[opendtv] What is HDMI 2.0a? - CNET

  • From: Craig Birkmaier <craig@xxxxxxxxxxxxx>
  • To: OpenDTV Mail List <opendtv@xxxxxxxxxxxxx>
  • Date: Thu, 21 May 2015 10:42:32 -0400


http://www.cnet.com/news/what-is-hdmi-2-0a/

What is HDMI 2.0a?

Geoffrey Morrison/HDMI.org
HDMI 2.0a is the latest version of the beloved/despised spec that regulates
those ubiquitous cables, inputs and outputs that connect pretty much everything
in your home entertainment center. It's a minor update, but a potentially
important one for this year and beyond.

The most important part up front: Just like before, this is not a cable change.
Your current HDMI cables should work fine.

If you haven't read about HDMI 2.0, definitely check that out first. Some big
changes were made from the previous version (1.4).

Each of these changes has to do with the chips inside the TVs and source
devices like Blu-ray players, not the cables themselves. The cable is just a
dumb pipe. It doesn't care if the data flowing through it is 4K video, high-def
video, standard-def video, or anything in between: HDR, 2160p, or 720p is all
just a variation on a theme -- lots of ones and zeroes.

It's also possible you may never see HDMI 2.0a even written anywhere on TV
specification sheets. A similar thing happened with HDMI 2.0. We'll see.

What changed?

The change has to do exclusively with High Dynamic Range (HDR) content. Not to
be confused with HDR for cameras, HDR for TVs promises better realism thanks to
brighter whites and other improvements, and requires compatible TVs, source
devices and specialized content.

We'll start with the summary of the actual language from the HDMI Forum, which
oversees the specification. Here's the relevant part of its April 8 press
release on HDMI 2.0a:

The specification has been updated to enable transmission of HDR formats,
which provide enhanced picture quality by simultaneously enabling greater
detail for both the dark and bright parts of an image. The HDR-related updates
include references to CEA-861.3, CEA's recently published update of HDR Static
Metadata Extensions. - HDMI Forum, Inc.

In essence, the change is just specifications on how to transmit HDR metadata.
That's information layered on top of the video image that tells the
HDR-compatible display how to best take advantage of the greater color and
contrast range in the underlying video image. So, for instance, a theoretical
future 4K Blu-ray player can take that shadowy scene in a dark village and
"tell" the display exactly how to render it in its HDR-enhanced glory.

Notably, the spec doesn't regulate streaming connections directly from the
Internet to a TV -- for example, HDR from Amazon or Netflix (coming later this
year) -- just those from HDMI sources. That's because streaming connections
skip HDMI entirely, allowing direct communication between the Internet and the
TV's decoder, which typically utilize HEVC (High Efficiency Video Coding) or
VP9 compression for 4K video.

What does it mean to you?

The main thing to know is that HDMI 2.0a is only relevant to new, high-end 2015
TVs that can accept and display HDR content. Most of the 4K TVs and non-4K
announced in 2015, including numerous high-end models such as LG's 2015 OLED
TVs , don't support HDR. They don't need HDMI 2.0a and have no use for HDR
signals, via HDMI or otherwise.

The only TVs we know about for 2015 that do support HDR are Samsung's SUHD
line, Vizio's Reference series, Panasonic's CX850 and two of Sony's
most-expensive XBR models.

CNET contacted those four manufacturers to determine whether their sets would
be compatible with HDMI 2.0a. Sony told us the XBR-75X940C and XBR-65X930C (its
only 2015 HDR TVs) will be compatible thanks to a software upgrade coming later
this year.

The others were more vague. Panasonic said that the CX850 will also be
compatible in the future, but the timing and method of the upgrade is still
uncertain. (Originally Panasonic told CNET that the CX850 would not be
compatible at all, but then said that information was incorrect.)

"Samsung is exploring HDMI 2.0a and will be able to offer an update," that
company's rep told me, but couldn't provide any details, such as which TVs
would get the update or how it would be delivered. The entirety of Vizio's
reply was "Vizio will have more detail on specs as we get closer to launch."

Bottom line

HDMI 2.0a is not a big change, and it likely won't affect you right now, but
like we've been doing for years, we wanted to hedge against the inevitable
claims of cable purveyors. Next time someone says "HDMI 2.0a compatible cables!
Only $999.99 per meter!," tell them you'll save some money and get the cheap
ones instead.

Updated April 30 with comments from Samsung and Vizio, and May 6 with comments
from Panasonic.

Got a question for Geoff? First, check out all the other articles he's written
on topics like why all HDMI cables are the same, LED LCD vs. OLED, why 4K TVs
aren't worth it and more. Still have a question? Send him an email! He won't
tell you what TV to buy, but he might use your letter in a future article. You
can also send him a message on Twitter @TechWriterGeoff or Google+.

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  • » [opendtv] What is HDMI 2.0a? - CNET - Craig Birkmaier