diff -r 000000000000 -r fd39db613f8b src/pyams_media/site.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pyams_media/site.py	Wed Sep 02 15:31:55 2015 +0200
@@ -0,0 +1,48 @@
+#
+# Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+
+__docformat__ = 'restructuredtext'
+
+
+# import standard library
+
+# import interfaces
+from pyams_media.interfaces import IMediaConversionUtility, CONVERTER_NAME
+from pyams_utils.interfaces.site import ISiteGenerations
+from zope.site.interfaces import INewLocalSite
+
+# import packages
+from pyams_media.utility import MediaConversionUtility
+from pyams_utils.registry import utility_config
+from pyams_utils.site import check_required_utilities
+from pyramid.events import subscriber
+
+
+REQUIRED_UTILITIES = ((IMediaConversionUtility, '', MediaConversionUtility, CONVERTER_NAME), )
+
+
+@subscriber(INewLocalSite)
+def handle_new_local_site(event):
+    """Create a new conversion utility when a site is created"""
+    site = event.manager.__parent__
+    check_required_utilities(site, REQUIRED_UTILITIES)
+
+
+@utility_config(name='PyAMS medias converter', provides=ISiteGenerations)
+class MediaConversionGenerationsChecker(object):
+    """Medias conversion utility generations checker"""
+
+    generation = 1
+
+    def evolve(self, site, current=None):
+        """Check for required utilities"""
+        check_required_utilities(site, REQUIRED_UTILITIES)