A control-based algorithm for rate adaption in MPEG- DASH

7/23/2019 A control-based algorithm for rate adaption in MPEG- DASH

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A control-basedalgorithm for rate

adaption in MPEG- DASH

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Outline

Introductionu!!" #ontrollers-Preliminaries

$he Proposed Algorithm

Simulation Setup and %esults

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Introduction

MPEG-DASH - D"namic AdaptationStreaming o'er H$$P

Impro'es the (ualit" percei'ed b" the user)

allo*s access to di+erent resolutions of the'ideo content 'ia H$$P)

MPEG-DASH speci,cation

Onl" de,nes the Media PresentationDescription MPD. and the segment formats)

Aspects such the media-encoding format/the adaptation techni(ues/ outside theMPEG DASH0s scope)


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Introduction

An algorithm for rate adaption inMPEG-DASH is proposed

Emplo"s fu!!" logic to estimate the

resolution of the ne2t 'ideo segmentthat each client should obtain fromthe ser'er)

3u+ering time at each client is 4eptabo'e a target bu+ering time bu+er under5o*s and unnecessar" bit

rate 5uctuations are a'oided)

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u!!" #ontroller-Preliminaries3asic steps

u!!i,cation7 A membership isassigned to the crisp input obtained

from di+erent membership sets) u!!" %ule or 4no*ledge. base7 It

associates the fu!!" output to thefu!!" inputs and is constructed to

control the fu!!" output)

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u!!" #ontroller-Preliminaries3asic steps

u!!" Inference Engine7 It computesthe acti'ation degree and the output

of each rule) Defu!!i,cation7 It transforms a fu!!"

set to a crisp set)

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E2ample

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u!!" %ules

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Input membership functions

??II#A$IO@ - GE$$I@G3A# $O #%ISP @>M3E%S

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3asic Idea7 Each client uses thefu!!" control rate adaptationalgorithm to estimate the

resolution of the ne2t 'ideosegment obtained from theser'er)

Be assume that a 'ideo streamconsisted of n segments ofduration C is a'ailable at the

ser'er) 1&


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Each client re(uests the ne2t'ideo segment *ith higherlo*eror e(ual resolution to the last

do*nloaded segment)$he increasedecrease in

resolution is determined b" the

fu!!" controller rate adaptationalgorithm)

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$he algorithm uses t*o crisp inputs bu+ering time t$ the time that the last recei'ed segment *aits at the

client until it starts pla"ing

the di+erence 't$( t$)t$)* di+erence of the last bu+ering time from the pre'ious

one)

target buffering time Tis also set to a'oid bu+er under runs

to retain the di+erence bet*een the current andthe pre'ious resolution close to !ero reduce consecuti'e changes of 'ideo resolution subFect

to continuous 'ariations of the net*or4 throughput)

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inguistic 'ariables

3u+ering time input Short/ #lose/ ong

Denote the distance of the current bu+ering time from

the target $) Di+erential of the 3u+ering time input alling/ Stead"/ %ising

Signif" that the rate bet*een subse(uent bu+eringtimes

Output %educe %./ small reduce S%./ @o #hange @#./ small

increase SI. and Increase I.

$he factor of the increasedecrease of the resolution ofthe ne2t segment

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# Structure

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1:

f # $ $


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Each output 'ariable iscalculated

$he output of the fu!!" algorithmis calculated using the centroidsof each output component

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$he output of the controller is anincreasedecrease factor/

refers to the bit-rate of the ne2t

segment b4./ in relation to theestimated channel throughput o'erthe last period

Bhere7 rdthe a'ailable

connection throughput 1<

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Simulation %esults

Simulation setup Simulator7 ns-

$opolog"7 one DASH MPEG ser'er and se'eral DASH MPEG clients)

Each client node tries to do*nload and pla" a 'ideo from the

ser'er using the proposed algorithm) $he bottlenec4 lin4 is a &Mbps lin4/ *ith a propagation

dela" of 8ms)

$he target bu+ering time $ *as e(ual to 8 sec)

$he time period d/ estimating the a'ailable connection

throughput at the client/ *as set to 9= sec)$he factors @&/ @1/ ?/ P1and P&of the output

membership function *ere set e(ual to =)&8/ =)8/ 1/ 1)8and respecti'el")

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Simulation %esults

$race ,les of se'eral dash 'ideo streams gi'en in

http7***-itec)uni4lu)ac)atftpdatasetsmms"s1&3ig3uc43unn"

Duration of each 'ideo segment7 & sec)ideo segment resolutions used in the

e2periments7 45000, 89000, 131000, 178000, 221000, 263000, 334000, 396000,522000,

595000, 791000, 1033000, 1245000, 1547000, 2134000, 2484000, 3079000,

3527000, 3840000, 4220000 bps)Scenarios

t*o clients attempting to access a DASH ser'er)

multiple clients attempting to access a DASH ser'er

&&

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Simulation %esults

Scenario7 t*o clients attemptingtoaccess a DASH ser'er bu+ering time

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Simulation %esults

Scenario7 multiple clientsattempting to access a DASHser'er

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Simulation %esults


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Simulation %esults


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Simulation %esults

Scenario7 multiple clientsattempting to access a DASHser'er bit rate

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A control-based algorithm for rate adaption in MPEG- DASH