e0262 - multimedia communications prof. pallapa venkataram, electrical communication engineering,...

E0262 - Multimedia Communications

Prof. Pallapa Venkataram,Electrical Communication Engineering,

Indian Institute of Science, Bangalore – 560012, India

Multimedia Communications


Objectives● To know the networking evolution.

● To understand the network types.

● To discuss multimedia requirements in the

communication systems.

● To understand the basics of a multimedia

communication system.

● To illustrate multimedia networks.

● To know the Internet protocol suite for multimedia

communications.


Networking Infrastructure Evolution● Network deployment issues


Network Topologies Evolution● LAN

– Linear topology

– Star-wired

– Multisegment

– Backbone-connected

– Switched-backbonet

● WLAN

● WAN


Multimedia Requirements● To develop schemes for multi-access networks which

can provide performance guarantees.

● To develop a distribute route-selection strategy for

point-to-point networks.

● Real-time multimedia applications require

guaranteed performance communication services,

such as throughput, delay, delay jitter and loss rate.

● The characteristics of a source, such as peak and

average rate, are known at channel establishment

time.

● Channel parameters have to be predicted in live

continuous video sources.


Communication Service for Multimedia● Quality-of-service (QoS) support and group communication

system:

– establishment and take-down of appropriately congured

channels;

– negotiation of QOS levels between end-systems,

intermediate systems, and network control; and

– control of the agreed QOS level

● bandwidth, delay, delay jitter (variance), and reliability.

● Audio/Video groups can:

– have static or dynamic memberships during their lifetime,

– have centrally (typically sender) or distributedly (typically

receiver) controlled membership,

– consist of members with homogeneous or be heterogeneous

characteristics and requirements.


Multimedia Communication System● Communication system - A system or facility

capable of providing information transfer between

persons and equipment.

● CD-ROM: “Compact disk read-only memory.”

● Client-Server Model: A client makes a request and

a server fulfills that request.

● Composite Video: Analog video signals can be

broken down into parts such as luminance (Black &

White) and chrominance (color).


Multimedia File types

● Here are some examples of le types:

● Text Files: .txt, .doc, .rtf

● Audio Files: .au, .aif, .wav

● Graphic

files: .jpg, .gif, .tif, .bmp, .pict, .pcx

● Moving video files: .qt, .mov, .avi

● Animation: .fli, .flc


Multimedia Communication System● Interactive Multimedia Design

● Interlacing

● Interleaved

● Linear Multimedia

● Non-Interactive Multimedia

● Nonlinear Multimedia

● Presentation Multimedia

● Latency and Bandwidth


Multimedia Application Environment


Multimedia Communication System● LAN Access Method

● Routing

● Frame and Packet Structures

● Packet Discrimination

● Identify packets that require special handling.

● Be capable of accommodating those special

requirements.

● Bandwidth Requirement, Reservation and

Conservation

● High bandwidth and low latency


Multimedia Communication System Architecture● The ability to manage dynamically the achieved QoS of each service

component

● The possibility for users to select some resources that best meet

their needs.

● The possibility to interact with another user whose equipment has

differing characteristics.

● The communications network must allow any user to select the

service components he/she wants:

● The possibility for users to join in or withdraw from a communication

session according to certain policies, such as agreement of all

interacting partners before admitting a new user.

● The possibility to set such quality of service parameters as the

synchronization tolerance between the service components, the echo

sensitivity, the burst sensitivity, and so on.


Multimedia Networks● Technical Issues

– Admission control

– Scheduling

– Resource management

– Congestion control

– Policing/Shaping


Multimedia Network Reference Model


Multimedia Hardware/Software● Audio/Video Hardware

● Digital Video (DV)

● Analog to Digital devices

● Built-in Hardware

● Digital Video Software

● Multimedia Software


Comparison of Stacks


INTERNET


Connection to Internet


Multimedia Internet Protocols

● Multimedia over TCP

● Multimedia over UDP


RTP● Real-time Transport Protocol (RTP) provides support

for the transport of real-time data such as video and

audio streams.

● RTP needs support from lower layers that actually

have control over resources in switches and routers

● RTP/RTCP provides functionality and control

mechanisms necessary for carrying real-time

content.

● RTP/RTCP itself is not responsible for the higher-level

tasks like assembly and synchronization. These have

to be done at application level.


RTCP● Real-Time Control Protocol extends RTP

● In an RTP session, participants periodically send RTCP packets to

convey feedback on quality of data delivery and information of

membership.

● Packets defined for carrying control information:

– SR: Sender report, for transmission and reception statistics from

session participants that are

– active senders.

– RR: Receiver report, for reception statistics from session

participants, that are not active

– senders.

– SDES: Source description items, including CNAME

– BYE: Indicates end of participation

– APP: Application specific functions


Multimedia Internet Protocols● SAP & SDP

– Peer to peer communication, the concept of session.

● SIP

– Signaling mechanisms that are necessary to establish

a session and to negotiate the parameters to be used

in it, such as codecs, media, location, etc.

● MBONE Tools

– SDR, VIC, VAT and RAT, WB, NTE.


Multimedia Internet Protocols● RSVP

– Network control protocol

– Allows data receiver to request a special end-to-end

quality of service for its data flows.

● RTSP

– A client-server multimedia presentation protocol to

enable controlled delivery of streamed multimedia

data over IP network.

– Aims to provide the same services on streamed audio

and video just as HTTP does for text and graphics.


Multimedia Communications● High-Density File Transfers

● Graphics File Transfers

● Audio File Transfers

● Video File Transfers

● Audio Communication

● Computer-Based Telephony

● Computer-Based Audio Conferencing

● Streaming Audio

● Video Communication

● Video Conferencing

● Streaming Video

e0262 - multimedia communications prof. pallapa venkataram, electrical communication engineering,...

Documents

multimedia networks

multimedia quality

communication systems

bandwidth slide

group communication

flc slide

video files

network types