create( _db.getSession(), name);
+			artist = Artist::create( _db->getSession(), name);
 
 		return artist;
 	}
 
-	return Artist::getNone( _db.getSession() );
+	return Artist::getNone( _db->getSession() );
 }
 
 Release::pointer
@@ -330,9 +347,9 @@ Updater::getRelease( const boost::filesystem::path& file, const std::string& nam
 	// First try to get by MBID
 	if (!mbid.empty())
 	{
-		release = Release::getByMBID( _db.getSession(), mbid );
+		release = Release::getByMBID( _db->getSession(), mbid );
 		if (!release)
-			release = Release::create( _db.getSession(), name, mbid);
+			release = Release::create( _db->getSession(), name, mbid);
 
 		return release;
 	}
@@ -340,7 +357,7 @@ Updater::getRelease( const boost::filesystem::path& file, const std::string& nam
 	// Fall back on release name (collisions may occur)
 	if (!name.empty())
 	{
-		for (Release::pointer sameNamedRelease : Release::getByName( _db.getSession(), name ))
+		for (Release::pointer sameNamedRelease : Release::getByName( _db->getSession(), name ))
 		{
 			if (sameNamedRelease->getMBID().empty())
 			{
@@ -351,12 +368,12 @@ Updater::getRelease( const boost::filesystem::path& file, const std::string& nam
 
 		// No release found with the same name and without MBID -> creating
 		if (!release)
-			release = Release::create( _db.getSession(), name);
+			release = Release::create( _db->getSession(), name);
 
 		return release;
 	}
 
-	return Release::getNone( _db.getSession() );
+	return Release::getNone( _db->getSession() );
 }
 
 std::vector<Genre::pointer>
@@ -366,15 +383,15 @@ Updater::getGenres( const std::list<std::string>& names)
 
 	for (const std::string& name : names)
 	{
-		Genre::pointer genre ( Genre::getByName(_db.getSession(), name) );
+		Genre::pointer genre ( Genre::getByName(_db->getSession(), name) );
 		if (!genre)
-			genre = Genre::create(_db.getSession(), name);
+			genre = Genre::create(_db->getSession(), name);
 
 		genres.push_back( genre );
 	}
 
 	if (genres.empty())
-		genres.push_back( Genre::getNone( _db.getSession() ));
+		genres.push_back( Genre::getNone( _db->getSession() ));
 
 	return genres;
 }
@@ -386,9 +403,9 @@ Updater::processAudioFile( const boost::filesystem::path& file, Stats& stats)
 
 	// Skip file if last write is the same
 	{
-		Wt::Dbo::Transaction transaction(_db.getSession());
+		Wt::Dbo::Transaction transaction(_db->getSession());
 
-		Wt::Dbo::ptr<Track> track = Track::getByPath(_db.getSession(), file);
+		Wt::Dbo::ptr<Track> track = Track::getByPath(_db->getSession(), file);
 
 		if (track && track->getLastWriteTime() == lastWriteTime)
 		{
@@ -412,9 +429,9 @@ Updater::processAudioFile( const boost::filesystem::path& file, Stats& stats)
 	std::vector<unsigned char> checksum ;
 	computeCrc(file, checksum);
 
-	Wt::Dbo::Transaction transaction(_db.getSession());
+	Wt::Dbo::Transaction transaction(_db->getSession());
 
-	Wt::Dbo::ptr<Track> track = Track::getByPath(_db.getSession(), file);
+	Wt::Dbo::ptr<Track> track = Track::getByPath(_db->getSession(), file);
 
 	// We estimate this is a audio file if:
 	// - we found a least one audio stream
@@ -510,7 +527,7 @@ Updater::processAudioFile( const boost::filesystem::path& file, Stats& stats)
 	if (!track)
 	{
 		// Create a new song
-		track = Track::create(_db.getSession(), file);
+		track = Track::create(_db->getSession(), file);
 		LMS_LOG(DBUPDATER, INFO) << "Adding '" << file << "'";
 		stats.nbAdded++;
 	}
@@ -675,8 +692,8 @@ Updater::checkAudioFiles( Stats& stats )
 {
 	LMS_LOG(DBUPDATER, INFO) << "Checking audio files...";
 
-	std::vector<boost::filesystem::path> trackPaths = Track::getAllPaths(_db.getSession());;
-	std::vector<boost::filesystem::path> rootDirs = getRootDirectoriesByType(_db.getSession(), Database::MediaDirectory::Audio);
+	std::vector<boost::filesystem::path> trackPaths = Track::getAllPaths(_db->getSession());;
+	std::vector<boost::filesystem::path> rootDirs = getRootDirectoriesByType(_db->getSession(), Database::MediaDirectory::Audio);
 
 	LMS_LOG(DBUPDATER, DEBUG) << "Checking tracks...";
 	for (auto& trackPath : trackPaths)
@@ -686,9 +703,9 @@ Updater::checkAudioFiles( Stats& stats )
 
 		if (!checkFile(trackPath, rootDirs, _audioFileExtensions))
 		{
-			Wt::Dbo::Transaction transaction(_db.getSession());
+			Wt::Dbo::Transaction transaction(_db->getSession());
 
-			Track::pointer track = Track::getByPath(_db.getSession(), trackPath);
+			Track::pointer track = Track::getByPath(_db->getSession(), trackPath);
 			if (track)
 			{
 				track.remove();
@@ -699,10 +716,10 @@ Updater::checkAudioFiles( Stats& stats )
 
 	LMS_LOG(DBUPDATER, DEBUG) << "Checking Genres...";
 	{
-		Wt::Dbo::Transaction transaction(_db.getSession());
+		Wt::Dbo::Transaction transaction(_db->getSession());
 
 		// Now process orphan Genre (no track)
-		auto genres = Genre::getAll(_db.getSession());
+		auto genres = Genre::getAll(_db->getSession());
 		for (auto genre : genres)
 		{
 			if (genre->getTracks().size() == 0)
@@ -715,9 +732,9 @@ Updater::checkAudioFiles( Stats& stats )
 
 	LMS_LOG(DBUPDATER, DEBUG) << "Checking artists...";
 	{
-		Wt::Dbo::Transaction transaction(_db.getSession());
+		Wt::Dbo::Transaction transaction(_db->getSession());
 
-		auto artists = Artist::getAllOrphans(_db.getSession());
+		auto artists = Artist::getAllOrphans(_db->getSession());
 		for (auto artist : artists)
 		{
 			LMS_LOG(DBUPDATER, DEBUG) << "Removing orphan artist '" << artist->getName() << "'";
@@ -727,9 +744,9 @@ Updater::checkAudioFiles( Stats& stats )
 
 	LMS_LOG(DBUPDATER, DEBUG) << "Checking releases...";
 	{
-		Wt::Dbo::Transaction transaction(_db.getSession());
+		Wt::Dbo::Transaction transaction(_db->getSession());
 
-		auto releases = Release::getAllOrphans(_db.getSession());
+		auto releases = Release::getAllOrphans(_db->getSession());
 		for (auto release : releases)
 		{
 			LMS_LOG(DBUPDATER, DEBUG) << "Removing orphan release '" << release->getName() << "'";
@@ -745,15 +762,15 @@ Updater::checkDuplicatedAudioFiles(Stats& stats)
 {
 	LMS_LOG(DBUPDATER, INFO) << "Checking duplicated audio files";
 
-	Wt::Dbo::Transaction transaction(_db.getSession());
+	Wt::Dbo::Transaction transaction(_db->getSession());
 
-	std::vector<Track::pointer> tracks = Database::Track::getMBIDDuplicates(_db.getSession());
+	std::vector<Track::pointer> tracks = Database::Track::getMBIDDuplicates(_db->getSession());
 	for (Track::pointer track : tracks)
 	{
 		LMS_LOG(DBUPDATER, INFO) << "Found duplicated MBID [" << track->getMBID() << "], file: " << track->getPath() << " - " << track->getArtist()->getName() << " - " << track->getName();
 	}
 
-	tracks = Database::Track::getChecksumDuplicates(_db.getSession());
+	tracks = Database::Track::getChecksumDuplicates(_db->getSession());
 	for (Track::pointer track : tracks)
 	{
 		LMS_LOG(DBUPDATER, INFO) << "Found duplicated checksum [" << bufferToString(track->getChecksum()) << "], file: " << track->getPath() << " - " << track->getArtist()->getName() << " - " << track->getName();
@@ -766,8 +783,8 @@ Updater::checkDuplicatedAudioFiles(Stats& stats)
 void
 Updater::checkVideoFiles( Stats& stats )
 {
-	std::vector<boost::filesystem::path> rootDirs = getRootDirectoriesByType(_db.getSession(), Database::MediaDirectory::Video);
-	std::vector<boost::filesystem::path> videoPaths = Video::getAllPaths(_db.getSession());
+	std::vector<boost::filesystem::path> rootDirs = getRootDirectoriesByType(_db->getSession(), Database::MediaDirectory::Video);
+	std::vector<boost::filesystem::path> videoPaths = Video::getAllPaths(_db->getSession());
 
 	LMS_LOG(DBUPDATER, DEBUG) << "Checking videos...";
 	for (auto& videoPath : videoPaths)
@@ -777,9 +794,9 @@ Updater::checkVideoFiles( Stats& stats )
 
 		if (!checkFile(videoPath, rootDirs, _videoFileExtensions))
 		{
-			Wt::Dbo::Transaction transaction(_db.getSession());
+			Wt::Dbo::Transaction transaction(_db->getSession());
 
-			Video::pointer video = Video::getByPath(_db.getSession(), videoPath);
+			Video::pointer video = Video::getByPath(_db->getSession(), videoPath);
 			if (video)
 			{
 				video.remove();
@@ -797,10 +814,10 @@ Updater::processVideoFile( const boost::filesystem::path& file, Stats& stats)
 	// Check last update time
 	boost::posix_time::ptime lastWriteTime (boost::posix_time::from_time_t( boost::filesystem::last_write_time( file ) ) );
 
-	Wt::Dbo::Transaction transaction(_db.getSession());
+	Wt::Dbo::Transaction transaction(_db->getSession());
 
 	// Skip file if last write is the same
-	Wt::Dbo::ptr<Video> video = Video::getByPath(_db.getSession(), file);
+	Wt::Dbo::ptr<Video> video = Video::getByPath(_db->getSession(), file);
 	if (video && video->getLastWriteTime() == lastWriteTime)
 		return;
 
@@ -841,7 +858,7 @@ Updater::processVideoFile( const boost::filesystem::path& file, Stats& stats)
 	// Today we are very aggressive, but we could also guess names from path, etc.
 	if (!video)
 	{
-		video = Video::create(_db.getSession(), file);
+		video = Video::create(_db->getSession(), file);
 		LMS_LOG(DBUPDATER, DEBUG) << "Adding '" << file << "'";
 		stats.nbAdded++;
 	}
@@ -860,4 +877,4 @@ Updater::processVideoFile( const boost::filesystem::path& file, Stats& stats)
 	transaction.commit();
 }
 
-} // namespace DatabaseUpdater
+} // namespace Database
diff --git a/src/database-updater/DatabaseUpdater.hpp b/src/database/DatabaseUpdater.hpp
similarity index 87%
rename from src/database-updater/DatabaseUpdater.hpp
rename to src/database/DatabaseUpdater.hpp
index f7cf9c8b..14e7e213 100644
--- a/src/database-updater/DatabaseUpdater.hpp
+++ b/src/database/DatabaseUpdater.hpp
@@ -20,28 +20,22 @@
 #ifndef DB_UPDATER_HPP
 #define DB_UPDATER_HPP
 
-#include <boost/asio/deadline_timer.hpp>
 #include <Wt/WIOService>
+#include <Wt/WSignal>
 
-#include "metadata/MetaData.hpp"
+#include <mutex>
+
+#include <boost/asio/deadline_timer.hpp>
+
+#include "metadata/AvFormat.hpp"
 
 #include "database/DatabaseHandler.hpp"
 
-namespace DatabaseUpdater {
+namespace Database {
 
 class Updater
 {
 	public:
-		Updater(Wt::Dbo::SqlConnectionPool& connectionPool, MetaData::Parser& parser);
-
-		void setAudioExtensions(const std::vector<std::string>&	extensions);
-		void setVideoExtensions(const std::vector<std::string>&	extensions);
-
-		void start();
-		void stop();
-
-	private:
-
 		struct Stats
 		{
 			std::size_t	nbSkipped = 0;		// no change since last scan
@@ -55,6 +49,25 @@ class Updater
 			std::size_t nbChanges() const { return nbAdded + nbRemoved + nbModified;}
 		};
 
+		static Updater& instance();
+
+		void setConnectionPool(Wt::Dbo::SqlConnectionPool& connectionPool);
+
+		void setAudioExtensions(const std::vector<std::string>&	extensions);
+		void setVideoExtensions(const std::vector<std::string>&	extensions);
+
+		void start();
+		void stop();
+		void restart();
+
+		Wt::Signal<Stats>& changed() { return _sigChanged; }
+
+		std::mutex&	getMutex(void) { return _mutex; }
+
+	private:
+
+		Updater();
+
 		struct RootDirectory
 		{
 			Database::MediaDirectory::Type type;
@@ -96,19 +109,21 @@ class Updater
 
 		bool			_running;
 		Wt::WIOService		_ioService;
+		Wt::Signal<Stats>	_sigChanged;
+		std::mutex		_mutex;
 
 		boost::asio::deadline_timer _scheduleTimer;
 
-		Database::Handler	_db;
+		Database::Handler*	_db = nullptr;
 
 		std::vector<boost::filesystem::path>	_audioFileExtensions;
 		std::vector<boost::filesystem::path>	_videoFileExtensions;
 
-		MetaData::Parser&	_metadataParser;
+		MetaData::AvFormat	_metadataParser;
 
 
 }; // class Updater
 
-} // DatabaseUpdater
+} // Database
 
 #endif
diff --git a/src/database/Track.hpp b/src/database/Track.hpp
index 5a13a980..d4d3c464 100644
--- a/src/database/Track.hpp
+++ b/src/database/Track.hpp
@@ -37,6 +37,8 @@ class Artist;
 class Release;
 class Track;
 class PlaylistEntry;
+class Classification;
+class ClassificationData;
 
 class Genre
 {
@@ -156,6 +158,8 @@ class Track
 		void setArtist(Wt::Dbo::ptr<Artist> artist)			{ _artist = artist; }
 		void setRelease(Wt::Dbo::ptr<Release> release)			{ _release = release; }
 		void setGenres(std::vector<Genre::pointer> genres);
+		void addClassifification(Wt::Dbo::ptr<Classification> classification);
+		void addClassifificationData(Wt::Dbo::ptr<ClassificationData> classificationData);
 
 		int				getTrackNumber(void) const		{ return _trackNumber; }
 		int				getTotalTrackNumber(void) const		{ return _totalTrackNumber; }
@@ -175,6 +179,8 @@ class Track
 		Wt::Dbo::ptr<Release>		getRelease(void) const			{ return _release; }
 		std::vector< Genre::pointer >	getGenres(void) const;
 		bool				hasGenre(Genre::pointer genre) const	{ return _genres.count(genre); }
+		std::vector< Wt::Dbo::ptr<Classification> >	getClassifications(void) const;
+		std::vector< Wt::Dbo::ptr<ClassificationData> >	getClassificationData(void) const;
 
 		template<class Action>
 			void persist(Action& a)
@@ -198,6 +204,8 @@ class Track
 				Wt::Dbo::belongsTo(a, _artist, "artist", Wt::Dbo::OnDeleteCascade);
 				Wt::Dbo::hasMany(a, _genres, Wt::Dbo::ManyToMany, "track_genre", "", Wt::Dbo::OnDeleteCascade);
 				Wt::Dbo::hasMany(a, _playlistEntries, Wt::Dbo::ManyToOne, "track");
+				Wt::Dbo::hasMany(a, _classifications, Wt::Dbo::ManyToOne, "track");
+				Wt::Dbo::hasMany(a, _classificationData, Wt::Dbo::ManyToOne, "track");
 			}
 
 	private:
@@ -228,7 +236,8 @@ class Track
 		Wt::Dbo::ptr<Release>			_release;
 		Wt::Dbo::collection< Genre::pointer >	_genres; // Genres that are related to this track
 		Wt::Dbo::collection< Wt::Dbo::ptr<PlaylistEntry> > _playlistEntries;
-
+		Wt::Dbo::collection< Wt::Dbo::ptr<Classification> > _classifications;
+		Wt::Dbo::collection< Wt::Dbo::ptr<ClassificationData> > _classificationData;
 };
 
 
diff --git a/src/database/Types.hpp b/src/database/Types.hpp
index a04b978b..0842ad7d 100644
--- a/src/database/Types.hpp
+++ b/src/database/Types.hpp
@@ -22,6 +22,7 @@
 #include "Artist.hpp"
 #include "Track.hpp"
 #include "Playlist.hpp"
+#include "Classification.hpp"
 #include "Release.hpp"
 #include "Video.hpp"
 #include "MediaDirectory.hpp"
diff --git a/src/main/main.cpp b/src/main/main.cpp
index 228678ff..61557773 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -19,18 +19,17 @@
 
 #include <boost/filesystem.hpp>
 
+#include <Wt/WServer>
+
 #include "config/config.h"
 #include "av/AvInfo.hpp"
 #include "av/AvTranscoder.hpp"
 #include "logger/Logger.hpp"
 #include "image/Image.hpp"
 
+#include "database/DatabaseUpdater.hpp"
 #include "ui/LmsApplication.hpp"
 
-#include "service/ServiceManager.hpp"
-#include "service/DatabaseUpdateService.hpp"
-
-#include <Wt/WServer>
 
 int main(int argc, char* argv[])
 {
@@ -49,8 +48,6 @@ int main(int argc, char* argv[])
 
 		Wt::WServer::instance()->logger().configure("*"); // log everything
 
-		Service::ServiceManager& serviceManager = Service::ServiceManager::instance();
-
 		// lib init
 		Image::init(argv[0]);
 		Av::AvInit();
@@ -60,30 +57,29 @@ int main(int argc, char* argv[])
 		// Initializing a connection pool to the database that will be shared along services
 		std::unique_ptr<Wt::Dbo::SqlConnectionPool> connectionPool( Database::Handler::createConnectionPool("/var/lms/lms.db")); // TODO use $datadir from autotools
 
-		serviceManager.add( std::make_shared<Service::DatabaseUpdateService>(*connectionPool));
+		Database::Updater::instance().setConnectionPool(*connectionPool);
 
 		// bind entry point
 		server.addEntryPoint(Wt::Application, boost::bind(UserInterface::LmsApplication::create, _1, boost::ref(*connectionPool)));
 
-		// Starting the main server
+		// Start
+		LMS_LOG(MAIN, INFO) << "Starting database updater...";
+		Database::Updater::instance().start();
+
 		LMS_LOG(MAIN, INFO) << "Starting server...";
 		server.start();
 
-		// Start underlying services
-		LMS_LOG(MAIN, INFO) << "Starting services...";
-		serviceManager.start();
-
+		// Wait
 		LMS_LOG(MAIN, INFO) << "Now running...";
-
-		// Waiting for shutdown command
 		Wt::WServer::waitForShutdown(argv[0]);
 
-		LMS_LOG(MAIN, INFO) << "Stopping services...";
-		serviceManager.stop();
-		serviceManager.clear();
-
+		// Stop
 		LMS_LOG(MAIN, INFO) << "Stopping server...";
-		server.stop();
+		Database::Updater::instance().stop();
+
+		LMS_LOG(MAIN, INFO) << "Stopping database updater...";
+		Database::Updater::instance().stop();
+
 
 		res = EXIT_SUCCESS;
 	}
diff --git a/src/service/DatabaseUpdateService.cpp b/src/service/DatabaseUpdateService.cpp
deleted file mode 100644
index e540a0b3..00000000
--- a/src/service/DatabaseUpdateService.cpp
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Copyright (C) 2013 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * LMS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <boost/thread.hpp>
-
-#include "DatabaseUpdateService.hpp"
-
-namespace Service {
-
-DatabaseUpdateService::DatabaseUpdateService(Wt::Dbo::SqlConnectionPool &connectionPool)
-: _metadataParser(),
- _databaseUpdater( connectionPool, _metadataParser)
-{
-}
-
-void
-DatabaseUpdateService::start(void)
-{
-	_databaseUpdater.start();
-}
-
-void
-DatabaseUpdateService::stop(void)
-{
-	_databaseUpdater.stop();
-}
-
-void
-DatabaseUpdateService::restart(void)
-{
-	stop();
-	start();
-}
-
-} // namespace Service
-
diff --git a/src/service/DatabaseUpdateService.hpp b/src/service/DatabaseUpdateService.hpp
deleted file mode 100644
index 2dbb0b97..00000000
--- a/src/service/DatabaseUpdateService.hpp
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright (C) 2013 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * LMS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef DB_UPDATE_SERVICE_HPP
-#define DB_UPDATE_SERVICE_HPP
-
-#include <boost/thread.hpp>
-#include <boost/asio/io_service.hpp>
-
-#include "metadata/AvFormat.hpp"
-#include "database-updater/DatabaseUpdater.hpp"
-
-#include "Service.hpp"
-
-namespace Service {
-
-class DatabaseUpdateService : public Service
-{
-	public:
-
-		typedef std::shared_ptr<DatabaseUpdateService>	pointer;
-
-		DatabaseUpdateService(Wt::Dbo::SqlConnectionPool &connectionPool);
-
-		// Service interface
-		void start(void);
-		void stop(void);
-		void restart(void);
-
-	private:
-
-		MetaData::AvFormat			_metadataParser;
-		DatabaseUpdater::Updater		_databaseUpdater;	// Todo use handler
-};
-
-} // namespace Service
-
-#endif
-
diff --git a/src/service/Service.hpp b/src/service/Service.hpp
deleted file mode 100644
index ce688bd0..00000000
--- a/src/service/Service.hpp
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * Copyright (C) 2013 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * LMS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef SERVICE_HPP
-#define SERVICE_HPP
-
-#include <boost/thread.hpp>
-#include <memory>
-#include <set>
-
-namespace Service {
-
-// Interface class wrapper for running services
-class Service
-{
-	public:
-
-		typedef std::shared_ptr<Service>	pointer;
-
-		Service(const Service&) = delete;
-		Service& operator=(const Service&) = delete;
-
-		Service() {}
-		virtual ~Service() {}
-
-		virtual void start(void) = 0;
-		virtual void stop(void) = 0;
-		virtual void restart(void) = 0;
-
-};
-
-} // namespace Service
-
-#endif
-
diff --git a/src/service/ServiceManager.cpp b/src/service/ServiceManager.cpp
deleted file mode 100644
index b5dd2d7c..00000000
--- a/src/service/ServiceManager.cpp
+++ /dev/null
@@ -1,84 +0,0 @@
-/*
- * Copyright (C) 2013 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * LMS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "ServiceManager.hpp"
-
-namespace Service {
-
-ServiceManager&
-ServiceManager::instance()
-{
-	static ServiceManager instance;
-	return instance;
-}
-
-ServiceManager::ServiceManager()
-{
-}
-
-ServiceManager::~ServiceManager()
-{
-	stop();
-}
-
-void
-ServiceManager::add(Service::pointer service)
-{
-	_services.insert(service);
-	service->start();
-}
-
-void
-ServiceManager::del(Service::pointer service)
-{
-	service->stop();
-	_services.erase(service);
-}
-
-void
-ServiceManager::clear(void)
-{
-	stop();
-	_services.clear();
-}
-
-void
-ServiceManager::start(void)
-{
-	for (Service::pointer service : _services)
-		service->start();
-}
-
-void
-ServiceManager::stop(void)
-{
-	for (Service::pointer service : _services)
-		service->stop();
-}
-
-
-void
-ServiceManager::restart(void)
-{
-	for (Service::pointer service : _services)
-		service->restart();
-}
-
-} // namespace Service
-
diff --git a/src/service/ServiceManager.hpp b/src/service/ServiceManager.hpp
deleted file mode 100644
index 84fcafab..00000000
--- a/src/service/ServiceManager.hpp
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * Copyright (C) 2013 Emeric Poupon
- *
- * This file is part of LMS.
- *
- * LMS is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * LMS is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef SERVICE_CONTROLER_HPP
-#define SERVICE_CONTROLER_HPP
-
-#include <set>
-
-#include "Service.hpp"
-
-namespace Service {
-
-// Start/Stop/Reload Services
-class ServiceManager
-{
-	public:
-
-		static ServiceManager& instance();
-		~ServiceManager();
-
-		void add(Service::pointer service);
-		void del(Service::pointer service);
-		void clear();
-
-		void start();
-		void stop();
-		void restart();
-
-		template <class T> typename T::pointer get();
-
-		boost::mutex&	mutex() { return _mutex;}
-
-	private:
-
-		ServiceManager();
-		ServiceManager(ServiceManager const&);	// Don't Implement
-		void operator=(ServiceManager const&);	// Don't implement
-
-		boost::mutex	_mutex;
-
-		std::set<Service::pointer>	_services;
-};
-
-
-template <class T> typename T::pointer
-ServiceManager::get()
-{
-	std::set<Service::pointer>::iterator it;
-	for (Service::pointer service : _services)
-	{
-		if (typeid(*(service)) == typeid(T)) {
-			return std::dynamic_pointer_cast<T>(service);
-		}
-	}
-	return std::shared_ptr<T>();
-}
-
-} // namespace Service
-
-#endif
-
diff --git a/src/ui/settings/Settings.cpp b/src/ui/settings/Settings.cpp
index 84e38fd3..3c68c6fc 100644
--- a/src/ui/settings/Settings.cpp
+++ b/src/ui/settings/Settings.cpp
@@ -30,8 +30,7 @@
 #include "SettingsUsers.hpp"
 
 #include "logger/Logger.hpp"
-#include "service/ServiceManager.hpp"
-#include "service/DatabaseUpdateService.hpp"
+#include "database/DatabaseUpdater.hpp"
 
 #include "LmsApplication.hpp"
 
@@ -74,11 +73,29 @@ Settings::Settings(Wt::WContainerWidget* parent)
 	if (userIsAdmin)
 	{
 		MediaDirectories* mediaDirectories = new MediaDirectories();
-		mediaDirectories->changed().connect(this, &Settings::handleDatabaseDirectoriesChanged);
+		mediaDirectories->changed().connect(std::bind([=]
+		{
+			LMS_LOG(UI, INFO) << "Media directories have changed: requesting imediate scan";
+
+			// On directory add or delete, request an immediate scan
+			//
+			{
+				Wt::Dbo::Transaction transaction(DboSession());
+				Database::MediaDirectorySettings::get(DboSession()).modify()->setManualScanRequested(true);
+			}
+			{
+				std::lock_guard<std::mutex> lock(Database::Updater::instance().getMutex());
+				Database::Updater::instance().restart();
+			}
+		}));
 		menu->addItem("Media Folders", mediaDirectories)->setPathComponent("mediadirectories");
 
 		DatabaseFormView* databaseFormView = new DatabaseFormView();
-		databaseFormView->changed().connect(this, &Settings::restartDatabaseUpdateService);
+		databaseFormView->changed().connect(std::bind([=]
+		{
+			std::lock_guard<std::mutex> lock(Database::Updater::instance().getMutex());
+			Database::Updater::instance().restart();
+		}));
 		menu->addItem("Database", databaseFormView)->setPathComponent("database");
 
 		menu->addItem("Users", new Users())->setPathComponent("users");
@@ -90,29 +107,5 @@ Settings::Settings(Wt::WContainerWidget* parent)
 
 }
 
-void
-Settings::handleDatabaseDirectoriesChanged()
-{
-	LMS_LOG(UI, INFO) << "Media directories have changed: requesting imediate scan";
-	// On directory add or delete, request an immediate scan
-	{
-		Wt::Dbo::Transaction transaction(DboSession());
-		Database::MediaDirectorySettings::get(DboSession()).modify()->setManualScanRequested(true);
-	}
-
-	restartDatabaseUpdateService();
-}
-
-void
-Settings::restartDatabaseUpdateService()
-{
-	// Restarting the update service
-	boost::lock_guard<boost::mutex> serviceLock (Service::ServiceManager::instance().mutex());
-
-	Service::DatabaseUpdateService::pointer service = Service::ServiceManager::instance().get<Service::DatabaseUpdateService>();
-	if (service)
-		service->restart();
-}
-
 } // namespace Settings
 } // namespace UserInterface
diff --git a/src/ui/settings/Settings.hpp b/src/ui/settings/Settings.hpp
index 2c6f0f76..30ffa0b8 100644
--- a/src/ui/settings/Settings.hpp
+++ b/src/ui/settings/Settings.hpp
@@ -28,11 +28,6 @@ class Settings : public Wt::WContainerWidget
 		Settings(Wt::WContainerWidget* parent = 0);
 
 	private:
-
-		void handleDatabaseDirectoriesChanged();
-
-		void restartDatabaseUpdateService(void);
-
 };
 
 } // namespace Settings
diff --git a/src/database-updater/Checksum.cpp b/src/utils/Checksum.cpp
similarity index 100%
rename from src/database-updater/Checksum.cpp
rename to src/utils/Checksum.cpp
diff --git a/src/database-updater/Checksum.hpp b/src/utils/Checksum.hpp
similarity index 97%
rename from src/database-updater/Checksum.hpp
rename to src/utils/Checksum.hpp
index aa2c6766..214c3dad 100644
--- a/src/database-updater/Checksum.hpp
+++ b/src/utils/Checksum.hpp
@@ -20,6 +20,6 @@
 #include <vector>
 #include <boost/filesystem.hpp>
 
-
+// TODO move to utils
 void computeCrc(const boost::filesystem::path& p, std::vector<unsigned char>& checksum);