A distributed multimedia system integrates various multimedia resources over a network, enabling users to control data flow and access quality content. The architecture includes an information server, a wide area network, and multimedia clients, requiring robust performance to handle real-time data delivery and manage quality of service. Current trends show applications in video on demand and interactive services, highlighting the necessity for resource reservation and strict control to ensure stable quality across a range of uses.

1. Distributed Multimedia
Systems
MCIT-103
CGMM

2. Introduction
 A distributed multimedia system combines
a variety of multimedia information
resources over a network into an
application used by the client.
 The system is based on the interaction
between the user and the application.
 The user can control when to receive what
data and also control the data flow.

3. Introduction
 Most multimedia is inherently time-based –
the arrival time and arrival order of data
packets is important.
 The distributed environment is capable of
serving a large number of end users to
concurrently access a large number of
repositories of stored data.
 We just don’t want interactive multimedia
over our networks… we want it to be
reliable and of high-quality also.

4. History
 60s-70s: Distributed computing research
with earliest networks
 80s: Compact disc, personal computer
explosion
 80s-90s: Distributed multimedia system
research (video conferencing, et al)
 90s: Current prevalent paradigm (quality of
service management)

5. Goal
 Simplicity in and of itself: We want and
need high quality, reliable, interactive
multimedia.
 The general Internet structure is not
sufficient to accomplish this,
 A distributed multimedia system will add
protocols and architectures on top of the
Internet (or LAN) to guarantee quality
levels, thereby satisfying our need.

6. Definitions
 Bandwidth: data rate through a
component.
 Latency: time needed for a packet to travel
end to end.
 Loss rate: acceptable drop-frame ratio.
 Quality of service management:
negotiation and allocation of computing
resources.

7. Definitions
 Flow specification: explicit representation
of required resources.
 Traffic shaping: using buffers at source
and destination to smooth data flow.
 Admission control: allowing or denying
client requests based on available
resources.

8. Architecture of DMMS
Distributed multimedia system
consists of three different basic
components:
• an Information server,
• a wide area network, and
• a multimedia client on the user
side.

9. Architecture of DMMS
Wide area gateway Video
server
Digital
TV/radio
server
Video camera
and mike
Local network Local network

10. Controller
Features and Structure
Client
Source Source Source
QOS QOS QOS
Main QOS
Transmission Line (Internet)

11. 1: Sources provide flow spec to main QOS manager through local QOS
managers
2: Main QOS ready to reserve resources
3: Client send request to main QOS
4: Main QOS decides if client can be served based on available
resources
5: If so, main QOS tells local QOS to allocate resources (if not, client is
rejected)
6: Service begins
7: Main QOS and local QOS monitor resource usage / quality, adjust
allocated resources if necessary
8: Return to step 4 if new client connects
9: Service ends, resources are freed

12. Need of Multimedia Server
 Current personal computers, workstations
and servers are designed to handle
traditional forms of data.
 These systems do not perform well for
multimedia data, requiring fast data
retrieval and guaranteed real time
capabilities.
 The I/O capacity is usually a severe
bottleneck.

13. Requirements for Multimedia
Server
 Minimal Response time: The server
must be able to minimize response time
to live onto the expectations of the
user.
 Fast Processing Capability: To
guarantee fast response time, clients
should be processed fast and data
access rates should be minimized.

14. Requirements for Multimedia
Server
 Reliability and availability:
 Like any other server, multimedia server
must be reliable.
 The larger the number of users and volume
of data handled by the server, the more
difficult is to guarantee reliability.
 To provide fault tolerance special hardware
and software mechanisms must be
employed. The time the server is unavailable
should be minimized.

15. Requirements for Multimedia
Server
 Ability to sustain guaranteed number of
streams:
 Another important factor is the
maximum number of data streams the
server can simultaneously handle.
 This affects the total number of clients
the server can handle.

16. Requirements for Multimedia
Server
 Real-time delivery:
 This needs profound requirements on
the resource scheduling at the
operating system level.
 For this accurate real-time operating
systems have to be developed.

17. Requirements for Multimedia
Server
 High storage capacity: The server must
have a large storage capacity to store
MM data and variety of information.
 For this, the server may be required to
compress and encode video and image
data prior to transport or storage.
 The performance of compression and
signal processing should be optimized.
This might require special hardware.

18. Requirements for Multimedia
Server
 Quality of Service: (Qos) is a set of
parameters describing the tolerable end-to-end
delay, throughput, and the level of reliability in
multimedia communication and presentation.
 The server should be able to provide and adapt
itself to different QoS requirements, according to
the characteristics of the client's terminal, the
network connection and the requested data
type.

19. How To Use
 A distributed multimedia system is a
combination of source hardware, QOS
manager software, and a transmission line
 Can be bought as a complete, dedicated,
proprietary package – very expensive!
 Can be built using existing hardware and
Internet / LAN connection lines… all that is
needed beyond that is QOS management
software – can be purchased or developed

20. Applications
 Video conferencing
 Live news feeds
 Video-on-demand
 Remote-control of exploratory robots
 Remote musical collaborations
 Remote surgical operations

21. Significant Points
 Distributed multimedia systems exist to
guarantee quality of delivery levels.
 Resource reservation is the key.
 Additional clients do not degrade system –
they can be refused if resources are
scarce.
 Quality guarantees are of paramount
importance, whether used for business,
entertainment, scientific or health-related
applications.

22. Current Trends in DMS
Currently some of the distributed multimedia
systems are:
 Video on Demand: The consumer can
select a video or any program on
demand. The application consists of
Interactive features like forward, rewind
and pause.
 Interactive shopping and electronic
commerce: Home shopping will provide
a customisable shopping environment.

23. Current Trends in DMS
 News and Reference Services: News on
Demand is similar to VOD but it
provides sophisticated news retrieval
and reference services that combine
live and achieved video, access to
textual data and still photography from
various sources.
 The information is delivered based on a
filtering criteria kept by the user.

24. Summary
 Serving multimedia requires strict resource control to
maintain quality.
 Resources consist of bandwidth, latency, and loss
rate, among others
 Source components declare the resources they need
in flow specifications.
 Quality of service managers negotiate and reserve
resources to guarantee quality.
 Source + flow spec + QOS manage + transmission
lines = distributed multimedia system

25. References
 Distributed Multimedia Systems – An Overview - Gaurav Jain , Indian Institute of
Information Technology

26. THANK YOU