The Computers-App can be used to play MP4 videos stored in your iTunes library.
But not all applications support both formats. But It is capable to play MP4 and MKV video files. This is because the default DVD file format is not supported by the Apple TV4. They all require a computer to convert the DVD to a playable format. I'll describe 3 different ways to play DVDs on the new Apple TV4.
Convert the saved DVD to a playable video format.
And in the next four pages, these steps are explained one by one. This instructable consists of the following four steps. But with the new Apple TV it's possible to install additonal applications. Also, an external hard drive cannot be connected. Unfortunately it's not possible to store videos directly on the Apple TV4. In this instructable I will describe how to play your own DVDs with an Apple TV4.