Cbmn4104 multimedia networking dec10 edit-mac15

2. uM4014NMBCEDIUGYDUTS ltimedia Networking 1 FACULTY OF SCIENCE AND TECHNOLOGY STUDY GUIDE CBMN4104 Multimedia Networking Writer: Khirulnizam Abd. Rahman egelloCytisrevinUcimalsIlanoitanretnIrognaleS Developed by: Centre for Instructional Design and Technology Open University Malaysia First Edition, December 2010 Copyright © Open University Malaysia (OUM), December 2010, CBMN4104 All rights reserved. No part of this work may be reproduced in any form or by any means without the written permission of the President, Open University Malaysia. Copyright © Open University Malaysia (OUM)

4. uM4014NMBCEDIUGYDUTS ltimedia Networking 3 Contents Course Introduction......................................................................................5 Synopsis ...................................................................................................5 Aims..........................................................................................................5 Outcomes..................................................................................................5 Load..........................................................................................................5 Course Requirements...................................................................................6 Prerequisites or Co-requisite ....................................................................6 Feedback and Course Evaluation.............................................................6 Course Resources and Requirements........................................................7 Set Textbook(S)........................................................................................7 Essential References................................................................................7 Extra Recommended Reading..................................................................7 my Virtual Learning Environment (myINSPIRE) .......................................8 OUM Digital Library Resources ................................................................8 Assessment...................................................................................................8 Assessment Format..................................................................................8 Assignment Question(S)...........................................................................8 Final Examination (Format).......................................................................9 Late Submission of Assignment(S)...........................................................9 Important Dates ........................................................................................9 Study Guide – By Tutorial Session ...........................................................10 Week 1....................................................................................................10 Week 2....................................................................................................16 Week 3....................................................................................................20 Week 4....................................................................................................28 Week 5....................................................................................................33 Week 6....................................................................................................37 Week 7....................................................................................................43 Week 8....................................................................................................51 Week 9....................................................................................................56 Week 10:.................................................................................................66 Appendix .....................................................................................................71 Copyright © Open University Malaysia (OUM)

6. STUDY GUIDE CBMN4104 Multimedia Networking 5 COURSE INTRODUCTION Course Synopsis This course offers the knowledge on concepts and principles of delivering multimedia elements through networks. With the rapid changes in networks development, multimedia is also considered as part of complex elements that has challenged networks experts in making sure the elements can be delivered correctly. Learners will have an opportunity to learn how multimedia should be delivered through the networks using certain methods, protocols, standards, security and many more. Aims The broad aims of this course are to: 1. Recognize the importance of networks services, protocols, standards and requirements for multimedia delivery. 2. Identify components of networks services, models and methods of delivery multimedia elements over the networks. 3. Classify policy and security of delivery multimedia elements over the networks. Outcomes At the completion of this course, it is expected that you will be able to: 1. Explain the importance of real time network capability for content delivery by considering factors of digital items, protocols, service models, multicast, multimedia sessions, security and many more. 2. Elaborate the network service models like RSVP, QoS, IP, ATM and multicast. 3. Perform skills in coding and compression for audio and video over the networks. 4. Identify the middleware and session protocols. 5. Evaluate the requirement for multimedia networking in terms of many aspects like protocols, standards, hardware and software. Copyright © Open University Malaysia (OUM)

7. STUDY GUIDE CBMN4104 Multimedia Networking 6 6. Propose the best multimedia networking architectures, protocols, standards, hardware or software especially in delivering multimedia components. Load It is a standard OUM practice that learners accumulate 40 study hours for every credit hour. As such, for a three-credit hour course, you are expected to spend at least 120 hours of learning. Table 1 gives an estimation of how the 120 hours could be accumulated. Table 1: Allocation of Study Hours Activities No of Hours Reading the module and completing the exercises 60 Attending 5 tutorial sessions (2 hours for each session) 10 Engage in online discussion 15 Completing assignment 20 Revision 15 Total 120 COURSE REQUIREMENTS Prerequisites or Co-requisite There are no prerequisites or co-requisites for this course. Feedback and Course Evaluation Besides attending lectures and tutorials, learners are expected to complete assignments, final examination (short question and essay question), presentation and participate in class and online discussion. Copyright © Open University Malaysia (OUM)

8. STUDY GUIDE CBMN4104 Multimedia Networking 7 COURSE RESOURCES AND REQUIREMENTS Set Textbook(s) Jenq-Neng Hwang. (2009). Multimedia Networking: From Theory to Practice. Add New York: Cambridge University Press. Essential References Halsall F. (2001). Multimedia Communications: Applications, Networks, Protocols and Standards. Essex: Pearson Education Limited. Rao K.R, Bojkovic Z.S & Milovanovic D.A. (2002). Multimedia Communication Systems: Techniques, Standards, and Networks. New Jersey: Prentice Hall. Rao K.R, Bojkovic Z.S & Milovanovic D.A. (2006). Introduction to Multimedia Communications: Applications, Middleware, Networking. New Jersey: John Wiley & Sons. Crowcroft J., Handley M. & Wakeman I. (1999). Internetworking Multimedia. San Francisco: Morgan Kauffman Publishers. Extra Recommended Reading Learners are expected to go through OUM’s Tan Sri Abdullah Sanusi Digital Library to search reliable online readings such as journals, proceedings, book or chapters, articles and etc using keyword of ‘multimedia networking’ and suitable keywords that related with topics in this study guide. Copyright © Open University Malaysia (OUM)

9. uM4014NMBCEDIUGYDUTS ltimedia Networking 8 my Virtual Learning Environment (myINSPIRE) myINSPIRE is an online Virtual Learning Environment that provides one stop portal for learners to get to know their courses in details, including online modules, forum discussion, announcement, online assignments and many more. Learners are expected to frequently visit myINSPIRE, especially for reading modules and participate in the forum discussion. Forum is useful medium for discussion when learners got problems in learning their respective courses. They can participate for discussion and exchange some idea with their respective tutors and peers. OUM Digital Library Resources OUM Digital Library provides a lot of accesses to online and digital resources such as ebooks, articles, journals, proceedings and theses for your further readings. Make use this utility to support your study. ASSESSMENT Assessment Format Continuous Assessment: 30% Final Examination: 70% Assignment Question(s) This is a sample of assignment questions: You are required to build a system for Open University Malaysia (OUM) to deliver video lectures using streaming method over the Internet. Explain preparation that should be taken, including video formats, standard recording, scripting, storyboarding or etc, method and techniques of recording, encoding and decoding video and finally the mechanism to publish the video on the Internet. Do you think this kind of content is reliable to be published based on our current Internet infrastructures? Copyright © Open University Malaysia (OUM)

10. uM4014NMBCEDIUGYDUTS ltimedia Networking 9 Final Examination (Format) Final examination format consists of: PART A – 5 short questions worth 4 marks for each (20 marks) PART B – 5 short essay questions; candidate needs to answer 3 questions only worth 20 marks for each (60 marks) PART C – 2 essay questions; candidate needs to answer only one question worth 20 marks (20 marks) So, total is 100 marks and its percentage turns to be 70% of the total percentage of assessment. Late Submission of Assignment(s) Failure to submit an assignment by the due date without the granting of an official extention of time by your course tutor will incur a penalty of ONE (1) mark per day. Important Dates Please constantly refer to myINSPIRE for updates and latest announcement(s) on this course. Copyright © Open University Malaysia (OUM)

11. STUDY GUIDE CBMN4104 Multimedia Networking 10 Study Guide – by Tutorial Session Week 1 Chapter 1: Introduction to Multimedia Networking Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapter. Study notes 1. Why Multimedia Networking?. (a) Rapid changes from conventional circuit-switching telephone networks to the packet-switching, data centric and IP-based Internet. Copyright © Open University Malaysia (OUM)

12. STUDY GUIDE CBMN4104 Multimedia Networking 11 (b) News, television and entertainment industry have started their own streaming infrastructures to deliver their content, either live or on-demand. (c) Maturity of multimedia networking applications such as distance learning, desktop video conferencing, instant messaging, workgroup collaboration, multimedia kiosks, entertainment, and imaging. 2. Paradigm Shift of Digital Media Delivery (a) Radio broadcasting is gradually replaced by digital broadcasting because of great advances of digital data compression (coding) technologies, better resolution, better quality, higher noise immunity and better interaction capabilities. (b) Rapid growth of IP-based Internet for business and home usage: (i) Quick deployment of broadband such as DSL/cable/T1 and optical fiber. Look at Table 1.1. (ii) Voice over IP (VoIP) is replacing traditional public-switched telephone networks (PSTNs). (iii) Local Area Networks (LAN, IEEE 802.3) or wireless LANs (WLANs, also called Wi-Fi, 802.11), enable the connection and content sharing of all office or home electronic appliances (e.g. computers, media centers, set-top boxes, personal digital assistants (PDAs), and smartphones). Look at Figure 1.1. (iv) Visionary of Digital Living Network Alliance (DLNA), a digital home consists of a network of consumer electronics, mobile and PC devices that cooperate transparently, delivering simple, seamless interoperability to enhance and enrich user experiences. Look at Figure 1.2. (v) Wireless connections are demanded, resulting in the fast- growing use of mobile Internet whenever people are on the move. Look at Figure 1.3. (c) Two social trends: (i) A shift from digital broadcasting to multimedia streaming over IP networks.  Digital broadcasting services (e.g.: digital cable for enhanced definition TV (EDTV) and high-definition TV (HDTV) broadcasting, direct TV via direct Copyright © Open University Malaysia (OUM)

13. STUDY GUIDE CBMN4104 Multimedia Networking 12 broadcastsatellite (DBS) services, and digital video broadcasting (DVB)) are maturing (see Table 1.2), while people also spend more time on the Internet browsing, watching video or movie by means of on-demand services, etc.  Consumer moved from “content push” to “content pull”.  Interactive multimedia services are growing rapidly such the use of video blogs and media podcasting.  Soon Internet-based multimedia content will no longer be produced by traditional large-capital-based media and TV stations, because everyone can have a media station that produces multimedia content whenever and wherever they want, as long as they have media- capturing devices (e.g., digital camera, camcorder, smart phone, etc.) with Internet access (see Figure 1.4).  A standardization body for TV over IP (IPTV) is formed, i.e., the IPTV Interoperability Forum (IIF), which will develop standards and to enable the interoperability, interconnection, and implementation of IPTV systems and services, including video-on-demand and interactive TV services. (ii) A shift from wired Internet to wireless Internet  The wireless LAN (WLAN or Wi-Fi standards) technologies, IEEE 802.11a/b/g and the next generation very-high-data-rate (> 200 Mbps) WLAN product IEEE 802.11n, to be approved in the near future, are being deployed everywhere with very affordable installation costs (see Figure 1.5).  Almost all newly shipped computer products and consumer electronics come with WLAN receivers for Internet access.  Furthermore wireless personal area network (WPAN) technologies, IEEE 802.15.1/3/4 (Bluetooth/UWB/ Zigbee), which span short-range data networking of computer peripherals and consumer electronics appliances with various bitrates, provide an easy and convenient mechanism for sending and receiving data to and from the Internet for the end devices.  To provide mobility support for Internet access, cellular- based technologies such as third generation (3G) networking are being aggressively deployed with Copyright © Open University Malaysia (OUM)

14. STUDY GUIDE CBMN4104 Multimedia Networking 13 increased multimedia application services from traditional telecommunication carriers.  Furthermore, mobile wireless microwave access (WiMAX) serves as another powerful alternative to mobile Internet access from data communication carriers. 3. Telematics: Infotainment in Automobiles (i) Telematics is the integrated use of telecommunications and informatics for sending, receiving, and storing information via telecommunication devices in road-traveling vehicles. (ii) It is growing fast because of mobile Internet access, such as the general packet radio service (GPRS) or 3G mobile access. (iii) It ranges from front-seat information and entertainment (infotainment) such as navigation, traffic status, hand-free communication, location-aware services, etc. to back-seat infotainment, such as multimedia entertainment and gaming, Internet browsing, email access, etc. (iv) Telematics systems have also been designed for engine and mechanical monitoring, such as remote diagnosis, care data collection, safety and security, and vehicle status and location monitoring (see Figure 1.7). (v) It is also important to note the exponentially growing number of WLAN and WPAN installations on vehicles that provides a good indication of the wireless-access demand for vehicles in a local vicinity, e.g., inside a parking lot and moving with a slow speed yet still enjoying location-aware services. 4. Major Components of Multimedia Networking (i) Data compression (ii) Quality of service (QoS) (iii) Wireless networks (iv) Interoperability Copyright © Open University Malaysia (OUM)

15. STUDY GUIDE CBMN4104 Multimedia Networking 14 Study questions 1. Why we need to learn multimedia networking?. 2. Discuss the examples of the growth of IP-based Internet for business and home usage. 3. Explain two social trends of multimedia networking. 4. Give some examples the usage of Telematics. 5. List major components of multimedia networking. Frequently Asked Questions 1. Why we need to learn multimedia networking? Multimedia Networking is important because of rapid changing in multimedia applications and streaming technology which are required to be delivered via latest networks technologies and infrastructures. 2. Why the digital broadcasting becomes more popular? Digital broadcasting becomes more popular because of great advances of digital data compression technologies, better resolution, better quality, higher noise immunity and better interaction capabilities. 3. Do we need to know or remember the standards of wireless networks? Yes of course, when you are responsible to manage the networks, or building multimedia applications to be delivered on the Internet. 4. Do we use telematics only on vehicles? No. It could be applied for any mobile devices or in the name of mobility. Glossary of important terms 1. Packet switching (pensuisan bingkisan): a digital networking communications method that groups all transmitted data - regardless of content, type, or structure - into suitably-sized blocks, called packets. 2. Digital broadcasting (penyiaran digital): the practice of using digital data rather than analogue waveforms to carry broadcasts over television channels or assigned radio frequency bands. Copyright © Open University Malaysia (OUM)

16. STUDY GUIDE CBMN4104 Multimedia Networking 15 3. Multimedia streaming (penstriman multimedia): an enabling technology for providing multimedia data delivery between clients in various multimedia applications on the Internet. 4. Wireless Personal Area Network (WPAN) (Rangkaian Kawasan Peribadi Tanpa Wayar): a network for interconnecting devices centered around an individual person's workspace - in which the connections are wireless. 5. Quality of Service (QoS) (Kualiti Servis): refers to a broad collection of networking technologies and techniques. The goal of QoS is to provide guarantees on the ability of a network to deliver predictable results. Copyright © Open University Malaysia (OUM)

17. STUDY GUIDE CBMN4104 Multimedia Networking 16 Week 2 Chapter 4: Digital Image Coding Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapter. Study notes Important note: Kindly ignore any complex formula and mathematical calculation, unless stated in the following notes. You just need to focus on concepts, architecture of networks and theory parts for this text book. You do not have to learn complex and in-depth of technical aspect of the networks infrastructures. 1. Image compression: (a) Image compression is the application of data compression techniques to two-dimensional digital images to reduce the redundancy of the image data for storage or transmission in an efficient form. (b) Image compression can be classified into two categories: lossless or lossy. Copyright © Open University Malaysia (OUM)

18. STUDY GUIDE CBMN4104 Multimedia Networking 17 (c) Lossless compression, which achieves smaller compression ratios than lossy compression, mainly takes advantage of the image contents containing a non-uniform probability distribution for a variable-length representation of the image pixels. Such images include technical drawings, icons or comics, and high-value contents such as medical imagery or image scans made for archival purposes. (d) Lossy compressions are especially suitable for natural images, such as photos, in applications where a minor loss of fidelity is acceptable when it is desirable to achieve a substantial reduction in bitrate. (e) The Joint Photographic Experts Group (JPEG), a discrete cosine transform (DCT)-based technique, is the most widely used standardized lossy image compression mechanism; it was designed for compressing either full-color or gray-scale images of natural, real-world, scenes. (f) It works well for photographs, naturalistic artwork and similar material if the compression ratio is about 20 : 1, which is much better than the 4 : 1 compression ratio provided by a lossless compression method such as the Graphics Interchange Format (GIF). (g) To provide better efficiency in hierarchical JPEG coding, JPEG2000 was proposed and standardized. 2. Information theory for image compression (Note: Ignore complex formula of compression, just focus on description and theory parts): (a) Entropy coding (b) Huffman coding (c) Arithmetic coding (d) Context-adaptive binary arithmetic coding (CABAC) (e) Run-length coding (RLC) 3. Lossy Image Compression 4. Joint Photographic Experts Group (JPEG) (a) JPEG progressive mode (b) JPEG hierarchical mode (c) JPEG lossless mode Copyright © Open University Malaysia (OUM)

19. STUDY GUIDE CBMN4104 Multimedia Networking 18 (d) JPEG codestream 5. JPEG2000 (a) Basic building blocks: (b) Preprocessing (c) Discrete wavelet transform and quantization (d) Codeblock and precinct partition (e) Bitplane entropy coding (f) Bitstream organization (g) Bitstream progression (h) JPEG2000 for Digital Cinema Initiatives (i) New parts of JPEG2000: JPIP, JPSEC, JP3D, and JPWL Study questions 1. What is the meaning of image compression? 2. Distinguish lossy and lossless compression 3. Which type of compression is used for JPEG? 4. What is the Huffman coding? Frequently Asked Questions 1. What is lossy compression? A compression technique that does not decompress data back to 100% of the original. Lossy methods provide high degrees of compression and result in very small compressed files, but there is a certain amount of loss when they are restored. 2. What is lossless compression? A compression technique that decompresses data back to its original form without any loss. The decompressed file and the original are identical. All compression methods used to compress text, databases Copyright © Open University Malaysia (OUM)

20. STUDY GUIDE CBMN4104 Multimedia Networking 19 and other business data are lossless. For example, the ZIP archiving technology (PKZIP, WinZip, etc.) is a widely used lossless method. 3. Which one is better JPEG or GIF? Depending to the usage. For natural or photography, JPEG is more suitable and GIF is used for less colours of image. Glossary of important terms 1. Image compression (pemampatan imej): minimizing the size in bytes of a graphics file without degrading the quality of the image to an unacceptable level. 2. Lossy compression (kompresi terhilang): Refers to data compression techniques in which some amount of data is lost. Lossy compression technologies attempt to eliminate redundant or unnecessary information. 3. Lossless compression (kompresi tak hilang): Refers to data compression techniques in which no data is lost. For most types of data, lossless compression techniques can reduce the space needed by only about 50%. 4. Bitstream (Strim bit): Refers to a stream of bits transmitted over a communications line between two devices. A bit is the smallest element of information in the digital system. Items are ingested into ScholarSpace as bitstreams. 5. Encoder (Pengekod): An algorithm that converts raw data to an encoded form, usually to physically compress the data. 6. Decoder (Penyahkod): An electronic or software device that converts telecommunication signals from their transmitted form into a form interpretable to other devices or to human beings. Copyright © Open University Malaysia (OUM)

21. STUDY GUIDE CBMN4104 Multimedia Networking 20 Week 3 Chapter 3: Digital Audio Coding Chapter 5: Digital Video Coding Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes Important note: Kindly ignore any complex formula and mathematical calculation, unless stated in the following notes. You just need to focus on concepts, architecture of networks and theory parts for this text book. You do not have to learn complex and in-depth of technical aspect of the networks infrastructures. 1. Digital Audio Coding History of the new digital audio disk for recording audio and music in digital format: (a) Compact disk (CD) standard. Copyright © Open University Malaysia (OUM)

22. STUDY GUIDE CBMN4104 Multimedia Networking 21 (b) An audio CD consists of one or more stereo tracks stored using 16-bit pulse code modulation (PCM) coding at a sampling rate of 44.1 kHz. (c) Standard compact disks have a diameter of 120 mm and can hold approximately 60–80 minutes of audio. (d) Grown to encompass other applications, e.g., the CD-ROM (read- only memory) and CD-R/W. (e) Widely used as a data storage medium for computers and consumer electronics. (f) The original capacity requirement for recording digital audio is about 635 megabytes (MB) per hour or 1.411 Mbps, i.e., 44100(samples/s) X 2(byte/sample) X 3600(s/h) X 2(channels) = 635 MB per hour of audio CD capacity (g) The famous computer-based waveform audio storage format, WAV (waveform audio format, with extension *.wav), was originally developed by Microsoft and IBM. 2. The human auditory system: Our ears consist of three fundamental physiological components, the inner, middle and outer ear (see Figure 3.2). 3. Human Psychoacoustics (focus on description, ignore all formula or calculation): (a) Hearing sensitivity (b) Frequency masking (c) Temporal masking 4. MPEG-1 Audio Layers (a) Adopted by the International Organization for Standardization and the International Electrotechnical Commission (ISO/IEC) at the end of 1992. (b) Originally proposed as one of three parts (audio, video, and system) in the compression standard, at a total bitrate of about 1.5 megabits per second (Mbps). Copyright © Open University Malaysia (OUM)

23. STUDY GUIDE CBMN4104 Multimedia Networking 22 (c) Accepts captured audio with sampling rates of 32, 44.1, or 48 kHz. (d) Compressed bitstream can support one or two audio channels and have one of several predefined fixed bitrates ranging from 32 to 224 kbps per channel, equivalent to a compression ratio of 24 to 2.7. (e) MPEG-1 audio offers three independent layers of compression: Layer 1, Layer 2, and Layer 3. 5. Dolby AC3 Audio Codec (a) AC3 was proposed and developed by Dolby Inc. for DVD, HDTV, home theater systems (HTSs), etc, in order to provide a superior audio coding for multichannel surround sound, so that it can be used for High Definition Television (HDTV) (b) The AC3 audio codec, so-called Dolby Digital Surround audio, follows the recommendation made by the Society for Motion Picture and Television Engineers (SMPTE, http: //www.smpte. org/home) that 5.1 channels (left, center, right, left surround, right surround, subwoofer, as shown in Figure 3.25) with a target bitrate of 320 kbps should be enough to provide the sound quality achieved by the 70 mm surround-sound format used in the cinema since 1979 6. MPEG-2 Advanced Audio Coding (AAC) (a) Research and development efforts from the world’s leading audio coding laboratories, such as Fraunhofer Institute, Dolby, Sony, and AT&T, to advance audio coding technologies beyond MP3 and AC3. This effort was initiated to create a new audio coder which can produce indistinguishable quality at 64 kbps per monochannel. (b) Technically, the AAC format can support up to 48 full-frequency sound channels and 16 low-frequency enhancement channels (c) It also supports sampling rates up to 96 khz, twice the maximum afforded by MP3 and AC3 and is now the format used for songs downloaded from the popular itunes music website (www.itune.com) (d) The AAC format, which was standardized in 1997, was built on a similar structure to MP3 and thus retains most of its design features Copyright © Open University Malaysia (OUM)

24. STUDY GUIDE CBMN4104 Multimedia Networking 23 (e) AAC uses a modular approach (see Figure 3.28): Filter bank; Temporal noise shaping (TNS); Prediction; MS stereo; Quantization; Huffman coding & Bitstream format; 7. MPEG-4 AAC (HE-AAC) (a) The MPEG-2 AAC system has been further enhanced and amended to become today’s most efficient audio coding standard, the so-called High Efficiency AAC (HE-AAC or HE-AAC v1) and HE-AAC v2. (b) These two coding formats were standardized in the years 2003 and 2004 separately within MPEG-4 audio. (c) The HE-AAC is the low-bitrate codec in the AAC family and is a combination of the MPEG-2 AAC LC (advanced audio coding low- complexity) audio coder and the spectral band replication (SBR) bandwidth expansion technique. 8. Digital Video Coding Overview: (a) Sony’s D-1 format, which digitally recorded an uncompressed standard definition (RGB) component video is produced in 1983. (b) Apple released the first commercial version of QuickTime video for streaming and playback in 1991, and this set a fast pace for international standardization efforts for consumer digital video. (c) Owing to the much larger amount of data generated by raw digital video, video compression becomes critically needed. (d) Many types of video coding standard are now available to serve digital video playback, storage in CD or DVD, and broadcasting or streaming over the Internet. (e) Digital videos are captured in two different forms: interlaced scan and progressive scan. (i) Interlaced scan, which is the format used by analog broadcast TV systems, records the image in alternating sets of even and odd lines, each set of odd or even lines being referred to as a field, and a consecutive pairing of even and odd fields is called a frame: see Figure 5.1(a). Copyright © Open University Malaysia (OUM)

25. STUDY GUIDE CBMN4104 Multimedia Networking 24 (ii) A progressive scanning digital video records each frame as distinct, both fields being identical. Thus interlaced video captures twice as many fields per second as progressive video does when both operate at the same number of frames per second: R = W x H x D x Fs where W denotes the width (in pixels) of the video frame, H denotes the height of the video frame (in pixels), D denotes the depth (in bits per pixel), and Fs denotes the frame rate. (f) Technical issues and formats (see Table 5.1) involved in digital video coding: (i) Chroma subsampling (ii) Intraframe compression (iii) Interframe compression (iv) Entropy coding (v) Rate control 9. Evolution of Digital Video Coding (a) The first practical digital video coding standard was H.261, proposed by theInternational Telecommunication Union (ITU-T) in 1990, originally designed for transmission over ISDN lines on which data rates are multiples of 64 kbps. (b) All subsequent international video coding standards (MPEG-1, MPEG-2/H.262, H.263, and even H.264) have been following a similar architectural design and standardization process. (c) The next international standard was MPEG-4. This was undertaken as a major task in 1998 with intention of getting compatibility between many multimedia components: video, synthetic structures (graphics-like), audio, systems, reference software, test bitstreams, digital rights management, and so on. (d) The next format is H.264 standard, also known as AVC and MPEG-4 Part 10. The H.264 standard was jointly developed by the ITU-T Video Coding Experts Group (VCEG) together with the Copyright © Open University Malaysia (OUM)

26. STUDY GUIDE CBMN4104 Multimedia Networking 25 ISO/IEC Moving Picture Experts Group (MPEG) as a collective partnership effort known as the Joint Video Team (JVT). (e) Windows Media 9 Series is the latest generation of digital media technologies developed by Microsoft, whose design objective is to enable the effective delivery of digital media through any network to any device. 10. Compression Techniques for Digital Video Coding (no need to learn details about this topic) (a) Simple techniques (b) Subsampling and interpolation (c) Entropy coding (d) Predictive coding and motion estimation (e) Transform domain coding (f) Rate control in video coding 11. Video formats and compression: (a) H.263 and H.263+ Video Coding (b) MPEG-1 and MPEG-2 Video Coding (c) MPEG-4 Video Coding and H.264/AVC (d) H.264/MPEG-4 AVC (e) Windows Media Video 9 (WMV-9) (f) Scalable Extension of H.264/AVC by HHI Study questions 1. What is the audio CD capacity for stereo audio with 44.1kHz sampling rate? 2. List FOUR (4) digital audio formats. 3. Discuss about interlaced scan and progressive scan for digital video. Copyright © Open University Malaysia (OUM)

27. STUDY GUIDE CBMN4104 Multimedia Networking 26 4. What are the technical issues and formats involved in digital video coding? 5. List digital video formats and compression. Frequently Asked Questions 1. What is meant by digital video? Refers to the capturing, manipulation and storage of video in digital formats. A digital video (DV) camcorder, for example, is a video camera that captures and stores images on a digital medium such as a DAT. 2. What is meant by kHz? Abbreviation for kilohertz. A unit of measurement of frequency, also known as cycles per second. One kiloHertz (kHz) is equal to 1,000 Hertz (Hz) or 1,000 cycles per second. 3. What is the meaning of kbps? Short for kilobits per second, a measure of data transfer speed. Modems, for example, are measured in Kbps. Note that one Kbps is 1,000 bits per second, whereas a KB (kilobyte) is 1,024 bytes. 4. What is the meaning of video capture? Converting analog video signals, such as those generated by a video camera, into a digital format and then storing the digital video on a computer's mass storage device. Glossary of important terms 1. Sampling rate (kadar persampelan): Also called a sample rate. Typically expressed in samples per second, or hertz (Hz), the rate at which samples of an analog signal are taken in order to be converted into digital form. 2. Psychoacoustics (Psikoakustik): a branch of psychophysics studying the relationship between acoustic stimuli and behavior. 3. Interlaced scan (Imbasan berjalin): Interlaced scan is designed for the analog NTSC television system, uses two fields to create a frame. One field contains all the odd lines in the image, the other contains all the even lines of the image. 4. Progressive Scan (Imbasan Progresif): Progressive scan is one of two methods used where the lines are drawn in one at a time in sequential Copyright © Open University Malaysia (OUM)

28. STUDY GUIDE CBMN4104 Multimedia Networking 27 order. The entire single frame image is painted every 1/60th of a second, allowing for twice the detail to be sent in the same amount of time used in interlaced systems. 5. Digital media (Media digital): Any type of information stored in the computer, including data, voice and video. Copyright © Open University Malaysia (OUM)

29. STUDY GUIDE CBMN4104 Multimedia Networking 28 Week 4 Chapter 6: Digital Multimedia Broadcasting Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. digital broadcasting permits a level of quality and flexibility unattainable with analog broadcasting and provides a wide range of convenient services, thanks to its high picture and sound quality, interactivity, and storage capability. 2. European broadcasters initiated the first attempt to implement a complete direct-to-home satellite digital television program delivery infrastructure having a capacity in excess of 100 channels from a single satellite. 3. This was the digital video broadcasting (DVB) project in 1993, and the main standardization work for satellite (DVB-S) and cable (DVB-C) delivery systems was completed in 1994. Copyright © Open University Malaysia (OUM)

30. STUDY GUIDE CBMN4104 Multimedia Networking 29 4. The fixed terrestrial version (DVB-T) was soon added to the DVB family to offer one-to-many broadband wireless data broadcasting based on roof-top antenna and the use of IP packets. 5. DVB provides superior picture quality with the opportunity to view pictures in standard format or wide screen (16 : 9) format, along with mono, stereo, or surround sound. 6. It also allows a range of new features and services including subtitling, electronic program guides (EPGs), multiple audio tracks, interactive content, multimedia content, etc. 7. Moreover, these programs may be linked to World Wide Web material to be disseminated through the Internet. 8. The Advanced Television Systems Committee (ATSC) in established in US. 9. ATSC committee adopted different standards such as the ATSC digital television (DTV) standard A/53 and the digital audio compression (AC3) standard A/52. 10. These ATSC standards, established in 1995, were the world’s first standards for DTV, and they established the precedent for system quality and flexibility that separates DTV from all the existing analog television systems. 11. In 1999, a formal process began to get the four network affiliates (ABC, CBS, NBC, Fox) in the top 30 markets on the air with DTV. 12. In 2001, the fourth-generation (4G) receivers had removed any doubts regarding the viability of outdoor DTV reception and, in 2005, the fifth- generation (5G) performance convinced many critics that successful indoor reception equivalent to NTSC could be achieved. 13. By the encapsulation of Internet protocol (IP) based services in DVB data streams, DVB networks are further opened up for transmission of graphics, photos, and data. 14. The advent of the multimedia home platform (MHP, http://www.mhp.org/), which is a set of Java-based interactive TV middleware specifications developed by the DVB Project, was another milestone since with MHP software applications can be run on all sorts of terminal devices. Copyright © Open University Malaysia (OUM)

31. STUDY GUIDE CBMN4104 Multimedia Networking 30 15. The DVB-T platform is a flexible system which can provide services for both fixed roof-top antenna and portable or mobile receptions, with some tradeoff between bitrate and signal robustness. 16. Another, competing, digital video broadcasting standard for handheld devices was developed in Korea, terrestrial digital multimedia broadcasting (T-DMB) standard. 17. The digital broadcasting offered in Japan is based on a highly versatile system called integrated services digital broadcasting (ISDB). 18. DVB-T to DVB-H (a) The two most important aspects of the DVB-T system are the use of the MPEG-2 transport stream (TS) and the use of the coded orthogonal frequency-division multiplex (COFDM) format. (b) More specifically, once the video and audio data in DVB-T are compressed according to MPEG-2 compression standards, they are packed by the packetized elementary stream (PES) layer and then each PES packet is divided into fixed-length packets of 188 bytes. 19. T-DMB Multimedia Broadcasting for Portable Devices (a) Terrestrial digital multimedia broadcasting (T-DMB), which was developed in Korea on the basis of the European Digital Audio Broadcasting standard (DAB, Eureka-147), has some similarities with the competing mobile TV standard DVB-H for handheld devices in terms of the use of multimedia data compression techniques. (b) More specifically, T-DMB uses MPEG-4 H.264/AVC for video coding and MPEG-4 bit-sliced arithmetic coding (BSAC) [28] or MPEG-4 HE AAC for audio coding. 20. ATSC for North America Terrestrial Video Broadcasting (a) The Advanced Television Systems Committee (ATSC) digital television (DTV, A/53) standard describes a system designed to transmit high-quality video and audio, and ancillary data, within a single 6 MHz terrestrial television broadcast channel. (b) The system can deliver about 19 Mbps in a 6 MHz terrestrial broadcasting channel and about 38 Mbps in a 6 MHz cable television channel. Copyright © Open University Malaysia (OUM)

32. STUDY GUIDE CBMN4104 Multimedia Networking 31 21. ISDB Digital Broadcasting in Japan (a) The ISDB system was designed to provide integrated digital information services consisting of audio, video and data via satellite, terrestrial, or cable TV network transmission channels. Study questions 1. Explain briefly the meaning of digital broadcasting? 2. What is the fixed reception standard for Asia region? 3. Describe briefly two important aspects of DVB-T system namely MPEG-2 transport stream (TS) and the use of the coded orthogonal frequency-division multiplex (COFDM) format 4. Draw a diagram to show multimedia specification architecture of a T-DMB system 5. What is ISDB? Frequently Asked Questions 1. What is a digital media network? A digital media network is a network consisting of different facets of digital media, such as advertising, television properties, Internet properties, and a wide selection of digital material. 2. What are the different types of digital media services? Digital media includes audio, visual, and text media that is transmitted, and usually created, digitally. Since digital media is commonly used in business, entertainment, and communication, the types of digital media services are many. 3. What is Digital Satellite TV? Digital satellite TV is broadcast from a satellite located on orbit around the Earth. A homeowner who subscribes to the service must put a satellite dish outside that picks up the signal and delivers it into the home. 4. What is DVB-T? DVB-T broadcasters transmit data using a compressed digital audio- video stream, with the entire process based on the MPEG-2 standard. Copyright © Open University Malaysia (OUM)

33. STUDY GUIDE CBMN4104 Multimedia Networking 32 These transmissions can include all kinds of digital broadcasting, including HDTV and other high-intensity methods. 5. What is DVB-H? DVB-H offers high-speed streaming video that can be used either on its own or as a piggyback signal on existing mobile telecommunication networks. The signals are designed to account for the limited battery life of small handheld devices by employing a technique called time-slicing, in which bursts of data are sent periodically and then stored, avoiding the need for a constant battery drain Glossary of important terms 1. Digital video broadcasting (penyiaran video digital): Digital Video Broadcasting (DVB) is a suite of internationally accepted open standards for digital television. DVB standards are maintained by the DVB Project 2. Wide screen (skrin lebar): A widescreen image is a film, computer, or television image with a width to height aspect ratio greater than the standard 1.37:1, Academy Frame aspect ratio. 3. Middleware (perisian tengah): Middleware is a layer of software that runs on top of set top box operating systems (OS) creating a consistent environment to run application software over a wide variety of set top boxes. 4. Robustness (keteguhan): Robustness is the quality of being able to withstand stresses, pressures, or changes in procedure or circumstance 5. Ancillary (sampingan): An addition to. Copyright © Open University Malaysia (OUM)

34. STUDY GUIDE CBMN4104 Multimedia Networking 33 Week 5 Chapter 7: Multimedia Quality of Service of IP Networks Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. Multimedia networking has to enable multimedia data that originate on a source host to be transmitted through the IP networks (the Internet) and displayed at the destination host 2. The Internet, which uses IP protocols and packet switching, has become the largest network of networks in the world (it consists of a combination of many wide area and local area networks, WANs and LANs (see Figure 7.1) 3. Multimedia over the Internet is fast growing among service providers and potential customers Copyright © Open University Malaysia (OUM)

35. STUDY GUIDE CBMN4104 Multimedia Networking 34 4. Real-time multimedia applications (e.g., live video streaming and video conferences), which are very sensitive to transmission delay and jitter and usually require a sufficiently high bandwidth 5. To this end, various systems have been made available on network protocols and architectures to support the quality of service (QoS) 6. The IP protocol is now commonly accepted as a top-down five-layer model, having application, transport, network, data-link, and physical layers (see Figure 7.2): (i) Application layer (ii) Transport layer (iii) Network layer (iv) Data-link layer (v) Physical layer 7. In the networking community, quality of service (QoS) commonly refers to the service level offered by the network to applications or users to match their performance needs in terms of network QoS metric parameters, including delay or latency, delay variation (delay jitter), throughput or bandwidth, and packet loss or error rate, etc. 8. There have been several QoS mechanisms based on bandwidth management, including traffic classification, packet scheduling, resource reservation, channel access, and traffic policing. (i) Traffic classification (ii) Packet traffic management (iii) Network resource management 9. To resolve effectively the matter of supporting a larger number of receivers for the same live-streamed media, the IP multicast delivery of UDP traffic was introduced; in this system the multicast receiver gets only the video content he or she desires, and this allows a significantly larger number of streams to be available. (i) IP multicast (ii) Application-level multicast Copyright © Open University Malaysia (OUM)

36. STUDY GUIDE CBMN4104 Multimedia Networking 35 10. If the transmitted multimedia data rate is too high, this may cause packet loss or even a congestion collapse whereas a low transmission data rate will leave some receivers underutilized. 11. To solve this issue, the transmission source should have a scalable rate, i.e., multirate, which allows transmission in a layered fashion. (i) Receiver-driven layered multicast (RLM) (ii) Receiver-driven layered congestion control (RLC) (iii) Packet-pair layered multicast (PLM) (iv) Bandwidth inference congestion control (BIC) layered multicast Study questions 1. Why Quality of Service (QoS) is an important element in delivering multimedia over the networks?. 2. What is meant by TCP/IP?. 3. Explain briefly the Application Layer of the Internet Protocol. 4. Explain briefly the several mechanisms of QoS. 5. What is the meaning of IP Multicast?. Frequently Asked Questions 1. What are the five top-down layers of the Internet Protocol? The IP protocol consists of the top-down five-layer model namely application, transport, network, data-link, and physical layers. 2. What are the causes of packet loss? There are two factors: (i) Network congestion, which results in dropped packets. (ii) the presence of a noisy communication channel, especially in a wireless channel. Copyright © Open University Malaysia (OUM)

37. STUDY GUIDE CBMN4104 Multimedia Networking 36 3. How does the Application Layer works? The application layer works in the following ways: (i) First, the application or user sends the connection request to the central station. (ii) Then, if the new connection is admitted, it will be assigned a unique ID number. (iii) Packets from the application will be associated with this ID number. 4. What is the example of application that uses P2P technique? Any torrent applications such as BitTorrent, Transmission, Deluge and etc. Glossary of important terms 1. Destination host (hos destinasi): A host to which ping sends request packets and from which it expects reply packets. 2. WAN (Wide Area Network) (Rangkaian Kawasan Luas): A WAN spans a large geographic area, such as a state, province or country. WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs). 3. LAN (Local Area Network) (Rangkaian Kawasan Setempat): A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. 4. Multicast (multisiar):Multicast is communication between a single sender and multiple receivers on a network. 5. Receiver (penerima): A device that accepts signals. Contrast with "transmitter," which sends signals. The term is used generically to refer to "the side being sent to.” For example, “by the time the signal gets to the receiver...” refers to whichever hardware device is at the other end of the communication. Copyright © Open University Malaysia (OUM)

38. STUDY GUIDE CBMN4104 Multimedia Networking 37 Week 6 Chapter 8: Quality of Service Issues in Streaming Architectures Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. Multimedia streaming is an important component of many Internet applications such as distance learning, digital libraries, video conferencing, home shopping, and video-on-demand. 2. However, the current best-effort Internet does not offer any quality of service (QoS) guarantees to streaming media over the Internet. 3. In terms of multimedia streaming over IP networks, there are two common delivery mechanisms in which multimedia information can be distributed over the Internet, namely, live streaming and on-demand streaming. 4. QoS Mechanisms for Multimedia Streaming. There are six key components of a multimedia streaming system: Copyright © Open University Malaysia (OUM)

39. STUDY GUIDE CBMN4104 Multimedia Networking 38 (a) Multimedia compression (i) Non-scalable audio coding is the most widely used coding in streaming systems. (ii) Scalable video is more adaptable to the varying available bandwidth in the network in comparison with non-scalable video coding. (iii) Streaming audio and/or video (A/V) requires bounded end- to-end delay so that packets can arrive at the receiver in time to be decoded and displayed. (iv) It is desirable that an A/V stream be robust to packet loss. (b) Application-layer QoS control (i) The objective of application-layer QoS control is to avoid congestion and maximize video quality in the presence of packet loss. (ii) The application-layer QoS control techniques include congestion control and error control. (c) Continuous media distribution services (i) Continuous media distribution services are built on top of the best-effort Internet with the aim of achieving QoS and efficiency for media streaming. (ii) Some representative techniques include network filtering, application-level multicast, content replication, etc. (d) Streaming servers (i) Streaming servers play a critical role to process multimedia data under strict timing constraints in order to provide synchronized A/V and data presentation as well as to prevent artifacts (e.g., jerkiness in video motion and pops in audio) during playback. (ii) Streaming servers also need to support VCR-like control operations, such as stop, pause or resume, fast forward, and fast backward. Copyright © Open University Malaysia (OUM)

40. STUDY GUIDE CBMN4104 Multimedia Networking 39 (e) A streaming server typically consists of the following three subsystems: (i) A communicator to handle the application-layer and transport protocols. (ii) A real-time operating system to satisfy real-time requirements for streaming applications. (iii) A storage system to support continuous media storage and retrieval in the streaming services. (f) Media synchronization mechanisms. (i) Media synchronization refers to the maintaining of temporal relationships within one data stream and between various media streams. (ii) There are three levels of synchronization, corresponding to three semantic layers of multimedia data:  Intramedia (e.g., between audio and video streams).  Intermedia.  Interobject (including texts and images). (g) Protocols for the streaming media The protocols directly related to Internet streaming video can be classified into the following three categories:  Network-layer protocols  Transport protocols  Session control protocols 5. Windows Media Streaming Technology by Microsoft (a) Microsoft Windows Media Services 9 Series is the server component of the Windows Media 9 Series platform, and works in conjunction with Windows Media Encoders and Windows Media Players to deliver audio and video streaming content to clients over the Internet or an intranet. Copyright © Open University Malaysia (OUM)

41. STUDY GUIDE CBMN4104 Multimedia Networking 40 (b) The container file format is known as the advanced systems format, and the files have extensions .WMV, .WMA, or .ASF, depending on whether they contain video and audio (WMV), only audio (WMA), or content that is not coded by Windows Media codecs (ASF). (c) Some technical features have been uniquely developed for Windows Media streaming systems, such as the fast streaming and dynamic content delivery technologies. 6. SureStream Streaming Technology by RealNetworks (a) RealMedia is a streaming technology, offered by RealNetworks, which runs on Windows and Linux. (b) Both the container format and the codecs are proprietary, and the files have extensions .RA, .RAM, .RM, and .RPM. (c) A RealMedia server called Helix Universal Server can handle RTSP and MMS control protocols and is able to deliver a large variety of container formats, including RealMedia, Windows Media (WM), Apple’s QuickTime (QT), MPEG, and others. (d) It can also accept connections from WM, QT, and MPEG-4 encoders, and from any of these players. (e) RealSystem G2 uses the standard RTSP protocol for session control, and supports the RTP standard for framing and transporting of data packets. (f) The key technological components of RealSystems G2 are: (i) An adaptive stream management (ASM) protocol (ii) SureStream file format access and rendering mechanisms (iii) Source and channel coding algorithms 7. Internet Protocol TV (IPTV) (a) The technological advances in the past decades for VoIP, last- mile IP connections, video streaming, and video conferencing over IP can now be applied to an emerging technology, Internet protocol TV (IPTV), which will provide a more function-rich, user- interactive form of TV to consumers. Copyright © Open University Malaysia (OUM)

42. STUDY GUIDE CBMN4104 Multimedia Networking 41 (b) It requires approximately 2 Mbps to transmit a broadcast-quality video stream using MPEG-2 compression; a DVD-quality TV signal takes 4 to 5 Mbps; and high-definition television (HDTV) requires approximately 9 Mbps. (c) These TV programs can now be delivered digitally to the ordinary household with the use of advanced DSL (ADSL2+ and VDSL) or fiber-to-the-home (FTTH) technologies. (d) Internet protocol TV is formally defined as multimedia services, such as audio and video, delivered over IP-based networks that are managed in such a way as to provide the required level of QoS and quality of experience (QoE), security, interactivity, and reliability. (e) requirements for various important aspects: IPTV architecture, QoS and performance, security and content protection, network and control, end systems and middleware, and public interest. Study questions 1. Name TWO (2) delivery mechanisms for multimedia elements over the Internet. 2. Discuss SIX (6) key components of multimedia streaming system. 3. What is the objective of application-layer QoS control?. 4. List protocols for the streaming media. 5. List extension supported by Windows Media Streaming by Microsoft. Frequently Asked Questions 1. Do you think the streaming media is good on the Internet? It depends to the current best-effort Internet does not offer any quality of service (QoS) guarantees to streaming media over the Internet. 2. What is meant by live-streaming? Broadcasting in real time using steaming media. Copyright © Open University Malaysia (OUM)

43. STUDY GUIDE CBMN4104 Multimedia Networking 42 3. What is streaming video or audio? Streaming video or audio is video (as on television) or sound (as on the radio) delivered over the Internet via a modem or broadband connection. 4. What difference does it make if content is streamed, rather than downloaded? Audio and video files can be very large. You would spend many minutes or even hours waiting for them to be downloaded to your computer if they weren't streamed. Streaming media technology allows you to see or hear the content in just a few seconds, instead of having to wait for it. 5. Can I receive streaming media via Web TV? Earlier versions of Web TV can't receive streaming media, but some later versions can. You should check your manual or ask the Web TV folks to see if your model supports streaming video/audio. Glossary of important terms 1. Multimedia streaming (Penstriman multimedia): Generally includes one or several forms of media which are streamed or transported to the client over a network. 2. Quality of service (QoS) (Kualiti Perkhidmatan): QoS (Quality of Service) refers to a broad collection of networking technologies and techniques. The goal of QoS is to provide guarantees on the ability of a network to deliver predictable results. Elements of network performance within the scope of QoS often include availability (uptime), bandwidth (throughput), latency (delay), and error rate. 3. Bandwidth (Lebarjalur):Bandwidth is often used as a synonym for data transfer rate - the amount of data that can be carried from one point to another in a given time period (usually a second). 4. Data synchronization (penyamaan data): Data synchronization technologies are designed to synchronize a single set of data between two or more devices, automatically copying changes back and forth. 5. Codecs (kodeks): a codec is any technology for compressing and decompressing data. Codecs can be implemented in software, hardware, or a combination of both. Copyright © Open University Malaysia (OUM)

44. STUDY GUIDE CBMN4104 Multimedia Networking 43 Week 7 Chapter 9: Wireless Broadband and Quality of Service Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. Overview (a) Wireless technology describes telecommunications in which electromagnetic waves carry the signal over part of or the entire communication path without cables. (b) Wireless broadband is an extension of point-to-point wireless communication for the delivery of high-speed and high-capacity pipe that can be used for voice, multimedia, and Internet access services. (c) The main focus is on 3G, Wi-Fi, and WiMAX. Copyright © Open University Malaysia (OUM)

45. STUDY GUIDE CBMN4104 Multimedia Networking 44 (d) The wireless LAN (WLAN or the so-called Wi-Fi standards) technologies IEEE 802.11a/b/g and the next generation very-high- data-rate (> 200 Mbps) IEEE 802.11n are being deployed everywhere for Internet access (the so-called hotspot) with very affordable installation costs. (e) WiMAX is regarded as the next generation (4G) wireless system. (f) A key distinction between 3G, Wi-Fi, and WiMAX is that the 3G and WiMAX technologies use a licensed spectrum, while Wi-Fi uses an unlicensed shared spectrum. 2. Evolution of 3G Technologies (a) The first generation mobile service was called the advanced mobile phone service (AMPS) and was based on analog frequency-division multiple access (FDMA) technology. (b) In the 1990s, mobile services were upgraded to digital mobile technologies; these are known as the second generation (2G) of mobile services. (c) To further support higher-bandwidth wireless digital data communications, a vision of the next generation (i.e., third generation, 3G) cellular networks for public land mobile telecommunications systems, called international mobile telecommunications 2000 (IMT-2000), was proposed by the Telecommunication Standardization Section of ITU. (d) As shown in Figure 9.4, for a technically stationary user operating in a picocell (100 m coverage area, within a building), the data rate would be up to 2.048 Mbps. (e) For a pedestrian user operating in a microcell (0.5 km coverage area, in an urban neighborhood), the data rates would be up to 384 kbps. (f) For a user with vehicular mobility operating in the macrocell (5–10 km metropolitan coverage area), the data rates would be up to 144 kbps. (g) The 3G wireless system evolved from GSM is called wideband CDMA (WCDMA) and is also referred to as the universal mobile telecommunications system (UMTS) in the European market. Copyright © Open University Malaysia (OUM)

46. STUDY GUIDE CBMN4104 Multimedia Networking 45 (h) Another effort moving GSM toward 3G in the US market was enhanced data rates for GSM evolution (EDGE), which can provide data rates up to 384 kbps. (i) The WCDMA variations include frequency-division duplex (FDD), time-division duplex (TDD), and time-division CDMA (TDCDMA). (j) But, as of 2006, the growing interest in high-speed downlink packet access (HSDPA) provides a smooth evolutionary path for UMTS networks to higher data rates and higher capacities, in the same way as EDGE does in the GSM world. (k) Even with today’s fast growing use of 3G mobile services, there are still important disadvantages in comparison with those of wired networks. One main concern is that the bandwidth is still not as large and as stable as for fixed wired networks. (l) These considerations call for the following three 4G wireless systems: the long term evolution (LTE) of 3GPP, the ultra mobile broadband (UMB) of 3GPP2, and the IEEE 802.16e WiMAX. (m) There are two main goals of 4G wireless systems. First of all, higher and more stable bandwidth is required. Second, and more importantly, 4G networks will no longer have a circuit-switched subsystem as do the current 2G and 3G networks. 3. Wi-Fi Wireless LAN (802.11) (a) In 1989, the IEEE 802.11 Working Group began elaborating on WLAN medium access control (MAC) and physical (PHY) layer specifications. (b) Since then 802.11-based WLANs have been rapidly accepted and recently deployed widely in many different environments, including campuses, offices, homes, and hotspots. (c) In the communication architecture of an IEEE 802.11, all components that can connect into a wireless medium in a network are referred to as stations (STAs). (i) All stations are equipped with wireless network interface cards (WNICs). (ii) Wireless stations fall into one of two categories, access points and clients. Copyright © Open University Malaysia (OUM)

47. STUDY GUIDE CBMN4104 Multimedia Networking 46 (iii) An access point (AP) is the base station for the wireless LAN. (iv) It transmits and receives the radio frequencies at which wireless enabled devices can communicate. (v) The transmitter of a WLAN AP sends out a wireless signal that allows wireless devices to access it within a circle of roughly 100 meters. (vi) The zone around the transmitter is known as a hotspot. (vii) A wireless client can be a mobile device such as a laptop, a personal digital assistant (PDA), an IP phone, or a fixed device such as a desktop or workstation equipped with a WNIC.  The growth of hotspots, free and fee-based public access points, has added to Wi-Fi’s popularity. There were several standards under the umbrella of IEEE 802.11 Wi-Fi as listed in Table 9.2. 4. QoS Enhancement Support of 802.11 (a) Two medium-access coordination functions are defined in the original 802.11 MAC: a mandatory distributed coordination function (DCF) and an optional point coordination function (PCF). (b) To improve the QoS and the overall system performance of 802.11, there have been several efforts to introduce service differentiation for the IEEE 802.11 based on the DCF MAC mechanism: (i) Varying the DIFS and backoff time (ii) Limiting the maximum frame length (iii) Varying the initial contention-window size (iv) Blackburst (v) Distributed fair scheduling (c) The IEEE 802.11e standard, which was finalized in 2003, is an approved amendment to the IEEE 802.11 standard that defines a Copyright © Open University Malaysia (OUM)

48. STUDY GUIDE CBMN4104 Multimedia Networking 47 set of QoS enhancements for WLAN applications through modifications to the MAC layer. (d) The IEEE 802.11e standard supports QoS on the basic of a hybrid coordination function (HCF), which defines two medium-access mechanisms: one is contention-based channel access and the other is controlled channel access. (e) To build a small-to-large-scale wireless distribution system based on the WLAN infrastructure, the IEEE 802.11s extended service set (ESS) was proposed for the installation, configuration, and operation of a WLAN multi-hop mesh. 5. Worldwide Interoperability for Microwave Access (WiMAX) (a) The IEEE 802.16 standard, commonly referred to as worldwide interoperability for microwave access (WiMAX), specifies the air interface, including the MAC and PHY layers, for the next generation wireless broadband access. (b) First published in 2001, the IEEE 802.16 standard specified a frequency range 10–66 GHz with a theoretical maximum bandwidth of 120 Mbps and maximum transmission range of 50 km. (c) A variant of the standard, IEEE 802.16a-2003, approved in April 2003, can support non-LOS (NLOS) transmission and adopts OFDM at the PHY layer. (d) The IEEE 802.16 standard evolved to the 802.16–2004 standard (also known as 802.16d). (e) To further support mobility, which is widely considered to be a key feature in wireless networks, the new IEEE 802.16e (also known as 802.16–2005) added mobility support and is generally referred to as mobile WiMAX. (f) Figure 9.20 shows a common protocol architecture of the WiMAX standard, where the MAC layer consists of three sublayers: the service-specific convergence sublayer (CS), the MAC common part sublayer (MAC CPS), and the security sublayer. Copyright © Open University Malaysia (OUM)

49. STUDY GUIDE CBMN4104 Multimedia Networking 48 6. Internetworking Between 802.16 and 802.11 (a) Figure 9.26 shows an integrated 802.16 and 802.11 system, where a WiMAX BS operating in a licensed band serves both WiMAX SSs and Wi-Fi APs or routers in its coverage area. (b) Protocol adaptation is critically required for two different wireless infrastructures, WiMAX and Wi-Fi, to internetwork with each other. Some protocol adaptation mechanisms originally proposed for internetworking between 3G and Wi-Fi can be extended for WiMAX–Wi-Fi integrated networks. (c) Quality of service support would be required for real-time (e.g., video and voice) traffic in an integrated WiMAX–Wi-Fi network. (d) The radio resource allocation mechanisms need to be developed accordingly. Specifically, optimal and adaptive bandwidth sharing mechanisms that satisfy both the WiMAX and Wi-Fi service providers need to be developed. Study questions 1. What is the meaning of wireless technology?. 2. Differentiate between 3G, Wi-Fi and WiMAX technologies. 3. How 3G has been evolved to CDMA technology?. 4. What are the mechanisms that can be used to improve QoS?. 5. Describe the protocol of WiMAX using a diagram. Frequently Asked Questions 1. Why wireless technologies always keep changing? The technologies always keep changing to cater the new findings, development and improvement of wireless technologies and also for user requirements. 2. I can see MAC configuration in my modem-router. What it does means? Short for Media Access Control address, a hardware address that uniquely identifies each node of a network. In IEEE 802 networks, the Data Link Control (DLC) layer of the OSI Reference Model is divided Copyright © Open University Malaysia (OUM)

50. STUDY GUIDE CBMN4104 Multimedia Networking 49 into two sub-layers: the Logical Link Control (LLC) layer and the Media Access Control (MAC) layer. The MAC layer interfaces directly with the network medium. Consequently, each different type of network medium requires a different MAC layer. 3. Do I need to know different WLAN standards produced by IEEE? Yes of course, so that you can understand the cronology of WLAN development. 4. What is Wireless Metropolitan Area Networks (WMANs)? A wireless metropolitan area network (WMAN) is a form of wireless networking that has an intended coverage area “a range” of approximately the size of a city. A WMAN spans a larger area than a wireless local area network (WLAN) but smaller than a wireless wide area network (WWAN). 5. What is different between IEEE 802.16 and IEEE 802.11? The basic difference between “normal wireless” or Wi-Fi and WiMAX is that they have different radio technologies that enable the delivery of high-speed internet access. Wi-Fi (IEEE 802.11) is a relatively mature technology, with equipment widely available for both domestic and office use. In addition, there are thousand of hotspots around the UK, offering wireless access in hotels, coffee shops and airports. WiMAX (IEEE 802.16) on the other hand is a very new technology, with very few services available in the UK. It offers higher bandwidth services over a longer range, compared with Wi-Fi. This means that when it becomes more mainstream, WiMAX is expected to give faster internet over a wider area. Glossary of important terms 1. Wireless (tanpa wayar): Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or all of the communication path. 2. Hotspot (titik utama): A specific geographic location in which an access point provides public wireless broadband network services to mobile visitors through a WLAN. Hotspots are often located in heavily populated places such as airports, train stations, libraries, marinas, conventions centers and hotels. Hotspots typically have a short range of access. Copyright © Open University Malaysia (OUM)

51. STUDY GUIDE CBMN4104 Multimedia Networking 50 3. Wi-Fi (Wi-Fi): A communication system that uses low-power microwave radio signals to connect laptop computers, PDAs, and web-enabled cell phones to the Internet. 4. WiMAX (WiMAX): WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. Copyright © Open University Malaysia (OUM)

52. STUDY GUIDE CBMN4104 Multimedia Networking 51 Week 8 Chapter 10: Multimedia Over Wireless Broadband Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. Overview (a) Wireless multimedia delivery faces several challenges, such as a high error rate, bandwidth variation and limitation, battery power limitation, and so on. (b) Wireless networks were not designed with real-time multimedia communication services. (c) Media coding over wireless networks are governed by two dominant rules: (i) Moore’s law, which states that computing power doubles every 18 months. Copyright © Open University Malaysia (OUM)

53. STUDY GUIDE CBMN4104 Multimedia Networking 52 (ii) The huge bandwidth gap (one or two orders of magnitude) between wireless and wired networks. 2. End-to-End Transport Error Control (a) In a wireless network environment, common channel errors due to multipath fading, shadowing, and attenuation may cause bit errors and packet loss; this is quite different from the packet loss caused by network congestion. (b) In congestion control, packet loss information can serve as an index of network congestion for effective rate adjustment; therefore wireless packet loss can mistakenly guide congestion control and lead to dramatic performance degradation. (c) For a network topology containing wireless links, packet loss can be caused by either congestion loss or wireless channel errors resulting from multipath fading, shadowing, or attenuation. (d) Packet loss due to wireless channel errors will result in an improper reduction in sending rate and dramatically throttle the throughput. (e) In general, two kinds of packet loss, congestion loss and wireless loss, as shown in Figure 10.2, are commonly categorized. 3. Error Resilience and Power Control at the Source Coding Layer (a) In addition to the error control techniques created for the various layers of multimedia-over-wireless-network protocols, there have been a great deal of efforts to provide error control and recovery technologies at the source coding layer (b) The standardized error-resilient encoding schemes include resynchronization marking, data partitioning, and data recovery (c) There are two basic approaches for error concealment, spatial and temporal interpolation: (i) The H.264 network abstraction layer for network adaptation (ii) Power control with rate–distortion optimization 4. Multimedia Over Wireless Mesh Copyright © Open University Malaysia (OUM)

54. STUDY GUIDE CBMN4104 Multimedia Networking 53 (a) To build a small-to-large-scale wireless distribution system based on a WLAN infrastructure, the IEEE 802.11s extended service set (ESS) was proposed for the installation, configuration, and operation of WLAN multi-hop mesh. (b) The 802.11-based wireless mesh networks (WMNs) have emerged as a key technology for a variety of new multimedia services that require flexible network support. (c) Therefore, in addition to the 802.11s standardization efforts, some proprietary radio technologies are used instead of IEEE 802.11- based radio technology, such as the products made by Radiant and MeshNetwork; their systems are, however, incompatible with others. And also MIT Roofnet and Microsoft Research. (d) In a typical WMN, the network configuration maintains the ad hoc communication structure but with two architectural levels, mesh routers and mesh clients. 5. Wireless VoIP and Scalable IPTV Video (a) Voice over IP (VoIP) applications in wireless networks have gained increasing popularity in recent years. (b) the advances in IEEE 802.16e wireless broadband and scalable video technologies have also made it possible for Internet protocol television (IPTV) to become the next “killer” application for modern Internet carriers in metropolitan areas with mobility support. (c) End-to-end WLAN-based VoIP system (d) Scalable IPTV video over WiMAX (e) Cross-layer congestion control for video over WLAN (f) Cross-layer scalable video over WiMAX Study questions 1. What are the challenges of wireless multimedia technology? 2. What are the common channel errors in wireless network environment? 3. In addition to the error control techniques created for the various layers of multimedia-over-wireless-network protocols, there have been a great Copyright © Open University Malaysia (OUM)

55. STUDY GUIDE CBMN4104 Multimedia Networking 54 deal of efforts to provide error control and recovery technologies at the source coding layer. Discuss the standardized error-resilient encoding schemes to control the errors. 4. Discuss the advantages of Wireless Mesh Networks. 5. Explain briefly the Wireless VoIP and Scalable IPTV Video. Frequently Asked Questions 1. What are the benefits of using a wireless mesh networking system? A wireless mesh network provides a secure information grid for use virtually anywhere. Users can transmit data instantly, intelligently, and securely over a highly redundant wireless network consisting of autonomous routers or nodes. The network can be deployed on land or sea, in rural or urban environments, to and from fixed or temporary sites, and even in remote or inhospitable terrain. 2. How does a mesh network work? Each node in a mesh network is a wireless router that connects to every other node in the system by forwarding data to neighboring nodes until the data reaches its final destination. This wireless peer-to-peer forwarding of data eliminates the need for wired networking infrastructure, greatly reducing the cost and time to deploy a network. 3. How is a wireless mesh network different from a standard wireless network? A standard Wi-Fi network operates on unlicensed radio spectrum with each router or node hardwire connected to the internet. A mesh network operates on the same radio spectrum but only one node in a particular network needs to be hardwired to the internet. This allows network signals to freely route via the most efficient path back to the hardwired node enhancing the speed and reliability of communications. 4. How would you describe the relationship between WMN and Wi-Fi? Technologically speaking, WMN is fully compatible with the Wi-Fi standard on the physical layer and the link layer; in addition, it strengthens the Wi-Fi standard. The traditional Wi-Fi technology requires each AP to be equipped with one wire to provide wireless coverage for a target area; in contrast, WMN employs a radio frequency to substitute its wired counterparts. Without the limitation of wires, WMN allows users to deploy dynamic networks in an area as vast as they may desire. Copyright © Open University Malaysia (OUM)

56. STUDY GUIDE CBMN4104 Multimedia Networking 55 5. What is Wireless VoIP? Wireless VoIP is VoIP running over a Wireless LAN (WLAN). These WLANs are typically compliant with the 802.11 standard. As long as callers are within range of a WLAN access point and using a VoIP enabled handset, they can make and receive calls over the wireless network. Wireless VoIP is gaining adoption in certain vertical industries, such as health care and retail, where worker mobility is critical to a productive workforce. Glossary of important terms 1. VoIP (Voice over Internet Protocol) (Suara melalui IP): VoIP is a technology that allows telephone calls to be made over computer networks like the Internet. VoIP converts analog voice signals into digital data packets and supports real-time, two-way transmission of conversations using Internet Protocol (IP). 2. UDP (User Datagram Protocol) (Protokol Datagram Pengguna): UDP is a communications protocol that offers a limited amount of service when messages are exchanged between computers in a network that uses the Internet Protocol (IP). 3. Network abstraction layer (NAL) (Lapisan Pengabstrakan Rangkaian): The Network Abstraction Layer (NAL) is a part of the H.264/AVC Video Coding Standard. The main goal of the H.264/AVC NAL is the provision of a "network-friendly" video representation addressing "conversational" (video telephony) and "non conversational" (storage, broadcast, or streaming) applications. 4. Signal-to-noise ratio (SNR) (Nisbah isyarat-hingar): Signal-to-noise ratio (often abbreviated SNR or S/N) is a measure used in science and engineering to quantify how much a signal has been corrupted by noise. It is defined as the ratio of signal power to the noise power corrupting the signal. A ratio higher than 1:1 indicates more signal than noise. 5. Wireless Mesh Network (WMN) (Rangkaian Jejaring Tanpa Wayar): A wireless mesh network (WMN) is a mesh network created through the connection of wireless access points installed at each network user's locale. Each network user is also a provider, forwarding data to the next node. The networking infrastructure is decentralized and simplified because each node need only transmit as far as the next node. Wireless mesh networking could allow people living in remote areas and small businesses operating in rural neighborhoods to connect their networks together for affordable Internet connections. Copyright © Open University Malaysia (OUM)

57. STUDY GUIDE CBMN4104 Multimedia Networking 56 Week 9 Chapter 11: Digital Rights Management of Multimedia Readings Hwang, Jenq-Neng. (2009). Multimedia networking: From theory to practice. Add New York: Cambridge University Press. e-Content The above reading can be accessed from TSASDL: 1. Login to OUM Portal. 2. Acess myLibrary. 3. Find Learning Resources > Online Databases on the left side of the page. 4. Choose Books24x7 and connect to the database. 5. Search for the title of the book, and open the respective chapters. Study notes 1. Overview (a) Owing to the proliferation of digitized media applications, such as e-Book, streaming videos, web images, shared music, etc., there is a growing need to protect the intellectual property rights of digital media and prevent illegal copying and falsification. (b) This explains the strong demand for digital rights management (DRM), which is an access control technology that protects and enforces the rights associated with the use of digital content, such as multimedia data. Copyright © Open University Malaysia (OUM)

58. STUDY GUIDE CBMN4104 Multimedia Networking 57 (c) The most important functions of DRM are to prevent unauthorized access and the creation of unauthorized copies of digital content, and moreover to provide a mechanism by which copies can be detected and traced (content tracking). (d) effective DRM system should have the following four requirements: (i) The DRM system must package the content to be protected in a secure manner. (ii) The DRM system must obtain the access conditions (license) specified by the owner of the protected content. (iii) The DRM system must determine whether the access conditions have been fulfilled. (iv) The DRM system must be tamper-proof to prevent or deter attempts to circumvent, modify, or reverse-engineer the security protocols used by the DRM system. 2. A Generic DRM Architecture (a) Figure 11.1 shows a generic DRM architecture, which consists of three modules: client, license server, and content server. (b) A user uses the client device to obtain, either by downloading in advance or live streaming online, multimedia content packages from the content server, and then requests operation (e.g., view, play) of these contents. (c) The DRM controller residing in the client device starts to collect information, such as the content ID, the user ID, and the requested rights, etc. (d) When the necessary information has been collected, the DRM controller contacts the license generator residing in the license server; the license generator validates (authorizes) the forwarded content ID and user ID, and calls for the requested rights from the client device to be imposed on the downloaded or streamed multimedia content. (e) The license generator goes on to extract the data encryption keys (commonly based on secret key encryption technologies such as DES or AES, to be discussed later) from the key repository corresponding to the downloaded or streamed multimedia content, Copyright © Open University Malaysia (OUM)

59. STUDY GUIDE CBMN4104 Multimedia Networking 58 then creates and sends the license to the client device; this is followed by the generation of a financial transaction, if necessary. (f) The sending of the license from DRM server to client again calls for the help of public key encryption, i.e., sending a digitally signed license. (g) The DRM controller at the client side, after receiving and opening the license from the DRM server, will extract data encryption keys from the received license to decrypt the downloaded or live streamed multimedia contents and will generate a financial transaction on the client side if necessary. (h) The DRM controller then hands the decrypted content to the rendering (i.e., media decoding) application to be played back. (i) DRM content server  A content server is a computer system that provides content or media to devices that are connected to a communication system. The main function of a content server is to receive and process requests for media content, to set up a connection to the requesting device, and to manage media transfer during the communication session. (j) DRM license server  A license server is a system that maintains a list of license holders and their associated permissions to access licensed content. The main function of a license server is to confirm or provide the necessary codes or information elements to users or systems with the ability to provide access to licensed content. (k) DRM client  A DRM client is either a hardware device or a software program that is configured to receive from the network the content package from the content server and request a DRM license from license server. (l) Separating content from license  In the common architecture for most modern DRM systems, the content and license are handled by the content server and license server separately, as shown in Figure 11.1. Copyright © Open University Malaysia (OUM)

60. STUDY GUIDE CBMN4104 Multimedia Networking 59  There are several reasons to support this separate server design: – There are normally multiple sets of rights for a given content, since there are multiple types of users with different access requirements. – One set of rights can be applicable to multiple content items, especially with regard to subscription to a library of content. – Contents such as the live streaming media from networks may not reside on a user’s device; this would make the license delivery with content more difficult. 3. Encryption (a) The encryption process uses a cryptographic algorithm scrambling confidential data (called plaintext) to an unintelligible form (called ciphertext) so as to keep it safe from external “eyes” and thus ensure a high level of security. (b) In multimedia networking applications, the plaintext is normally referred as a block (say 128 bits) of compressed audio or video bitstream data. (c) There are two major types of encryption: one is symmetric encryption (secret key cryptography, SKC) and the other is asymmetric encryption (public key cryptography, PKC). Note: Ignore mathematical formula and calculation in this topic. (i) Secret key cryptography (SKC)  Since only a single key is used for both encryption and decryption, secret key cryptography (SKC) is called symmetric encryption.  In SKC the sender uses the key to encrypt the plaintext and sends the ciphertext to the receiver. The receiver applies the same key to decrypt the cyphertext and recover the plaintext. (ii) Public key cryptography  One of the most challenging issues of secret key cryptography (SKC) is the key exchange (or key distribution) problem, i.e., the problem of securely transmitting keys to the users who need them. Copyright © Open University Malaysia (OUM)

61. STUDY GUIDE CBMN4104 Multimedia Networking 60  Diffie and Hellman in 1976 and independently Merkle in 1978 proposed a radically different approach, called public key cryptography (PKC), to resolve the key distribution problem in SKC.  Furthermore, PKC also resolves the problem of digital signature, which would provide the recipient of a purely digital electronic message with a way of demonstrating to other people that the message had come from a particular person, just as a written signature on a letter allows the recipient to trust the authenticity of the author and the content. 4. Digital Watermarking (a) Encryption is very effective in restricting access to data; however, once the encrypted data has been decrypted, encryption techniques cannot offer any protection at all. (b) Digital watermarking has thus been proposed as a complementary means (rather than a replacement) for content protection even after data has been decrypted or when using the existing multimedia appliances. (c) Digital watermarking is defined as the imperceptible insertion or embedding of information into multimedia data, i.e., the digital data is modified in an imperceptible way so as to avoid degradation of the host data or easy perceptual identification of the embedded information. (d) Digital watermarking, being a technique for embedding information into digital content, requires no decryption for playing back the digital content unless an attempt has been made to extract the embedded watermark. (e) This technique is not the same as the use of digital signatures, which encrypt a hashed file. (f) Watermarking applications (i) Identification of legal ownership (ii) Usage restriction (iii) Fingerprinting or content tracking (iv) Authenticity checking Copyright © Open University Malaysia (OUM)

62. STUDY GUIDE CBMN4104 Multimedia Networking 61 (g) Components of digital watermarking (i) Watermark embedding (ii) Watermark attack (iii) Watermark detection 5. MPEG-21 (a) MPEG-21, formally referred to as ISO/IEC 21000 multimedia framework, was thus proposed to address the secure and interoperability problem by standardizing interfaces and tools to facilitate the exchange of multimedia resources across heterogeneous devices, networks, and users. (b) More specifically, MPEG-21 standardizes the requisite elements for packaging, identifying, adapting, and processing these resources as well as managing their usage rights. (c) The basic unit of transaction in the MPEG-21 multimedia framework is the digital item (DI), which packages resources along with identifiers, metadata, licenses, and methods that enable interaction with the Dis. (d) Another key concept in the MPEG-21 multimedia framework is that of a user, which stands for any entity that interacts in the MPEG-21 environment or makes use of DIs. Such users include individuals, consumers, communities, organizations, corporations, consortia, and governments. (e) Digital item declaration (i) A digital item (DI) is defined as a structured digital object with a standard representation, identification, and metadata. (ii) The relationship between these resources and how they relate to the DI itself is expressed in a digital item declaration (DID), which is a document that specifies the makeup, structure, and organization of a DI. (iii) The MPEG-21 abstract model defines several constituent entities of a DID. These entities make up the backbone of a DID and are presented in a bottom-to-top approach for declaring digital items. Copyright © Open University Malaysia (OUM)

63. STUDY GUIDE CBMN4104 Multimedia Networking 62 (f) Digital item identification (i) The digital item identification (DII) part of MPEG-21 simply integrates existing identification schemes for various application space into the MPEG-21 framework, instead of creating a new identification scheme. (g) Intellectual property management and protection (IPMP) (ii) MPEG-21 Part 4 defines an interoperable framework for intellectual property management and protection (IPMP), which is a much more interoperable extension of MPEG-4 IPMP. (iii) The project includes standardized ways of retrieving IPMP tools from remote locations and exchanging messages between IPMP tools and between these tools and the terminal. (iv) It also addresses the authentication of IPMP tools and has provisions for integrating rights expressions according to the rights expression language (REL) and the rights data dictionary. (h) Digital item adaptation (DIA) (i) The standardization of metadata interfacing to adaptation is highly desired. The MPEG-21 digital item adaptation (DIA) was thus proposed, to achieve interoperable transparent access to distributed multimedia content by shielding users from network and terminal installation, management, and implementation issues. (i) Digital item processing (i) Digital item processing (DIP, ISO/IEC 21000-10) was proposed to incorporate more interoperable descriptions of programmability related to multimedia experience and to further allow interactions between a user (the term includes both human end users and machines, as defined in MPEG-21), a digital item (DI), and the other parts of MPEG-21, MPEG-21 Part 10. Copyright © Open University Malaysia (OUM)

64. STUDY GUIDE CBMN4104 Multimedia Networking 63 Study questions 1. An effective DRM system should have four requirements. Describe briefly the requirements. 2. Describe briefly the process of encryption and two major types of encryption. 3. What is meant by Digital Watermarking?. 4. What is the purpose of introducing MPEG-21 standard?. 5. Explain the RDD context model with the support of appropriate diagram. Frequently Asked Questions 1. Why DRM is important? DRM (digital rights management) is a way to protect digital files from copyright theft, and it can apply in several different circumstances. Many big companies are now using DRM (digital rights management) to protect their goods. So for example, you might buy a DVD of your favorite television program and find that you cannot make a copy of it. 2. Why we need data encryption? Intellectual property such as your employee and client information, product descriptions and business outline all qualify as invaluable information. These critical details should be secured at all times to ensure the integrity and confidentiality of your organization. This information is the core of your business and without it, you can't operate. If a criminal is able to access this data, there is no limit to the damage they can inflict. 3. Can I Remove a Watermark from a Picture? People generally put a watermark on a picture to acknowledge the creator and because they don't want the images to be altered or used without permission. A watermark is intentionally hard to remove. Graphic design, digital art, and photography are valuable skills and the artists should be recognized and compensated for their time and their work. If you want to use someone else's photos or images, you should purchase them or ask permission. Copyright © Open University Malaysia (OUM)

65. STUDY GUIDE CBMN4104 Multimedia Networking 64 4. Can you explain the difference between MPEG-1, MPEG-2, and MPEG-4 and what their possible uses are? (a) MPEG stands for Motion Picture Experts Group, the standards body made up of many large companies involved in technology and content creation in the video industry. (b) MPEG-1 compression is the oldest MPEG compression standard. At its highest quality level, MPEG-1 formatted video is compressed to approximately 1.5Mbps. MPEG-1 video is used for VCD video disks and is typically no better than VHS quality video. (c) MPEG-2 improves upon the MPEG-1 standard by increasing the data throughput a video file is capable of. Where MPEG-1 maxes out around 1.5Mbps, MPEG-2 is typically compressed to between 3.5Mbps and 6Mbps. MPEG-2 is the standard used by DVD and SVCD formats for encoding video, as well as the digital cable and satellite industries. (d) MPEG-4 compresses files in a range from 5Kbps to 10Mbps making it adaptable for delivering video to everything from cell phones to HD quality output. MPEG-4 compresses images by dealing with objects in the video, meaning it efficiently reuses image information without throwing away as much image data. Two of the more commonly available uses for MPEG-4 are DivX movies, widely found on p2p networks and the audio and video data being created through Apple's QuickTime format as MP4 video and AAC audio. Glossary of important terms 1. Digital Rights Management (DRM) (Pengurusan Hak-Hak Digital): DRM refers to a collection of systems used to protect the copyrights of electronic media. These include digital music and movies, as well as other data that is stored and transferred digitally. For example, the Apple iTunes Music Store uses a DRM system to limit the number of computers that songs can be played on. 2. Digital Asset Management (DAM) (Pengurusan Aset Digital): Digital asset management (DAM) consists of management tasks and decisions surrounding the ingestion, annotation, cataloguing, storage, retrieval and distribution of digital assets. Digital photographs, animations, videos and music are samples of media asset management (a sub- category of DAM). Copyright © Open University Malaysia (OUM)

66. STUDY GUIDE CBMN4104 Multimedia Networking 65 3. Cryptographic (cryptographic): Based on cryptography - is the science of information security. Cryptography includes techniques such as microdots, merging words with images, and other ways to hide information in storage or transit. 4. Intellectual property (harta intelektual): Intellectual property (IP) is a term referring to a number of distinct types of creations of the mind for which property rights are recognized - and the corresponding fields of law. Under intellectual property law, owners are granted certain exclusive rights to a variety of intangible assets, such as musical, literary, and artistic works; discoveries and inventions; and words, phrases, symbols, and designs. 5. Metadata (metadata): Metadata is commonly used to describe three aspects of digital documents and data. Copyright © Open University Malaysia (OUM)

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