The Register®

Original URL: http://www.theregister.co.uk/2012/09/19/miracast/

Hello Miracast vid-beaming: ANOTHER thing the iPhone 5 hasn't got

Shiver me timbers, 'tis on the Galaxy SIII though

By Bill Ray

Posted in Phones, 19th September 2012 09:36 GMT

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The Wi-Fi Alliance has formally launched Miracast, the 5GHz peer-to-peer wireless connection for echoing a phone onto a TV, with a test suite and the first devices supporting the protocol.

Those devices are the Samsung Galaxy SIII and Echo-P Series TVs, with support promised for the Note range of tablets. Less-specific messages of support have come from Sony, LG, Intel and a host of other silicon manufacturers who reckon Miracast will be the next big thing in Wi-Fi.

Miracast uses the existing 2.4GHz Wi-Fi connection to negotiate a 5GHz Wi-Fi Direct connection specifically for the streaming of video. Chip makers have talked about background streaming, but the killer application is replicating the tablet/phone display on a big screen without all that mucking about with codecs and DRM which DLNA involves (though without the quality too).

DLNA also uses the existing IP network to negotiate use of a big screen, but it also offloads decoding of the video stream to that device, which can be an advantage - the big screen may be better at rendering video than the phone - however it also limits the technique to content both devices can decode, and content which isn't protected by rights management locked to a specific device.

Miracast, in contrast, is effectively a wireless HDMI cable, copying everything from one screen to another using the H.264 codec and its own DRM layer emulating the HDMI system. The Wi-Fi Alliance suggests Miracast could also be used by a set-top box wanting to stream content to a TV, or tablet, but the killer app is replication.

When DLNA works it is top: being able to throw a YouTube clip to the living-room TV and see the quality improve is like science fiction to most of us, but if TV and/or content refuse to play nicely then it all breaks down. Miracast is hoping to capitalise on that failure by reducing the intelligence required of the display, using standard Wi-Fi communications and separating devices into "Source [1]" and "Display [2]" categories.

Wi-Fi Direct, the peer-to-peer protocol used by Miracast, has been almost entirely ignored by the world despite backers (primarily Intel) pushing it as the next evolution of Wi-Fi. The standard allows a device to maintain multiple wi-fi connections, and has been touted as the ideal tech of mice, keyboards and all sorts of unlikely things [3], but so far adoption has been very slow. Miracast could be the killer app for Wi-Fi Direct, if the DLNA team doesn't get its act together first. ®