A large portion of the content here was contributed by Alexander Cameron, Managing Director, Digital TX Ltd. Digital TX Limited is a provider of technology and consultancy solutions for interactive digital television and broadband media.
What is IPTV?
Internet Protocol Television (IPTV) is broadcast-quality television and/or video signals that are delivered to subscribers or viewers using a broadband connection over Internet Protocol (IP). While IP stands for Internet Protocol, it does not actually mean the television content is streaming over the Internet. IP is simply the same method, protocol, or technology that enables you to access the Internet and IP-delivered television content is utilizing the same technology for delivery. IPTV operates on a different premise than traditional satellite or cable television in that only selected programming and on-demand content are delivered to the consumer. With Satellite and cable, all channels are being pushed all the time to the consumer's home rather than a per-selection basis. IPTV's ability to provide two-way communication (you request a program from the TV guide and the program is delivered to you) offers true interactivity for the customer with the environment. HDTV, movies, past TV shows, and all other content can be distributed on demand and service providers can tailor the requested content and advertising based on customer preference.
IPTV also offers such potential as on-demand video gaming and because it is using your broadband connection, it can interact with other Internet services such as Voice over IP (VoIP). Consumers may have caller ID displayed on their television. The potential is truly unlimited.
When will I be able to watch it?
IPTV rollouts are taking place around the globe. Multimedia Research Group, Inc. is projecting global growth from 3.7 million subscribers in 2005 to 36.9 million in 2009, the report also forecasts subscriber revenue growth from $880 million to $9.9 billion in 2005-2009. Check with your local telephone or cable company to see if they are working on offering IPTV.
Who is offering IPTV?
Verizon has already begun rolling out their IPTV initiative, called FiOS, up and down the east coast and in Texas. SBC and Bellsouth have initiatives of their own. There are smaller telecom companies rolling out their own services across the U.S. In Europe, IPTV services already in place include Fastweb in Italy, HomeChoice in the U.K., MaLigne and Free in France, Telefonica in Spain,
In Asia, you can choose from Chunghwa Telecom in Taiwan, PCCW Ltd. in Hong Kong and Softbank/Yahoo BB in Japan.
Click over to TVover.net to find a more detailed list of IPTV service providers by country and/or state.
What is the minimum bandwidth you need for full screen TV and video?
Typically video broadcast as MPEG-2 (the current standard for digital television and DVD) takes 4-6Mbit/s, whereas newer, advanced codecs (e.g. MPEG-4 H.264, VP6, VC-1) are designed to consume 1-2.5Mbit/s. Generally, the lower the bandwidth, the lower the video quality. It is possible to deliver video at well below these levels if the environment is optimal – e.g. the picture size is smaller or the content is fairly static. What happens if the TV is in a different room to the broadband gateway/router?
Short answer: use HomePlug. There are three options for solving this problem, as all set-top boxes require a simple Ethernet connection for basic operation. The first is to place your router next to the TV. The second is to provide Ethernet cabling from wherever the router is (usually the hall or study) to the TV. The third, and most elegant solution is to use HomePlug (14-200Mbit/s) broadband over powerline technology to extend the connectivity to every room in the house. In this scenario, 1 adaptor would be plugged in next to the central router, and the other by the television, invisibly connecting the two.
Can other people in the same house watch video at the same time as the main user of the connection?
Yes. Most modern analogue and digital television platforms support some form of 'multi-room' capability as they use the broadcast model of transmitting a whole spectrum of channels at once, instead of one at a time as IP delivery does. It is possible to stream (multicast) the output of a central set-top box across the network to other devices. The ability to receive different channels in separate rooms is dependent on whether the home broadband connection has enough bandwidth to support it. In most cases, ADSL2+ (or 12Mbit/s +) technology is needed for this functionality, along with strict quality of service. For example, three rooms watching three different channels of live TV encoded at 1.5Mbit/s would need 4.5Mbit/s bandwidth, with an additional guarantee of 1Mbit/s to compensate for network overhead and transit problems. Do you need multicast capability, and what are the implications for our network?
Yes. IPTV channels can only be delivered over IP networks as multicast, so if you want to deliver live television, your network (from DSLAM to peering hub access) must be multicast-enabled from end to end. Live TV cannot be delivered by unicast, and multicast also enables the most efficient delivery of video data and the smoothest channel changing speed. For example if you wanted to offer 100 live TV channels in 4Mbit/s MPEG-2, you would need 400Mbit/s backhaul multicast bandwidth. Using dynamic technologies such as PIM can help to reduce network overhead by only relaying the channels that have been specifically requested. How can we get the best content, and how will we have to pay for it?
Whether or not you have compelling content is the deciding factor in whether you succeed or fail – you can have the best technical implementation in the world, but if you have nothing worth watching you will have no subscribers. 'Content' encapsulates live TV channel carriage, movie titles, TV archive footage, computer games, animation and more. Gaining the rights to use these directly from the rightsholder or through an aggregator is fraught with difficulty, extremely expensive and takes a very long time. Most licensing agreements need extensive pre-paid guarantees, minimum subscriber/viewer levels and work on a revenue share basis with at least 60% or more in favour of the rightsholder. Can you really transmit TV video over a normal DSL line reliably?
Yes, with conditions. Although they need powerful processors for both encoding and decoding, the latest MPEG-4 video compression formats (e.g. H.264 etc) can faithfully reproduce DVD-quality video over a 2Mbit/s connection with plenty of room to spare. How can video-on-demand be as compelling as renting a DVD?
The main driving benefits of VoD are sold as convenience and choice. However, with their comprehensive features, DVDs are perceived as much better value than just watching a video stream of the main future. Most streaming platforms are based on the heavily compressed MPEG-4 video format, which does not offer a way to replicate the DVD experience that is offered through MPEG-2 (chapters, subtitles, languages, special features etc). Several companies have developed technologies that use the in-built BIFS/XMT API in MP4 to create commercial applications which can generate titles that are billed as 'network DVD without the disc', and early studies suggest they are received extremely well. Can't we just send the video over wireless/wi-fi?
No. It is now widely accepted that wi-fi is unacceptable for most video applications, although they are fine for simple computer networking. Trying to send MPEG-4 (even simple and advanced profiles such as DivX and xVid) is extremely difficult and unreliable. Newer technologies such as WiMax have yet to prove stable enough in a commercial setting even for PC connectivity. Won't the TV picture go wrong if someone steals all the available bandwidth on the connection (e.g. by downloading a large file etc)?
No. This happens when you try to receive video over an uncontrolled, congested 'best effort' network, such as most DSL networks are based on today. Networks carrying multiple real-time services (e.g. voice, video and data) need strict quality of service (QoS) rules applied to them that effectively 'partition' each service into a separate 'virtual channel' that is separate from the others. These rules need to be enforced by the ISP and mirrored in the home network, usually by the router/broadband gateway. As every network operator's topology is different, a custom mixture of ATM and IP QoS methodologies can be used to label, protect/reserve and prioritise bandwidth for the devices that need it most. Each of these 'virtual channels' has a specified capacity and expand/contract ('burst') allowance that can be dynamically allocated according to an operator's business rules. A typical configuration is guaranteed A1 priority 2.5Mbit VBR (variable bit rate) for video, 256kbit/s CBR (constant bit rate) for voice and the remainder as UBR (unspecified bit rate) data for internet connectivity. Is triple play compatible with newer DSL technologies, such as VDSL2 and ADSL2+?
Yes. Consumer broadband CPE will certainly need to be upgraded to support either, in the form of a software update or replacement unit. Both work over copper telephone lines and offer massively higher bandwidth (~25Mbit and ~75Mbit respectively) than conventional ADSL technology at the right distance from an exchange. This additional bandwidth can offer the ability to receive multiple signals in different rooms of a house and also high definition (HD) video.
Could we provide high-definition (HD) video?
Yes. In normal digital television MPEG-2, HD video requires around 30Mbit/s of bandwidth, but newer compression technologies (such as MPEG-4 H.264) require only 6-9Mbit/s, which is very achievable over existing DSL infrastructure using ADSL2+ and VDSL2. However, it also requires considerable investment in reception equipment to view (TV screen, decoder etc), which makes it currently prohibitive to deploy.
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