Internet originated from a military research project sponsored by Department of Defense's (DoD) Advanced Research Projects Agency (ARPA) in the late 60s and the 70s. The original ARPANET included military, university and research sites, and a main goal of the project was to investigate how to build networks that would withstand partial outages and still function [1] [2].
In the early 80s, a new set of protocols were developed for use on the
ARPANET, the TCP/IP protocol suite (as described in
section 3.1 on
page 
). The TCP/IP protocol suite is not
bound to any particular type of hardware, making it possible to
connect any computer to the network, as long as an implementation of
the protocols is available. Development of protocols and other
standards for the Internet is an open effort; people all over the
world participate in extending the functionality of the net,
communicating using the Internet itself. Standards are published as
``Request for Comments'' (RFC) -documents, where the somewhat
misleading name is kept for historical reasons [3].
During the last years, the Internet has grown rapidly. Since 1988, the number of hosts connected has doubled each year [4]. In 1990, the first commercial provider of dial-up Internet access got online, opening the network to the non-research community [5].
Over the years, information has been transferred across the Internet using a plethora of different protocols, all requiring separate programs implementing the protocol in question. Also, lots of information have been available as files in local filesystems. Access to several computers, possibly running different operating systems, may have been necessary to reach the information.
Making all available information more accessible has probably been in
the minds of several people, but in 1989 and 1990 Tom
Berners-Lee of
CERN proposed the initiation of a
project that would revolutionize the way we access the world of
information on the Internet [6]. The World Wide
Web
was
born [7].
Hypertext documents play a central part in the World Wide Web concept. Aided by a browser program, users may view documents (popularly named ``pages'') in which highlighted parts ``links'' to other documents anywhere on the Internet. Pages may contain various media types, most commonly text and images, but also sound, video and 3D graphics, limited only by the capabilities of the browsers.
To many people, WWW is the Internet. Nowadays, Internet service providers (ISP) typically equip their new users with a Web browser, and possibly a separate E-mail program in addition to the dial-up software. Non-technical users will depend on these programs, never exploring the parts of the Internet that cannot be reached by their aid. Also Internet veterans now seem to find the WWW a valuable source of easily searchable information, starting a Web browser along with other useful programs at login time.
The increased use of Web browsing programs, makes it a goal to include more of the Internet under the World Wide Web, making new services just a ``mouseclick'' or a ``keypress'' away for both novice and advanced users.
Live video is an area that has begun emerging on the Web, and it
is relatively new on the Internet itself. An important reason for a
late introduction, is that the bandwidth of the lines connecting the
Internet networks together, has been too low for transferring video at
acceptable rates. Today, aided by compression technologies that
preserve reasonable quality even at excessive levels of compression,
combined with higher available bandwidths, the Internet has become a
promising ground for transferring and sharing live images.
There are several applications for live video on the Internet. Much research is taking place to develop software, hardware and standards for video conferencing, in which two or more people may participate in a meeting or a class from possibly distant locations on the globe. Members of a conference may be seated in front of workstations, or they may be located in special conference rooms, equipped with cameras and microphones. In addition to video and audio, software exists to let the participants use a shared whiteboard for illustrations.
An application similar to video conferencing, is video telephony, which has been available on the regular phone network for some years. Enabling telephony, with or without video, on the Internet, will drastically reduce the costs of long distance calls for end users, as the price will be limited by the connection to the local ISP.
Television and cinema play important roles in entertaining the 20th century human. A drawback with these media, is that deciding when a certain movie or program is viewed, is not left to the viewer, but rather to the provider. The idea behind video on demand systems, is to hand this control to the viewer. In the future, the Internet may be the transport medium of such services.
The aim of this report is to describe existing and evolving methods for transferring miscellaneous kinds of video on the Internet, and outline ideas on how to incorporate these methods into the World Wide Web, making the video accessible from current or future Web browsers. Although a natural companion to video in the above mentioned applications is sound, this report does not focus on that topic.
Chapter 2 gives an overview of video representation; what a video stream is, and how compression is done. The chapter includes an overview of the compression in JPEG, a standard for still images, in addition to brief explanations of H.261 and MPEG, two standards for video representation.
In chapter 3, methods for video transfer and synchronization on the Internet, including multicasting and the MBone, is described. A short introduction to Internet networking is given.
The next chapter describes the current possibilities and future extensions to allow inclusion of video in Web browsers.
Chapter 5 documents the implementation of a simple program that allows playing MPEG videos inside a popular browser.
Chapter 6 describes the implementation of a Java applet and accompaniment C-programs for receiving video from a remote, computer-mounted camera.
The final chapter contains a discussion and a conclusion.
There are six appendixes: The first gives an introduction to general data compression, to aid in the understanding of chapter 2. The three next contain the source code of the Java applet and C-programs described in chapter 6. The next appendix describes how to recode an MPEG-file to JPEG and GIF, while the last appendix contains a collection of Internet resources with relevance in our context.