Miracast, Wi-Fi Direct and DLNA explained
Miracast 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.