Seems to be working as we were able to stream tUNEyARDS earlier today. Used iPad to ATV via AirPlay. Quality was decent at best, grainy at times. Good luck , Radiohead streaming later!!!!
Certain links to the Coachella streaming video channels work with AirPlay to AppleTV.
Note: the video streams posted at http://www.coachella.com/ don't work via AirPlay. You get the error message "An error occured loading this content. Try again later."
1) Starting from your computer, go to the Coachella website: http://www.coachella.com
2) Click the "Watch on Youtube.com" button (located in the embedded video player window below the playing coachella video; it's the one to the left of the "Fullscreen" button). This opens that same channel in YouTube.
3) Click "Share" and...
4) Click "Email"... (use YouTube to share a private email link to your email).
5) Open the Coachella channel on your IPhone from the link in your email.
6) Using Airplay, send this streaming Coachella Youtube Channel to your Apple TV from your IPhone.
If your AirPlay videos are interupted by your IPhone Auto-lock then you can fix that using:
IPhone --> Settings --> General --> Auto-Lock --> "Never".
Happy Coachella watching!