Miracast is awireless communications standard created by theWi-Fi Alliance which is designed to transmit video and sound from devices (such as laptops or smartphones) to display receivers (such as TVs, monitors, or projectors). It usesWi-Fi Direct to create anad hoc encrypted wireless connection[1] and can roughly be described as "HDMI overWi-Fi", replacing cables in favor of wireless.[2] Miracast is utilised in many devices and is used or branded under various names by different manufacturers, includingSmart View (by Samsung),[3][4]SmartShare (by LG),screen mirroring (by Sony),Cast (in Windows 11) andConnect (in Windows 10),wireless display andscreen casting.[5][6][7]
A related enterprise protocol namedMiracast over Infrastructure (MS-MICE) functions using a centrallocal area network instead, and is supported inMicrosoft Windows.[8]
The Wi-Fi Alliance launched the Miracast certification program at the end of 2012.[9] Devices that are Miracast-certified can communicate with each other, regardless of manufacturer.Nvidia announced support in 2012 for theirTegra 3 platform,[10] andFreescale Semiconductor,Texas Instruments,Qualcomm,Marvell Technology Group and other chip vendors have also announced their plans to support the Miracast standard.[11][12]
TheWi-Fi Alliance maintains a list of certified device models, which numbered over 13,200 as of 31 October 2024.[update][13]
Miracast is based on thepeer-to-peerWi-Fi Direct standard. It allows sending up to1080p HD video (H.264 codec) and5.1 surround sound (AAC andAC3 are optional codecs, mandated codec islinear pulse-code modulation – 16 bits 48 kHz 2 channels).[14] The connection is created viaWPS and therefore is secured withWPA2. IPv4 is used on theInternet layer. On the transport layer,TCP orUDP are used. On theapplication layer, the stream is initiated and controlled viaRTSP,RTP for the data transfer.[15][16][17][18]
| Version | Date | Remarks[19] |
|---|---|---|
| 1.0 | 2012-08-24 | Public release version |
| 1.1 | 2014-04-24 | Public release for HDCPv2.2 updates. |
| 2.0 | 2017-04-21 | Release 2 final version. |
| 2.1 | 2017-07-31 | Corrected heading errors in sections 4.3 and 4.4. Miracast as a use forWi-Fi Direct.[1] Miracast hardware now supports HD, FHD and 4K screen streaming. |
The technology was promoted to work across devices, regardless of brand. Miracast devices negotiate settings for each connection, which simplifies the process for the users. In particular, it obviates having to worry about format orcodec details.[20] Miracast is "effectively a wirelessHDMI cable, copying everything from one screen to another using the H.264 codec and its owndigital rights management (DRM) layer emulating the HDMI system". The Wi-Fi Alliance suggested that Miracast could also be used by aset-top box wanting tostream content to a TV or tablet.
Both devices (the sender and the receiver) need to be Miracast certified for the technology to work. However, to stream music and movies to a non-certified device, Miracast adapters are available that plug intoHDMI orUSB ports.[21] Certification does not mandate a maximum latency (i.e. the time between the display of pictures on the source and display of the mirrored image on the sync display). Even with certification, it is possible an underpowered device will be constrained in performance or bandwidth.[citation needed]
Miracast can stream videos that are in1080p, media with DRM such asDVDs, as well as protected premium content streaming, enabling devices to stream feature films and other copy-protected materials. This is accomplished by using a Wi-Fi version of the same trusted content mechanisms used on cable-based HDMI andDisplayPort connections.[22]
Mandatory: ITU-T H.264 (Advanced Video Coding [AVC]) for HD and Ultra HD video; supports several profiles in transcoding and non-transcoding modes, including Constrained Baseline Profile (CBP), at levels ranging from 3.1 to 5.2
Optional: ITU-T H.265 (High Efficiency Video Coding [HEVC]) for HD and Ultra HD video; supports several profiles in transcoding and non-transcoding modes, including Main Profile, Main 444, SCC-8 bit 444, Main 444 10, at levels ranging from 3.1 to 5.1
Mandated audio codec: Linear Pulse-Code Modulation (LPCM) 16 bits, 48 kHz sampling, 2 channels
Optional audio codecs, including:
A device's wireless network adapter must supportWi-Fi Direct and Virtual Wi-Fi for it to work with Miracast; generally most adapters built since 2013 should meet the criteria. In Windows computers this can be checked by looking at the adapter'sNDIS version which must be 6.3 or above.[24] However Miracast support also depends on the software implementation by manufacturers. Most modern devices support Miracast, with notable exceptions being products fromGoogle[25] andApple.[26]
Microsoft also added support for Miracast in Windows 8.1 (announced in June 2013)[27][28] and available on hardware with supported Miracast drivers from hardware (GPU) manufacturers.Windows 10 andWindows 11 support Miracast transmitting along with User Input Back Channel (UIBC) support to allow forhuman interface devices (touch screens, mouse, keyboard) abbreviated asHID, to also have wireless connectivity (provided the host hardware also supports this). The transmit feature is built-in from launch for all Miracast devices with no additional setup past using the WIN+K keystroke to pair with a compatible display sink (including Microsoft's own Wireless Display Adapter).
Developers can also implement Miracast on top of the built-inWi-Fi Direct support inWindows 7 andWindows 8.[29]Windows 8.1 supports broadcasting/sending the screen via Miracast.[30] Another way to support Miracast in Windows is with Intel's proprietaryWiDi (v3.5 or higher).
While Linux does not feature native support, several add-on software solutions exist.[31][32][33] In theGNOME ecosystem, the GNOME Network Displays application has allowed for Miracast screen sharing. As part of the 2023Google Summer of Code, an effort to integrate this as a feature in the GNOME Settings was announced, which would mean functionality would be hadout of the box with that desktop environment.[34]
Windows 11 and Windows 10 (sinceWindows 10 version 2004) also have the ability to use Miracast to make a monitor display (of a computer running Windows) act as a secondary screen of another device. This feature can be set up in theProjecting to this PC setting. It requires the downloading of the optional Wireless Display add-in feature in Windows, which adds the UWP-based Wireless Display app (known as Connect beforeWindows 11 version 22H2)[35] and is launched on the receiving device.[36][37]
Miracast support was built into stockAndroid as of version 4.2 (Android Jelly Bean)[38][39][40] - as of January 2013, theLGNexus 4 andSony'sXperia Z, ZL, T and V officially supported the function,[41] as didHTC One,Motorola in theirDroid Maxx andDroid Ultra flagships, andSamsung in itsGalaxy S III andGalaxy Note II under the monikerAllShare Cast.[42] TheGalaxy S4 usesSamsung Link for its implementation.[43] Some devices such as theNexus 7 don't support it due to hardware limitations.[44]
SinceAndroid 6.0 Marshmallow released in 2015, Google dropped[25] Miracast support in favor of their own proprietaryGoogle Cast protocol[25] which was introduced with theirChromecast device.[45] Despite this there are third-party Miracast apps for Android available.[46] Many device manufacturers have retained Miracast support through their customized versions of Android (for example: Smart View on Samsung'sOne UI, Cast on Xiaomi'sMIUI, Screencast on Oppo'sColorOS, Wireless Projection on Huawei'sEMUI,HTC Sense,LG UX,Asus ZenUI,Sony Xperia devices, OnePlus'sOxygenOS etc.).[47] The performance and quality of the streamed video is dependent on the device's hardware.
Nokia devices, which ran a near-stock version of Android, originally did not support Miracast. However, Nokia 7 Plus, 8, 8 Sirocco, and 8.1 smartphones that have been upgraded to Android 9 or 10 are able to support Miracast, after enabling Wireless Display Certification in Developer Options. Devices such as Nokia 2.3, 2.4, 3.4, 5.4, and 8.3 5G have Miracast support enabled by default.[48] The same option is present to stock Android as well, with Google describing it as based on the "Wi-Fi Alliance Wi-Fi Display Specification",[49] but it tends to be useless as Miracast code was removed.[50]
Samsung televisions support Miracast[51] where it is namedSmart View (including all models made since 2016[52]). Miracast is also supported onLG smart TV models, someToshiba TVs,[53]Sharp,Philips (Wireless Screencasting),[54] andPanasonic televisions andBlu-ray players.[55][56]Sony Bravia models of televisions released between 2013 and 2020 normally have Miracast. The feature is namedscreen mirroring.[57] Newer models withAndroid TV instead make use of theGoogle Cast protocol.[58]
On 23 September 2014, Microsoft announced the Microsoft Wireless Display Adaptor, a USB-powered HDMIdongle for high definition televisions.[59][60] Simple dongles such as these can be used to provide Miracast to a television (or other display) that lacks the feature built-in.[58]
Miracast over Infrastructure Connection Establishment Protocol (MS-MICE) allows the capabilities of Miracast but through a local network instead of directly. It has been supported in Microsoft Windows sinceWindows 10, version 1703. MS-MICE connects with computers that are connected to the network via secure Wi-Fi or throughEthernet.[67]
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