Apple TV is a really good machine. The disadvantage is that the built-in memory reserved for the operating system, applications, and media files. It creates problems for those who want to watch their own files, such as vacation video or film of last year's Christmas celebration.
There are a lot of solutions and we will guide you how to get started.
The simplest, and perhaps most obvious, is Airplay. In addition to stream the media files you have on your iOS device or Mac can also Airplay streaming videos from various websites and apps without any problems. In IOS 10 are just the file you want to watch, wraps up the control center from the bottom of your phone and then sweeps again – but to the right. This takes you to control the menu of the media. At the bottom is the default "iPhone" but if you choose the arrow to the right, you can switch to other devices. In this case, the Apple TV.
Once selected, the Apple TV, play video and after a few seconds, it should appear on your TV screen.
There is something more complicated on the Mac OS, and the experience is not always good. If it does not move a Quicktime compatible video file, you are limited to reflect the duration of your Mac's screen on your Apple TV. And since the entire screen is mirrored buffers the video file is not in the same way as on an iOS device. Expect other words, with some delay and synchronization issues, especially in the video of a higher quality.
if you have a QuickTime-compatible video file, open it in QuickTime and select AirPlay button that appears in the media controls. Then select the Apple TV and the buffer function to operate the same as on the iOS.