What is screen mirroring?

Screen mirroring is a combination of hardware and software that allows you to display the contents of a smartphone, tablet, or computer screen on another screen, such as a TV, monitor, or video game console. This feature is widely used today for presenting and viewing content on a larger screen. Either a wired or wireless network can be used to transmit the signal from one device to another.

Screen mirroring and use cases

Screen mirroring is the process of copying media content displayed on one device’s screen to another in real time. It’s a very convenient solution for a variety of use cases, including sharing images, watching videos, and more. This feature allows users to share their device’s screen wirelessly.
For screen sharing, the user can provide wired or wireless equipment. The specific use case determines the type of communication channel between the devices. To provide the best image quality and instant system response, it’s essential to ensure a good communication channel between the two devices. In this case, it’s best to use a wired connection through a router or a direct connection (Ad-Hoc mode) between the devices. If you only have a wireless connection, you need to make sure that this connection is high-quality and reliable for transmitting the video signal, for example: select a Wi-Fi router frequency of 5 GHz and a wider data transmission bandwidth.

How does screen mirroring work?

Screen mirroring is based on establishing a network connection between a broadcast device (for example: a mobile phone screen) and a viewing device (for example: a TV). So, let’s try to understand what happens inside the screen mirroring process. It includes the following steps:
• Screen capturing of the image on the broadcast device
• Then the captured image is processed according to the video encoder’s requirements: the video resolution is scaled, image is converted to the required format, etc
• The encoded video data is processed and transmitted over the network
• The encoded video signal is received on the viewing device side
• The received video signal is decoded, processed and displayed on the screen of the viewing device
The above steps are performed continuously in real time. To achieve this functionality, screen mirroring application must be optimized for different devices: mobile phones, TVs, desktop computers, etc.

Video streaming and real time screen mirroring

Today, there are many technologies available, and sometimes it can be difficult to understand the differences between them. Next, we will try to explain the difference between video streaming and screen mirroring in general terms.

Video streaming: The process of transmitting a video signal from a broadcast device to a viewing device. This is a more general concept. The broadcast device can be a phone or laptop camera, screen of device or a video file. There is such a thing as delay (or latency) between the broadcast device and the playback device. In this more general case, the latency between the broadcast device and the viewing device is less important than for screen mirroring. The latency can be, for example: 100 milliseconds (1 / 10 of second), 1000 milliseconds (on second) or 10 seconds.

Screen mirroring: The process of displaying the entire screen of one device to another in real time. In this case, it’s important to transmit and to broadcast the image in real time with minimal latency. Screen mirroring imposes some requirements on the latency between devices. It’s clear to everyone: if we have minimal latency between devices, then we’ll be able to see the updated image on the viewing device faster.

App description

To achieve screen mirroring functionality user can use alfacast app. Alfacast app allows you to stream and to view video from the screen of device (screen mirror). The application automatically detects all devices inside your network on which the alfacast is installed and running. The application supports audio and video stream splitting to broadcast screen content in real time. The rest part of this article is described actions need to stream and view of your screen, general system requirements, tips and so on.

Steps for screen streaming

Please follow the steps below on your broadcast devices:
• Download alfacast application on your devices
• Connect your devices to the same network
• Run alfacast application on your devices
• Now your are ready to accept incoming connection
• Please find more detailed info about supported OS for streaming in the Supported platforms section

Steps for screen viewing

Please follow the steps below on your viewing device:
• Download alfacast application on your devices
• Connect your devices to the same network
• Run alfacast application on your devices
• Wait end of the discovery process (approximately 15-30 seconds)
• Select the required streamer from the list and wait end of the connection process
• Now your will view remote screen

General requirements

Please note, alfacast app has some requirements for usage:
• Support IPv4 networks only
• The devices should be connected to the same network
• Supporting the next video codecs: hardware accelerated H.264, H.265, VP8, VP9 or similar software video codecs

4K Ultra HD resolution and 60 FPS requirements

Please read the following points to ensure proper support for 4K Ultra HD resolution on your devices:
• Extended version of application on streamer and viewer side
• Display with 4K Ultra HD resolution and 60 Hz on streamer side
• Hardware accelerated H.264, H.265, VP8 or VP9 video codec with 4K Ultra HD support
• The final video stream resolution and refresh rate depends from the maximum resolution and refresh rate of streamer’s display, current video codec configuration and network bandwidth

Supported platforms

Now alfacast app supports the next platforms:
• Apple macOS™ (Streamer and Viewer)
• Apple iOS™ (Streamer and Viewer)
• Apple tvOS™ (Viewer Only)
• Amazon Fire OS™ (Streamer and Viewer)
• Google Android™ (Streamer and Viewer)
• Google Android TV™ (Streamer and Viewer)
• Google Wear OS™ (Streamer and Viewer)
• Linux™ (Streamer and Viewer). Not all devices based on this OS support streaming mode
• Microsoft Windows™ (Streamer and Viewer). Not all devices based on this OS support streaming mode

The application supports

For a better understanding, we provide the following list of features that our application supports:
• Streaming audio & video from your screen
• Playback audio & video on the side of the viewer
• Screen streamer and viewer in one application
• Audio and video splitter for simultaneously streaming screen content to multiple devices in real time
• Secure connection with end-to-end encryption
• Display current streaming information
• Automatic users discovery in the local area network
• Connection only over local area network

The application does not support

To avoid any misunderstandings, we provide the following list of what our application does not support:
• Alfacast is not DLNA™, UPnP™ media render or media server
• Alfacast is not Apple AirPlay™ receiver or transmitter
• Alfacast is not Google Chromecast™ receiver or transmitter
• Alfacast is not Miracast™ receiver or transmitter
As we can see there are various screen mirroring technologies. Alfacast app is an independent streaming technology based on Netstream proprietary technology. As a result, the user has to install alfacast on both sides: on the streamer and on the viewer devices.

Tips for the best screen mirroring experience

We provide the following tips to make the best use of the screen mirroring feature:
• Make sure your streaming and viewing devices are updated and you use the latest version of software
• Make sure your router has the latest firmware
• If you have any general problems with screen mirroring please read our Troubleshooting page
• If you have problems with the router then you can find more tips on Router Setup page