Articles and whitepapers

IPTV for TV Distribution in Large Dwellings (5/11/2007)

By Jonathan Rackowe, Netvue

As UK digital switch-over draws near and the last days of analogue television hasten to a close, many people are wondering which way to turn when it comes to replacing analogue RF distribution in their homes.

For those living in large blocks of apartments, or mansions with lots of rooms, it very soon becomes apparent that simply plugging Freeview receivers into each point where television is wanted does not provide a very satisfactory solution. In many cases, the RF distribution that used to deliver the analogue TV signal is simply not good enough to deliver digital Freeview DVB signals throughout the building.

Digital signals

Whereas an analogue TV signal can be really quite poor and still give a watchable picture - albeit a grainy one - a digital signal either works or it does not. It will not degrade slowly in the same way. With a good signal, the digital TV picture will be virtually perfect, but if the signal strength is poor, there will be blockiness and occasional freezing, and at worst, no picture at all. Combating this may require a better roof-top aerial, one or more RF distribution amplifiers and possibly replacement cabling, but if you add to this the complication of distributing other video signals, such as satellite channels or DVD player feeds, across the same cabling, it quickly becomes apparent that something rather better than old-style coax is called for.

Perhaps the answer lies with Internet TV then. TV over the Internet has possible strengths for its variety of channels, but real weaknesses when it comes to quality. The potential immediacy of live news and unlimited content direct from the Internet is very attractive, but in reality, Internet TV is dogged by the irritation of sluggish connection speeds and small, poor-quality images due to the inherent low quality of service.

The IPTV solution

The alternative is IPTV distributed over standard local area network (LAN) cabling. IPTV systems take digital terrestrial and satellite DVB television signals received at broadcast quality, de-multiplex them into individual channels, and IP wrap them to provide live IPTV streams on a CAT5 or CAT6 LAN.

The IP wrapping involves parcelling up the broadcast digital TV data streams (which are already MPEG encoded) into streams of IP packets so that they can travel over the computer network.

These IPTV packets are transmitted across the computer network just like other IP packets such as data or VOIP packets, but network switches recognise the time-sensitive nature of IPTV packets and give them a higher priority than other network traffic. This ensures that the TV pictures are displayed as they should be.

This IP transport approach to TV distribution can be extended to include video on demand (VOD) channels from client-owned servers and encoded local video sources such as DVD players. For these video sources, the signal is MPEG encoded as necessary before being IP packetised and delivered onto the network.

Block diagram of the Netvue IPTV System.

The benefits of IPTV

Using IPTV for distribution of TV and video in this way offers many significant benefits over conventional analogue distribution:

* IPTV is digital - so it is immune from the problems of noise, distortion, ghosting and signal degradation that affect analogue signals. The result is that IPTV gives you high quality pictures and sound.

* IPTV channels can be watched on PC and Mac desktops at the same time as distributing channels to IPTV receivers for viewing on conventional TV screens, projectors, plasma screens and LCD displays.

* IPTV can use the existing computer network - no new cables, no hassle! For new installations this is where IPTV really comes into its own.

* IPTV distributes an unlimited number of channels - a typical IPTV system shows any desired mixture of Freeview TV and radio channels, plus any number of additional channels from other sources.

* IPTV supports widescreen and 4:3 picture formats - the widescreen digital picture flag is carried by the IPTV channels so that the IPTV receiver automatically shows the correct aspect ratio picture on the display screen.

* IPTV allows distribution of high definition (HD) signals - HD is becoming more and more widely used; IPTV allows you to upgrade your channels to HD at any time in the future, though some hardware changes may be necessary to achieve this.

* IPTV allows new services to be included, such as VOD, scheduled recording of TV and video, and scheduled playout channels.

Conclusion

IPTV streaming provides an ideal solution for distribution of television and video channels in multiple apartments or the multi-screen home environment. It provides better quality than conventional analogue distribution and also offers the advantages of new services, such as VOD, whilst using standard computer network cabling.

Jonathan Rackowe is the Managing Director of Netvue. Netvue is a business division of Projects UK Ltd, and a provider of new technology IPTV solutions to companies across a range of business sectors.

www.netvue.co.uk