Performance / Buffering issues

There are two possible reason for buffering pauses:

Network throughput issues

Some wireless networks might be surprisingly slow when moving data between computer and Chromecast / Apple TV.

Speed Test for Chromecast: Airflow can measure network throughput between you computer and the Chromecast. Note that this is different and completely unrelated your internet connection speed, as all data transfer happens within your local network. SpeedTest is not available for Apple TV.

In good conditions, the speed should be at least 30mbit/s for first generation Chromecast and over 50mbit/s on newer devices.

Improving network throughput

Make sure your computer is connected to 5Ghz network. This can give you massive improvements in connection reliability and speed. All devices (except first generation Chromecast that only supports 2.4Ghz) should also be connected to 5Ghz.

2.4Ghz network become very unreliable in recent years, as they are very prone to interference from other network, bluetooth and even USB 3 devices.

Video being converted too slow

Normally Airflow will try very hard not to convert the video if not necessary (passhtrough). Look at the bottom of Airflow playback settings window, it will tell you if video is being converted and for what reason.