The main function of the increased bandwidth (previous versions maxed out at 10.2 Gbps) is to carry 4Kx2K 2160p resolutions (see #2).
The HDMI 2.0 standard will support 4Kx2K Ultra HD resolutions up to 60fps, providing four times the clarity of 1080p video. This also ensures full 3D support for 4K resolutions and higher frame-rate 2D video.
HDMI.org calls this the “multi-dimensional immersive audio experience”. This is probably way more capability than most of us will ever use, but will come in handy for audio professionals and enthusiasts not satisfied with 7.1 surround sound.
The HDMI Forum describes this as the “highest audio fidelity”, but humans cannot detect a difference above 60kHz, so this likely falls into the same realm as the 32 audio channels – more of a benefit for audio professionals.
This means multiple users can be on the same screen at the same time, watching two separate video streams. Or one user watching multiple streams, if you’re a multitasker.
Because we all know bigger is better.
HDMI 2.0 will automatically keep your video and audio in check when it comes to different video processing times, so there won’t be any need for manual adjustments.
HDMI 2.0 uses CEC extensions to provide expanded command control. This means fewer remote controls to lose in the couch cushions.
Just like previous HDMI releases, the 2.0 standard is fully backwards compatible with any previous standards. Your existing equipment will work fine with newer 2.0 compliant devices.
I repeat: You do not need new HDMI cables to take advantage of HDMI 2.0. The HDMI 2.0 standard applies to devices. Any current High Speed HDMI cables will carry the increased bandwidth without any problems. It uses the same connectors, as well.
And there you have it. You can rest assured your older equipment and cables will work fine with the shiny new HDMI 2.0 devices expected to flood the market in 2014. Invest more in the device and have confidence in your cheap HDMI cable. :)