Android device screen mirroring

The article was supplemented on June 12, 2015 with a number of information about the Miracast and Intel WiDi protocols.

Apple has its own protocol AirPlay (uses Bonjour), which may require special WiFi settings to communicate on the network at all. But when it works, the video transmission is quite good. It supports media streaming, but also AirPlay Mirroring (mirroring the entire screen). It was assumed that we would use AirPlay together with the Apple TV, a hardware device connected via HDMI to the TV or projector and at the same time to the same WiFi network as the mobile device. We can then wirelessly transmit the image to the Apple TV and it will ensure the display on some screen. But today there are a number of applications that are installed on the computer (Windows or OS X) and serve as an AirPlay Receiver. Almost all of them are paid (but quite reasonably), an example is Reflector. On the PC, we can display several devices side by side, play the image on the projector, save video, etc.

Various solutions for Android

On Android, the situation is more complicated. There are many options, but they are usually limited or don't work very well. We can mention the following categories/properties:

• output only to TV/projector vs. computer
• need special HW vs. special SW vs. native solution
• free solution vs. paid
• generally functional vs. for certain manufacturers or devices
• standard Android vs. requires Root

VNC server

First, I'll mention an option that turned out to be the best at the end of the testing. It requires a rooted device, a special (free) application on the mobile device and the computer, and a network connection. It allows you to display the Android device's screen on the computer and remotely control the mobile device. We can open several devices side by side. There is one disadvantage, because VNC is not designed for Android, so we don't have access to the HW keys (like menu, home, back). If the device is turned on, we can also remotely control gestures, like for unlocking.

On the Android device, we install the VNC server, for example VNC server, VNC Server Ultimate or the paid VMLite VNC Server (reportedly works even on non-rooted devices). On the computer, we use a VNC client, like Ultra VNC.

HDMI output

For a number of devices, we can buy a special cable or they have an HDMI connector directly, and we can transmit the screen to a TV/projector. I tested this on Samsung Galaxy S3 to S5.

Android SDK (ADK)

We can also use the Android developer tools and connect the phone via USB cable to the computer for image transmission. Unfortunately, the transmission is not smooth (probably only a few frames per second are transmitted). We need the Android SDK and some application/script that uses it, such as Droid@Screen, Android Screen Monitor or androidscreencast.

AirPlay media, DLNA, Miracast

There are several (let's say) standards for network media/screen transfer (often using WiFi). One is the already mentioned AirPlay. For Android, there are a number of applications that support the AirPlay protocol for transmitting media content to an AirPlay receiver. Unfortunately, it can only transfer certain applications and data (video, photo, web).

Similarly (often using the same application), the DLNA (Digital Living Network Alliance) protocol can be used to transfer media content. Some mobile devices (like Samsung) support DLNA out of the box, and we can connect to a variety of TVs (on Samsung AllShare Cast) and other hardware devices.

Examples of applications AllCast and iMediaShare Personal.For Android, there are also AirPlay/DLNA receivers, such as AllCast Receiver and AirPlay/DLNA Receiver (LITE).

More recent is the Miracast standard for multimedia transmission, which is supported in newer versions of Android. We need a receiver again, which are often hardware devices. This protocol is natively supported, for example, on new Panasonic projectors and displays.

For home use, various HW HDMI dongle/stick are sold. It's kind of like Apple TV or Chromecast. Small devices (with a processor and memory) that have an HDMI connector for connecting to a TV and connect to the WiFi network. These devices support one or more protocols DLNA, Miracast, AirPlay. We can often find them labeled as EZcast dongle, one of the cheaper devices is the Sencor HDMI Miracast dongle, another one is the renkCast Stick. In connection with these devices, the EZCast application is often mentioned.

AirPlay Mirroring

For Android, there are currently only about two applications that are said to support screen mirroring using the AirPlay protocol. But we couldn't get either of them to work. Both require a rooted device and are in beta version.

The AirPlay Mirror application has little description beyond various articles, and we couldn't get it to run on several different devices.

The Shou application is often mentioned, with a large discussion on XDA-developers. The latest version looks different from the various screenshots and doesn't offer AirPlay. Older versions didn't detect our Apple TV.

Special HW

Google Chromecast is something like an Android Mini PC directly from Google. It connects via HDMI to a display and we can transmit the image (support is still limited). It's essentially an alternative to Apple TV.

Another device of this type is Roku, which seems to be quite popular.

As a mention, another possibility. Some Panasonic projectors have supported network connectivity and projection for years using the Wireless Manager ME 6.2 for Windows application for Windows or more recently for Android (and iOS) Wireless Projector for Android (can't mirror the whole screen, only displays limited content).

Applications and server - remote access

There are various applications where a server/receiver is installed on the computer and a client/transmitter on the mobile device (similar to the VNC described above). An example is the paid application MirrorOp. The Android transmitter requires a rooted device. This is a functional solution and allows controlling Android.

Another well-known application is TeamViewer, which also supports Android devices in the TeamViewer QuickSupport application. I haven't tested it, according to the information it should work on some devices even without root, but on others it requires root (according to the discussions, many people couldn't get it to work). At least for use in a company, it is a paid application.

Some applications start a web server on the phone, and when we connect to it from a regular browser, we can control the display. An example would be AirDroid (requires root to display the screen).

Miracast and Intel WiDi

Thanks to the new EPSON EB-1985WU projector, which supports WiDi and Miracast, we have tested them. The quality depends on the hardware used, but on new notebooks and Android phones it is perfect.

Miracast

Miracast is a streaming protocol and Wi-Fi Alliance standard for wireless display or screen mirroring, described as wireless HDMI. It uses wireless WiFi Direct connection between two devices. It supports video up to Full HD 1080p and 5.1 surround sound.

Miracast supports the H.264 video codec, Constrained Baseline Profile (CBP), Constrained High Profile (CHP), a wide range of resolutions, and for audio Linear Pulse-Code Modulation (LPCM), Advanced Audio Coding (AAC) and Dolby Advanced Codec 3 (AC3) modes.

On the Wi-Fi Alliance website, there is an official list of devices that support Miracast Miracast-certified products.

Intel Wireless Display (WiDi)

Intel has created its own Wireless Display - WiDi protocol, which is very similar to Miracast and is largely compatible with it (Intel WiDi 3.5 officially supports Miracast). It also supports video up to Full HD 1080p, 5.1 surround sound and uses WiFi Direct. It should achieve very low latency.

The graphics data is encoded using the H.264 video stream and transmitted wirelessly via the WiFi Direct connection to the receiver, which decodes and displays it.

For businesses, Intel has created the Intel Pro WiDi version, which offers a number of additional features. For example, access control to the display device, switching between presenters, preventing projection to other devices, notification that projection is in progress, WiFi property management. More information Intel Pro Wireless Display.

WiFi Direct

Wi-Fi Direct is a technology that allows WiFi devices to connect directly to each other. It's a simple and secure way to synchronize, share, display, print, etc. It uses WPA2 and Wi-Fi Protected Setup.

To establish a WiFi Direct connection, a WiFi network does not need to be created. Some devices allow a classic WiFi network connection (to the internet) to be established at the same time as a WiFi Direct connection. So we can, for example, stream video from the internet using WiDi from a phone.

Clients

Miracast and WiDi support should be in Android 4.2 and above and in Windows 8.1, but not all hardware devices support them.

Native Miracast support in Windows 8.1

In Windows, the wireless display behaves like a standard secondary screen, so we can use mirroring or display extension functions. Microsoft uses the term Wireless Displays (Miracast).

To be able to use Miracast (otherwise we won't see the option in Windows), we need a WiFi network card (and the corresponding driver) with support for Virtual Wi-Fi (allows multiple connections on a single wireless interface) at least NDIS 6.2 and WiFi Direct (direct connection) at least NDIS 6.3 (we can list the NDIS driver versions in PowerShell Get-NetAdapter | Select Name, NdisVersion). And a graphics card with a driver at least Windows Display Driver Model (WDDM) 1.3 with Miracast support. Such drivers are provided by Microsoft, Intel, Nvidia and AMD, they must be newer versions designed for Windows 8.1.

Usage is simple, we display the Windows right-hand menu (by dragging from the right side of the screen or hovering the cursor in the corner on the right side), we choose Devices – Project - Add a wireless display. The system searches for suitable devices within range. More information Project to a wireless display with Miracast.

Windows and Intel WiDi

Another option is to use Intel WiDi in Windows. The official hardware and driver requirements are System requirements for Intel® WiDi, Requirements: Intel WiDi for Home. If we meet the hardware requirements, we can use the Intel WiDi Update Tool to update the drivers.

Intel Pro WiDi requires the Intel Pro WiDi Software for Windows v5.1.x application, and there are also a number of other (additional) applications Intel Wireless Display (Intel WiDi).

For Intel WiDi, we only need the application on lower OS, on Windows 8.1 it's no longer required and we can optionally use supplementary applications like WiDi Remote or WiDi Media Share.

Various materials from Intel Connect to TV Wirelessly with Intel WiDi, Intel Pro Wireless Display, Wireless Streaming to Your TV, Guided Help for Intel WiDi.

Android

On Android devices, the function is located differently depending on the manufacturer. Samsung uses Settings – Connections – Screen Mirroring. Again, suitable devices within range are searched for and we can connect.