The first video, from the National Museum of American History, examines Commodore Matthew Perry's entrance into Tokyo Bay in 1853, with the hope of opening trade between Japan and America. The host reviews a Japanese book from the time period that shows how the Japanese viewed the Americans.
Al Jazeera has an excellent documentary that reviews the Scramble for Africa. The first twenty minutes offers a good overview. The full documentary runs 44 minutes.
BBCFOUR has an excellent nine minute clip about the Congo and King Leopold.
Finally, here's a primary source from Jules Ferry on French colonialism written in 1858. Ferry outlines the reasons the French were so interested in colonialism. He's pretty blunt--We must say openly that indeed the higher races have a right over the lower races . . . .