[mythtv-users] One HDMI question from (Hijacked): HDMI sound issues

[Stephen Worthington]

On Wed, 28 Aug 2013 18:04:54 +1000, you wrote:

>On 28 August 2013 17:57, Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:
>> A digital signal is a digital signal.  It is either correct data, or
>> it does not work.  So the digital output from an SPDIF port will be
>> identical to the output from a TOSLINK port, as far as the
>> specifications for the digital data are concerned.  If you are really
>
>it's a very simplistic view of things...
>
>It's definitely possible to get corruption one long cable; same as you
>can get digital interferences if you use a very long, not great
>quality hdmi cable

In which case the cable is faulty.  By definition, an HDMI cable must
put out a signal that meets the HDMI specification.  If it puts out a
corrupt signal, it is not an HDMI cable.  That is the fundamental
difference between an analogue signal and a digital one.  There is no
such thing as a degraded or corrupt digital signal - that is a faulty
digital signal.

So if someone sells you an HDMI cable that is supposed to work over 20
metres, and it does not work when installed according to its
specifications, then they sold you a faulty cable.  That presumes that
the equipment on either end of that cable also actually meets the HDMI
specification.

HDMI signals were never supposed to work over long distances - that
was never part of their design.  If you want a really long HDMI cable,
it will need one or more regenerators in the cable (and power for them
to work from), or it will need to convert the HDMI signal to something
else (eg ethernet) that will travel over a longer distance, and then
be reconverted to HDMI at the other end.  There are lots of long
"HDMI" cables out there that put out a signal at the far end that does
not actually meet the HDMI specification.  If your equipment works
with that signal (and some will), that is fine.  But the cable should
not be sold as something that is actually meeting the HDMI
specification.