We explain how to choose media keys for HTML5 video. Read About Video Plugin to understand media keys and the other services supported by the plugin.
Provide a mime video subtype and the URL to the video source. Example mime video subtypes: mozilla 
This option can be used to display videos uploaded to wiki with the assets plugin. About Assets Plugin
This is an embedded video hosted at Wikipedia. Double-click the caption to see the plugin markup.
HTML5 webm https://upload.wikimedia.org/wikipedia/commons/a/a1/Burgruine_Marmels%2C_aerial_video.webm
Burgruine Marmels aerial video (wikimedia )