the compassionate, the merciful S. Kasaei S. Kasaei Room: CE 307 - - PowerPoint PPT Presentation

the compassionate, the merciful

• S. Kasaei
• S. Kasaei

Room: CE 307 Department of Computer Engineering Sharif University of Technology y gy E‐Mail: skasaei@sharif.edu Webpage: http://sharif.edu/~skasaei

• Lab. Website: http://ipl.ce.sharif.edu

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Most of the slides used in this lecture have been provided by: Dr. Dapeng Wu (University of Florida, Department of Electrical &Computer Engineering) based on the book: Video Processing & Communications written by: Yao Wang, Jom Ostermann, & Ya‐Oin Zhang Prentice Hall 1st edition 2001 ISBN: 0130175471 Prentice Hall, 1 edition, 2001, ISBN: 0130175471. [SUT Code: TK 5105 .2 .W36 2001].

Scalable Video Transport p

• ver Wireless IP Networks

Outline Outline

Challenges for quality video transport

Challenges for quality video transport

Architecture for Video Streaming Systems

Video Compression

Video Compression

Application‐Layer QoS Control for Streaming Video Continuous Media Distribution Services Streaming Services Media Synchronization Protocols for Streaming Video Streaming Video over Wireless IP Networks

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Summary

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Lecture Outline Lecture Outline

• Challenges for video over wireless IP

Challenges for video over wireless IP networks.

• An adaptive framework for video over wireless
• An adaptive framework for video over wireless

IP networks:

Scalable video representations – Scalable video representations. – Network-aware end systems. Ad ti i – Adaptive services.

• Summary

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Bandwidth Fluctuations Bandwidth Fluctuations

Access Access SW SW

Domain A Domain B Domain A Domain C

Internet

Source

Access Access SW SW Gateway Gateway

1 Mb/s

Cellular Networks Wireless LAN Receiver

64 kb/s

Mobile PC

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Mobile PC Mobile PC

Challenges Challenges

• Unreliability:

– Fading. – Noise.

• Bandwidth fluctuations:

– Moving between different networks (LAN to WAN). – Hand-off. – …

• Heterogeneity for multicast.

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Unicast vs Multicast Unicast vs. Multicast

Unicast Multicast

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Three Independent Techniques Three Independent Techniques

• Scalable video coding

Scalable video coding.

• Network-aware adaptation of end systems:

N t k – Network awareness. – Adaptation.

• Adaptive QoS support from networks:
• adaptive services.

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Scalable Video Representations Scalable Video Representations

Layered video encoding/decoding. [D denotes the decoder.]

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An Application: IP Multicast An Application: IP Multicast

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Our Approach Our Approach

• Unify the three techniques:

Unify the three techniques: an adaptive framework

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Network‐Aware End Systems Network‐Aware End Systems

Why using network‐aware end systems?

y g y

All layers may get corrupted with equal probability

without awareness of channel status.

How? How?

Discard enhancement layers at the sender based on

network status.

Network‐aware adaptation:

Network monitoring: collect information.

Ad t ti d t id t ti b d

Adaptation: adapt video representations based on

network status.

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T f N k M i i Taxonomy of Network Monitoring

Criteria Type of monitoring Method of monitoring Active Passive Monitoring frequency On demand Continuous g q y Replication of information Centralized Distributed

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Ad t ti /S li Adaptation/Scaling

An architecture for transporting scalable video from a mobile terminal

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An architecture for transporting scalable video from a mobile terminal to a wired terminal.

Scaling Scaling

The operations of a scaler:

Drop the enhancement layers. Do not scale the video.

Scaling based on network status:

A il bl b d idth

Available bandwidth. Channel quality (BER).

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Ad ti S i Adaptive Services

Objective:

Achieve smooth change of perceptual quality in

f b d idth fl t ti presence of bandwidth fluctuations.

Functions:

Reserve a minimum bandwidth for the base layer Reserve a minimum bandwidth for the base layer. Adapt enhancement layers based on available

bandwidth and the fairness policy.

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Adaptive Services Adaptive Services

Provisioning: Provisioning:

End‐to‐end deployment (our focus). Local deployment.

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Components:

Service contract. Call admission control and resource reservation. Substream scaling. Substream scheduling. Link‐layer error control.

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Service Contract Service Contract

A service contract consists of multiple A service contract consists of multiple

subcontracts:

Bandwidth reservation for the base layer .

y

No QoS guarantee for enhancement layers.

Enforcement:

Shaping. Priority.

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Call Admission Control (CAC) Call Admission Control (CAC)

Objective:

Object e:

Provide a QoS guarantee while efficiently utilizing

network resources.

The operation of CAC: check

Whether QoS for existing connections is violated.

Wh h h i i i ’ Q S b

Whether the incoming connection’s QoS can be met.

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Resource Reservation Resource Reservation

Different from the counterpart in wired networks:

e e t

• t e cou te pa t

ed et o s:

The reserved bandwidth may not be rigidly

guaranteed in wireless networks.

Two parts of resource reservation:

Reserve resources along the current path.

R h h f h b

Reserve resource on the paths from the current base

station to neighboring base stations.

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Mobile Multicast Mechanism Mobile Multicast Mechanism

• Objective:

Objective:

– Provide seamless QoS during a handoff.

M lti t h i

• Multicast mechanism:

– Multicast the base layer to the neighboring base t ti stations.

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Substream Scaling Substream Scaling

Objective:

Object e:

Adapt video streams during bandwidth fluctuations

and/or under poor channel conditions.

Scaling decision based on utility fairness or max‐min

fairness:

Utilit f i i b d tilit f ti

Utility fairness is based on utility functions. Max‐min fairness is based on revenue.

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Substream Scaling Substream Scaling

An architecture for transporting scalable video from a wired terminal to a mobile terminal

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to a mobile terminal.

Utility Functions Utility Functions

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Substream Scheduling Substream Scheduling

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Link Layer Error Control Link‐Layer Error Control

Forward error correction (FEC). Automatic repeat request (ARQ). Truncated type‐II hybrid ARQ. Delay constrained hybrid ARQ.

A receiver sends request based on delay bound of the

packet.

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Delay Constrained Hybrid ARQ Delay‐Constrained Hybrid ARQ

RCPC: Rate compatible punctured convolution

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RCPC: Rate compatible punctured convolution.

Summary Summary

Objective: end‐to‐end solution to providing QoS

for video transport over wireless IP networks.

Our approach: an adaptive framework

Scalable video representations. Network‐aware end systems.

Ad i i

Adaptive services.

Advantages of the adaptive framework:

P t l lit i h d f ll

Perceptual quality is changed gracefully. Resources are shared in a fair manner.

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Homework 13 Homework 13

• Reading assignment:

– Chap. 15 p

• Computer assignment:

– Course project Course project

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