Digital Video, MPEG and Associated Dgital Artifacts

  Introduction:

Reducing the amount of data needed to reproduce video saves storage space, increases access speed and is the only way to achieve motion video on digital computers. This document looks at digital video and explains some techniques of reducing the storage space needed. 

After looking at the Moving Pictures Experts Group (MPEG) standard, an objective look at some of its many competitors in the same market place is looked at. Some applications of digital video are presented.

Digital video is not without its problems, many of which are shared by all digital medium. These problems are discussed to some length. 

Compression and Digital Video

A great deal of research has gone into image and video compression and indeed it is quite difficult to invent something new in this field. A diagram showing the many compression techniques are shown in figure 2.1. The assumption is that the input is always a PCM digitised signal in colour components. The output of the compression process is a bitstream. Lets consider each technique briefly :

Figure 2.1 - Compression Techniques

Simple Compression Techniques Various techniques exist, including :

• Truncation Reduces data by reducing the number of bits per pixel. This suffers from contouring (resolution loss) but has the advantage that processing is simple.
• Colour Lookup Table (CLUT) Pixel values represent an index into a table of colours. The processing for this is non-trivial.
• Run length coding Blocks of repeated pixels are replaced with a pixel value and a count. This works well on images with blocks of single colours and can achieve a high compression ratio. However it not effective if images contain no repetitive areas.

Interpolative Techniques
This technique aims to send a subset of the pixels and use interpolation to reconstruct the intervening pixels. This technique is particularly useful for motion sequences, as certain frames are compressed by still compression ; the frames between these are compressed by doing an interpolation between the other frames and sending only the data needed to correct the interpolation.
Predictive Techniques
This relies on the fact that there is nearly always some redundancy between frames in a sequence. There are two common methods :

• DPCM (Differential Pulse Code Modulation) This operates at the pixel level and sends only the difference between successive pixels. Since there is likely to be very little difference between adjacent pixels we can encode the value into smaller data widths. This technique suffers from slope-overload which causes smearing at high contrast edges in an image.
• ADPCM (Adaptive DPCM) This tries to reduces the slope-overload by using smaller steps for the difference values.

Transform Coding Techniques
A transform is a process that converts data into an alternate form which is more convenient for some particular purpose. Transforms are ordinarily designed to be reversible. Useful transforms typically operate on large blocks of data and perform some complex calculations. In general transform coding becomes more useful with larger blocks. The Discrete Cosine Transform (DCT) is especially important for video compression.

The DCT The DCT is performed on a block of horizontally and vertically adjacent pixels (typically an 8 by 8 block of pixels). The outputs represent amplitudes of two dimensional spatial frequency components. These are called DCT coefficients. The coefficient for zero spatial frequency is called the DC coefficient and it is the average value of all the pixels in the block. The rest of the coefficients represent progressively higher horizontal and vertical spatial frequencies in the block.
Since adjacent pixel values tend to be similar or vary slowly from one to another, the DCT processing provides opportunity for compression by forcing most of the energy into lower spatial frequency components. In most cases, many of the higher frequency coefficients will have zero or new-zero values and therefore can be ignored.
The decoder performs the reverse process, but due to the transcendental nature of the DCT the reverse process can only be approximated and hence some loss takes place. The trick is to use some cunning methods of keeping coefficients so that the loss is minimally visible.

Statistical Coding (or Entropy Coding) This takes advantage of the statistical distribution of the pixel values. Some data values can occur more frequently then others and therefore we can set up a coding technique that use less bits for these values. One widely used form of this coding is Huffman encoding. This technique has the overhead that a syntax has to be pre-defined or sent for the decoder to work.

Need for Compression

Compression is needed to simply reduce the amount of space that video would otherwise take to store. There are many factors to consider when choosing a compression technique :

• Real-Time / Non-Real-Time This refers to capturing, compressing, decompressing and playing back all in real time with no delays. The requirement is to have sufficient frame rate (frames per second)to make sure that there is no jerky motion.
• Symmetrical / Asymmetrical Symmetrical implies capturing, storing, and playback at the same rate. Asymmetrical uses more time to compress and hence may have an advantage for playback speed.
• Compression Ratio The compression ratio relates the numerical representation of the original video in comparison to the compressed video. Generally the higher the compression ratio the poorer the video quality.
• Lossless / Lossy The loss factor determines whether there is a loss of quality between the original image and the image after it has been compressed and played back (decompressed). Again this is affected by the amount of compression.
• Inter-frame / Intra-frame Inter-frame compresses each frame of the sequence as a discrete picture. Intra-frame is a more powerful method which uses a predictive technique.

Compared to traditional analogue video, digital video provides the following advantages :

• There is no copy from copy loss
• Picture does not get fuzzy
• Signal-to-Noise ratio goes down slowly
• Editing, storage and retrieval is simpler, quicker and cheaper

When dealing with digital video a number of points have to be kept in mind :

• Frame Rate How many frames are displayed per second, also the method of frame display : progressive - each line of video is shown one after the other; interlaced - odd lines (fields) are shown then the even fields.
• Colour Resolution This refers to the number of colours displayed at any one time. There are also various colour formats : RGB and YUV are two common formats. Colour depth is the maximum number of colours displayed.
• Spatial Resolution This deals with the size of the picture.
• Image quality Does the final sequence match the requirements of the application. 
  

  Applications of Digital Video

  Digital video has many and varied applications, here we briefly look at some applications. The number of applications is growing rapidly as the need for compression and digital transmission grows.
• High Definition Television (HDTV)

HDTV is defined as having twice the horizontal and vertical resolution of conventional television, a 16:9 picture ratio and at least 24 frames per second. Using this definition, HDTV has approximately double the number of lines of current broadcast television. This combined with the resolution increase means that 6 times more bandwidth is needed for transmission. This is an ideal place for compression, as this will reduce the data rate and hence the bandwidth.

• Presentations

This is the number one application for digital video. This application includes video kiosks, training, corporate presentations and video libraries. The advantages of using digital video (and particularly MPEG) are :

• Footage can be updated or changed with ease
• MPEG has network capabilities which means the presentation can be distributed
• Digital video adds a whole new dimension to presentation. Moving pictures can be incorporated into computer presentations with ease.

Multimedia used in student training has also been shown to improve achievement by an average of 38 percent.

• Digital Video Database:

Since digital video clips are stored in files, they can be easily integrated into many databases just like text or numeric fields. For example, a travel agency can keep video clips of their holiday locations as well as more mundane information and really show what it is like to go for a holiday in a particular resort.

references:

www.wiki.org

www.ic.ac.uk

www.mit.edu

Akash Mondal

MM09b001

ATM- Automated Teller Machine

Science and technology are making rapid progress in the world we live in – the pace at which new inventions are made is almost mind boggling. So are the changes that they bring in their wake. Technology has certainly made life easier for man. Of course we also hear the constant debate on the pros and cons of these inventions –whether they are all indeed beneficial to mankind, or are fraught with inherent dangers. But the fact is that we cannot imagine life in the world today without computers, the Internet, mobile phones, satellites and of course the ubiquitous ATMs –automated teller machines. These friendly neighbourhood fixtures have become a mandatory convenience for millions of users and brought in a revolution in the sector of banking.

The Automated Teller Machine, also known as the Automated Banking Machine is a computerised telecommunication device providing access to all banking transactions, in public spaces such as shopping centres, airports, malls, railway stations, grocery stores, petrol/gas stations, and in or near banks, everywhere in the world. It eliminates the need to travel to a bank and seek the services of a cashier, clerk or teller. Most ATMs are connected to interbank networks. They are client-friendly devices, easy to operate using a keypad and touch-screen. Bank accounts can be accessed, cash withdrawals made, and account balances checked at an ATM. The customer is identified by the machine when he or she inserts a plastic ATM card with a magnetic stripe or chip which contains a unique card number. Authentication is provided by the customer by typing a Personal Identification Number.

The first ATM or ‘’hole-in-the wall’’ machine was invented and patented in 1939 by an American Luther Simjian. James Goodfellow of Scotland created and patented the first modern ATM in 1966. The first ATM to use a card with a magnetic strip was patented in 1977. Even though the machines came into existence rather early, they became commonplace and a part of mainstream banking only in the mid to late 1980s.
ATMs are no doubt immensely popular with the public because of the convenience they offer- easy accessibility for making cash withdrawals for everyday requirements, in emergencies or at odd hours and on holidays. It is also a time- saving facility, doing away with the need to physically make a trip to a bank. However it is not without its share of security risks. It’s very purpose of providing easy access to cash also makes it vulnerable to attacks of different sorts. The three basic types of such attacks are –
1] Attempt to steal a customer’s ATM card
2] Attempt to gather confidential information of the customer from the computer and network.
3] Physical break- in or attacks on the ATM.

ATM cards are often lost or misplaced by customers, sometimes even left behind at the location of the ATM. This definitely poses a big security risk if the card falls into the wrong hands. To gather confidential information, thieves set up ‘skimmers’ in the cash machine that captures the magnetic stripe and keypad information of customers. ‘Lebanese loop’- so called because it was first used by Lebanese criminals, is a common cash dispenser fraud. The cash machine is tampered with and the card is often not returned to the customer. It is later removed by the thieves. Such ‘skimmer’ devices have replaced the traditional, physical robbery attempts which posed the biggest security challenge in the earlier decades of the twentieth century. Security guards at ATMs and hidden security cameras have proved to be effective in countering the menace.

However, as these machines have grown to become an integral part of our daily lives, banks have started taking advantage of this by indulging in demand-based price discrimination — the banks realize that people have fewer alternatives (no bank tellers available) at certain times of the day, and price accordingly. For example,in Japan, there is an extra charge of ¥100 (about $1.20) if you withdraw cash from an ATM during evenings or on weekends.The only possible cost-based justification for this price discrimination in ATM usage is that workers might have to make sure the machines don’t run out of cash at those times, and their labor requires overtime pay. But surely the same thing is true in the U.S. and Europe, and yet we don’t see this ATM surcharge there.


ATMs also depersonalise service, doing away with all human contact. In the past banking was a personalised, relationship oriented service and depended on person-to-person contact. The human element has been lost in such transactions which has probably had a negative impact on customer-satisfaction levels, especially when things go wrong.

Recent research in the United Kingdom has also brought to light the fact that ATMs are a health hazard as well, the keypads and touch screens teeming with dangerous bacteria, contaminated by the fingers of several hundred users on any given day. The machines reportedly carry the same germs as public toilets.


Like all the products of modern technology, the ATM too poses challenges. Man will find solutions to them, again with the help of science and technology.

Govind Menon
CH09B022

References:
1.www.ehow.com
2.The Daily Mail Website
3.The New York Times Website

How Internet addiction is affecting lives

   The Internet – millions of people rely on it for everyday tasks. From paying bills to the tasks of the workplace, it seems that internet is integrating into our lives in such a way as to be an essential ingredient. Companies now opt to have customers keep track of accounts and updates via the internet, not leaving a great deal of alternatives in some cases, leaving internet as a necessity.
Just the Facts
      Online computer use is widespread and growing. Current estimates indicate that 19.6 billion people are online worldwide, and that number is increasing at the rate of 28% a year . It was also reported that many children uses a computer at school, and school was the most common place for children to access the Internet. With these staggering numbers, there is little doubt as to the proliferation and popularity of Internet use.

Graph of Internet users per 100 inhabitants between 1997 and 2007 by International Telecommunication Union

But when is the line crossed between average use and addiction?


Few would dispute the idea that internet has transformed economic and social life.at the same time, however, the internet’s impact on interpersonal communication and sociability remains a source of heated debate one group of researchers conclude that that platforms such as Facebook and email merely act to schedule their social life in a more structured way, saving their time  i.e. the internet leads to more and better social relationships by creating additional medium of communication with friends and family, and by enabling the creation of new relationships through internet interactions.in contrast, other researchers find internet use to be socially isolating, because time on internet replaces other social activities and face-to-face interactions.
The internet can be viewed as a fantastic opportunity to reach out and connect globally, share ideas and make positive change. The availability of information, products and ideas is amazing and unrivalled.
It was found that teenagers are much heavier Internet users than their parents. While adults tend to use the Internet as part of their jobs and to get employment-related information, teenagers were more likely to use the Internet to play games, to listen to music, and to meet new people. This particular appeal has caused further concern among educators such as Michael A. Weinstein, professor of Political Science at Purdue University. In a somewhat Archie Bunkerian way of expression, he believes Internet users will "lose the savvy and skills and patience to conduct social relations in the corporeal world," and that the Internet will intensify the negative effect television has already had on our social skills. Taking his view then, it is assumed that we are encouraging our children to become social nitwits!

While not yet defined as a true addiction, many are suffering the consequences of obsession with the online world, unable to control their use. From gaming to sexual and emotional relationships, the internet is taking over lives. More and more people will be confronted with consequences such as divorce and physical symptoms which will force them to seek both medical and psychological treatment. Online marital infidelity can lead to divorce and harm personal relationships. 
An article published in Perspectives in Psychiatric Care states, “The Internet has properties that for some individuals promote addictive behaviours and pseudo-intimate interpersonal relationships”. “Some physical symptoms include "cyber shakes," dry eyes, carpal tunnel syndrome and headaches. "A focus on the computer and lack of attention to daily reality is indicative of poor judgment and results on lowered grades in school, job loss, and indebtedness.”

Conclusion:

The Internet is most assuredly alluring with its research and communicative capacities. But overall, technology can be considered a positive enhancement to growth. This feature is eloquently affirmed by author Don Tapscott (1999):

“…When kids are online, they're reading, thinking, analysing, criticizing and authenticating - composing their thoughts. Kids use computers for activities that go hand-in-hand with our understanding of what constitutes a traditional childhood. They use the technology to play, learn, communicate and form relationships as children always have. Development is enhanced in an interactive world."

The Impact of Digital Audio

Digital audio is the result of sound reproduction, using pulse-code modulation and digital signals. This includes analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), storage, and transmission.

Digitalization of music is causing threats in economical and cultural aspects and the contributing to globalization in the issue. Digital technologies have become a major attraction for an improved social life and also in the communication and technology arena. Digital technologies have also become one of the most sorts after technology of music among the world population and any other sector in the world today.

"All too often technology facilitates laziness, blunts sensibilities and distracts people into a futile and sterile quest after perfection." Rikky Rooksby

The music industry recognizes the value of two distinct disciplines,

1- writing a great song

2- 2- making a great record

It’s ironic that digital has slowed the creative process by offering so many additional possibilities. He who commands these technologies is empowered creatively.

A good music technology can be characterized as that which facilitates creativity by freeing the music maker from uncreative tasks and suggests and allows additional ways of creating .However, it may also impose new limitations that demand and inspire the application of creative solutions. Undoubtedly the implementation of new technology is widening the gap between the recording and live performance of a composition and redefining the roles of producer and engineer.

The music industry is estimated to be worth 35 billion US dollars in the whole world this is according to IFPI (2004). Music is playing a significant Role in lives of many people; they frequently spend quite a lot of hours per day listening to recorded music. A variation in the manner music is listened to, is most likely to have an effect on many people.

Music sales over time

First let us examine global sales of recorded music in diverse formats between the year1991 and 2003. The combined market was comparatively even from 1991 to1999 (increase in CDs compensating reduction in other recording formats) however the industry has witnessed a sharp reduction starting from the year, 2000 in terms of units and also dollar amounts. Thus, it is certainly tempting for one to attribute the CD sales decline to the accessibility of free music files found on the internet. Apparently, recorded music sales showed stabilization through the second part of 2003, after a decrease of as up to 12% and sales started to show an increase in the last quarter of 2003 to attain an annual fall of 6%. The creation of new file formats for example DVD audio VCD and Super Audio CD is evidently assisting the industry.

Globalization and music

Globalization can be defined as international integration; it could be described further as a process through which the citizens of the world are integrated into one society. This process combines economic, socio-cultural, technological, and political aspects. Globalization involves the interaction of people from different cultures, societies, and diverse background. The present globalization effects such as free trade and fast flow of information has presented different challenges to the music industry, apart from increasing the flow of music across countries it has technology has made it possible more people to be able to access music in different formats.

Conclusion

Digital technology has made it possible for people to be able to download music freely from the internet, another artifact. Today record companies make claims that increasing internet music piracy could lead to the collapse of the industry. However, music has continued to play important role in globalization through the creation of music culture which has continued to integrate people around the world. The industry players have realized that they cannot control piracy and have thus began to offer licenses and rights to competitors in order to allow these companies offer their music to people who through the internet. Nonetheless, digital technology has created many opportunities for the industry and the consumers. Hence we can conclude that, the technological artifacts are rising in the current world and after a certain period of time seems supplement each other at the economic perspective.

A.PRAVEEN KUMAR,

CH09B003

Mobile Phone as a Digital Artifact

Since the 1990s , mobile phones have proliferated at an astonishing rate in developing countries.South Asia and Sub-Saharan Africa,two of the world's poorest and remotest regions of the world, have been catching up rapidly in mobile access. Since mobile phones became available in 1994, subscriptions increased at a compound annual growth rate of 95 percent. This has made India the fastest growig market in the world with nearly 6 million additional mobile phone subscriptions per month. The number of mobile phones per 100 inhabitants in India increased from 0.4 in 2000 to 20 by 2007, and surpassed landline phones by 2004 (ITU 2010).

Mobile phones have a phenomenal impact on users world-wide, so much so that they have become indispensable. Their ingenuity was an integral part since their inception. The cellular phone business is today a multi-billion dollar industry with mind boggling profit margins. Little did we know when telephones were first introduced, that they were set to embark on a revolution like never before? Although they made their foray a decade ago, the impact they have on the masses is incredible. It gets you thinking, if it is the technology or the resourcefulness which makes them so indispensable.

There are many brands available in India and most popular among them are Nokia, Samsung, Motorola and LG mobiles. This industry is immensely popular and despite being a third world nation, India is one of the leading mobile phone users in the world.


How - The Function:
It may mean different things to different people. Technically they are two way radios, quite similar to the time honored walkie-talkies. Mobiles are much advanced and diligent as compared to the earlier devices. The basic principle involved, is the conversion of sound waves into radio waves and vice versa.


Impact: 
Phones have impacted our lives to such an extent that it is not merely restricted to the elite but is also one of the most common gadgets owned by almost every individual. So what has added to their rising popularity? Is it the standard voice function or much more than that? The voice function is only one of the enticing features and mobile phones have features like texting, voice calls, internet browsing, music playback, multimedia features and a host of other user friendly options embedded in the handset which adds to its durability. Besides, camcorders, ring tones, games, radio, push to talk (PTT), infrared and Bluetooth connectivity are the features that add to their rising popularity.


In Business: 
Advancement in technology has made possible, the usage in fields like business and internet marketing. Smartphones are the most ideal forms of business phones which not only ease communication but also enhance business communication and work related tasks and transactions. Scheduling interviews, appointments, sending e-mails, developing business contacts and having access to work related documents and contacts, while you are on the go are a few aspects of business phones that add to their permanence. Palm Treo smart phones are business handsets with simple user interface which adds to their appeal. Smartphones, windows mobiles and blackberry, rule the roost and are amongst the best known business phones.


In Communication:
The most basic phones which fall in the highly affordable bracket are a boon for communication. Not only are they handy and affordable but their versatility makes them all the more appealing. Many service providers offer user friendly options that make communication with friends and colleague's all the more simple and hassle free.


For The Youth:
The popularity of social networking is on a rise and what better way to make mobiles more appealing to the younger generation than to integrate social networking options in a handset. Advanced mobile phones from Nokia, Samsung and Sony Ericsson, have an edge over the rest of the handsets as they are well equipped for social networking in addition to other features like MP3s, memo recording, multimedia features, games and connectivity options.
Its popularity is on a constant rise and in most countries; cellular phones outnumber land-line phones, and in some markets from Japan and South Korea, there are customers as young as 6 and 7.


In Our Society: 
Mobile phones have carved a prominent niche as well, more so in recent times, with the ever-growing importance for effective communication. A busy schedule may interfere with good communication but technology has solved that problem for most of us, and interacting with friends is so much easier with the recent developments in the telecommunication industry. Traditional modes of communication however, have taken a backseat with technological progress.

Mobile phones have impacted the present era phenomenally and handsets that offer entertainment, internet options, email facility and social networking facilities are a boon for mobile technology aficionados. The internet enabled services incorporated in mobile phones have helped mobile phones replace PDA, Computer, laptop, tablet and other high tech gadgets. Camera phones have, to a certain extent, replaced the mid range digital cameras and with progress in technology; they are bound to find a more prominent place. Technology never tires of up gradation which is a positive aspect, as mobile phones and the embedded technologies will continue to improve in the years to come, adding to the rising popularity of cellular phones.


YASIR C.M
CS09B035

impact of digital camera on society

The world of today has become nearly completely digital.  More and more, people are turning to digital technologies to help them in their daily lives.  Digital music, videos, and perhaps the most commonly-used digital technology, cameras, have more than replaced the ways in which we used to use these technologies in our lives.  Digital cameras, especially, have exploded into the mainstream of consumers’ lives, and have easily become the preferred choice for photography.  These cameras have had a dramatic effect on society on the way photography is done today, for a number of reasons.

            A recent survey was conducted by The Digital Journalist asking its readers the impact that digital had in their lives.  Out of all that responded to the survey, not one of the readers longed to return to film.  All of them preferred digital for their photojournalism.  In university of Texas ,the course on Advanced Photojournalism is taught entirely on digital.  The wet labs are in the process of being shut down.  This means that students who emerge into the profession take digital as a matter of course.”   some interesting findings from the survey was that they  expected that most readers would rank speed as the number one effect that digital has had on their work, but in fact, only 20% of the respondents actually did.  It also reported that, “A far larger number wrote that digital has actually stimulated their ability to experiment.”  According to some people , they find that they are able to shoot more varied pictures and try different techniques since they are  able to monitor their shots as soon as they make them.  This happens to be one of the biggest reasons for why people are switching to digital cameras - the ability to know what you have before you leave, so that if you don't like what you have you can usually stay at the scene until you get the something you like, by clicking the same seen over and over again until we are satisfied.  This feature of digital cameras wipes out the possibility that one might go back to the darkroom and find out that they missed something important. With this very cheap technology  people tend to take more photographs thus catching almost every  happy moments of their life which can be cherished later .

            However, there is also negativity surrounding the use of digital cameras.  Jayne West writes in an article for BBC News that digital photos are causing us to “lose the past.”  What he means by this is that we lose the sequence of images that captures the events leading up to whatever image is chosen for publication. When you shoot traditional stills, you shoot rolls of film and there are a series of pictures taken while you wait for the news to happen.  You shoot everything in the possibility that one of those shots may be the news story.  With digital capture, the photographer arrives and shoots his images in the same way.  But, because of storage issues on the camera, he will have to delete some of those images as he goes along.  A whole collection of material, that may well be far more interesting in the months and years after the even than in the hard news context, is being lost at that stage  In short, West is making the claim that, because of the digital capabilities and limits, many of the photographs are lost, thus losing a possible alternative viewpoint in the process.

            Jane Wakefield offers another positive opinion for the use of digital cameras in an article titled, “Digital Cameras Capture Imagination,” also published by BBC News. Digital photography gives you the ability to decide what you want to print and the freedom to manipulate images, unlike going to traditional photo print shops where you might get just four decent images back.  A great example of the capabilities of using digital photography is that, for couples staying away from their parents , for the price of an e-mail, the first proud picture of your newborn infant can be sent to grandparents the other side of the globe in an instant.”

One more interesting effect of ditalization of photography is that we can edit the image according to our requirements. This has both negative and positive effects , positive is that  we can use our creativity and modify the image this has become a career nowadays and the negative side is that due to the modifications one can defame famous people ,there are lots of scams involving stars and ministers ,who knows they are real or morphed or modified images . This can be used as means to take revenge even .

There are definitely pros and cons associated with digital cameras, but this has been the norm for new technologies for years and will continue to be.  The ultimate decision to use digital or film is left up to the consumers, as it should be.  People must evaluate how they will use their camera, and make a decision based on that.
                                                                                                          prajul bagri
                                                                                                          ch09b045