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What is IPTV

Written By: 

Ashok Sharma


Televisions have been the prime source of entertainment since their commercialization. New display technologies as well as the content over the TV channels are continuously enhancing the user experience since its invention. In the twenty first century, mobile and internet technologies have revolutionized the entire civilization. Televisions have also been influenced by the internet technology. The conventional methods to serve the television programs like cables, satellite or broadcasting are getting replaced with the broadband cables used for internet.

 A Representational Image of IPTV or Internet Protocol Television

Fig. 1: A Representational Image of IPTV or Internet Protocol Television

What is IPTV?

IPTV (Internet Protocol Television) is a system where digital television services are delivered over the internet by using Internet Protocol. The video channels and programs are delivered to the television sets through a broadband connection, instead of being delivered through the conventional cable or broadcast formats. The video streams are encoded into a series of internet protocol packets and then carried out through the public internet means which can be received by anyone by having a set-top box and a subscription for the service. IPTV is generally provided bundled with the VoIP and the internet access which is referred as “Triple Play” service. So this service is a complete package that allows customers to watch TV, browser the internet and making a long distance calls using the VoIP. This service is typically provided by a service provider using a closed network infrastructure.

Multicasting & Unicasting
IPTV supports both live TV (multicasting) and the stored videos also called Video on Demand (unicasting) services. In order to receive the IPTV signals a computer or a television set with a set-top box is required. The video content is typically compressed using either a MPEG2 or a MPEG4 codec and then sent in the MPEG transport stream via IP multicast in case of the live TV or via IP Unicast in case of VoD. IP multicast is the technology that delivers the video content to various users simultaneously whereas the Unicast technology delivers the video content specifically for each user.
The basic protocols used in the IPTV forecasting are the HTTP (Hyper Text Transfer Protocol), IGMP (IP Group Membership Protocol) and RTSP (Real Time Streaming Protocol). HTTP is the protocol that browsers use to communicate with the servers and computers for data transfer. Live TV uses IGMP version 2 for connecting television sets with the multicast stream and switching to another multicast stream while RTSP protocol is used for Video on Demand services
 A Figure Depicting Basic Protocols Used in an IPTV Along With Their Respective Uses

Fig. 2: A Figure Depicting Basic Protocols Used in an IPTV Along With Their Respective Uses

Working of IPTV

How IPTV works
IPTV combines TV compression technology and IT data technology to stream TV and video as a continuous flow of data over the internet. A set top box is provided by the IP TV service provider which is connected to the DSL line. The set-top box is responsible for reassembling the packets into the coherent video streams and then decoding those contents. In the case of computers there is no need of the set top boxes. IPTV services are of two types - Multicast and Unicast streaming. There are hundreds of channels which are multicast from the national headend to the local offices at the same time. But unlike the cable systems only a few channels are sent at a time as the bandwidth of DSL lines is far less than the cables. When a user changes the channel on the set top box, it does not simply tune to the other channel like a cable system. Instead of this by using the IP Group Membership Protocol (IGMP), the set top box requests a new channel. When the local office receives the request, it first checks if the user has permissions to access the new channel and then directs the routers to add the specific user to the channel’s distribution list. Hence the signals that are currently requested are sent to the user. The Multicast technology does not support the Video on Demand (VoD) services as it requires a unique stream for a particular user. To support VoD services the local office need to generate the unicast stream that targets a particular user. Unicast stream, controlled by the Real Time Streaming Protocol (RTSP), provides a DVD style control over the television programs and allow users to stop, play or pause programs they are watching.
The whole process of delivering IP TV streams to the end user is described in detail:
A Diagram Illustrating Process Flow of IPTV Streams to the End Users

Fig. 3: A Diagram Illustrating Process Flow of IPTV Streams to the End Users

·         Acquiring the programming
The video/audio programs that the IPTV Company delivers to its end users are owned by some entity. In order to distribute the content, the IP TV Company should acquire the rights to collect and redistribute this material. A Headend is the physical unit which collects the media streams and by decoding/re-coding, multicast it for distribution. The IPTV headend can be divided into three different sections – satellite reception, encoding and encryption, and distribution.
The reception of the content is done by using a large multi-focal point c-band dish or a group of several such dishes which receives the content signals coming from the various satellite transmitters. The signals that reach the earth are quite weak so they need amplification. Then the received signals are decrypted as the different channels encrypt the content to protect their intellectual property.
·         Encoding the Streams
The received output from various receivers will be injected into an encoding device to deliver to the multicast IP addresses. Generally these streams are encoded in MPEG2 or MPEG4 format. The MPEG4 encoding equipments cost higher but the encoded data needs less bandwidth.
Once all the received contents are demodulated and multicast IP encoded, encryption is applied to the content to protect it from unauthorized access. The sub-system responsible for encryption content is known as the Digital Rights Management (DRM) package. The DRM provider also ensures full compatibility with the set top box manufacturers, OS vendor and set top box video presenting software so that the set top box can be able to decrypt the stream at the user’s end.
·         IPTV Distribution Network
The network that can be used as IPTV Distribution network should cover wide area, provide adequate bandwidth and quality of service to the end users to deliver the IP TV content. Additionally network needs a small amount of bandwidth to deliver the revenue generating programs – like advertising, etc. Usually the networks for IPTV distribution are Fiber To The Home (FTTH/FTTx), Ethernet Passive Optical Networks (PONs) or a hybrid network with a Digital Subscriber Line (DSL) for signal transportation.
·         Middleware
Middleware is the set top box software that performs various operations on the set top box and allows viewing the video content on TV. It manages inputs and outputs to or from several databases, generates the presentation to the TV viewer in the form of Electronic Program Guide. It does the following functions:
a.       The middleware accesses and manages the database of content streams on various IP addresses and port numbers.
b.      It also accesses and manages the database of what channel number the IPTV wants to assign to each content stream.
c.       The middleware manages the various other databases for – what package each channel is a member of, database of subscribers, their set top boxes and what packages or channels they subscribed to, and the database of VOD purchases.
d.      The middleware generates and distribute a functioning, navigable guide to the set top box that enables the end user to watch a program as well as to navigate up and down within the channels they are subscribed.
For example when a user switches on the set top box, the middleware first ensures that the unique set top box number is assigned to a subscriber whose accounts are up to date. Then the middleware delivers the box the list of channels that user is subscribed to. When user presses the guide button on the remote, the Electronic Program Guide displays all the subscribed program titles and descriptions.
IPTV can also be viewed on computers without the need of the middleware. The content can be shown through the web browsers by typing the following information in the address bar:
Igmp://<ipadress>:<port>     example – igmp://

Working of IPTV Contd.

·         IPTV Viewing Device (Set Top Box)
The Set Top Box is a hardware device similar in appearance to the set top boxes that come with cable or satellite TVs. The modern STBs are quite advanced with a processor and memory and able to decode MPEG2 or MPEG4 encoded videos. They work together with the middleware to connect the end user’s television with the IPTV service provider.
The working of whole IPTV system is nicely explained in this video.

Advantages and Markets

Advantage of IPTV
There are several advantages of IPTV over the traditional cable and satellite TV.
·         The IP TV subscribers have a full control over the functionalities such as pause, rewind, fast forward, etc in the services like Video on Demand (VoD).
·         Network Personal Video Recording (NPVR) is a service that allows users to record the scheduled programs and then watch them whenever they want. The NPVR system provides the time-shift viewing of the broadcast programs allowing users to record the programs without requirement of any special device. In this service the IPTV servers facilitates the users to store their favorite programs on the network based library and can access them whenever they want.
·         The biggest advantage of IP televisions is that they use internet protocols to provide a two way communication for interactive televisions. You can also view a video with multiple angles simultaneously by using the picture in picture facility.
·         The web service notifications like incoming mails or chat messages can be viewed while watching the TV.
·         Unlike conventional TV system, the requested channel is only sent to the viewer instead of broadcasting all channels which saves the bandwidth.
·         Various services like Video on Demand, Scheduled Recording, Scheduled Playback, Digital Signage, Business channels, Rolling Recording, etc are bundled with the IP TV services.
·         The videos are encrypted and then compressed to send as IP packets. This ensures authorized access only.
·         With the services like triple play, providers also avail the services like Voice over Internet Protocol (VoIP) and internet access along with the video services that makes this service far better than the traditional cable/satellite TV services.


Market Scenario
In the past few years IP TV has emerged as a hot topic in the entertainment and telecommunication industry. The pay-TV market is a multi-billion dollar business and this new technology has been successfully tapped into this multi-billion dollar market and gradually replacing the traditional technologies. The growth rate can be observed in the below figure.
 A Bar Diagram Depicting Growth Rate of IPTV Over Years

Fig. 4: A Bar Diagram Depicting Growth Rate of IPTV Over Years

As per the reports of Multimedia Research Group (MRG), the total IPTV subscribers have reached to 21.3 millions in 2009. With the growth of IP TV markets, many new services and technologies are emerging like DVRs, high definition programming, MPEG-4, etc. to improve the IP TV experience. More than 700 companies are deploying IPTV services worldwide. The total count of global IPTV subscribers is expected to grow from 26.7 million in 2009 to 81 million by 2013 with annual growth rate of 32%. The leading regions that are experiencing the growth are North America, Europe, China and India.
A Bar Diagram Illustrating Global IPTV Services Revenue Over Years

Fig. 5: A Bar Diagram Illustrating Global IPTV Services Revenue Over Years

In the context of total revenue, the total IPTV market is expected to grow from $6.7 billion in 2009 to $19.9 billion in 2013 with a growth rate of 31%.  Europe and North America have a larger share in the global revenue because of the lower Average Revenue Per User (ARPUs) in the China and India which are the largest markets in Asia.


its good article



Its useful

I like the article .thanks for sharing  ,

Good Article

Great Article. I learned lot. Thanks :)

yes Thanks I learned alot from this article.

Nice Article.Thanks:)


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