Re: Article: How the designers of the HDMI standard screwed up...
Lawrence D'Oliveiro
> An interesting article, IMHO, explaining why DVI/HDMI is electrically a
> poor format for a cable connection between two digital devices.
>
> http://www.audioholics.com/education/cables/whats-the-matter-with-hdmi
I don't understand what the big deal is. We computer folks would never think
of running dedicated cables all over the place just to feed audio or video
signals, so the limitations of DVI or HDMI in that respect are moot.
Instead, the only kind of data cables we would run are Ethernet (currently
1-gigabit or 10-gigabit, your choice). And that can carry universal comms
protocols like TCP/IP, that can transmit audio, video or any other kind of
data. Convert to a video-specific protocol (and connector) only when you
get near a video device. And similarly for other devices. Problem solved.
whoisthis
100% agreed. I am already using 802.11g to transmit the audio from my
Mac laptop to my stereo, Apples "Apple TV" will be using 802.11n to do
AV.
Lawrence D'Oliveiro
> The HDMI cabling standard in use in consumer electronics equipment for
> connecting video signals to display equipment such as TVs or monitors, is
> substantially inferior to the cabling standard used in professional
> equipment.
That cabling system designed for professional equipment would cost a
fortune. Probably even more than 10-gigabit Ethernet. Guess which one gives
you more flexibility for the future?
Lawrence D'Oliveiro
> On Sun, 20 May 2007 19:39:30 +1200, Lawrence D'Oliveiro wrote:
>
>> That cabling system designed for professional equipment would cost a
>> fortune. Probably even more than 10-gigabit Ethernet. Guess which one
>> gives you more flexibility for the future?
>
> The cable format that was already in use, that uses standard coaxial
> cables...
...that Ethernet tried and gave up on, over a decade ago.
Richard
Cable costs, since twisted pair is cheaper it allowed for a much cheaper
move to a switched environment then a separate coax run to each computer
Lawrence D'Oliveiro
> On Sat, 19 May 2007 20:43:08 +1200, Lawrence D'Oliveiro wrote:
>
>> I don't understand what the big deal is. We computer folks would never
>> think of running dedicated cables all over the place just to feed audio
>> or video signals, so the limitations of DVI or HDMI in that respect are
>> moot.
>
> ... unless you're wiring up a studio where the PC is not located in the
> same room as where the editor will be working, or where the monitor needs
> to be located in a place where it is not practical to put the computer...
Sounds like you're trying to fit equipment into a room which was never
designed as a studio. I mean, if you could afford HD-SDI, couldn't you
afford to design the room properly in the first place?
> ... or where a person simply wants the PC in another room (like, maybe,
> a server room on the other end of the floor in order to reduce noise.
There are low-noise PCs, like the Via Epia range, that can run entirely
without fans. Of course, trying to run Dimdows Vista on them is pretty
hopeless--even XP can be a struggle. But is that such a big loss? :)
sam
I expect pro users will use HDMI just like they use analog vga, dvi,
firewire, sdi, ethernet, usb, component and composite.
There really is no pro vs consumer split.
SDI uses the coax infrastructure that broadcast facilities already have
A typical broadcast facility monitor has sdi, vga hd15, composite video
and component video, so you can plug it into an sdi switcher, or a PC or
Mac display card and switch between inputs. Manufacturers will just add
HDMI to the list, no big deal.
sam
> In message <464e...@clear.net.nz>, Jonathan Walker wrote:
>
>> An interesting article, IMHO, explaining why DVI/HDMI is electrically a
>> poor format for a cable connection between two digital devices.
>>
>> http://www.audioholics.com/education/cables/whats-the-matter-with-hdmi
>
> I don't understand what the big deal is. We computer folks would never think
> of running dedicated cables all over the place just to feed audio or video
> signals, so the limitations of DVI or HDMI in that respect are moot.
>
TV folk use computers with SDI and firewire inputs and DVI display
outputs, and connect to servers via ethernet.
Much like the rest of us, they don't bother running display cables all
over the place.
When they use SDI to monitors, it is for a single frame rate and
resolution. It works for television, not for all computers.
Computer display cables are for multiple frame rates and resolutions
They will often run SDI signals from point to point, but they do also
use MUX and DEMUX boxes from SDI to ethernet.
Bruce Sinclair
>On Mon, 21 May 2007 16:39:46 +1200, sam wrote:
>
>> Manufacturers will just add HDMI to the list, no big deal.
>
>entire point of the article - and it explains how and why.
.. and beta was technically superior to VHS. Your point ? :)
sam
The article is wrong, its a stupid audiophool rant like the monster
speaker cable foolishness
-=rjh=-
There is a big difference between how a signal propagates on twisted
pair vs coax; that was the point of the article. It is a whole different
situation to Monster cable thing, though bigger speaker cable is better
(to a point, and depending on what you are driving your speakers with).
DisplayPort also uses twisted pairs, and the official spec rates 3m
cables at something around 4x HD resolution, this drops to 1080p for 15m
cables. That pretty well ties in with the point of the HDMI article.
sam
The point of the article was to sell this bunch of HT gear pimps super
exotic improved HDMI cable that they got Belden to make especially for
them (yeah right !)
Thats the monster cable scam part, the pseudo technical tosh.
Sticking a digital signal down a coax is not an improvement over utp,
they are just different types of transmission line.
Lawrence D'Oliveiro
> On Mon, 21 May 2007 17:17:13 +1200, sam wrote:
>
>> TV folk use computers with SDI and firewire inputs and DVI display
>> outputs, and connect to servers via ethernet. Much like the rest of us,
>> they don't bother running display cables all over the place.
>
> You've missed the point of the article!
Sounds like Sam was reinforcing my point--namely, that your article was
pointless.
Lawrence D'Oliveiro
> On Mon, 21 May 2007 06:14:42 +1200, Lawrence D'Oliveiro wrote:
>
>>> ... unless you're wiring up a studio where the PC is not located in the
>>> same room as where the editor will be working, or where the monitor
>>> needs to be located in a place where it is not practical to put the
>>> computer...
>>
>> Sounds like you're trying to fit equipment into a room which was never
>> designed as a studio. I mean, if you could afford HD-SDI, couldn't you
>> afford to design the room properly in the first place?
>
> You're ignoring the point of that article - and that is the HDMI cable is
> an electrically poor design for carrying such high frequency signals as
> video output to a monitor.
My point is--so what?
Lawrence D'Oliveiro
> On Tue, 22 May 2007 13:23:13 +1200, sam wrote:
>
>> The article is wrong, its a stupid audiophool rant like the monster
>> speaker cable foolishness
>
> And what is your proof that multiple unshielded twisted pairs bundled
> close together and with UHF digital data going across them simultaneously
> will not electrically interfere with each other in ways that multiple
> shielded coaxial cables bundled together do not?
So what if there's a bit of interference? Just use a carefully-designed
digital encoding that gives you resistance to that. It's cheaper than
putting in more expensive cabling.
Lawrence D'Oliveiro
> On Tue, 22 May 2007 14:25:46 +1200, sam wrote:
>
>> Thats the monster cable scam part, the pseudo technical tosh. Sticking a
>> digital signal down a coax is not an improvement over utp, they are just
>> different types of transmission line.
>
> ... with quite different electrical characteristics.
With digital, it no longer matters.
Lawrence D'Oliveiro
> On Sun, 20 May 2007 21:33:25 +1200, Lawrence D'Oliveiro wrote:
>
>>>> That cabling system designed for professional equipment would cost a
>>>> fortune. Probably even more than 10-gigabit Ethernet. Guess which one
>>>> gives you more flexibility for the future?
>>>
>>> The cable format that was already in use, that uses standard coaxial
>>> cables...
>>
>> ...that Ethernet tried and gave up on, over a decade ago.
>
> Have you ever wondered why it is that all very high frequency video
> equipment EXCEPT for equipment using the consumer grade HDMI interface
> uses coaxial connectors.
No, only analog would still bother with coax. Digital runs just fine over
cheaper cabling.
Richard
HDMI has no forward error correction in it, and if there is noise it
really screws up a hdcp signal, whereas a non-protected one just gets a
few sparkely bits over it.
sam
HDMI/DVI cable is shielded, so the noise issue is even less significant
because of the differential nature of twisted pairs vs coax for this
data cable.
stp wins hands down for manufacturers of cable and connectors.
Notice the absence of coax cables in use for computer HD connections.
The article was pimping Blue Jeans Cables shopping site promoting their
run of glued pair Belden.
Hifi wonks will debate this crap ad infinitum, its their hobby
obsession, waffling about oxygen free copper and skin effect in
applications where it doesn't matter.
No one uses multiple shielded coaxes for digital video, professional or
consumer.
David Murray is confusing digital display cables with analogue component
cables.
Kent Smith
I always have a good laugh when I look at some digital cable. I can't
believe the prices and claims some manufacturers will make on some digital
cables:
http://search.dse.co.nz/search.php?w=C1362
http://search.dse.co.nz/search.php?w=C1218
http://search.dse.co.nz/search.php?w=CA1015
http://search.dse.co.nz/search.php?w=C1219
Enhanced sound reproduction
Improved clarity
More natural sound
Enjoy better audio quality
Higher purity copper for greater clarity and detail
Smoother. more natural sound
Exeptional imaging
Increased clarity and resolution
It's like saying if you use this to copy word documents, it will format them
to make them look better. Make games run faster, etc.
They could argue compared when an anolog connection but this should be
stated. When comparing a high priced digital cable with a low priced one,
you can bet the sales guy will quote these reasons improving on the cheaper
digital cable.
In reality if you get a reliable signal out of the other end, it will be no
different from a $2 cable.
-KENT
Lawrence D'Oliveiro
> On Wed, 23 May 2007 00:35:55 +1200, Lawrence D'Oliveiro wrote:
>
>> No, only analog would still bother with coax. Digital runs just fine over
>> cheaper cabling.
>
> Over what maximum distance?
Well, signals seem to be running just fine between you and me, and we aren't
even in the same town...
Lawrence D'Oliveiro
> On Wed, 23 May 2007 13:59:35 +1200, Lawrence D'Oliveiro wrote:
>
>>>> No, only analog would still bother with coax. Digital runs just fine
>>>> over cheaper cabling.
>>>
>>> Over what maximum distance?
>>
>> Well, signals seem to be running just fine between you and me, and we
>> aren't even in the same town...
>
> Funny that, but I didn't realise that link was transmitting the high
> frequency output of your video display card directly into my monitor.
Where did I say it should?
Richard
> HDMI/DVI cable is shielded, so the noise issue is even less significant
> because of the differential nature of twisted pairs vs coax for this
> data cable.
> stp wins hands down for manufacturers of cable and connectors.
> Notice the absence of coax cables in use for computer HD connections.
> The article was pimping Blue Jeans Cables shopping site promoting their
> run of glued pair Belden.
> Hifi wonks will debate this crap ad infinitum, its their hobby
> obsession, waffling about oxygen free copper and skin effect in
> applications where it doesn't matter.
> No one uses multiple shielded coaxes for digital video, professional or
> consumer.
> David Murray is confusing digital display cables with analogue component
> cables.
Here are the issues.
Projectors typically have hdmi inputs, in wanting to be able to play hd
content after the ICT is activated on the HD media whenever that will
be, people HAVE to put in an hdmi cable when building their home theaters.
At the moment, yeah, 3 runs of RG6 or 59 are great to run component up
to the projector, and support 1080p just fine since its a relatively low
bandwidth signal compared to other things. This cable run costs stuff
all - 30 meters@ 40-50c a meter is still nothing IMO.
Whereas a 10 meter hdmi cable to go to the projector from the source is
going to cost a hell of a lot more then that. The connectors are such
they cannot be field terminated, so they need bigger holes thru studs
etc, and if you want a plate on the wall then you have the added
impedance mismatch of a back to back connector and a second cable -
these are a non-issue for coax where bnc or even rca plugs give a pretty
good reflection free connection.
So if your projector is 5 meters from the wall that the home theater is
in, the wall is a pretty standard 2.7 high and you want your plate at
300mm off the floor, you already have 7.5m of cable, add in a 1m
connecting cable at each end and its a pretty sure thing that its not
gonna work at 1080p res. Its worse if you have a bigger room, higher
ceilings or want to feed it from a source in another room. coax with
component has none of these issues at all.
What WOULD make sense for a home theater application would be to pass
the compressed bit stream up to the projector and put a video decoder
there, but sadly that just seems too logical.
Richard
> On Wed, 23 May 2007 20:22:46 +1200, Richard wrote:
>
>> What WOULD make sense for a home theater application would be to pass the
>> compressed bit stream up to the projector and put a video decoder there,
>> but sadly that just seems too logical.
>
Projector.
I guess like its not logical to put audio decoding in your amplifier.
Lawrence D'Oliveiro
> On Wed, 23 May 2007 16:33:12 +1200, Lawrence D'Oliveiro wrote:
>
>>> Funny that, but I didn't realise that link was transmitting the high
>>> frequency output of your video display card directly into my monitor.
>>
>> Where did I say it should?
>
> [sign]
>
> Well wasn't that the type of transmission that we were talking about?
>
> You know - output of a video card into the input of a monitor?
You mean, the one I pointed out it was a waste of time to run over long
distances?
Lawrence D'Oliveiro
> On Wed, 23 May 2007 20:22:46 +1200, Richard wrote:
>
>> What WOULD make sense for a home theater application would be to pass the
>> compressed bit stream up to the projector and put a video decoder there,
>> but sadly that just seems too logical.
>
> It does not seem logical to put data processing into a monitor.
Why not?