HDMI eARC / ARC
HDMI ARC provides for transferring audio from the TV back to a home theater receiver with the same HDMI connection that’s used to transfer video from a home theater receiver to the TV.
With HDMI ARC you can hear TV audio through a home theater audio system instead of the TV’s speakers without having to also connect analog or digital optical audio cables between the TV and home theater system.
HDMI eARC adds the ability to transfer immersive audio formats, such as Dolby Atmos, DTS: X offering a 37 Mbits/sec vs 1Mbits/Sec from ARC vs eARC.
HDMI CEC
Besides transferring both video and audio in a single feed, HDMI was also designed to carry what the industry refers to as “handshake” information from one device to another. These shared transmissions were originally intended to communicate copy protection data to prevent piracy and transfer messages about what type of components were connected, as well as what their capabilities were (and weren’t).
But the system was also designed to share more complex messages as a part of what’s called Consumer Electronics Control (CEC). CEC lets a single remote control operate features on up to 15 connected devices. There are nearly as many names for CEC as there are electronics brands: Samsung has called it “Anynet+,” LG “SimpLink,” and Sony “Bravia Sync.” Unfortunately, the system has never really lived up to its potential, and is often mistranslated or simply lost between components from different manufacturers. ARC can help.