Q: On the second-generation Apple TV, is it possible to upload video clips that will play along with photos in the screensaver slideshow?
A: On the second-generation Apple TV you can include videos in any photo album as long as they are in a supported format. Unfortunately, these videos will not be included in slideshows, whether you’re playing them from the Photos section or as part of the Apple TV screensaver.
Videos located in a photo album or photo folder that is being shared to your Apple TV can be made available by selecting the Include Videos checkbox in your photo sharing settings in iTunes.
When this option is selected, any Apple TV compatible video file in the album/folder will be available when browsing that particular photo album on your Apple TV. The user interface is similar to that found on the iPhone and iPad; videos will be shown with a playback icon superimposed over the thumbnail or static full-screen view, and you can begin playing back a video simply by pressing the centre button on the Apple Remote.
When playing back a slideshow, however, any videos contained in the album/folder will simply be skipped as if they weren’t there, regardless of the specific slideshow format chosen.
In fact, you can create an album or folder with nothing but video files in it for viewing on your Apple TV—often a more useful way to handle home movies than trying to fit them in as “Movies” or “TV Shows”—in which case the “Slideshow” button will appear for that album, but will not actually do anything. Unfortunately, these “video-only” albums and folders are not filtered out from the Screensaver selection, however choosing one will result in no screensaver appearing at all (i.e. a blank screen).