What exactly does HDMI ARC do? Is it actually worth using?

The trusty High-Definition Multimedia Interface has been the go-to digital connector for flatscreen TVs, projectors and other AV equipment for getting on for 15 years now. Over that time it’s evolved into a do-it-all connection, acting as a medium for various video and audio formats.

HDMI ARC (Audio Return Channel) is a clever protocol that sits within the HDMI standard and, in theory, it can help simplify a complicated AV set-up and reduce the number of cables you need.
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