It's the most popular display connection format currently available, but do you know how it works... or even what it stands for?
Short for High-Definition Multimedia Interface, HDMI is a proprietary format for transmitting uncompressed digital video and audio from a source such as a computer or media player, to a display such as a TV or monitor.
The format uses transition-minimised differential signalling (TMDS), for eliminating electromagnetic noise. This uses twisted groups of wires, like those found in network cables, plus a sophisticated coding algorithm to ensure the signal is not corrupted.
Sending an audio stream alongside the video is a valuable advantage of HDMI, as is the option of extracting that audio to TOSLINK, 3.5mm aux and digital coax output.
Another benefit is that there's no problem with splitting or switching HDMI. Splitting is when you send one source signal, for example from a media player, to several displays. Switching is the opposite: you have several source options, such as a games console, a casting dongle and a laptop, and you want to choose which one you're watching from.
You might be frustrated that you have no way of connecting an old plasma TV that you're sentimentally attached to, or an LCD monitor that still works perfectly well, to hardware that only has an HDMI output. Don't despair! There are converters and adaptors available to make just about anything HDMI-compatible.
‣ Plug an HDMI source into VGA input
‣ Connect HDMI to DVI-D
‣ Convert HDMI signal to composite analogue RCA
And going in the other direction:
‣ Convert VGA output plus stereo audio into HDMI
‣ Use an HDMI monitor or TV with a composite source signal
‣ Plug a smartphone into an HDMI input
‣ Convert Type-C USB to HDMI
‣ Connect HDMI to a USB 3.0 port
‣ Plug a Mac® with Mini DisplayPort into an HDMI monitor
See below for more details about HDMI cables.