• What is Miracast?

    By Josh Bethell , February 3, 2014 - Leave a comment

    Miracast, Wi-Fi Direct and DLNA explained

    wifi allianceMiracast is a wireless, peer-to-peer screencasting technology that allows you to output video & audio both to and from a number of devices, although most usually from a mobile device to a compatible screen or receiver.

    Miracast can be used to effectively mirror content stored on one device to another. For instance this could be a game you are playing or a movie you are watching (stored locally or streamed via the Internet). Business uses could include streaming a presentation or meeting content from a laptop to a projector.

    The most common analogy to understand Miracast is to think of it as a ‘wireless HDMI cable’. Like HDMI, both ends must support Miracast or use an adapter. The content that can be shared is almost identical too; Miracast can securely transmit video up to 1080p with 5.1 channel sound.

    Miracast uses Wi-Fi Direct

    Wi-Fi Direct is an extension to the Wi-Fi protocol developed by the Wi-Fi Alliance and designed so that compatible devices can connect directly to each other, without the need for an intermediary router or hub. This is often referred to as an ‘ad-hoc’ network. Using Wi-Fi Direct to communicate ensures that traffic on a local network is kept to a minimum. This also makes Miracast a great choice for wireless communication in an environment where you don’t have access to the local network, such as corporate buildings or public Wi-Fi areas with strict rules on the content that can be transmitted.

    You cannot use Miracast to stream content from an enabled device to a router / access point.

    The following image explains the connections in a little more detail. The Miracast connection is between the source & display devices. A router / local network access point may be available, in some cases connected to one or both devices, and even delivering /receiving content to either, however its presence is irrelevant to the actual Miracast connection.

    miracast connections

    Are Miracast and MHL related?

    MHL-Cable.pngNo, MHL has been designed as a universal method of transmitting content between devices using a cable.

    Many modern smartphones use MHL or Slimport technology in their USB connectors; this enables you to attach an adapter and plug in a standard HDMI cable between them.

    Not every phone has this capability and we have written an extensive overview of MHL and related technology HERE.

    What about Miracast and copy-protected content?

    Miracast supports High-bandwidth Digital Content Protection (HDCP), the same trusted mechanism used by wired interface technologies including HDMI and DisplayPort.

    Miracast’s wireless implementation of this protocol allows for the secure transmission of copy protected content from streaming services and recorded physical or digital media (DVD / Blu-ray / download etc.). This protects the interests of digital content owners, allowing for personal transmission and minimising unauthorised broadcast.

    Which devices are Miracast compatible?

    wifi certifiedMiracast has now been available for some time and as such the number of devices that have been registered with the Wi-Fi alliance has grown substantially. Using the links below you can search the Wi-Fi Alliance website for both certified source & display devices:

    Many new higher end smartphones and tablets have support for Miracast, although not all do and some manufacturers have adapted the specification to their own end. Jump to the end

    Does Miracast need any other equipment?

    If both of your devices are Miracast enabled then no, you can connect straight away.

    Most likely though, you will find that your smartphone or other device has Miracast but your TV or other second device does not. In these cases you will need to attach a Miracast enabled adapter or dongle. There are a number of these available from established manufacturers including Sony, Netgear, Linksys etc. Clove have a few ranged which you can view at the following links:

    • NetGear Push2TV Wireless Display Adapter PTV3000
    • Nokia HD-10 Miracast Screen Sharing Adapter

    Is Samsung AllShare / Link the same as Miracast?

    samsung linkSamsung are arguably the most popular Android smartphone and Smart TV manufacturer right now. If you have owned a higher end Samsung device from the last few years then may well have seen the Samsung Link or Samsung AllShare app / option on your homescreen or settings.

    AllShare / Link are not the same as Miracast, although they share some similar features. AllShare used to encompass the DLNA based Play service and the Miracast based Cast service. Play has since been superseded by the Samsung Link moniker, removing the AllShare branding to avoid confusion and create a newer, more powerful service. The bullet points below provide a concise explanation:

    AllShare Play (now obsolete)

    • Utilised DLNA (Digital Living Network Alliance) guidelines for playback of files from one device on another
    • DLNA requires a local home network for device communication and content transmission
    • Superseded by Samsung Link

    Samsung Link (present on newer Samsung devices, post 2013)

    • Uses the DLNA features of AllShare Play
    • Features a centralised online hub to access devices & physical network or cloud storage services registered with your Samsung account
    • Accessible as an app on mobile devices / Smart TV or through a web portal
    • From the portal/app you can stream content from a registered device or ‘throw’ content from your device to another
    • File sharing only, not interoperable with AllShare Cast (screen casting)

    AllShare Cast (present on select Samsung devices)

    • Based on Miracast for direct screen mirroring / screen casting between devices
    • Miracast is an open standard so Samsung were able to modify it
    • Creates a direct connection to another AllShare Cast enabled device such as the AllShare Cast Dongle or Smart TV with AllShare Cast capability
    • Compatible with Samsung devices only, not with other manufacturer’s products
    • Screen casting only, not interoperable with Samsung Link (file sharing)

    Does Miracast use DLNA?

    No, although used for similar means, DLNA (Digital Living Network Alliance) is a different technology. DLNA was established as a nonprofit organisation by Sony in 2003 as a means to organise the sharing of content between devices. DLNA certified devices connect to each other over a local network, with a router acting as an intermediary.

    This differs to Miracast which does not need the router for a connection. DLNA and Miracast can work hand-in-hand though; for instance you could be using DLNA get content delivered from a NAS, desktop PC or other networked storage device directly to your mobile, then push that to a dongle connected to the TV using Miracast. In this situation, the Miracast connection is independent of the DLNA connections between other devices.

    One thing to remember is that whenever DLNA is introduced, their is extra traffic on your local network transmitting the information. With Miracast, whatever is being streamed does not add to the load on the local network.

    Does Miracast need extra power?

    No, Miracast technology is built on top of the existing Wi-Fi technology. This runs from the device’s existing power source.

    Does Miracast provide wireless charging?

    No, wireless charging is catered for by a completely different physical electrical technology. Miracast is a software protocol designed purely for transmitting video & audio over Wi-Fi direct.

    Are Miracast and Apple AirPlay compatible?

    No, Apple AirPlay is a proprietary technology. It provides a similar service to Miracast, however is not compatible outside of Apple products.

    Operating System Support

    Miracast has been available via manufacturer additions in many Android devices since 4.0 Ice Cream Sandwich. Google officially added support to clean Android in the 4.2 Jelly Bean update. Since 4.4 KitKat, devices can be registered with the Wi-Fi Alliance as officially Miracast compatible.

    BlackBerry 10.2 devices natively support Miracast.

    Microsoft Windows 8.1 has Miracast support natively. Developers can implement Miracast on top of the standard Wi-Fi Direct support in Windows 7 and Windows 8. This can also be done through the use of Intel’s proprietary WiDi v3.5 or above. Since Windows Phone 8.1, some devices have had Miracast added via software updates or are compatible from sale – you will need to check individual device specifications in Settings > Project My Screen. The option will not be available if incompatible.

    Apple supports its own AirPlay mirroring instead of Miracast on OS X and compatible iOS devices.

     

    Josh Bethell

    Josh joined Clove part time a few years ago whilst studying Computing at Bournemouth University. Since finishing his studies he has remained at Clove in a full time position, involved in sales, returns and social media. Involved with both consumer electronics and software since the mid 2000s, keeping up to date with industry developments is as much a hobby as it is a job. Easy going but never afraid to share an opinion, Josh can often be found in his spare time listening to some heavy rock or at a local gig as well as playing with the latest gadgets and video games.

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