Miracast is a standard for wireless connections from devices (such as laptops, tablets, or smartphones) to displays (such as TVs, monitors or projectors), introduced in 2012. It can roughly be described as "HDMI over Wi-Fi", replacing the cable from the device to the display.
The Wi-Fi Alliance launched the Miracast certification program at the end of 2012. Devices that are Miracast-certified can communicate with each other, regardless of manufacturer. Adapters became available that plug into HDMI or USB ports, allowing devices without built-in Miracast support to connect via Miracast. By 2017, ComputerWorld observed that "Miracast never quite caught on as a standard", with the Android operating system having dropped support in 2015 already.
Miracast employs the peer-to-peer Wi-Fi Direct standard. It allows sending up to 1080p HD video (H.264 codec) and 5.1 surround sound (AAC and AC3 are optional codecs, mandated codec is linear pulse-code modulation - 16 bits 48 kHz 2 channels). The connection is created via WPS and therefore is secured with WPA2. IPv4 is used on the Internet layer. On the transport layer, TCP or UDP are used. On the application layer, the stream is initiated and controlled via RTSP, RTP for the data transfer.
Video Miracast
Devices
The Wi-Fi Alliance maintains a list of certified devices, which numbered over 6,700 as of 9 March 2017.
Nvidia announced support in 2012 for their Tegra 3 platform, and Freescale Semiconductor, Texas Instruments, Qualcomm, Marvell Technology Group and other chip vendors have also announced their plans to support it. ActionTec Electronics also supports Miracast with its line of Screenbeam products.
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 into HDMI or USB ports.
On 29 October 2012, Google announced that Android version 4.2+ (from updated version of Jelly Bean) are supporting the Miracast wireless display standard, and by default have it integrated. With Android 6.0 Marshmallow, released in 2015, Miracast support was dropped again.
As of 8 January 2013, the LG Nexus 4 and Sony's Xperia Z, ZL, T and V officially supported the function, as did HTC One, Motorola in their Droid Maxx & Ultra flagships, and Samsung in its Galaxy S III and Galaxy Note II under the moniker AllShare Cast. The Galaxy S4 uses Samsung Link for its implementation. In October 2013, BlackBerry released its 10.2.1 update to most of the existing BlackBerry 10 devices available at that time. As of March 2015, the BlackBerry Q10, Q5, Z30, and later models support Miracast streaming; the BlackBerry Z10 does not support Miracast, due to hardware limitations.
In April 2013, Rockchip unveiled a Miracast adapter powered by the RK2928.
Microsoft also added support for Miracast in Windows 8.1 (announced in June 2013) and Windows 10. This functionality first became available in the Windows 8.1 Preview, and is available on hardware with supported Miracast drivers from hardware (GPU) manufacturers such as those listed above.
The WDTV Live Streaming Media Player added Miracast support with firmware version 2.02.32
The Amazon Fire TV Stick, which started shipping on 19 November 2014, also supports Miracast.
The Roku streaming stick and Roku TV started providing support for Miracast starting October 2014.
On 28 July 2013, Google announced the availability of the Chromecast powered by a Marvell DE3005-A1, but despite the similarity in name and Google's early support of Miracast in Android, the Chromecast does not support Miracast.
As of late April 2016, the Ubuntu Touch-powered Meizu Pro 5 supported Miracast in OTA-11.
Maps Miracast
Functionality
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 or codec details. Miracast is "effectively a wireless HDMI cable, copying everything from one screen to another using the H.264 codec and its own digital rights management (DRM) layer emulating the HDMI system". The Wi-Fi Alliance suggested that Miracast could also be used by a set-top box wanting to stream content to a TV or tablet.
Types of media streamed
Miracast can stream videos that are in 1080p, media with DRM such as DVDs, 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 and DisplayPort connections.
Display resolution
- 27 Consumer Electronics Association (CEA) formats, from 640 x 480 up to 4096 x 2160 pixels, and from 24 to 60 frames per second (fps)
- 34 Video Electronics Standards Association (VESA) formats, from 800 x 600 up to 2560 x 1600 pixels, and from 30 to 60 fps
- 12 handheld formats, from 640 x 360 up to 960 x 540 pixels, and from 30 to 60 fps
- Mandatory: 1280 x 720p30 (HD)
- Optional: 3840 x 2160p60 (4K Ultra HD)
Video
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
Audio
Mandated audio codec: Linear Pulse-Code Modulation (LPCM) 16 bits, 48 kHz sampling, 2 channels
Optional audio codecs, including:
- LPCM mode 16 bits, 44.1 kHz sampling, 2 channels
- Advanced Audio Coding (AAC) modes
- Dolby Advanced Codec 3 (AC3) modes
- E-AC-3
- Dolby TrueHD, Dolby MAT modes
- DTS-HD mode
- MPEG-4 AAC and MPEG-H 3D Audio modes
- AAC-ELDv2
Version history
Issues
Certification does not mandate a maximum latency (i.e. the time between display of picture on the source and display of the mirrored image on the sync display).
OS support
Windows
The latest Windows 10 release supports Miracast receiving along with UIBC support to allow for human interface devices (touch screens, mouse, keyboard) to also have wireless connectivity. Windows 8.1 supports broadcasting/sending the screen via Miracast. Miracast is also built into Windows Phone 8.1. Developers can also implement Miracast on top of the built-in Wi-Fi Direct support in Windows 7 and Windows 8. Another way to support Miracast in Windows is with Intel's proprietary WiDi (v3.5 or higher). A software-based Miracast receiver for Windows 8.1, AirServer Universal, was made available on 31 October 2014 by App Dynamic.
iOS and macOS
Apple does not support the Miracast standard on iOS or macOS, instead using its own older proprietary peer-to-peer AirPlay protocol.
Linux desktop
MiracleCast provides early support for Miracast, but is not tied to that single protocol.
Android
Miracast support was built into Android with version 4.2 and starting with Android 4.4, devices could be certified to the Wi-Fi Alliance Display Specification as Miracast compatible. Support was dropped again with Android 6.0 Marshmallow in 2015, in favor of Google's own Google Cast protocol.
BlackBerry OS
Miracast is also supported by BlackBerry OS from version 10.2.1 onwards.
See also
- Digital Living Network Alliance (DLNA)
References
External links
- "Wi-Fi Certified Miracast: Extending the Wi-Fi experience to seamless video display - Industry" (pdf). Wi-Fi Alliance. 2012.
- "The Main Wireless HDMI Transmission Protocols and Their Typical Products". Portable Hi-Fi. 2014.
Source of article : Wikipedia
0 Comments