Sixty years ago, families in USA used to watch television programs in 14” CRT (Cathode Ray Tube) screens. Today, an Indian teenager waiting for a bus in a bus stop uses his 5” smartphone and access video through Internet. Digitized colour video signals are streamed to an individual. Earlier analogue B&W (Black and White) Television (TV) signals were broadcasted to all the viewers. In the span of six decades lot of changes have occurred. The video resolution has increased; use of digitized video signals (colour) became the norm; wide use of LED and LCD screens; wide range of screens (4” to 80”). In the video distribution front, Internet is competing with traditional TV broadcasting stations. The way viewers consume the video content has changed too. The shift is from ‘fixed-time and family-centred’ to ‘any-time and individual-centred.’ Half a century ago if any one prophesied that “One day people will have telephone at their hands and using that telephone they will watch TV,” he/she would be branded as lunatic. Today we use smart-phone to talk, run few apps (applications) as well as to watch videos from YouTube.
Earlier TV sets were connected to roof top Yagi-Uda antenna using flat ribbon cable. Unlike FM antenna (i.e. dipole antenna) Yagi-Uda antenna is a directional antenna. So, it has to be positioned towards the direction of TV signal broadcasting station. Channel changing has to be carried out by changing the position of the knob in the TV. Wired or wireless remote control was not available. Receiving two TV channels is a luxury.
Today we don’t need dedicated system to see video. We use smartphone as a TV and Internet as a broadcasting station. In one sense, smartphone is a poor cousin of multimedia computer (both in size and computing power) with an inbuilt communication transceiver (transmitter and receiver). Smartphone users access video servers via 3G (third generation) cellular networks. Alternatively Wi-Fi may be used by smartphone users to connect to the Internet. It is shown in dotted line in the Figure 1.
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| Fig. 1. Broadcast vs. Access |
In the inception every gadget will have a well defined purpose. The technologies that are used to build the appliance will dictate the size, shape, weight, cost and user interaction. Any advancement in technology or change in market conditions will have a direct impact on the gadget. Due to this reduction in shape, size and cost is expected. Some times the gadgets become multi-functional. Basically computing machines were invented to crunch numbers. They are expected to collect data, process it and provide an output. Internet was designed to transfer data from one computer to another. Telephone is meant for interactive communication between two persons. Television is expected to provide “visual information” to its viewers. Today computers and Internet have become multi-functional. They have ushered a new way of video delivery and become contenders for traditional TV broadcasting. This kind of unexpected twists and turns are expected in mystery novels only. So, enjoy this series of posts.
Computers
Number crunching i.e. performing arithmetic operations was tedious to humans. So, tables (for example Fahrenheit to Centigrade conversion) were prepared beforehand and used extensively. Mechanical computers were developed to speed up the table preparation work. But they were not very successful. Later electronics was used to build computers. First vacuum tubes were used as processing elements in the computers. Later transistors were used. They used less power and size and in turn cost of computer started falling. Use of electronic technologies (Integrated Circuits, Very Large Scale Integration) improved computer performance as well as reduced the cost of production. Soon computer became affordable to the mass. But requirements like computer literacy and programming skills became an impediment to acquire computer by public.
Computer Manufacturers and Operating System (OS) designers revamped the computer and introduced Multimedia Personal Computer (MPC) to expand the market. It had Graphical User Interface (GUI) which facilitated user interaction. It was able to operate as an audio player, video player, music synthesizer, gaming console and educational tool. Thus computer became multi-functional.
Even though smartphone functions like a MPC its’ origin is connected to mobile or cell phone. Let us see evolution of smartphone in upcoming post.
Evolution of Internet
After the World War II, Russia and United States of America (USA) emerged as super powers. Fear of another war was looming and ‘defence preparedness’ was high on their agenda. As American armed forces used computers extensively, a seamless connection between the army headquarters and the military bases across the country became a necessity. For this Defense Advanced Research Projects Agency (DARPA) of US army developed data network called ‘ARPANET.’ It used packet switched network to transfer data instead of traditional circuit switching used in telephones. It introduced TCP/IP protocol. TCP/IP stands for Transmission Control Protocol/ Internet Protocol. It became the defacto standard for packet communication.
Initially computer programmers (mostly University students) were forming a small virtual community and posting the contents via Bulletin Board Services (BBS). Topic of the discussion was mainly on computer related things. Tim burners Lee a programmer working for CERN laboratory developed World Wide Web (WWW). He developed the idea of ‘hypertext.’ This made linking of documents that are housed in various computers became child’s play. This was developed to assist collaborative research work. Slowly people started posting their topics-of-interest. This non-technical content pulled lot of users into the Web (pun intended). As Website increased rapidly remembering the Website name became tedious. ‘Website directories’ were developed (ex. dmoz.org) to assist the users. Websites were listed in categories like yellow pages of telephone. To overcome the shortcomings of Website directory, search engine were developed. Google emerged as the best engine and it helped to get any information across the Internet. In the meanwhile apart from text, audio and images were stored in the Internet. Thus Internet moved from “Scientists’ Tool” to “People Media.”
Earlier computers were connected by dedicated data networks. Computers that are far away are connected by telephone networks. Connection between Internet Service Provider (ISP) and user was through telephone network. They used dial-up network and it reached a speed of 38 Kbps (Max. 56 Kbps). Improvement in technology made 1.5 Mbps a possibility. This speed and above are called as broadband speed.
Digitized videos are stored in the Internet. Video consume lot of storage space and are delay sensitive. If a client (user) access a movie from a video server (youtube, dailymotion, etc) then duration of connection will be for 90 minutes. Thus video content transfer requires huge bandwidth and long duration. Videos are not fully downloaded and played. Instead a small portion of video (say 60 seconds) is downloaded first and that portion is played. In the mean time next portion or chunk is downloaded (technical term buffered). This process continues till end of the video. This procedure is called Video streaming. Today all computers are multimedia enabled with broadband facility. So, accessing video content is not a big issue.
Few benefits exist for viewing video in computer. First we can choose a video from the huge pool of videos. We need not pay for viewing the content. Advertisers who sponsor the video servers are able to target their audience properly.
In this post we have discussed about video streaming through Internet to a multimedia PC. Upcoming posts will deal about video streaming to smart phone and broadcasting to Television.
Note
This series of posts are meant to give an idea about video streaming. Thus content accuracy cannot be assured. So, take this article for guidance and don’t use it as a reference.
