Roku is striking back at Chromecast and Apple TV's Airplay with screen mirroring for Android and Windows.

The beta feature lets users beam video and audio from a phone, tablet or PC to the big screen. It's available now for the Roku 3 and Roku Streaming Stick HDMI version, and requires a device running at least Windows 8, Windows Phone 8 or Android 4.4.2.

Why this matters: Roku already lets users share their photos and videos on the big screen through the Roku mobile app, and allows Chromecast-like remote control through Netflix and YouTube apps. Still, screen mirroring is one of those nice-to-have features for sharing a Web page, displaying a presentation or playing music and video from apps that aren't natively supported on the set-top box.

Living room table stakes

Screen mirroring has slowly become a table-stakes feature among set-top boxes and TV dongles. Microsoft recently launched a $60 Miracast dongle for beaming content from Windows devices, and Google flipped on Chromecast mirroring from certain Android devices in July. Amazon's Fire TV has allowed mirroring from Kindle Fire HDX tablets since launch, and Apple added AirPlay Mirroring for Apple TV back in 2011. For Roku, it's better late than never.

Just remember that direct screen mirroring isn't always the best way to beam content from your phone. It tends to drain battery life in a hurry, and it prevents you from doing other things on your device. Mirroring is great in a pinch, but users should stick with Roku's mobile app and cast-enabled apps when possible.

For more details on how to set up screen mirroring, head to Roku's website.