I just noticed that the William H. Malm-hosted documentary Gagaku: The Court Music of Japan is on YouTube in its entirety! Great watching if you're into gagaku (the court music of Japan).

The Kyoto City University of Arts' Research Center for Japanese Traditional Music (京都市立芸術大学 日本伝統音楽研究センター) has also put some interesting performances online, apparently reconstructed (by them) from Heian/Kamakura manuscripts rather than inheriting an active transmission. Seigaiha 青海波 ("Waves on the Blue Sea") is one of a series focusing on the music of the Tale of Genji (which you can see collected on this page); this solo koto performance of Bushō Taiheiraku 武昌太平楽 may be more to the tastes of those who for some reason don't enjoy high-register wind instruments playing slightly out of tune with each other. (Barbarians!)

Bonus: Here's another enjoyable documentary about the Music Department of the Imperial Household (宮内庁式部職楽部)'s appearance at the 2012 Edinburgh Festival. No Malm, but a lot of footage of actual court musicians explaining what it is they do and how they think.