[opendtv] Re: HDMI attracts three challengers

  • From: dan.grimes@xxxxxxxx
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Tue, 9 Jun 2009 09:25:54 -0700

I've just completed an install with HDMI technologies, and I believe the 
state of digital connections is in serious trouble.  We (not me but a 
bunch of engineers specializing in AV technologies) tried doing a complete 
digital path with DVI from the computers, HDMI from the Blu-Ray players, 
DVI from the document camera, etc. to the projector for an auditorium. 
This requires converting everything to HDMI to get the Blu-Ray player to 
work.  We had to really mess with the design to get things to work (in 
fact we didn't with DVI as I'll explain later).

The first problem is the distance limitations.  Then there is constant 
converting of DVI to HDMI and back (HD-SDI, too).  But the worst is trying 
to get the EDID to work.  It seems that most of the electronics out there 
do not properly handle the keys.  Naturally, there are specifications that 
provide requirements to properly handle things (with up to 40 keys 
shifting around), but it turns out that most electronics do not handle 
them properly, in fact sometimes not at all or at least enough of them. 
HDMI works when you have one player plugged into one monitor, but as soon 
as one starts using switches and routers, getting pictures is very 
difficult.  I must disagree with the quote:

" 'These technologies do start at the professional level, but it's such an
easy technology to use that people won't hesitate linking their Blu-Ray
player to a digital TV over HDMI' for applications like whole-home video
recording, said Rob Tobias, director of market development for Silicon

In our installation, there were no recording devices, only sources 
(camera, computer display, Blu-ray) and monitors (projector and LCDs).

After doing some research, we discovered there are some technologies on 
the horizon to deal with the issue.  For instance, Crestron will have an 
image processor with card slots and proprietary processing to handle the 
EDID keys.  The results will be active switching with key handling. Active 
(hot switching) will not currently work with EDID, at least not reasonable 
enough to use in production.

So what did we do?  We went back to RGBHV analog signals for almost 
everything and are routing and processing them instead of digital. 
Unfortunately, there are some distortions due to processing but at least 
the picture is there. 

We do still use some digital: in order to get 1080p from the Blu-ray 
through the HDMI to the projector, we must turn on or turn off certain 
pieces of equipment.  We do that when we need the pure path for a Blu-ray.

By the way, the RGBHV outputs on our Panasonic Blu-ray players do still 
put out a 720p signal.  I understand there is a moratorium until 2012 on 
scaling the analog signal back to 480p.  I do not know if this is just a 
"gentleman's agreement" or if it is official.


Subject: [opendtv] HDMI attracts three challengers
Date: Mon, 8 Jun 2009 11:24:08 -0400
From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>

Very timely article. So, should someone be lobbying NOT to have HDMI 1.4
incorporated in TVs and other boxes, because I prefer to use HDMI 1.2,
1.3, DVI, or component analog ionterfaces? All of which have lower or no
royalty fees at all?

Maybe I should become indignant about HDMI 1.4.

The reality is that we'll be seeing more and more alternatives built
into every box, we'll be paying the separate royalties, and we can
either whine about it or have fun with the added possibilities.


HDMI attracts three challengers
Players aim to enable new class of home nets
Rick Merritt
(06/05/2009 8:00 PM EDT)
URL: http://www.eetimes.com/showArticle.jhtml?articleID=217702149


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