Wikipedia
Miracast is standard for wireless connections from devices (such as laptops, tablets, or smartphones) to displays (such as TVs or monitors). 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 are available that plug into HDMI or USB ports, allowing even non-Miracast devices to connect via Miracast.
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.