How Chromecast Works

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In the year 2021, over-the-air broadcasting fell to last place in terms of viewership. Cable TV is still king, but for the first time, streaming video moved in to second place. Its popularity is due to devices like Google's Chromecast, easy and affordable devices you can plug into your TV. With that, streaming moved from the computer and smartphone screens to the family room TV.

First launched in 2013, the Google Chromecast is a family of devices you can plug into the HDMI (high-definition multimedia interface) on a TV or other monitor. Once installed, it allows you to cast video and audio streams from an iOS or Android device, or from the Chrome web browser.

As of 2021, there are two Chromecast models available. Both have the basic casting functionality, but the newer Chromecast with Google TV has its own operating system that runs streaming media apps and other functionality without a smartphone or other device. In the U.S., the Chromecast retails for $29.99, and the Chromecast with Google TV is priced at $49.99. Google also offers a Chromecast with Google TV bundled with six months of Netflix for $89.99.

When you cast media to your TV with a Chromecast device, your phone, tablet, laptop or desktop acts as the initial launching site for the entertainment and as the remote for controlling what you see and hear on your TV screen. The Chromecast with Google TV is the first Chromecast that comes with its own remote to help you choose what to watch.

Chromecast Technical Specifications

Although the original Chromecast looked a lot like a bulbous flash drive, the third-generation model is disc-shaped with a cord permanently attached that you plug into your TV. It's 6.4 inches long (162 millimeters) from end to end with the cord included, but the device itself is 2 inches (51.8 millimeters) in diameter and half an inch (13.8 millimeters) thick. In addition to its HDMI connector, it has a micro USB port for power. It comes in two colors — chalk and charcoal.

The Chromecast with Google TV has a similar form factor, although the device itself is ovular. It is 6.4 inches (162 millimeters) long, 2.4 inches (61 millimeters) wide and 0.5 inches (12.5 millimeters) thick. It comes in three colors: snow, sunrise and sky. The remote control for each is color coordinated and offers voice control in addition to physical buttons. Like its brother, the Chromecast with Google TV has an HDMI connector to plug into the TV, but the power cable uses a USB-C connection rather than micro USB.

Specifications for the two are similar, but the Chromecast with Google TV needs additional storage for any apps the user wants to add. Although it has 8GB flash storage, the operating system itself takes around 3GB, cutting usable storage nearly in half.

The third-generation Chromecast offers 1080p resolution with a 60 frames-per-second refresh rate. The Chromecast with Google TV can handle 4k HDR video with a refresh rate of 60 frames per second. It also has functionality the basic Chromecast doesn't. Its voice remote lets you use Google Assistant, you can play games on Google's Stadia service and you can control smart-home devices with it as well.

Chromecast is supported by the following operating systems, although some of its features may work with slightly older OSes in a few cases:

  • Android 6.0 or higher

  • iOS or iPadOS 12.0 or higher

  • Mac OS 10.9 or higher

  • Windows 7 or higher

  • Linux computers' compatibility is based on the distribution, desktop support and available drivers

What Makes Chromecast Stream to Your TV?

Chromecast gets content to your TV screen from a remote device in part by using something called the DIAL (Discovery And Launch) protocol. DIAL was developed jointly by Netflix and YouTube, which is owned by Google. DIAL is free for others to use and is used in devices and apps by many manufacturers and content providers.

One of Chromecast's components, the DIAL Service Discovery protocol, uses Simple Service Discovery Protocol (SSDP) version 1.1, which is defined by UPnP (Universal Plug and Play), to allow a DIAL client device to locate a DIAL server device running on the same network. The other component, the DIAL REST (representational state transfer) Service, is then accessed to query, launch or stop applications using HTTP (hypertext transfer protocol) requests from the client device to the server device. In the case of Chromecast, your phone, tablet or computer is the client and the Chromecast itself is the server.

Google created Google Cast screen-sharing technology to work on top of DIAL, adding a lot more functionality than DIAL could offer alone. It developed the Google Cast SDK (software development kit) to enable developers to add related functionality to third-party apps that can be used to launch media from the client device to the Chromecast. There are Google Cast APIs (application programming interfaces) for each compatible operating system. All this allows for functionality such as pausing and volume control, as well as additional features that app developers are free to implement.

The basic Chromecast runs a pared-down version of the Chrome browser. The applications on the device are web applications that receive the aforementioned HTTP requests and react accordingly. Once an app is launched, it runs on the Chromecast, but a communication channel will be open that allows the client device to act as a sort of remote control. This dynamic allows you to turn off your mobile device without stopping whatever is streaming from the Chromecast to your TV.

To set up Chromecast, you have to use the Google Home app on mobile devices, or Google's Chrome web browser on a computer. Once the Chromecast is set up, you use third-party apps like Netflix, YouTube or the Chrome browser to do the actual launching and controlling of your content.

There are currently other apps that work in conjunction with set-top boxes like gaming systems to enable you to use a smartphone or tablet as a remote control. But in those cases, you have to launch the app on the set-top box and the app on the mobile device and run them simultaneously. Chromecast (via DIAL) eliminates a step by allowing launch and control of an app from a single device for playback on the TV through the Chromecast. It may herald the future simplification of our living room remote control situation.

The Chromecast with Google TV uses the Android TV operating system, rather than a modified Chrome browser. It can run many Android apps from the Google Play Store, including popular streaming media apps. Although you can cast media from your phone or computer to the device, the Chromecast with Google TV can run apps all by itself. Google TV is an interface running on top of the Android TV system that adds Google Assistant, Google Knowledge Graph and machine-learning capability.

What Services Work With Chromecast?

At launch, not much besides Netflix and YouTube worked on Chromecast, but many other services have become integrated with the device since then, including video, music, news, media storage and sharing apps, productivity tools and games. Many of them require paid subscriptions to third-party providers.

Neither the Chromecast nor the Chromecast with Google TV require a special app for casting. Instead, developers use Google's Software Development Kit (SDK) to build compatibility into the apps themselves. Casting requires WiFi, and Google cautions that if you have more than one network in your home, you must be sure that both the device and the Chromecast are on the same WiFi network.

That's also true if you're streaming from the Chrome browser to your TV.

What You Can Do With Chromecast

There are many other methods of streaming content to your television, including game systems, DVRs and Blu-ray players. If you have one of those and don't mind the inconvenience of regular remote controls (or you're willing to buy a universal remote), you may not need an additional device. But if you're interested in a stand-alone streaming device, Chromecast is one of many devices you can choose from.

Roku is one of Chromecast's larger competitors. There are four different models ranging from $30 to $100 as of mid-2021. The lower-end Roku Express and Express+ stream at a maximum of 1080p, whereas the others can stream at 4k. All include WiFi, but the two most expensive, the Roku Ultra LT and Roku Ultra also includes Ethernet for more reliable connections. Roku supports many of the same streaming channels as the Chromecast, although Roku now has its own channel as well. They all come with remotes and don't require that you have a tablet or smartphone for control, but you can download an app to use your mobile device as a remote if you want. Roku also uses the DIAL protocol in its devices.

The Apple TV 4k starts at $179 and is more like the Roku and Chromecast with Google TV devices. It's able to run many iPhone and iPad apps. You can cast media to the Apple TV as well. At the time of writing, Apple still sells its Apple TV HD for $149. Both of Apple's products run the tvOS operating system — the primary difference between the two being screen resolution. It also supports streaming to other devices, though not to Chromecasts.

Miracast isn't a device but a software standard that connects the casting device and receiving device through peer-to-peer WiFi. Because it works peer-to-peer, Miracast doesn't need an internet connection. Created by the Wifi Alliance, Miracast technology can be found in devices from many manufacturers.

Critical Reception and Future Development

The Chromecast has been very successful since it went on the market in July 2013. Initially, it sold out very quickly, and the availability of a limited Netflix promotion (three free months of service) ran out within a few hours of launch — the device wound up on backorder for up to three months for some purchasers. By the end of 2013, Chromecast was readily available from retailers.

Reviewers praised the device for being one of the cheapest streaming options, for ease of setup, for working quite well via its supported apps and for its unobtrusive form factor that allows it to hide behind your TV in most cases. It does require a power cable, however, which can make it a slightly awkward addition to your home entertainment system, perhaps especially as these devices have become smaller and sleeker and eventually disappear into the smart TV.

The strength of your WiFi network can also affect Chromecast's streaming picture quality. Some users experience a lag of a few seconds between casting media and when it actually plays. And if you don't have a compatible client device running a supported OS and a compatible router, you're out of luck entirely.

Because any compatible device on the same network can control any Chromecast on that network, multiple devices can interfere with each other. The last one that tries to play a video or music or cast a tab to your Chromecast will win out. This might not be much of a problem on a home network, unless someone unintentionally casts something they wouldn't want their family or visiting friends to see (or if you live with a jerk).

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