Infuse, one of the most popular media players for iOS, is coming soon to the new Apple (it should be availabe on the Apple TV App Store by the end of the year). The first beta has been sent out to beta testers on Wednesday and some of them have already managed to record and share the videos showing the app in action on the Apple TV 4.
Until now, streaming media files from a Windows PC to an Apple TV was only possible with iTunes (for supported file types only) or AirParrot (using its media streaming or specific app mirroring features). Recently released PopCast is a new player to the market. It lets you stream all of your videos to your Apple TV or Chromecast, no matter what file format.