HDMI splitter to different display capabilities

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GoTBoy

Guest
Hi there,

I intend to have three LCD displays. A 1080p capable device, and two which have a max capability of 1080i.

Question: Will an HDMI splitter, say from Gefen, allow viewing of the same HD broadcast on these three displays simultaneously?

My limited understanding is that the display handshakes with the source and tells it all about its capabilities. So, if that's true (and I'm not at all certain that it is) won't the splitter be getting mixed signals (literally) about the capabilities of the devices it's splitting the signal to?

I wrote to Gefen about this and they replied:

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"All 4 outputs display exactly the same image. That much we publish in the web page for the product. The manual is very brief and makes absolutely no mention of connecting monitors with multiple resolutions.

You may be more in the market for this device, the 4x4 HDMI Matrix:"
-----

Not the clearest reply, since the HDMI matrix *also* makes no mention of connection monitors with multiple resolutions. Oh, and I don't really have the cash for that kind of top-end device.

Not sure I'm making a lot of sense here, but if someone knows what I'm going on about, I'd appreciate the help! :)

Could it simply be the case that the switcher will reproduce (split) whatever the input signal is, and the displays themselves will sort out how to display it?

Many thanks in advance,
 

ginger123456

Active Member
Hi Gotboy, my understanding is that using the gefen splitter each screen must be set up the same, in your case setting the output to 1080i for all screens and maintaining the same resolution, so the answer is yes you can view a hd broadcast on all three displays, out of your three screens pick the lowest spec screen what ever its max resolution is will be your setting for all screens. The 4x4 matrix switch will do what you really want max pq on all three screens, all down to the hdcp chips on the switch i think, great if you can afford one :D hope this helps
ginger123456
 
G

GoTBoy

Guest
Hiya, thanks for the reply, that helps a lot.

After a hell of a lot more research (AKA googling and phoning HDTV stockists) it looks like the best option for me is to use HDMI for the primary display, and switch and split the signal via component for the secondary displays (kitchen, bedroom). News to me, but looks like the component signal is still true HD and can be split this way and then it will be up to the individual display units on how to downscale the signal and display it.

I've been getting so focused on the HDMI digital solution, I had blinded myself to the other options :oops:

Also looking at about 1/5th of the price of an all HDMI solution, which suits me just fine! :thumbsup:

Cheers for now,
 

Jay53

Active Member
Hmm, not convinced.

You originally posted "I intend to have three LCD displays. A 1080p capable device, and two which have a max capability of 1080i." which implies to me that one of your TV's is 1080p (at least accepts 1080p but may not be a 1080p panel and is converting to native resolution and refresh rate) and the other two are 1080i capable (and again they may not be 1080i panels but are able to accept and convert 1080i into panels native resolution and refresh rate e.g. mine is capable of accepting 1080i signal but its panel is only 768p so it converts all resolution and refresh rates to that)

Anyway, each TV has on its HDMI and Component inputs a maximum input resolution and refresh rate. I was under the impression that on the majority of TV's that this is usually the same for both the HDMI and component. Hence if the TV is capable of accepting a 1080p signal over component (and then downscaling to 1080i) then I would suspect its also able to do this over HDMI? You orginal statement seems to suggest the 2nd and 3rd TV's would only accept 1080i max?
 
G

GoTBoy

Guest
Ahh, you see, there's the problem. Because of the handshaking that goes on via HDMI from the display unit to the source, the source modifies the output according to the max capabilities of the display. So, if you've got two displays, one with 720p max res, and you split the HDMI signal, the source would downgrade the output to 720p even though it's a 1080p true source.

I don't know what this means when the displays are *both* switched on and *both* handshaking with the source via the splitter. My head starts to explode at this point.

Oh, I made a suggestion to Gefen support about perhaps splitting the signal into the primary (1080p) display and to a downscaler which could act as a 1080p sink and downscale the signal to 1080i downstream, so the source would think everything is 1080p. They told me this solution would work, and then listed the kit I would need.... All the kit, plus cables etc, came to a whopping £1800. All to display the same HD signal via HDMI on 3 displays at the same time... This is an *insane* amount of money for such a simple requirement.

Therefore, I am taking the component route. All done and dusted in the region of £400. :)
 

Jay53

Active Member
Not necessarily

My TV is capable of accepting 1080i via HDMI. Even though its a 768p panel, via HDMI source is told it can handle 1080i and so that is what is sent.

Plus auto negotiation of max res over HDMI isn't mandatory so the source can just output the chosen res/refresh rate i.e. 1080p and the display can just put up a message saying not supported. This is what SkyHD box does as when set to Auto it just outputs 1080i for HD and that is what my TV says the input signal is. What its acutally showing is 768p as the TV deinterlaces the 1080i signal and downsamples it to 768 lines progressive


As to the component route. Have you confirmed that ALL your TV's are able to accept 1080p. If they can't then it will not work as the TV's that can't accept it will just put up a message along the lines of "Our of range" or "Not supported mode" when you set the source to 1080p.

What TV's do you actually have as then members who each own one of them might beable to advise on what they have found in terms of component capabilities for each TV :smashin:
 
G

GoTBoy

Guest
Well, the good news, is that no money has been spent yet. This is all in my head 'cos I'm moving into my new flat soon, and want to do things right :)

After weighing up the options, from a cost/performance perspective, I'll probably going with Samsung across the board. Primary display will almost certainly be Samsung LE-40M87BDX.

Secondary displays will be a 32" and a 23". Looking at these models:

For the 32": LE-32M86BD

This is a 1080i set, which, I've been told, accepts 1080p via component.

For the 23": LE-23R87BD, or LE-23R88BD (can't for the life of find the difference between these two models), they're even the same price, give or take £10. Specifications don't list the max HD it supports. Resolution is 1366*768 so is that 720? Anyway... I'm going to pester some more retailers about this issue.

The reason I think this will work, is because the HD signal in showrooms is usually farmed out via component. So the 1080p signal must surely be understood (for want of a better word) by the less capable displays, and downscaled accordingly.

No?
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Hello GoTBoy

The Gefen HDMI Distribution Amp (DA) works on a Primary Output with all other Outputs 'following' the Primary - you therefore need to ensure the signal you are sending to the Primary Display is compatible with the Displays on the Second, Third, Forth Output of the HDMI DA.

With everything attached to the Gefen DA you switch on your Source and three Displays.

The Gefen DA then negotiates with the Display attached to Output 01 (this is now the Primary Output) and between them work out what Resolution the Display will accept and what the Source is set to.

If your Source is set to Output 1080p and the Primary Display is also 1080p capable that's what they will work with - if not they will renegotiate a compatible signal.

Once the Primary is working at 1080p the DA will then go and HDCP handshake with the other Displays and will try and send them 1080p - if they don't like it then your stuffed you wont get an image.

If all three Displays in your system are 1080i compatible then that would be the best 'global' signal to set at the Source - have you looked to see how 1080i differs from 1080p to the 1080p capable Display; it may not be very different.

Analogue HD ought not to look too different to Digital HD and you don't have the hassle of HDCP with Analogue - though you can and do run into the same 'compatibility' problems in terms of what does and doesn't support 1080p over Analogue.

Lots of options to explore - some less obvious than others; maybe talk to another couple of dealers who spend way too much time playing with Digital and Analogue DA's, Switches and Matrices:)

Joe
 
G

GoTBoy

Guest
Cheers Jeff,

That explains why there is still a "primary" display on the Gefen splitter. I thought it was a leftover designation from the time when the primary display had to be switched on in order for it to all work. Makes a lot more sense, now.

Thanks for all the info. I'll certainly do some more checking around, and post anything useful I learn.

All the best,
 

Jay53

Active Member
I like Samsung's (I have an LE32R41BDX and a 940mw) and the picture is great on both.

Only thing I would say is that neither accept 1080p over HDMI or component but that's no suprise since they are both over a year old now.

However something for you to consider is that Samsung don't auto switch aspect ratio over HDMI even though it maybe present within the HDMI signal. So if you happen to be watching 4:3 source over hdmi you have to manually switch the TV picture size to make the picture the correct shape or it will appear stretched horizontally. You then have to remember to switch it back to "wide" again when viewing 16:9 content or else you get black bars either side and tall skinny picture. Then again you may prefer waitching 4:3 content stretched rather than having black bars either side of the 4:3 picture so not such as big problem in that case as you just leave the TV always in wide mode :smashin:
 
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GoTBoy

Guest
thanks for the info, Neil. Not too fussed about auto-switching for aspect ratio; my current TV needs to be told, and it's always worked for me :)

My latest problem is the signal distribution via component.

I could get a relatively cheap component splitter, and then have bulky component cables (well, unless I spend LOADS of money on the thin ones) going all round my flat. Or, I could get a component - cat5 splitter and have that running round instead. Problem is, it starts to get really pricey, when you factor in the remote cat5 - component baluns. I could get a pair for ~£80, but the initial component - cat5 splitters I've found seem to be several hundred.

Does anyone know:

a) are there any relatively cheap component cables which are *thin*. Packaged with stereo audio cables would be sweet, but I can get those separately

b) a cheap component - cat5 splitting solution. Also, does cat5 really work with no signal degradation < 30m?

I'm certainly open to suggestions, if other people have solved this problem in a cost-effective way I haven't considered.

Many thanks,
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Hello GoTBoy

Lost of asks in one system in terms of technology and costs.

VanDamme have a very decent quality AV Multicore with the ability to carry YPbPr+Stereo (+spares) at 13.8mm (OD) with a UK SRP of 9.98 GBP/m (bulk pricing is also available).

How many Source's to how many locations do you require and have you considered a YPbPr Matrix - see http://www.neothings.com/consumer.html

HD YPbPr over CAT5 at 30m will require a test run to see if you are happy with the results or not.

Joe
 
G

GoTBoy

Guest
Heh, well, I'm nothing if not demanding :)

Those Van Damme cables look like just the ticket. If I can keep the costs down by just going with component, that's great.

Basically, I'm going for a primary display in the lounge, and secondary displays for the two bedrooms, and kitchen. I want to be able to walk through the flat and watch whatever I'm watching, wherever I am. Or, perhaps pipe music through. So, the main problem is signal distribution.

I think with a combination of this switcher:

http://www.keene.co.uk/electronics/multi.php?mycode=AVT5841

and this splitter:

http://www.cyberselect.co.uk/product/1028

and with those nice cables you mentioned, I'm all set, really.

Thanks for all the help!

Oh, can anyone recommend a company who installs this stuff? You know, chasing cables, mounting screens on walls etc, in the London Area? I'm SOOOO not a DIYer ;)
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Hello GoTBoy

Ensure you Test out the combination of Switch/Distribution products your considering - what works on paper doesn't always deliver once you start getting critical with the images your viewing at your remote screens.

Joe
 

Jay53

Active Member
Are these any good to you.

The 1st two are the same wire from two different suppliers and contains 6 (75ohm) mini co-ax feeds, 4 audio feeds and two co-ax digital feeds so I believe its good for 2x(Component+Stereo+coax digital audio).

RS supplies &#163;125 per 25m reel.
http://rswww.com/cgi-bin/bv/rswww/s...kklmdjhgcefeceeldgkidhgj.0&cacheID=uknetscape

Sold by the metre here for &#163;5.57
http://www.canford.co.uk/commerce/productdetails.aspx?productid=36-901

with complete spec of the cable
http://www.canford.co.uk/commerce/resources/catdetails/3749.pdf

This 3rd one which is cheaper has individually screened R,G and B wires along with wires for composite and stereo audio.

http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=293&doy=1m5

Any reasons as to why these wouldn't be acceptable for making up custom cables to suit?
 

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