HDMI and splitter conundrum

I don't think you can, you need two outputs

are you sure the splitters aren't swtches ?  Didn't know you could get one that duplicates (apart from fancy docking things)

Few thoughts / queries -

as per scaredypants - is it defo a splitter/distribution amp rather than switch?

is it directional?

whats the brand / model? gives us a chance to look at it.

What resolution are you outputting? What resolution is the TV? What TV/screen is it?

Does it manage EDID/HDCP?

Are all 4 splitters the same brand/model? have they all worked previously?

Check what resolution/setup you're sending via HDMI ie mirror/extra screen etc Set it to extra screen/display ie a second monitor & change the resolution to see if any work. Sounds like the box may have changed the output resolution on the mac maybe?

It could just be a dodgy box ie loose connection or a really fussy one ie it needs specific resolution/colour space/EDID.

i dont know enough techy stuff to be able to answer some of those questions but i'll try and describe them as best i can....

1. 1X2 HDMI 4K2K Splitter. one input, 2 outputs. cant see a maker name, made in china.
2. HDMI2.0 1X2 splitter. 3D ultra HD 4K@60Hz 18Gbps. 2 way HDMI splitter. support HDCP2.2. maker could be 'pro-signal'. chinese again.
3 and 4 are the same. 2 port HDMI splitter.

so at least i think that satisfies the 'are you sure theyre splitters' question 🙂

I don’t think you can, you need two outputs

if thats true then that could explain it, i just assumed that they would be like plug socket extensions, there if you need more but you could still use just one to extend and leave the others empty.

are they directional? the ports are labelled input and output so id say so yes.

whats the brand / model? gives us a chance to look at it.

What resolution are you outputting? What resolution is the TV? What TV/screen is it?

Does it manage EDID/HDCP?

Are all 4 splitters the same brand/model? have they all worked previously?

as per previous, no names to be seen. theyve been part of quite a complicated techy set up that we're trying to simplify, so theyve worked before, theyre just not needed now for that function and are just lying around with their (mixed up) power units. but we'd like to use one in a different way to get the same pic on two tv's in two different rooms now.
dont know about resolutions, tried them with a cheap 'cello' (i think) tv and an oldish sony at home in spare room.
sorry, dont know what EDID/HDCP is.

its just curious that none of them are doing what we expected them to (we're no experts tho), and even more curious is why we could get a picture initially, then piss about with the splitters, go back to how it was, but no picture now.
thats happened two or three times on the cheap cello, but havent been able to get a pic at all on the sony, not even direct hdmi from macbook to tv.

that seems odd as im sure a few years ago i used this macbook to watch youtube vids on a (albeit different) tv before with direct hdmi connection so just assumed it to be a given that itd work.

thanks

These things can be a bit of a nightmare to setup. Sometimes you need power to the splitter (and sometimes a precise amount of power), sometimes you need to mess about with the resolution. FWIW I manage to drive two external monitors off my work laptop using a Kensington USB C - Dual HDMI. I effectively get three screens this way and it works well. Doesn't really help you solve your particular issue but there could be so many potential things causing it unfortunately.

USB C is a bit different though.

could be an hdmi/hdcp handshake issue - when you introduce the splitter the source and destination get out of sync - when you set it back to the original setup turn on the screen (destination) before you turn on the pc (worth a shot)

when you set it back to the original setup turn on the screen (destination) before you turn on the pc (worth a shot)

nope, that didnt work. i connected hdmi to tv first, turned screen on (blank obviously), then connected laptop. nothing. laptop screen goes off then back on as tho it knows somethings just connected, but no picture of my desktop appears. so i cant even replicate the start of yesterdays issue at the moment.

which means i cant really test out the 'i think splitters need 2 outputs' theory, as if i cant even get one direct hdmi to come up with a picture, then i havent much hope of testing it out with two.

thanks

Have you activated the screen splitter thing on the Mac - DisplayLink Manager or something like that (can't remember what it is called now!)? The Mac might need to realise it has access to multiple screens...theoretically the splitter should be seen as a single output as the 2 screens should be showing the same thing.

When I go in to the office and hook up my Mac it doesn't default to using both screens, I need to open an app so it splits the signal across both...but both is my laptop screen and the desktop screen.

Have you activated the screen splitter thing on the Mac – DisplayLink Manager or something like that (can’t remember what it is called now!)?

dont seem to have this where google says it should be (old macbook), and im not very savvy with apple anyway.

to try and keep it simple then, i also have access to a windows pc which i know the system a little better but still have same issue. no desktop on tv when connected.

could be an hdmi/hdcp handshake issue

My guess would be this.

Splitting HDMI isn't easy at all, professionally we do it by converting HDMI to SDI, then putting that through a router or DA, run SDI to the TV (because it works better over distance) and then convert back back to HDMI with a little mini-converter.

For what you describe, I'd just get a laptop dock and setup the laptop to output two identical screens.

Silly Q (and other have much more idea about this than I) but..... have you checked - with something else - that the HDMI port on the TV is still working?

Isn't there some anti-piracy thing built into HDMI? So playback devices won't use the output if the other end doesn't report that it's a display that can't record? It may be that it's working as intended, detecting the splitter and so refuses to output incase you're trying to record DVDs or other naughty activity.

If you reboot the laptop when it's in it's "not working state" after tyring a splitter does it then work?

Have you actually tried it with both outputs of the splitter connected to different TVs?

Edit: Yes, it appears to be called HDCP if you can find a setting to disable that on your laptop(s), it may allow you to use the splitter while disabling things like DVD playback?

The thing with HDMI is, it's 'protected'. The receiving end has to go "hello, I'm a display and totally not a recording device!" This causes problems for things like, say, cheap HDMI splitters where you could, say, stick a TV in one side and a recording device in the other.

You need one of two things. Either what in HDMI parlance is called a Repeater - a device which has the brains (and licence) to accept and decode an encrypted signal, recode it and pass it on - or for the source to send unprotected content. Any copyrighted source is vanishingly unlikely to play ball; a laptop as a source may work if your "picture" is a desktop or presentation rather than a video, I honestly wouldn't be confident in guessing either way.

... and if the act of connecting a splitter to a TV renders that TV's input subsequently useless, I'd be introducing that splitter to a large hammer before it roasts any more TVs and asking work to buy me a new telly.

... and and,

What are you actually trying to achieve? Protocols like DisplayPort inherently support multiple monitors, you can just daisy-chain them together.

The thing with HDMI is, it’s ‘protected’. The receiving end has to go “hello, I’m a display and totally not a recording device!” This causes problems for things like, say, cheap HDMI splitters where you could, say, stick a TV in one side and a recording device in the other.

We have HDMI recording devices by ATMOS, BlackMagic Design and Elgato and are distributing to projectors and screens with runs of 50M+ with multiple da's without issue. Everything is input to a switcher which means the output is scaled and there is a constant resolution and refresh rate. HDCP is disabled on the switcher.

All issues we have come up against have been caused by HDCP issues. I'd also say I'd not be using a da unless it was from a recognised brand.

well this is all sounding far more complicated than i ever thought 😀 id have thought that its sooooo simple to just connect a laptop to tv and watch youtube vids (thats not the aim by the way) 😀

What are you actually trying to achieve?

we run assessments using software that allows candidates to manage incidents, all a bit 'gamey'. we facilitate them 'virtually' wandering around incident grounds, deploying personnel to do tasks etc.
so we're in a command centre with 2 PC's linked to each other, which feed into a main cab. then that feeds different rooms, all containing cctv and TV's which show the incident grounds.
we're 'simply' trying to add a tv to one room which doesnt have one yet and trying to understand the spaghetti junction of cables.
so before we start connecting into the cabinet we want to just ensure that the tv can see a pc by way of HDMI (as thats what the others are fed by)

like i said, i thought we'd start simple by saying yes this tv can see the pc, then try and split it to two tv's, then do this via the main cab. we're falling at the first hurdle tho.

we've got the techy expert in in a couple of months who im sure will be able to sort it, but we just want to understand it ourselves and get cracking with improvements.

thanks for your help, it may just be a bit beyond us if we cant even get the tv to see one laptop directly from one cable 😀

Ideally you want 2 HDMI outputs from the laptop/PC/Mac... (and then set up mirroring at source)... not 1 HDMI output that you're then trying to "split" with dubious hardware of unknown specification and origin.

I gather from this that cheap hardware isn't the way to go.

https://www.cnet.com/tech/home-entertainment/hdmi-switch-vs-hdmi-splitter-everything-you-need-to-know/

https://twitter.com/dkatzmaier/status/758296801543917573

How about a usb hub with multiple external outputs ? If you've USB C then all the easier ?