Multimedia Over Internet

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Multimedia Over Internet. Growth of Internet. No production cost Low cost infrastructure No fees for joining or licenses to buy Choice of products and services No sales experience needed No employees required No expensive accounts needed. No inventory to carry No order processing - PowerPoint PPT Presentation

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Multimedia Over Internet

Growth of Internet● No production cost

● Low cost infrastructure

● No fees for joining or licenses

to buy

● Choice of products and

services

● No sales experience needed

● No employees required

● No expensive accounts

needed

● No inventory to carry

● No order processing

● No product shipping

● No customer service

concerns

● Make money while you

sleep

● The world at your doorstep

● Minimal risk

● High income potential

Multimedia Over IP Multicast Network

Multimedia Over IP Multicast Network

Delivering Real-time Multimedia over Internet

● framework for transporting real-time Internet video

includes two components: congestion control and

error control

● Congestion control consists of rate control, rate-

adaptive encoding, and rate shaping

● Error control consists of forward error correction

(FEC), retransmission, error resilience, and error

concealment

● QoS issues are bandwidth, delays and loss of data

Heterogeneity Network Environment● Network heterogeneity and Receiver heterogeneity

● Network heterogeneity refers to the subnetworks

in the Internet having unevenly distributed resources

(e.g., processing, bandwidth, storage, and

congestion control policies).

● Receiver heterogeneity means that receivers have

different or even varying latency requirements,

visual quality requirements, and/or processing

capability.

Heterogeneity Network Environment● Network-centric approach:

– Routers/switches in the network are required to provide

QoS support to guarantee bandwidth, bounded delay,

delay jitter, and packet loss for video applications (e.g.,

integrated services, or differentiated services).

● End-system based approach:

– Control techniques to maximize the video quality

without any QoS support from the transport network.

– The integrated solutions is based on both transport (use

of control/processing techniques without regard of the

specific video) and compression perspectives

(employing signal processing techniques with

consideration of the video semantics).

Heterogeneity Network Environment● Congestion Control:

● Bursty loss and excessive delay are caused by

network congestion

● Reduce packet loss and delay

● Rate control matches the rate of the video stream to

the available network bandwidth.

● Rate-adaptive video encoding or rate shaping is

required.

● Rate control is from the transport perspective, while

rate-adaptive video encoding is from the

compression perspective; rate shaping is in both

transport and compression domain.

Heterogeneity Network Environment

● Error Control

● Four types: Forward error correction (FEC),

retransmission, error resilience, and error

concealment.

● FEC adds redundant information to a compressed

video bit stream so that the original video can be

reconstructed the in presence of packet loss. Three

kinds of FEC:

– channel coding;

– source coding-based FEC;

– joint source/channel coding.

Internet Multimedia Applications● Classes of multimedia applications

● Streaming Stored Multimedia Data Applications

– Clients request on-demand data (for example,

compressed audio or video files) which is stored on

servers.

● One to many streaming of real-time data applications

– Similar to ordinary broadcast of radio and television,

except the transmission takes place over the Internet.

● Real-time interactive multimedia applications

– Allows people to use audio/video to communicate with

each other in real-time

Multimedia Data Streaming● Significant improvement over the download-and-play

approach to multimedia file distribution

● Allows the data to be delivered to the client as a

continuous flow with minimal delay before playback

can begin

● Streaming is a server/client technology that allows live

or pre-recorded data to be broadcast in real time

● Multimedia applications such as news, education,

training, entertainment, advertising, and a host of

other uses

● Streaming enables the Internet or company Intranet

as a new broadcast medium for audio and video.

Multimedia Data Streaming● Example:

● If there are 100 requests for a video stream

compressed at 28.8 Kbps,

– the server would require at least a 3 Mbps connection.

– The Encoding Station and the Video Streaming Server

can be one single system.

– However, unless hardware encoding is used, this would

typically be for a situations requiring limited

performance (e.g. a single input stream and a small

number of viewer requests).

– Even so, it would still require a fairly high-performance

system.

– It is much more common to have two separate

systems.

Multimedia Data Streaming

Unicast vs. IP Multicast● Streaming delivery techniques: Unicast and Multicast.

● Unicast: Computers establish two-way,

– point-to-point connections.

● Client computer can communicate with the computer supplying

the multimedia stream.

● Each client that connects to the server receives a separate

stream, which rapidly uses up network bandwidth.

● IP Multicast: One computer sends a single copy of the data over

the network and many computers receive that data.

– Only a single copy of the data is sent across the network, which

preserves network bandwidth.

– It is connectionless; clients have no control over the streams they

receive

Web Multimedia Information Systems● Web Process

– Organizing entity that determines a set of activities

and specifies their relations

● Activity

– Process step, which participates in the fulfillment of

an overall objective. An agent who satisfies the

required skills and rights (paradigm of role) fulfilled it.

● Activities Synchronization

– Temporal preconditions to define a temporal order

between activities, Alternatives to let the user decide

on the media to use for a specific purpose, Parallelism

between activities what is especially useful in the case

of collaborative work.

Web Information System Architecture

Interactive Web Pages

Interactive Multimedia Applications

Multimedia Services & Applications

Multimedia Services & Applications

Video Streaming

Interactive Multimedia Applications

● Flexible scheduling based on a finite set of channels

available to all viewers

● A set of channels are multicast to all viewers tuned to the

respective channel.

● Viewers may watch a program playing on any channel or

make a request for something of their own choosing.

Viewers' requests are scheduled on one of the jukebox's

channels using scheduling criteria like minimum waiting

time, etc.

● A schedule of currently playing and scheduled programs,

updated in real-time, is available to all viewers. Viewers

can watch any program, including those scheduled by

others, by tuning to the appropriate channel.

Jukebox Policies● Content-based scheduling

– Limitations may be imposed based on the content

● Service provider scheduling

– A service provider may have a desire or obligation to

schedule certain programs at certain times

● Limited viewer input

● A service provider may want to blunt the ability of

individual viewers to control what programs are

playing

Jukebox - Architecture

Jukebox - Architecture● Scheduling control: The scheduler receivers viewer

requests, performs scheduling, controls the video

server, and provides a schedule of programs to all

viewers.

● Video server: The video server transmits audio/video

streams into the network

● Network: The network must provide an effcient

multicast facility and have sufficient bandwidth to

meeting viewer quality expectations

● Receivers: Receivers must be able to receive,

decode, and display an audio/video stream.

Collaborative Work

Collaboration Work

● Client: A client can send some session requests to a

session server to create or join the session so that it

can take part in some meeting.

● Media Server: A media server is a RTP Channel for

audio and video communication between clients.

● Session Server: The session server is the core of the

XGSP, which can accept request of various clients

and organize the video conference.

Multimedia Messaging System

MMS Network Architecture

MMS Operation● Sending Messages: A user sends a message by having its MMS-

UA submit the message to its home MMS-RS.

● Receiving Messages: Upon reception of a message, the

recipient MMS-RS verifies the recipient profile and generates a

notification to the recipient MMS-UA.

● Message Adaptation: Within a request for delivery of a

message, the recipient MMS-UA can indicate its capabilities,

e.g., a list of supported media types and media formats, for the

recipient MMS-RS.t

● Delivery Reports: If a delivery report has been requested by

the originator MMS-UA and if the recipient MMS-UA did not

request a delivery report not to be generated, the recipient

MMS-RS generates a delivery report and delivers the delivery

report to the originator MMS-RS.