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“Necessity is the mother of invention,” as the saying goes, and in this case, it surely was. A telecommuting faculty for a Midwest public university wanted to see a graduate student’s presentation as a guest speaker in an instructional technology course on campus. However, this faculty lives in another state, so that was impossible. As a daily user and enthusiast of Skype, she thought of using it to “attend” this presentation. Skype is a software-based Internet telephone and videophone service for making free, computerto-computer voice calls over the Internet Pcmag.com Encyclopedia (n.d.). to anyone else who is also using Skype. This article details the logistics involved in setting up and using Skype, with the assistance of an on-site faculty member, for attending a presentation in real-time at a distance.

The rapid spread of broadband always-on Internet is expected to change the way people will communicate and share content and experiences in the near future. This broadband connection can enhance the communication among family members and friends. It can also make it easy to share content and activities such as watching a movie together or listening to the same music while having a videophone chat. While using all these functions people want to be able to move freely through their home. The advance of portable devices fulfils this need for mobility. These portable devices can be used either in isolation or in co-operation with the stationary devices in the house. This paper describes the development and evaluation of two novel interaction concepts that support sociability and mobility for people inhabiting the connected home.

In the field of the multimedia applications, future standards as mpeg4 or mpeg7 allow new image content representation that goes far from the basic compression. This way, the objects of interest become entities that the user can manipulate. Nevertheless, the norm does not specify how objects have to be segmented, even if in some cases this is a complex task. In the framework of the European project m4m (mpeg fo(u)r Mobiles, Medea project Al 16), we have in charge the development of a demonstrator able to segment and track a speaker in videophone and videoconference applications.

In this paper, a joint CDMA/TDMA protocol has been proposed for integrated video-phone/voice/data traffic in personal communication networks (PCN). The videophone service is implemented according to H.261 standard. The concept of dynamic boundary is adopted in both code and time domains to meet the different requirements for videophone, voice and data traffic. Two mathematical analysis methods are adopted to evaluate the system performance. One is the traditional Markov analysis (TDMA), which is used to calculate the average videophone and voice call blocking probabilities. The other is Transient Fluid Analysis (TFA), which is adopted to evaluate the data delay and channel utilization performance. Results show that two dynamic boundaries can be adjusted to achieve the optimal system performance, and suggestions of how to adjust these boundaries are also given.

This research was designed to examine the task-media fit hypothesis, an extension to media richness theory that predicts the objective performance of various media for a number of task types. To examine this model, dyads communicating through face-to-face, videophone, telephone (i.e., audio-only communication), or synchronous computer-mediated communication worked in a laboratory experiment to address an intellective or negotiation task. The intellective task required that each dyad member effectively share factual information that each individual independently held. The negotiation task required that each dyad member effectively share preferences based on personal values and reach an agreement. The results of the study provide mixed support for the task-media fit hypothesis. In general, the results for the negotiation task largely supported the theory while the results for the intellective task did not support the theory. These results help to clarify limitations and provide extensions to the theory by demonstrating how variations in task processes and communication media act to mediate task performance. The implications of these results for future research and practice are discussed.

What lies behind that querulous mixture of success and failure called videotelephony? Why has its popularity not matched its market potential, almost every time the idea has been tested? Developments in technology now mean it is time for a fresh look at video communications. Can the troubled past of the videophone be laid to rest and what can be done to make its future more productive and less turbulent? How do you untangle a knotted knot?

In the domain of telecommunication applications, videophony, teleconferency, the representation and modelization of human face, and its expressions, knows an important development. In this paper, we present the basic principles of image sequences coding with main approaches and methods to lead to 3D model-based coding. Then, we introduce our 3D wire-frame model with which we have developed some compression and triangulated surface representation methods. An original approach to simulate and reproduce facial expressions with radial basis functions is also presented.

The US Vice President, Al Gore, in a speech on the information superhighway, suggested that it could be used to remotely control a nuclear reactor. We do not have enough confidence in computer software, hardware, or networks to attempt this experiment, but have instead built a Internet-accessible, remote-controlled model car that provides a race driver's view via a video camera mounted on the model car. The remote user can see live video from the car, and, using a mouse, control the speed and direction of the car. The challenge was to build a car that could be controlled by novice users in narrow corridors, and that would work not only with the full motion video that the car natively provides, but also with the limited size and frame rate video available over the Internet multicast backbone. We have built a car that has been driven from a site 50 miles away over a 56-kbps IP link using nv format video at as little as one frame per second and at as low as 100 × 100 pixels resolution. We also built hardware to control the car, using a slightly modified voice grade channel videophone. Our experience leads us to believe that it is now possible to put together readily available hardware and software components to build a cheap and effective telepresence.

Stopping to think becomes more important to do the harder that doing it becomes. Television is very popular and has been used with great success for many decades all over the world. Videotelephony is relatively unpopular, despite long study and some recent advances. It seems obvious to adopt the pictorial culture of television as a guide to the development of videotelephony. The authors believe this assumption is not only fundamentally mistaken, but is partly responsible for the unpopularity of videotelephony. To encourage broader and deeper debate, some artistic and engineering aspects of pictorial culture are discussed in exploring how videotelephony might be made more appealing. The implications for future telepresence systems and for new ‘virtual-world‘ multimedia environments are discussed and topics for further work suggested.

A personal communication system (PCS) transceiver is proposed and investigated. A 4.8 kbit/s transformed binary pulse excited (TBPE) linear predictive speech codec, embedded source sensitivity-matched binary Bose-Chaudhuri-Hocquenghem (BCH) block error correction codecs, non-coherent differentially coded 16-level quadrature amplitude modulation (16-QAM) modem and packet reservation multiple access (PRUA) are deployed. The 2.15 kBd transceiver requires a signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR) in excess of about 24 dB over Rayleigh-fading channels in order to support 1&11 nearly un-impaired voice conversations within a bandwidth of 30 kHz. Additionally, by reserving two PRMA time slots for video telephony, an 8.52 kbps videophone user can also be supported. Key words: Wireless multimedia communications, mobile voice and video telephony, transformed binary pulse excited speech coding, multilevel modulation, packet reservation multiple access, the Pan-American IS-54 mobile system.

This paper presents a motion analysis algorithm (MAA) and a hybrid coding method for contour image sequence compression. The contour image sequence consists of objects moving and rotating in a 3-D world with occlusion, shape, and size variations from frame to frame. The MAA separates the moving image sequence into several object-oriented subsequences (OOSs). In each OOS, the component is either stationary or moves smoothly, and the motion parameters can be easily estimated. The first and last frames of OOS are key frames, and the others are in-between frames. The key frames are unpredictable, and the entire frames need to be encoded. The in-between frames are compensable, and they are encoded by the motion parameter coding. The hybrid coder uses vectorgraph coding to remove spatial redundancy of the key frames and motion parameter coding to reduce the temporal redundancy of the OOSs. The motion parameters are encoded as combinations of 2-D translation, 2-D rotation, and scaling. There are many applications for contour image sequence compression. The cartoon image sequence (a sequence of line drawing sketches) and the high-frame-rate videophone for sign language transmission are good examples. Experiments show that our method encodes the contour image sequence at a very high compression ratio without losing intelligibility.