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 PresentationTRANSCRIPT
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.