This document introduces multimedia communications and the different types of media that can be transferred over a network, including text, images, audio, and video. It describes how continuous media like audio and video are real-time streams, while block-mode media like text and images can be downloaded. Example applications of multimedia discussed include interpersonal communications like videoconferencing, interactive applications on the internet like streaming media, and entertainment applications like video-on-demand and interactive television.

1. Multimedia Communications
Chapter 1
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2. Introduction
 “Multimedia” indicates that the information/data being
transferred over the network may be composed of one
or more of the following media types:
 Text
 Images
 Audio
 Video
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3. Multimedia Information Representation
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 Text: codeword
 Image: picture element (pixel)
 Audio and video: analog signals- the amplitude of the
speech, audio, or video signal vary continuously with time

4. Media Types
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 Continuous media: real-time media
 The information stream is generated by the source
continuously in a time-dependent way
 Streaming -The information stream is played out directly as it
is received
 Audio and video
 Constant bit rate (CBR) or a variable bit rate (VBR)
 Block-mode media
 A single block of information that is created in a time-
independent way
 Downloading
 Text and image

5. Multimedia Applications
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 Interpersonal communications
 Interactive applications over the Internet
 Entertainment applications

6. Interpersonal Communications
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 May involve speech, image, text, or video
 Speech only
 Teleconferencing
 VoIP (voice over IP)
 Speech and video
 Videoconferencing
 Video telephony
 Text, image, audio and video
 Multiparty video games

7. Interactive Applications over the Internet
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 Streaming
 Media stored at source transmitted to client
 Client playout begins before all data has arrived
 VCR-like functionality - client can pause, rewind, FF, push
slider bar

8. Entertainment Applications
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 Movie/video-on-demand
 A subscriber can initiate the showing of a movie selected from
a large library of movies at any time of the day or night
 High server throughput
 Interactive television
 Subscriber can actively respond to broadcast information
 Voting
 Participation in games
 Home shopping