tesy of Intel). Figure 15-2. Personal Conferencing (courtesy of Polycom) Figure 15-3. Personal Conferencing (courtesy of Tandberg). Figure 18-1. Direct Media Broadcast TV Phone. Samsung SCH-B100 Figure Appendix B-1. Forward Prediction (Michel Bayard) Figure Appendix B-2. Bi-Directional Interpolated Coding (Michel Bayard). Figure Appendix B-3. MPEG-2 Levels Figure Appendix B-4. MPEG-2 Profiles Figure Appendix B-5. MPEG-4 Tools Figure Appendix B-6. MPEG-4 Object Types xviii PART ONE VIDEO COMMUNICATION: TERMS, CONCEPTS AND APPLICATIONS This Page Intentionally Left Blank AN INTRODUCTION TO VIDEO COMMUNICATIONS Vision is the art of seeing things invisible. Jonathan Swift WHAT Is VIDEO COMMUNICATION? hat is video communication? To define the subject, we examine the (unfairly stigmatized) term that we used in the title of the first three editions of this book, videoconferencing. The term videoconferencing is rooted in two Latin words: videre, or "I see," and conferre, or "to bring together." Videoconferencing (or video communication) enables people to share visual information to overcome distance as a barrier to collaborative work. The combination of the words videre and audio (the latter of which, in turn, stems from the Latin audire, or "to hear") gives us the word video. We define video as a system that records and transmits visual information by conveying that information with electrical (or electronic) signals. Although the term video, in its strictest sense, refers only to images, common vernacular reflects the common synchronization of audio with these images. Video communication is real-time exchange of digitized video images and sounds (ideas and information) between conference participants at two or more separate sites. To meet our definition of video communication, an exchange must be interactive; it must be two-way. Transferred images may include pictures of participants, but may also include material as diverse as video clips, still pictures (e.g., product photos, diagrams, charts, graphics, data files, ap