In most cases, Apple AirPlay works by beaming the video or audio directly from an iOS device to the television over Wi-Fi. Your iPhone or iPad must remain connected to the network, and it can’t play any other video or music while AirPlay is in use. By comparison, Chromecast merely sends a set of instructions to the television, which then starts streaming straight from the Internet, so you’re free to use your phone or tablet however you want. Casting has virtually no impact on battery life either, since it’s not responsible for beaming the actual content.