How does Google Cast work?

You're really tired of watching your favorite movies and TV series on the small screen of your smartphone and, after asking your friend for advice, you're thinking of relying on a streaming device like the Chromecast, which can allow even the oldest TVs to receive content from smartphones and tablets. Almost convinced of your choice, however, you decided to get more information about how it works and the technology it's based on. What better opportunity, then, to understand how Google Cast works, the transmission protocol used by Chromecast, Android TV and other compatible applications? Below, we'll explain the working principle of this technology, which has also become widespread thanks to its proverbial ease of use, and is now supported by many devices and services. We'll also show you the practical side of it, illustrating the ways in which content is transmitted and received by various devices.

How does Google Cast work?

This is the protocol designed and developed by Google to allow the transmission of audio and video content from one device to another, completely wireless. To better understand the peculiarity of this approach and the reason for its success, however, it is good to go back in time. The practice of transmitting the screen from one device to another, known in the technical jargon as mirroring, has been around since before the introduction of Google Cast: keys and devices that support the Miracast transmission protocol, for example, simply mirror the entire stream from the primary device's screen, the one that is actually running the app or program you want to display on the second screen, onto the second screen. In practice, the Miracast mirroring technique allows everything that is played on the main device's screen to be displayed on the second screen, regardless of the type of content, exactly like a mirror; as a direct consequence, when the main device stops sending content, the mirroring is interrupted and the second screen no longer transmits anything. In other words, the secondary display is not only a complete copy of the main device's display, but it depends entirely on it. This approach, on the other hand, profoundly changes the Google Cast protocol: in this case, the main device has the task of initiating the transmission of content, which is however reworked within the receiving device and reproduced independently. The main device becomes a kind of remote control to choose what is to be played. Over time, pure mirroring functions have been implemented, i.e. screen mirroring: they can be obtained both on Android, in native mode and on a computer.

How to use Google Cast?

This technology relies mainly on two categories of devices: those that activate the playback of content through applications, programs or functions compatible with the protocols, and those that receive the order to play the content and then take care of the task through the screen to which they are connected. For this to be successful, it is essential that both the remote control application or program and the playback device are connected to the same Wi-Fi network. The applications and programs capable of streaming content via Google Cast are really numerous: they range from well-known applications dedicated to streaming content over the Internet, to the most popular on-demand portals related to TV content, via the Google Chrome browser.

Smart TV compatibility

All televisions equipped with the Android TV operating system are natively compatible with this protocol: this means, in practice, that it is possible to send content via this technology without any additional configuration. All you have to do is launch the application you're interested in, press the broadcast button, and select the Android TV in question from the list of nearby devices. As for smart TVs not equipped with the Google operating system, the subject changes slightly: in this case, it is possible to play content through the YouTube application only: once the latter is installed both on the TV and on the remote control device, simply press the broadcast button of the "mobile" application and choose the TV from the list of nearby playback devices.

How to transmit content via Google Cast?

The first thing to do is to turn on the device on which you want to broadcast. Then, if you want to play content from smartphones or tablets, start the application you are interested in, select the content you want to play and press the broadcast button on the player's screen; this button looks like a screen with waves in the lower left corner. Finally, identify the device you intend to use for transmission, from the list proposed and the game is over: a few moments later, the latter should start playing the content you have chosen, totally independent of the smartphone or tablet from which you acted. It is also possible to transmit the entire screen to the Chromecast or the receiving device of your choice: to do this from Android, tap on the Settings icon located on the home screen, access the connected devices and connection preferences sections and, finally, tap on the transmit on item. In addition, one of the programs that offers full compatibility with transmission is Chrome, the browser dedicated to the main desktop platforms: it allows you to send to a Google Cast receiving device the currently active map, the entire desktop or a selected audio and video file in the computer's memory.