Digital distribution by Crestron, Abramovich's new superyacht and why HDMI isn't the answer for whole-house HD

I've just spent a fascinating few hours at Crestron's UK HQ, just outside London, where I've been learning all about the problems created by HDMI when it comes to distributing high-definition content around the house.

Or Roman Abramovich's new boat.

The company was launching a range of new products, and took the opportunity to give us an overview of developments in the custom-install field. Which is how I came to learn about some of the foibles of HDMI, how to run HD audio and video all the way around a 170m superyacht, and why iPods are the new whole-house music server.

And why the demands of high-definition distributed entertainment mean the company has racked up the same sales in the last month, since launching its DigitalMedia solution, as it did in the whole of the previous year with conventional CAT5-based distribution systems.

Kicking off a fascinating presentation of the latest products, UK Residential Sales Manager Phil Solomons showed us the new iPod docks, available in both free-standing and in-wall designs.

Its Crestron-Mobile iPod Touch/iPhone app was launched earlier in the year, allowing complete control of a Crestron multiroom entertainment system from one of the little touchscreen devices, but Solomons explains there's more to their role than that.

iPod is the new server
Increasingly, the massive 'server under the stairs' is being replaced by iPods in custom installations, allowing local libraries of music to be played via the audio system in the room where they're docked, or accessed remotely across a whole-house system.

A simple push-button on the docks lets the iPod switch from local use to access anywhere, and you can also sync the player with any computer on the network running iTunes, just as if you had a direct USB connection between the two.

That's just one of the innovations in Crestron's latest line-up. For example, you can also buy a new remote handset able to control the complete system via wi-fi, while also doubling as an intercom/phone handset.

Intriguing, too, is that the handset operates on the 'slowest' 802.11a-type wi-fi, while also having b/g compatibility. Why so? Solomons explains that as home wi-fi has moved up from b to g and n versions, things have got a bit cluttered in those parts of the spectrum. So the Crestron handset runs 'a', where's there's not much else going on.

How to do HD distribution
It's all a matter of bandwidth, and that brings us on to the biggest problem of all in the modern custom-install arena – distributing HD video content, for example from Blu-ray Disc, around the home.

And it's bad news for those fortunate enough to have existing integrated home systems for audio and video: right now there simply isn't enough bandwidth on existing Cat5-based distribution to carry HD video and audio to multiple zones. So that means time for a re-cable.

HDMI: point-to-point, 7m max
The HDMI system makes things even trickier. As Solomons explains it, HDMI was only ever designed as system for transmitting content securely over relatively short distances, point to point. In other words, from a Blu-ray Disc player to a TV, for example, over cable runs of about 7m maximum.

Anything else, from switching in AV receivers to long runs to projectors, is a bonus – and things get even more complex when you start to factor in multiple sources and multiple destinations, as you'd have in a distributed entertainment system.

After all, improving video standards mean huge amounts of data need to be transmitted. 1080i requires 2.23 Gigabits per second, 1080p twice the bandwidth, and 1080p with Deep Color 6.68Gbps.

Not only are there the obvious problems of the image flashing, audio or video drop outs or simply no signal at all over long runs, you can also run into difficulties created by the flow of information between components linked by HDMI, not to mention the HDCP – High Definition Bandwidth Content Protection – built into the HDMI standard.

Too much protection?
For example, the HDCP system uses 40 56-bit keys to protect the content, and if those aren't resolved correctly in the handshake procedure, all you'll get down the line is a blank screen. And the same's true for the DisplayPort digital outputs increasingly being fitted to computer hardware.

What's more, the fact that HDMI requires this 'handshake' to occur every two seconds brings its own problems in a distributed system. Say you're watching a BD movie, and you decide to flick over to Sky HD for a moment or two to catch the sports news; when you switch back you'll find the BD player's HDMI signal has gone to sleep, as it hasn't received the handshake in a while, and will take several seconds to re-establish itself.

Crestron tackles this with switching systems enabling all the HDMI connections to be kept 'live' and handshaking at the same time, allowing instant switching between sources if required.

But there's more, as they say, in the form of the Image Constraint Token built into the Blu-ray Disc system, and the Extended Display Identification Data that's a part of the Display Data Channel carried between HDMI sources and displays.

Blu-ray's built-in time bomb
Solomons describes Blu-ray Disc's Image Constraint Token as the format's 'built-in time bomb'. If one tries to get round the deficiences of HDMI by taking an analogue video feed, for example using component video outputs, it's possible for an embedded flag in the software to tell the player to downgrade the picture quality on those outputs to standard definition.

Oh, and that EDID information on the DDC? This sets up the HDCP encryption between the source and destination device, but has a nasty trick up its sleeve in multisource, multiscreen systems: if you have multiple displays in use, the EDID – which determines the 'best fit' of audio and video for the displays – will always go for the lowest common denominator.

In other words, imagine you've splashed out on that megabucks home cinema, complete with serious projector, but also have the content streaming to a smaller HD-ready TV in the kitchen so you don't miss anything when you sneak out to top up the popcorn.

The EDID system will only allow the projector to receive the resolution of which the kitchen TV is capable.

And there's also the small matter of that Hot Plug Detect, with which downstream devices announce their presence to the source components. Turn on the kitchen TV, and the image resolution all round the home might change again!

Crestron 16x16 matrix switcher

Crestron has solutions for all these problems, including scalable switchers able to do everything from one source into two screens to 16 sources into 16 screens, and installers can use multiples of these units to run even more complex systems.

It can also integrate scaling to match signal to screens, and has input modules to allow legacy analogue video to be integrated into one digital distribution system.

It can even offer a box (left) able to take an HDMI input and deliver stereo sound, downmixed from the datastream, as you might want in a room where you have a display, but don't want the complete surround shebang. That kitchen again, for example.

By this point in the presentation my head was spinning with the sheer amount of useful information being delivered, and my note-taking getting ever more frantic, but we still had to address The Big Question.

If HDMI is only good for fairly short runs of cabling – too short even to do room-to-room in most homes – how do you do distributed HD entertainment in palatial piles with many rooms, not to mention superyachts?

Or "boats – but I really shouldn't call them that," as Solomons puts it.

Here's how it's done. The Crestron answer is really two answers, both part of its DigitalMedia solution.

The conventional cable (above) uses twisted pair cabling, with multiple cores carrying signal and control data: one bundle carries high-speed Ethernet and other data, plus 5V power; a dedicated bundle carries high-def audio and video, and a final set of conductors carries Crestron control signals and 24V power.

A single cable can carry the signal – supporting current and future HD audio and video standards – between the company's components, and do so over runs of about 50m, or well beyond the 10m maximum it sees as possible with HDMI.

However, step up to the company's CresFiber fibre-optic system (above), using a bundle of four glass fibres – two for current applications, and two more for future expansion – and it's possible to extend the runs up to 300m.

In fact, the company is working on 1km, making the system able to distribute HD entertainment around the largest of homes, not to mention the likes of conference venues and sports stadia.

The DigitalMedia system also allows sound and vision to be synchronised all round the home, so none of that nasty delayed audio just heard from the next room, or video out of whack: Solomons demonstrated this with the rig above, using two Pioneer screens linked via DM cable and transmitters/receivers to a single Blu-ray Disc player.

One uses a shortish run of cable, the other a long run, then a repeater, then another long run – equivalent to the far TV being at the other end of a reasonable-sized home. And yet both sound and vision are in perfect synchronisation, so fast is the data-transfer on the system.Perfect anything from a normal semi to the largest house.

Or indeed a superyacht, which brings us back to Roman Abramovich.

The Russian billionaire's recently-launched new toy, the Eclipse, is estimated to be 170m – or around 560ft – stem to stern, and has HD entertainment piped throughout.

Guess which company supplied the equipment?

Andrew has written about audio and video products for the past 20+ years, and been a consumer journalist for more than 30 years, starting his career on camera magazines. Andrew has contributed to titles including What Hi-Fi?, GramophoneJazzwise and Hi-Fi CriticHi-Fi News & Record Review and Hi-Fi Choice. I’ve also written for a number of non-specialist and overseas magazines.