You can use QuickTime on a Mac to record content playing on an Apple TV.

  • Create a new Movie Recording with QuickTime (under the File menu)
  • Next to the record button, click the menu to choose camera and audio sources
  • Your Apple TV(s) should appear as a source in both options
  • Select it, and QuickTime will present a random code to authorize your Mac to record it
  • Content from your Apple TV should start streaming into QuickTime, ready for recording

Content with DRM (like iTunes movies) seems to error out, but ungracefully (for me, QuickTime just throws a ‘could not connect’ error). YouTube works fine though.