admin/filter/oembed/manageproviders
From MoodleDocs
The list of providers is maintained automatically from http://oembed.com/providers.json
Adding your own (local) provider can be done by adding one in the database in mdl_filter_oembed where you leave the source column empty. Once created, you can edit it in the Moodle administration interface under moodle/filter/oembed/manageproviders.php
