If you watch a 2-hour film in English, your aim should be to understand the general idea or the story. Don't worry about understanding every word!
However, if you watch a 2-minute online video, your aim should be different. Watch the video several times, look up new words or phrases, and take notes. You could even try to write your own subtitles for the whole video.
The Economist website has a great selection of short videos that you could study in this way. Click here to go to the site, or watch the example below.