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.
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.
Wireless Display (WiDi) was technology developed by Intel that enabled users to stream music, movies, photos, videos and apps without wires from a compatible computer to a compatible HDTV or through the use of an adapter with other HDTVs or monitors. Intel WiDi supported HD 1080p video quality, 5.1 surround sound, and low latency for interacting with applications sent to the TV from a PC.
Using the Intel WiDi Widget users could perform different functions simultaneously on their PC and TV such as checking email on the PC while streaming a movie to the TV from the same device.
WiDi was discontinued in 2015 in favour of Miracast, a standard developed by the Wi-Fi Alliance and natively supported by Windows 8.1 and later.