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Topic # 232016 25-Mar-2018 23:51
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From the image above, what would happen if there were two HDMI over Ethernet transmitters on the same LAN? Would the receivers just crap itself?





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  Reply # 1983105 26-Mar-2018 01:44
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If both were transmitting I would assume so.  If these are the LENKENG LKV372 I run them for my sky around the house (4 in total).  I have a newer sky box and found the IR never made it through, so went with a Harmony Hub to change the screen.  In my setup the sky is the only thing getting split.

 

 

 

Sky->HDMI splitter->4 LV372 (4 direct 5e runs of ethernet) -> 4 recievers

 

 

 

They are pretty good, can get out of sync and stutter occasionally but you just hit the reset button.  In the setup you provided I am not sure how the router replicates and passes through the signal of the transmitting device to all of the receivers.




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  Reply # 1983314 26-Mar-2018 11:28
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Ah, the ones you're using are just HDMI over cat 5e/6 adapters. The one I linked are HDMI over Ethernet, a one-to-many stream. I'm pretty sure they use multicast to do just that.





 
 
 
 


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  Reply # 1983500 26-Mar-2018 14:40
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sonyxperiageek:

 

Ah, the ones you're using are just HDMI over cat 5e/6 adapters. The one I linked are HDMI over Ethernet, a one-to-many stream. I'm pretty sure they use multicast to do just that.

 

 

The giveaway in that diagram that they are using HDMI over IP rather than HDMI over Ethernet cable is the "max 253 pcs Receiver" and that they are showing the connection going via a router.  It is likely multicast, in which case you can have it running over more than one subnet to more than 253 receivers if your router and/or switch can handle sending multicast traffic to more than one subnet.  And it is best if you are doing multicast to be using an intelligent Ethernet switch that does IGMP (multicast) snooping.  Without that, all the HDMI traffic will be seen on every port of the switch running that subnet.  With IGMP snooping, only the ports that actually use the IGMP multicast traffic will be sent that traffic, so that it will not clog up the network.  There is sufficient traffic sending a full HDMI signal over IP that it would noticeably slow down transfer rates for sending large files around your network if it was mixed in with the normal traffic.  So the best way to do the HDMI is to have all the receivers and the transmitter on their own subnet so that the HDMI traffic is completely isolated, and does not even need to go through the router.




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  Reply # 1983507 26-Mar-2018 14:46
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So would I be able to have one transmitter transmitting to one subnet, and another transmitter transmitting on another subnet, and I would be able to use two transmitters at once?





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  Reply # 1983578 26-Mar-2018 15:58
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Yes.  Unless you do some specific config on a router or switch that supports it, the IGMP multicast traffic is restricted to the current subnet - it uses broadcast packets, and broadcast packets are never routed without specific rules.  In theory you should be able to run a network that is isolated on its own switch and only use its ports for the HDMI over IP traffic, if you want to.  There is no need for that traffic to be connected to a network with Internet access.  All it needs is a switch, and if you are not mixing real networking and the HDMI over IP, then you can use a dumb switch as all the connected ports will want the IGMP traffic.




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  Reply # 1983700 26-Mar-2018 18:00
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fe31nz:

 

Yes.  Unless you do some specific config on a router or switch that supports it, the IGMP multicast traffic is restricted to the current subnet - it uses broadcast packets, and broadcast packets are never routed without specific rules.  In theory you should be able to run a network that is isolated on its own switch and only use its ports for the HDMI over IP traffic, if you want to.  There is no need for that traffic to be connected to a network with Internet access.  All it needs is a switch, and if you are not mixing real networking and the HDMI over IP, then you can use a dumb switch as all the connected ports will want the IGMP traffic.

 

 

Thanks for confirming my thoughts.





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  Reply # 1983740 26-Mar-2018 19:16
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The ones I have just do broadcast, not even multicast so it completely nukes wifi on the same network. Plug 2 of them in and it just shows garbage on any reciever. I have made 2 vlans to take 2 different DVR outputs around the place, and only taken those VLANs to the places that need them. Picture quality is worse than steam inhome streaming. There is no synchornization between sender and recievers frame clocks, so its unsuitable for anything you care about dropped/duplicated frames on, and the sound is often having micro-stutters.

 

I was hoping they would be an answer to the lack of multiroom on the video chromecasts to watch youtube and twitch around the house and workshop from one playing chromecast since they are so slow to get going and a hassle to change where I am watching, but quality was too bad on them for that. Couldnt even read the twich chat if there was lots of movement on the video side of it from the android tv boxes output - was that bad.

 

If you;re the sort of person that can stand watching the trash picture quality on SD broadcast tv then these would be fine.

 

these are the ones I got.





Richard rich.ms



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  Reply # 1983831 26-Mar-2018 21:25
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Oh! Those look like exactly the ones in my picture on my OP! Doesn't sound very promising those devices then. What is the rough range of cat 5e cable you are running between them?




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  Reply # 1983835 26-Mar-2018 21:28
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Its just going thru my switches and stuff, they only link at 100 megabit and wouldnt even use 1/3 of that for data. Should be able to push 140+ m of cat 6 easy enough if direct between them but im not about to go chopping cable off a roll to find the exact limit.

 

The output resolution doesnt track the input either, so put 50i into it and 60p comes out with the resulting judder that makes it prettymuch useless.





Richard rich.ms

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