1. Department of Computer and IT Engineering University of Kurdistan
Computer Networks II
IPTV
By: Dr. Alireza Abdollahpouri

2. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 2 2

3. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 3 3

4. IPTV Introduction and Motivation
Television (TV) is a dominant and pervasive mass media
The recently rapid growth of IP-based networks, and the trend of network convergence
The tremendous increase in real-time & multimedia communications in Internet
The advantages of TV delivery via IP-based network
IPTV 4

5. Introduction
History … 5

6. Introduction
History …
And future trends! 6

7. What is IPTV? IPTV = (IP) + (TV)
An emerging technology that delivers video, audio or TV broadcasts over (IP) based networks with the required level of QoS/QoE, security, interactivity, and reliability.
It means:
Television you fully control
Any content, any time, any place
Television that can take you anywhere
Unlimited visual interactive applications
It’s the IP in IPTV that’s important!
IPTV requires new technology in:
Access networks
Compression
Middleware
Customer premises equipment (CPE) 7

8. What is NOT IPTV? Video streaming over internet Watching TV on your PC
IPTV is distinctly different from “Internet video” that simply allows users to watch videos 8

9. Differences in technology
IPTV:
Two way communication
100% interaction
Consumer can select the format of the signal (e.g. Mpeg2 / Mpeg4)
Allows significantly more content and functionality
Web browser
Weather forecast ( Maxivision )
Interactive Games
Chat
Digital TV:
One way communication
No interaction
One format at a time 9

10. Applications (some examples)
Education: There have been some attempts to use regular TV as a medium of education. But regular TV is unidirectional in nature. Taking advantage of the bidirectional capability of IPTV, it can be used as an education environment especially in some developing countries.
Healthcare: Elderly people or people in remote locations (e.g., in rural area) cannot easily access doctors for checkup or treatment. This problem can be solved by monitoring and treatment of patients by means of IPTV (without need to leave the home).
Financial services: Some people need instant access to business or financial developments and news. Taking advantage of its bidirectional capabilities, IPTV can be used as a powerful tool in stock market and television banking.
Instant feedback capability: Considering appropriate security and privacy options, IPTV enables the people to play an instant role in voting and elections .
Travel and tourism: You are watching a commercial advertisement regarding discounts in ticket prices; thanks to IPTV, you can book it immediately just by clicking the buttons on your remote control. 10

11. Services
Live broadcasts: It's like watching live TV on your computer screen. You can NOT pause, back up or skip through parts of the broadcast that do NOT interest you.
On-demand videos (VoD): Arranged like a playlist. Episodes or clips are arranged by title or channel or in categories like news, sports or music videos. You choose exactly what you want to watch, when you want to watch it. 11

12. World Coverage
Source: Wikipedia 12

13. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 13 13

14. IPTV Capacity Requirements
Service
Coding
Capacity Mbps
Note
HDTV
MPEG2 20
1080i 16
720p
SDTV 5
VoD
MPEG4 8 6 2 14

15. Multicast forwarding protocols Group management protocols
IP multicast
DVMRP,PIM, MOSPF
IGMP, MLD
Multicast forwarding protocols
Group management protocols

16. Multicast vs. Unicast
In Multicasting, each channels is transmitted once through the backbone
Multicast is more efficient in terms of bandwidth usage

17. Video Compression
1:1 17 17

18. Compression- Spatial Redundancy elimination
Correlations between neighboring pixels within a frame.
The spatial encoder typically works on 8 x 8 pixel blocks of a frame 18 18

19. Compression- Spatial Redundancy elimination
27:1 19 19

20. Compression- Spatial Redundancy elimination
192:1 20 20

21. Compression- Temporal Redundancy elimination
Difference between consecutive frames is often small
Remove inter-frame redundancy 21 21

22. I-frame: Intra coded picture P-frame: Predictive coded picture
MPEG- frames
I-frame: Intra coded picture
P-frame: Predictive coded picture 
B-frame: Bipredictive coded picture  22

23. An Example for Video Compression
Uncompressed
Compressed
Bit Rate= 4,562 Kbits/s
Bit Rate= 100 Kbits/s 23 23

24. Single B frame packet loss Single I frame packet loss
Effect of packet loss
Single B frame packet loss
(only 1 frame affected)
Single I frame packet loss
(14 frames affected)
Impact 3.75Mb/s stream: B frame packet loss vs I frame packet loss
Source: Nortel 24

25. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 25 25

26. IPTV System Structure 1 2 3 4 5 WiMAX ASN IPTV Head-end xDSL
Video Source
Core Network
Metro Backbone
VoD Server 2 3
Access Network 4
Customer Network 5 26

27. IPTV Head-end Building Blocks27

28. IPTV Head-end MPEG-TS Encapsulated Video stream
Raw data
SDI
(270Mbit/s)
MPEG2/4/H.264
Element Stream (ES) (1.5-6Mbit/s)
Packetized ES with header
(1.5-6Mb/s)
Video
Audio
MPEG2 or
H.264
Encoder
Video
Video
Audio
ES Packetizer
(PES frame forming)
Audio
Encoder
ES Packetizer
(PES frame forming)
Audio
Data
PES A.V.D MUX
(Transport Stream
188 byte forming)
MPEG2/4/AVC
MPEG-TS
Transport Streams encapsulated into IP (1.6-40Mb/s)
Encapsulated Video stream
H.264/TS/RTP/UDP/IP/Ethernet
MUXed Multi programs TS
(1.6-40Mb/s)
Single program Transport Stream
(1.6-8Mb/s)
RTP
UDP
TS encapsulated
into RTP/UDP/IP
Multi-program
MPEG TS
Multiplexer
Program 1 IP
Program 2
Ethernet
Program 3 28

29. Core Network Central portion of an IPTV system
Provides interconnection between several metro networks
IP/MPLS and traffic engineering techniques
Use High Capacity links (e.g., 10 Gbps) 29

30. Distribution Network Serves a region or a metropolitan area
Insertion of local content such as local TV channels or commercial advertisements
Provides on-demand video services to local clients 30

31. Access Network Provides last-mile for IPTV subscribers
Can be based on wired technologies (e.g., xDSL, FTTx) or Wireless networks (High Speed WiFi, WiMAX, LTE , 3G). 31

32. Home Network
Provides TV, IP phone and Internet (triple play) services to subscribers.
Connects to Access network via a Home-gateway. 32

33. Video reconstruction in STB
Decoder
MPEG DATA
Buffer
Ethernet/IP/UDP/Payload
Socket
Payload
Video
Decode
Buffer
Buffer
Audio
Decode
STB
PCR: Program Clock Reference
PAT: Program Association Table
PID: Packet IDentifier
PMT: Program Map Table 33

34. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 34 34

35. Advantages
Provides decent quality TV-service for Terrestrial “dead zones”
Time Shift TV: enable stores feature and store any Broad cast and can be seen at any time of the customer
Large selection of channels, VoD, Video Conferencing
In the future, a real interactive TV
Targeted (personalized) advertisement
TV shopping, TV Ticketing, TV Banking
Parental Control
Camera angle selection
Alert message for favorites programms- SMS alert and many more… 35

36. Targeted Advertisements

37. Camera angle selection

38. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 38 38

39. IPTV Recommender systems
Challenges
IPTV Recommender systems
Modeling
Zapping delay
And
many more …
Wireless IPTV
IPTV in Iran

40. TV channel popularity criteria modeling
Popularity based on holding time
53%
17.5%
15.5%
14%
Popularity based on number of users
56.25%
18.75%
12.5%
Popularity based on Access frequency
38.1%
33.30%
14.3%

41. Number of simultaneous online users in one week period (Real IPTV system)

42. Peak hours
Number of simultaneous online users in one day period (precision 15 minutes)
10PM
3PM

43. User arrival and departure rates
For a popular channel in a real IPTV system
Sort IGMP leave messages in their order of time occurrence
Sort IGMP join messages in their order of time occurrence
High spikes in departure pattern (during a commercial advertisement in a popular program), should be considered in the design of P2P IPTV systems.
User arrival rate
User departure rate

44. Distribution of TV Channel Popularity
Popular channel
High p
Popularity
Rank 44

45. Distribution of TV Channel Popularity
Unpopular channel
Low p
Rank 45

46. TV channel classification
Favorite
Normal
Rarely watched
multicast pull
(on demand)
Unicast
multicast push 46

47. Channel Switching Delay (Zapping Delay)
TV subscribers usually like to surf the channels
(e.g., during a commercial advertisement)
To satisfy subscribers that migrate from traditional TV systems, switching delay should be comparable to the one that exists in current systems
Definition:
The time between pushing the channel change button and the first video frame being displayed on the TV, is called zapping delay 47

48. Zapping Delay in IPTV Systems (Reason)
Internet
VoIP
IPTV
1-2 channels
Last mile (6 Mb/s) 48

49. Zapping Delay in IPTV Systems
Traditional analog broadcast
About 2 s
IPTV
MPEG and dejitter
Buffering delay
Other
factors
I-frame acquisition delay 49

50. Zapping Delay in IPTV Systems
The frequency of I-frames
Reordering delay
Size of video buffer in STB
PAT and PMT frequency
Multicast Leave and Join times
The delay of access link
STB jitter buffer
Conditional access and digital rights management system
Packet recovery with FEC/ARQ
Processing time in the STB
Processing time in display device 50

51. Methods to Reduce Zapping Delay
Unicast stream
Use additional stream
Reduce I-frame
acquisition delay
Multicast stream
Insert extra I-frames
Adjust GOP length
Using Scalable Video Coding (SVC)
Prediction and prejoining methods
Using IGMP schemes

52. IPTV Recommender Systems
The problem of quickly finding the right channel becomes harder as the number of offered channels grows in modern IPTV systems

53. IPTV Recommender Systems
The integration of a recommender system into the IPTV infrastructure improves the user experience by providing a new and more effective way of browsing for interesting programs and movies.

54. Challenges of IPTV over Wireless Networks
Terminal capabilities
limited capabilities of mobile terminals (small video display, low-
power processor because of a small battery, limited storage)
Bandwidth
IPTV applications are bandwidth-hungry, and bandwidth is a scarce
resource in wireless environments
Wireless link
Vulnerable to physical factors
Dynamic Environment
Service coverage
Handover problem specially in heterogeneous wireless networks
Diversity in channel quality (SNR) in wireless clients

55. IPTV in Iran
IRIB started IPTV project definition in 2009 (1388) with the cooperation of Telecommunication Company
IRIB had to produce the content and TC had to provide the Infrastructure
1000 subscribers at the first phase
Still in progress due to some conflicts between IRIB, TC and Ministry of culture and Islamic guidance

56. Outline Introduction and Motivation Background IPTV System Structure
IPTV Advantages
Challenges
Summary and Conclusion 56 56

57. Summary and Conclusion
IPTV develops rapidly and market potentials are high
IPTV is more than another platform for broadcast TV
Multicasting, RTP and Compression techniques are the key factors in IPTV technology
Channel switching delay is an important factor in user satisfaction and Reducing zapping delay is one of the main challenges in IPTV systems.
Channel popularity and user behavior modeling are very important for performance evaluation and capacity planning in IPTV systems
Recommender systems can help the subscribers to find the items of interest
Providing IPTV services in wireless environments is even more challenging

58. Questions!