Few days ago, we mentioned that WP8.1 brings Miracast support. However according to the recent tweet from Joe Belfiore, Miracast requires new hardware. He hints a phone with at least Lumia 1520 specifications is required which means you would need a powerful quad core phone with ample memory to enjoy this feature.
In other words, Miracast would not be coming to most of the currently available windows phones and to get it you must get a 1520 or the new 930.
Miracast is very much like wireless HDMI cable that lets you mirror your device’s screen onto a HDTV screen with high definition and audio. It creates a ad-hoc network (also known as Wi-Fi direct) and does not rely on your home / office’s Wi-Fi network to work.