e0262 - multimedia communications prof. pallapa venkataram, electrical communication engineering,...
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E0262 - Multimedia Communications
Prof. Pallapa Venkataram,Electrical Communication Engineering,
Indian Institute of Science, Bangalore – 560012, India
Multimedia Communications
E0262 - 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.
E0262 - Multimedia Communications
Networking Infrastructure Evolution● Network deployment issues
E0262 - Multimedia Communications
Network Topologies Evolution● LAN
– Linear topology
– Star-wired
– Multisegment
– Backbone-connected
– Switched-backbonet
● WLAN
● WAN
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
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).
E0262 - Multimedia Communications
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
E0262 - Multimedia Communications
Multimedia Communication System● Interactive Multimedia Design
● Interlacing
● Interleaved
● Linear Multimedia
● Non-Interactive Multimedia
● Nonlinear Multimedia
● Presentation Multimedia
● Latency and Bandwidth
E0262 - Multimedia Communications
Multimedia Application Environment
E0262 - Multimedia Communications
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
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
Multimedia Networks● Technical Issues
– Admission control
– Scheduling
– Resource management
– Congestion control
– Policing/Shaping
E0262 - Multimedia Communications
Multimedia Network Reference Model
E0262 - Multimedia Communications
Multimedia Hardware/Software● Audio/Video Hardware
● Digital Video (DV)
● Analog to Digital devices
● Built-in Hardware
● Digital Video Software
● Multimedia Software
E0262 - Multimedia Communications
Comparison of Stacks
E0262 - Multimedia Communications
INTERNET
E0262 - Multimedia Communications
Connection to Internet
E0262 - Multimedia Communications
Multimedia Internet Protocols
● Multimedia over TCP
● Multimedia over UDP
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
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
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
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.
E0262 - Multimedia Communications
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