video::video_file.mp4[]
>>>
Document
  { docMeta =
      Meta
        { docTitle = []
        , docTitleAttributes = Nothing
        , docAuthors = []
        , docRevision = Nothing
        , docAttributes = fromList [ ( "sectids" , "" ) ]
        }
  , docBlocks =
      [ Block mempty Nothing (BlockVideo (Target "video_file.mp4")) ]
  }