Prof Pallapa Venkataram,

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Multimedia Over Internet

• Prof Pallapa Venkataram,
• Electrical Communication Engineering,
• Indian Institute of Science,
• Bangalore 560012, India

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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

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Multimedia Over IP Multicast Network
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Multimedia Over IP Multicast Network
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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

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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.

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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).

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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.

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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.

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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

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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.

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Multimedia Data Streaming

• Example
• If there are 100 requests for example, 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.

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Multimedia Data Streaming
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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

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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.

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Web Information System Architecture
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Interactive Web Pages
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Interactive Multimedia Applications
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Multimedia Services Applications
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Multimedia Services Applications
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Video Streaming
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Interactive Multimedia Applications
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Interactive Multimedia Applications
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• 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.

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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

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Jukebox - Architecture
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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.

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Collaborative Work
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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.

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Multimedia Messaging System
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MMS Network Architecture
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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.