Adding a new filter to Media Manager's search requires three actions: adding a new filter to the "DigiZuite_System_Framework_Search" search → adding the same filter to the searches "DigiZuite_System_Framework_My_Favorites" and "DigiZuite_System_Framework_My_Videoes" → creating a new label (if one does not already exist), whose Constant matches the new Filter's ID.

Media Manager uses the search "DigiZuite_System_Framework_Search" to search for assets. A user can input text in the wide text field (this is how any FreeText filters are used), and/or choose to add filters such as "Date" or "Keywords":

2.1 Adding an Asset type filter

First the filter must be added to the search "DigiZuite_System_Framework_Search":

Go to the DAM Center → System tools → ConfigManager → choose DigiZuite™ Media Manager → choose the version, which your Media Manager is set up to use → click the "Searches" tab → add an asset type filter → save the search → populate the search → ensure that the search has been populated by refreshing the page; if the "populate search cache" cog-wheel button is not present, the search has been successfully populated.

Then you MUST add the same filter to the searches "DigiZuite_System_Framework_My_Favorites" and "DigiZuite_System_Framework_My_Videoes". 

If a label with the correct Constant and Label does not exist, then you MUST create one. Unlike Add new meta data field to Media Manager's Asset Preview, if a label with a Constant matching the added filter's ID does not exists, the Media Manager will throw an error, which results in the filters being unavailable.

In this case, a label already exists with a Constant "sAssetType" and Label "Asset type".

After doing so, refreshing Media Manager will display three filters:

2.2 Removing a filter

This is done by removing the filter from the search "DigiZuite_System_Framework_Search". You MAY also clean up the searches "DigiZuite_System_Framework_My_Favorites" and "DigiZuite_System_Framework_My_Videoes".