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How Different is HDMI 1.4 from 1.3?

Jeff Boccaccio says "very little has actually changed" between the two specs.


It's been months since HDMI Licensing's new HDMI 1.4 spec was announced, but people seem as confused as ever.

Very little has actually changed. In the case of HDMI Rev. 1.4 with Ethernet, a couple of interesting capabilities have been added. In the case of Rev. 1.4 without Ethernet, however, there is no difference. The new Rev 1.4 spec is completely backwards compatible with the previous Rev 1.3 spec.

The HDMI Rev 1.4 cable without Ethernet uses the same connector and wires we have used from the days of Rev. 1.0. The connector and cable has 19 pins and wires that are laid out like this:

  • 8 wires are used for the balanced TMDS (Transition Minimized Differential Signaling) video
  • 2 wires are used for DDC (Digital Display Channel), which carries EDID (Extended Display Identification Data) and HDCP (High Definition Content Protection)
  • 1 wire is used for the 5-volt power line
  • 1 wire is used for the HotPlug Detect signal
  • 1 wire is used for the CEC (Consumer Electronic Control)
  • 1 wire was left undefined, open for future use
Add them up and you get 13 wires out of the original 19 that are used as actually signal-carrying wires with an extra for future use. The balance of the 19 wires are used to ground these channels individually and many times wired in a common ground configuration.

In the case of HDMI 1.4 with Ethernet - now known as HEAC (HDMI, Ethernet, Audio, Control) - the wire scheme is exactly the same except for one change: the wire used for HotPlug Detect and the unused, undefined wire are now used for Ethernet and the Audio Return Channel. Under HEAC, this pair is balanced and should be twisted with a shield. Although it is not mandatory for cable makers to provide this modification to the cable, without it cables will likely fail HDMI compliance and DPL Certification.

Yep, HDMI was able to use the HotPlug Detect wire for two jobs, one being HotPlug detection and the other to support the opposite polarity of the balanced line for Ethernet and the Audio Return Channel. As far as system sources (such as Blu-ray players) and display devices (such as flat panels) are concerned, nothing has changed; the cables really "look" the same. Neat trick!

So does this mean you can ignore Rev. 1.4 and skip merrily along your way? Not quite! Longer term technology trends must be addressed in your system design. I will cover this part of the story in a future column.




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Article Topics

News · Wire and Cable · HDMI · Wire And Cable · Hdmi 1.4 · All topics

About the Author

Jeff Boccaccio, President, DPL Labs
Jeff Boccaccio, president of DPL Labs, can be reached at jeff@dpllabs.com.

10 Comments (displayed in order by date/time)

Posted by Dave Stevens  on  04/14  at  12:44 PM

I hope Noel Lee is tuned in…  grin

Posted by Guyman  on  04/14  at  01:15 PM

I wonder how many times that I have to tell the clients that their expensive cables/equipment are obsolete AGAIN before I need to start wearing body armor to the jobsite?

This is ridiculous.  I am not giving the HDMI engineers the benefit of the doubt anymore that they just poorly designed this interface. 

Everything that the HDMI does with a bunch of ancient technology shielded twisted pair wires could be done with one Toslink.  Or even one coax. 

Crappy connector
short distance
expensive
bulky
no field termination
slow switching times

It’s like the government designed it.  smile

There’s a fine line between planned obsolescence and just plain ripping people off.

Posted by Dave Stevens  on  04/14  at  03:25 PM

Guyman,
I agree with you that HDMI is an abortion and has many incompatibility issues from component to component.  I also agree that it seems like the government invented it, but it was Hollywood who made it the standard cable in order to protect their copyrighted movies from being copied. For lack of better words, today’s HDMI standard is yesterday’s VHS’s Macrovision body guard.

The bottom line regarding this article is that Jeff Boccaccio is the true, “Monster,” in this field by creating a DPL standard to eliminate the problems you’ve mentioned. Not only do major manufacturers want to obtain a passing DPL rating, they will need it to sell their new products.

P.S. @ Noel Lee…  Just in case you are following/reading this thread, please feel free to send all legal papers directly to my office for using the adverb/noun, “Monster,” in this post.
  cheese

Posted by DrFlick  on  04/15  at  04:18 AM

Jeff,

Not to be critical <g>, but HEAC, from Supplement 2 of the 1.4 specification, is HDMI Ethernet and Audio Return Channel (HEAC), not Control.

  =D-

Posted by DrFlick  on  04/15  at  04:25 AM

Guyman - I am sorry to say, but a single TOSLINK connection cannot come anywhere close to what an HDMI cable can do.  It technically cannot even provide the full audio experience that just the audio side of HDMI can deliver (and that is even when it is multiplexed over the TMDS lines).

  =D-

Posted by afliss  on  04/15  at  05:02 AM

Just a quick, but important note: HDMI 1.3 will not support 3D sources and content. Theoretically, the bandwidth is sufficient, but we’re going to need 1.4 repeaters to deal with the new wave of 3D displays. confused

Posted by DrFlick  on  04/15  at  05:18 AM

afliss,

Technically, 1.3 COULD support the new 3-D standards, but it is not MANDATORY that they do.  If they understood the E-EDID information and could interpret the appropriate extended HDMI defined CEA-861 InfoFrame VSDBs and 3D_Structures, it would work.  It is just not required, which (at least to me) means that you do not want to use any legacy equipment (unless you are sure it works).  That is how Sony is going to do it with their PS3 upgrade.

You are right though, everything in the chain will have to be up to it for an end-to-end experience.

  =D-

Posted by Julie Jacobson  on  04/15  at  10:57 AM

DrFlick vs. Jeff B. Love it!

Posted by Dave Stevens  on  04/15  at  11:02 AM

Julie,
Better yet, put/add Noel Lee in the same room and I’d buy a ticket to that show! I’m sure you already know who I’d bet on…

Posted by CybrSage  on  05/24  at  07:14 AM

Thank you for an informative article.  It contains useful information.

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