S-Video in the context of Video-in video-out

HDMI (High-Definition Multimedia Interface) is a brand of proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gaming consoles, and personal computers. HDMI supports uncompressed video and either compressed or uncompressed digital audio, allowing a single cable to carry both signals.

Introduced in 2003, HDMI largely replaced older analog video standards such as composite video, S-Video, and VGA in consumer electronics. It was developed based on the CEA-861 standard, which was also used with the earlier Digital Visual Interface (DVI). HDMI is electrically compatible with DVI video signals, and adapters allow interoperability between the two without signal conversion or loss of quality. Adapters and active converters are also available for connecting HDMI to other video interfaces, including the older analog formats, as well as digital formats such as DisplayPort.

Mini-VGA connectors are proprietary and non-standard alternative video connectors that were used on some laptops and other computer systems in place of a standard VGA connector. Apple, HP, and Asus each introduced separate connectors using the same moniker of "mini-VGA", but which are otherwise physically incompatible with each other (though all of them are compatible with standard VGA using the correct adapter).

Apple's mini-VGA ports may be found on some older Apple computers, including iBooks, eMacs, certain PowerBooks (e.g., early G4 12-inch), and some iMacs (e.g., iMac G4, G5). In addition to a more compact form-factor, Apple's mini-VGA ports also have the added ability to output composite as well as S-Video, in addition to VGA signals, through the use of EDID. When used for S-Video, S-Video's chrominance (C) and luminance (Y) signals replace VGA's red (R) and green (G) channels, while for composite video, the signal is output through VGA's blue (B) channel. (The horizontal and vertical sync pins of VGA are left unused.)