REVIEW: HD Intelligence HDMI for Networks
Hills has released a new product that enables HD reoslutions over network cables. Stephen Dawson explains.
Although we love looking at fancy TVs and glorious loudspeaker systems, we try not to overlook deeper matters of in-house infrastructure. And here we come to a new product from Hills A&TV: the HD Intelligence HDMI for Networks system.
Henceforth to be called herein HDMI for Networks.
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What it is
HDMI for Networks is a way of delivering HDMI over network cables. This is not a new idea, but the HDMI for Networks people say that their way is different, and way more capable.
First, what’s the major problem with HDMI? HDMI cables, of course. About the longest reliable run for HDMI – using a really high quality HDMI cable – is about 15m. Go much beyond that and your cable will need some kind of active component to reinvigorate the signal for the rest of the journey.
The HDMI for Networks system supports runs of up to 100m with 1080p60 signals. And that’s just from transmitter to receiver. Even greater distances are possible, as we shall see shortly.
At its most basic you purchase a system consisting of one HDMI for Networks transmitter and one HDMI for Networks receiver. The transmitter has a HDMI input socket and an RJ45 network connection, plus a socket for an IR blaster. The receiver has a HDMI output socket, an RJ45 network connection, and a socket for an IR receiver. The IR receivers and blasters are supplied with the units.
You plug the HDMI output of – say – your home theatre receiver into the transmitter. You run a network cable from the transmitter to the receiver. You connect the receiver’s HDMI output to your display. Plug the power in and you’re right to go.
The transmitter doesn’t merely turn the HDMI signal into something proprietary which can cope with network cabling. It turns it into standard Internet Protocol packets.
IP works both ways of course. So if you have the IR peripherals attached, then you can send IR commands back to the originating equipment. Stick your home theatre receiver somewhere out of sight and you can still easily control it.
A&TV reckons that using solid copper core Category 6 network cable, a connection is good not for 15 metres, but for 100 metres at 1080p60.
Now here’s the cool thing about IP: a packet is a packet is a packet. If you plug the transmitter not into a receiver but into a network switch, then you can plug several receivers into the switch and all will receive the signal. You can run several display devices.
A&TV also supplied the one in, four out system for the review. This comes with an infrastructure quality 8 port network switch, one transmitter and four receivers. With this you can run four displays.
A&TV have a quite a few packages with different numbers of outputs: 6, 8, 12, 14, 16, 20, 30, 44 and 47. One of those ought to suffice for a display in every room of your home should you want that, even the smallest room. Prices for those systems start at $2,265 and go up to $12,608 for the 47 output system.
If 100 metres is not enough then you can plug another network switch into the first network switch with up to a 100 metres of Cat6 solid copper cable. And then another one into that with similar cable.
Net result? Up to 300 metres of signal carriage and lots of displays.
There is also controllable ‘matrix’ system in which multiple sources can be connected to multiple displays, all controlled by a WiFi receiver and a smart phone app. But the equipment for that wasn’t supplied, so I shan’t remark further on it.
In Use
Initially I decided to go for a minimal system of one transmitter to one receiver. A&TV made a point of saying that in this configuration you must use a cable with T568B plugs, whereas if a network switch is in the system then you can use either T568A or T568B without problems.
It is not always obvious whether a cable is terminated with T568A or T568B plugs. They are physically the same, but the conductors on two pins are swapped. This led to a bit of confusion. A&TV had provided me with two clearly different – but both very long – sets of Cat6 cables. One was labelled T568B so I used. The TV reported that it was receiving no signal, so after a couple of minutes I switched to one of my own cables, a Cat5e one, but that was only ten metres long, and which was labelled T568B. Same thing. So I switched to the other cable A&TV had supplied – which did not indicate the cable type, but had a transparent plug moulding that allowed me to check the internal connections and confirm that this, too, was a T568B cable (thanks Wikipedia!).
While I was switching cables, I was noticed that my TV was no longer indicating that it was lacking a signal. Instead it had a plain text message up – obviously from the HDMI for Networks receiver – indicating that there was no network connection. I plugged in third cable and, voila, the picture came through. But I was suspicious. Why this cable, and not the others. Why had my TV been receiving no signal at all rather than a message from the receiver?
I reverted to the previously tried cables, and they all worked pretty much instantly. The problem, it seemed, had been my impatience. Clearly the HDMI for Networks receiver took a little while to complete its handshaking with the TV. I checked the other three receivers and they managed to connect to the TV quite a bit faster, typically around 15 seconds. So the first one may have been a bit wobbly. Still, thereafter it worked efficiently.
Running via the supplied network switch worked smoothly. I used three displays connected to HDMI for Networks receivers and all seemingly worked perfectly.
At no time was there even a flash of the picture noise that the HDCP (High-bandwidth Digital Content Protection) system sometimes generates during device handshakes.
The system was happy with common HDMI signal standards, but apparently would not work with interlaced standard definition (576i50) or 1080p24 frame packed 3D signals. It seemed to convert the former rather brutally to 576p, deinterlacing by the simple means of abandoning every second field. With 3D the result was high quality 2D, suggesting the system simply stripped out the second of the two packed frames.
One issue I expected was a delay in the video. The whole process of converting from HDMI’s streaming style of signal to IP packets, and deconversion at the other end must, I figured, take time. Well of course it does. But it is such a short time it won’t interfere with your enjoyment. I used an AV sync test to determine how much delay it inserted, and there was none. This test resolves down to a less than five milliseconds. Whatever audio delay you dial into your home theatre system now is the appropriate amount if you’re using this system.
However running through a switch did slow things down a bit. I connected two displays connected via the HDMI for Networks receivers to the switch, and one of them slowed down from a native lag of a little over 30ms to a little over 100ms. That can be easily fixed with a home theatre receiver for matching sound and image in movie watching, but could impact on gamers’ performances.
What if things go wrong?
I suspect that my ten metre Cat5e cable was pretty much at its limit when running 1080p60 video. With 1080p24 it seemed identical in every way to a direct HDMI connection to the source. But at 1080p60 it seemed even jerkier than the direct connection (I was using 1080p24 video delivered at 1080p60).
I noticed that if I pulled the network cable from a receiver, the last frame would be held steady on the screen for touch over five seconds. So I suspect that if there are a sufficient number of irretrievable errors in a frame, the frame is just omitted and the last good frame held over.
Conclusion
The HD Intelligence HDMI for Networks system is extremely clever, and actually a rather low cost solution to the problem of long HDMI cable runs.
Now that an increasing number of home theatre receivers offer a dedicated Zone B HDMI output, getting its content elsewhere in the home is turned by HDMI for Networks from prohibitively expensive to quite reasonable.
It’s also hard to think of an easier and lower cost way of running multiple displays in different locations with high quality HDMI signals.
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