'media' attribute is 'all' by default.

Wait until the text "Waiting ..." does not appear in the "Test Result" column below.

Test Result Test Assertion
Waiting ... Test passes if the text 'PASS' appears to the left and the text 'Your browser does not support media elements.' does not appear anywhere on this page.

http://www.w3.org/TR/html5/video.html#the-source-element

The default, if the media attribute is omitted, is "all", meaning that 
by default the media resource is suitable for all media.