apple tv buffering

Apple DVD Player doesn’t support AirPlay.

Third party media players do not support content-only AirPlay, so you must do Screen Mirroring. Screen Mirroring re-encodes the screen as an on-the-fly live streaming movie, which may be give undesired results. Reserve that functionality for photos and browsers, where the frames per second do not matter as much.

To view DVD-Video through your MacBook Air and external optical drive, you are advised to use one of the HDMI adapters*, and plug that into your tv or receiver. The Apple TV is not suited for that. Use the Apple TV for movies from the iTunes Store, and compatible movie files in your iTunes Library shared through Home Sharing.

* Compatible cable/adapters are Mini DisplayPort/Thunderbolt to HDMI for the models MacBook Air after 2011.

the reason why it does not work is because it's not legal, airplay and the likes unencrypt the encryption protected optical disc and send the frames across the network and that is not legal, because they could be grabbed and save and in the process making a digital copy of the optical movie which is the purpose of the encryption to prevent.