Madek is a web-based system to share and archive images, video and audio files as well as documents. It has a few design goals and focus areas:

• Support for many different media types: images, audio, video, etc.
• Flexible metadata schema, flexible input fields and forms so that each Madek instance can be customized to your needs.
• Fine-grained permission system so that any user or user group sees only what they are meant to see.
• Most files can be viewed directly in the web interface, but the original file is always left untouched, which is important for archival purposes.
• Metadata entered through the web can also be embedded in the media file you export, making the best use of metadata that was acquired through collaborative editing.
• 100% Free Software under the GNU GPL.
• Relatively easy to install: Just one single Ruby on Rails web application.

There are screenshots of the most important features in a slideshow on the Madek project page (in German).