How Screen Mirroring Works

Screen mirroring, streaming, casting. There are a lot of names out there for sharing content from a PC to TV, but they don’t all mean the same thing. Here we cover what wireless screen mirroring is, how it differs from media streaming, and why mirroring is the best solution for classrooms and meeting rooms.

Screen mirroring and media streaming both refer to using a computer to share content to a TV or projector. However, the difference between screen mirroring and media streaming can often be misunderstood. We get this question a lot and want to clear up the confusion between the two types of technology.


Oh, by the way, we’re always happy to tell you more about Airtame. Let’s find a time to talk ☎️.

Screen mirroring and streaming

The major difference between wireless screen mirroring and media streaming is that screen mirroring sends your full computer screen exactly as it is to a larger TV, while media streaming receives content via a digital media player to your TV.

Screen mirroring

Screen mirroring involves sending the information from your computer or mobile device screen to a TV screen or monitor. You can do this with wires or wirelessly.

Wired screen mirroring

For example, how HDMI cables work is that they digitally transfer the information (0s and 1s) from PC to TV. Let’s break down the 3 steps that make this happen.

1. Detecting a connection

This step detects a connection between your computer and TV. When you connect the cable, your computer’s graphic card detects a second screen.

2. Sharing information

Since there are many different screens and resolutions, your computer needs to know some information before it can start a connection with a second screen. This second step tells your computer what the audio and video settings of your TV are, so your computer can display the information properly.

This is also called E.D.I.D. (Extended Display Identification Data).

3. Mirroring starts

After a connection is detected and the computer knows your TV’s settings, the computer sends its information to your TV. What you see on your TV screen is exactly what you see on your computer screen.

Wireless screen mirroring

Wireless screen mirroring, however, comes in different flavors. In this article, we’ll cover cableless HDMI, streaming, and casting.

Cableless HDMI

Cableless HDMI refers to the life mirroring of your PC screen to TV using WiFi.

The Airtame device, for example, uses a WiFi connection to mirror your computer screen. How Airtame works is that it uses PC software to capture your computer screen. It does this by taking screen shots at a rate of 30 images per second.

The computer then packages this data so that it can be sent via a WiFi connection to the Airtame device, which is plugged into the TV or monitor via an HDMI port.

The Airtame device unpacks this information and displays it to the TV. It’s a kind of magic when you consider that this all happens in real-time as you are moving around on your computer.

How screen mirroring works

You can read more about cableless HDMI in our article The cableless HDMI Overview.

Media streaming/casting

Media streaming refers to receiving online content from a streaming device to a TV.

Google Chromecast, which is referred to as a digital media player, is a great example of media streaming. Unlike cableless HDMI, your computer does not send its screen to your TV.

Instead, a media streamer like Chromecast downloads content from the internet to your TV. Because of the predictable nature of the content (in contrast to the unpredictable mouse movements that have to be accounted for in screen mirroring), digital media players can offer better encoding and compression. In turn, streaming media has less delay and is better suited to watching films or other entertainment.

How Media Streaming Works

Note: We’ve had some feedback about our Chromecast vs Airtame article. Some have claimed that Chromecast does offer screen mirroring from a computer, however, we disagree that what Chromecast offers qualifies as full screen mirroring. Chromecast lets you cast a whole browser window to a TV, however, this feature is still in beta and requires some workarounds to accomplish.

Pros and cons

The greatest advantage of wireless screen mirroring over streaming through a digital media player is that the user gets more control over what they share on the big screen.

Screen mirroring allows for more professional use cases than with media streaming, where you are often limited to devices and apps geared towards consumers.

However, if your main use case is to watch media and entertainment, a digital media streamer, like Chromecast, is made to suit your media needs.