Multiplexing - Data Communication - Lecture Slides, Slides of Data Communication Systems and Computer Networks

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Multiplexing

Streaming Protocols

UDP User Datagram Protocol

UDP is the alternative to TCP. UDP forsakes TCP's error correction and allows packets to drop out if they're late or damaged. Access Problems (firewalls).

RTP

The data part of RTP is a thin protocol providing support for applications with real-time properties.  continuous media (timing reconstruction ) loss detection security  content identification.

RTSP

. RTSP is a communications protocol for control and delivery of real- time media.  It defines the connection between streaming media client and server software  Provides a standard way for clients and servers from multiple vendors to stream multimedia content.

RSVP

Protocol designed to allow the assignment of priorities to "streaming" applications. Works by permitting an application transmitting data over a routed network to request and receive a given level of bandwidth.

Comparison of Commercial Video Streaming

Products

 Deliver highest quality video for a given

bandwidth, lowest delay, no jitter(low frame loss),

good audio/visual synchronization, high quality

audio, and image resolution.

 Best possible video quality over a range of

networks/bandwidths without content duplication

is highly desirable. This characteristic is referred to

as scalability.

 Commercial products offer two types of

scalability.

Continued…

 One is the encoding state. A range of encoding formats to choose from, which correspond to a range of bandwidths.  Two is the dynamic scalability based on the available bandwidth at the time. Where dynamic scalability is provided it is usually simple frame dropping.

Research on Continuous Media Toolkits and QoS Architectures

 The following are the major research project investigating

the use of scalable video compression to dynamically adapt

to variable bandwidth, to ensure multimedia delivery.

 Berkeley Continuous Media Toolkit

 Application Level Gateway

 Distributed Real-time MPEG Video Audio Player

 Multimedia Communication Filters

 Image and Advanced TV Lab, Columbia

 DSTC SuperNova

Video Streaming Standards

• H.
• H.
• MPEG
• MPEG
• MPEG

H.

H.263 is design for low bitrate communication. H.263 expected to be use for wide range of bitrate and expected to replace H.261. H.263 supports 5 resolutions, able to compete with MPEG standards.

MPEG- 1

MPEG-1 offers VHS quality video at a bandwidth of

1 - 1.5Mbps.

The resolution id at 30 frames per second

MPEG-1 requires expensive hardware for real-time

encoding.

MPEG-1 does not offer resolution scalability

MPEG-1 is not suitable for video conferencing

MPEG- 4

MPEG-4 is still in its experimental stage Compression scheme for video conferencing , MPEG-4 can be use for multiplexing for transmission over different networks MPEG-4 framework focuses on a language called MSDL

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