Description and Lookup of Media-Stream Adaptation Services

Description and Lookup of Media-Stream Adaptation Services

Andreas Schorr, Franz Hauck

Dept. of Distributed Systems, University of Ulm, Germany

[email protected]

Andreas Kassler

Dept. of Computer Science, Karlstad University, Sweden

Andreas Schorr, Dept. of Distributed Systems, University of Ulm

229.09.2006

Outline of this Talk

• Introduction to Multimedia-Stream Adaptation Services (MSAS)

• Dynamic Discovery of MSAS

• Description of MSAS with RDF

• Conclusion / Outlook

Multimedia Stream Adaptation Services


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Motivation

• Multimedia-streaming over IP is widely used today (VoIP, Video Conferences, VoD, Audio/Video-Broadcast)

• But there still exist compatibility problems because of– Heterogeneous Hardware: screen sizes, CPU power, amount of memory,

audio/video capture hardware

– Large number of different media formats, e.g., MJPEG, H.263, MPEG-2, MPEG-4, G.711, G.726, proprietary formats

– Different network technologies with different bandwidth, bit error rate, delay, and jitter and with variable resource availability

Adaptation of multimedia streams requiredStreaming applications require adaptation in real-time

Multimedia Stream Adaptation Services – Introduction to Stream Adaptation Services (MSAS)


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Location of Adaptation Services

• On the sender/receiver terminal– Provided by a middleware system if applications themselves are not able to

perform the conversion

– If possible, this is often the most efficient solution, but• Software/hardware modules for adaptation may not available

• CPU or memory resources for adaptation process may not be available

• On a proxy node on the network– Enables communication between incompatible terminals

– No additional load on terminals

– Efficient usage of network resources in heterogeneous multicast scenarios

Multimedia Stream Adaptation Services - Introduction to Stream Adaptation Services (MSAS)


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Multimedia-Stream Adaptation Node (MSAN)


codec: MPEG-2codec: H.263

Receiver A

codec: MPEG-4

Receiver B

GPRS-Network

Video Server

MSAN


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Heterogeneous Broadcast Services


BroadcastServer

MPEG-26 Mbps

MPEG-26 Mbps

MPEG-41 Mbps

MPEG-41 Mbps

MPEG-4384 kbps

MSAN 2

H.26364 kbps

H.26448 kbps

H.26364 kbps

MSAN 3

WLAN

UMTS

GPRS

DVB-T

M-JPEG128 kbps

AD HOC

MSAN 1


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Types of Adaptation Services

• Transcoding• Scaling (spatial, temporal, signal-to-noise ratio)• Mixing (e.g., audio streams)• Media translation• Multipoint session• Protocol adaptation• Rate control• Adaptation of (application-layer) error correction mechanisms• Support for MPEG-21 Digital Item Adapation (DIA) tools:

– generic Bitstream Syntax Description (gBSD)– usage environment description (UED)



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Properties of Adaptation Services

• Different MSANs may offer operations for different media formats and protocols

• Adaptation causes delay, quality reduction, and (optionally) costs

• Delay, costs, and quality reduction caused by adaptation may be different for each media format and for each MSAN because transformation from Format A to Format B can be achieved through techniques



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• Introduction to Stream Adaptation Services (MSAS)





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Dynamic Service Discovery of Multimedia-Stream Adaptation Services• Daidalos: EU Integrated Project (http://www.ist-daidalos.org)• Service discovery protocols and frameworks:

SLP, Jini, Salutation, UPnP, ...• Service-specific vocabulary

– Integrated into the service discovery protocol– Independent of any protocols

• Drawbacks of tradition service discovery protocols– Programming-language specific (Jini)– Limited expressiveness of service description language (SLP)– XML description, but only rooted tree structure (UPnP)

RDF-based vocabulary, independent of the discovery protocol

Multimedia Stream Adaptation Services – Dynamic Discovery of MSAS


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Daidalos service discovery architecture

Multimedia Stream Adaptation Services – Dynamic Discovery of MSAS

SLP + RDF

ServiceDiscovery

Server

MEGACO MSANClient

RDQL,SPARQL

Service Invocation

Service RegistrationService Query

Service Description


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High-level Properties of an MSANMultimedia Stream Adaptation Services – Description of MSAS with RDF

http://example.org/MSAN1

msas:gBSD-supported

_:1msas:contact-info-settrue^^xsd:boolean

true^^xsd:boolean

msas:ued-supported

_:2

msas:proto-trans-ops_:3

msas:media-adapt-ops

_:4msas:error-cor-ops

_:5msas:mix-ops

_:6msas:rate-control-schemes

_:7msas:rtp-profiles

_:8msas:out-multiplicities

msas:MSAN

rdf:type

rdf:type

rdf:type

rdf:type

rdf:type

rdf:type

rdf:type

rdf:type

rdf:type

msas:RTP-Profile-List

msas:Out-Multiplicity-List

msas:Rate-Control-Scheme-List

msas:Mix-Ops-List

msas:Error-Corr-Ops-List

msas:Media-Adapt-Ops-List

msas:Proto-Trans-Ops-List

msas:Contact-List

_:0 msas:RTP-Format-Listrdf:typemsas:rtp-payload-formats


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MSAN Contact Information

Multimedia Stream Adaptation Services – Description of MSAS with RDF

_:1

_:9

_:10

contact-info

contact-info123.45.57.89

2944

megacosig-proto

port

contact-address

tcptransp-layer

transp-layer-proto_:12

sip:[email protected]

sipsig-proto

udp_:11

5060

port tcp

transp-layer-proto

transp-layer-proto

contact-address

transp-layer

_:13

session-desc-formats

session-desc-formats

sdp

sdpng

sdpng++

session-desc-format

session-desc-format

session-desc-format


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_:14

vcf:2.1

50in-format

milliseconds

out-format

scale-ops scale-op

scale-op

scale-spatial

scale-opdelay

time-value

time-unit

false

content-dependent

_:2

vcf:3.1

_:17

scale-snr-bitrate

scale-snr-qual-level

_:19

_:20

cost

media-adapt-op

_:18

qual-reduction

psnr

1.5qual-red-value

measurement-method

_:15

_:16

media-adapt-op

media-adapt-op

in-format

out-format

qual-reduction

_:21

scale-ops

scale-temporalscale-op

_:22delay

falsecontent-dependent

20time-value

acf:11 acf:11

in-formatout-format

delay

cost

cost _:24qual-reduction

0.0qual-red-value

_:23scale-ops scale-color-to-greyscale-op

_:26

_:27

pay-per-time

pay-per-volume

cost-dollarcost-unit

cost-unit0.05

cost-value

500

kilobytes

10

0.01cost-value

interval

time-unit

scale-op


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Sample Query

Find an adaptation service that

• supports the MEGACO signalling protocol

• can transcode a media stream from format MPEG-2 Simple Profile to MPEG-4 Simple Profile in less than 100 ms

Return IP-address and port of at most 4 suitable adaptation services, in ascending order of the delay caused by the adaptation process



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Sample SPARQL Query

PREFIX msas: <http://mqos.de/ns/msas-schema-v1.rdf#>

SELECT ?address ?port ?delayvalue

WHERE { ?msan msas:contact-info-set ?cis .

?cis msas:contact-info ?ci .

?ci msas:sig-proto msas:megaco ;

msas:contact-address ?address ;

msas:transp-layer ?transp .

?transp msas:port ?port .

?msan msas:media-adapt-ops ?ops .

?ops msas:media-adapt-op ?op .

?op msas:in-format <urn:mpeg:mpeg7:cs:VisualCodingFormatCS:2001:2.1> ;

msas:out-format <urn:mpeg:mpeg7:cs:VisualCodingFormatCS:2001:3.1> ;

msas:delay ?delay .

?delay msas:content-dependent false ;

msas:time-value ?delayvalue .

FILTER (?delayvalue < 100) . }

ORDER BY ?delayvalue

LIMIT 4



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Result Set

• address port delayvalue

• 134.60.77.210 2944 50

• 134.60.77.202 2944 75

• 134.60.77.200 2944 85

• 134.60.77.205 2944 99



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Summary

• Dynamic discovery of Adaptation Services

• RDF Schema for the Description of Media-Stream Adaptation Services (http://mqos.de/ns/msas-schema-v1.rdf#)

• Decoupling of Service Discovery Protocol (SLP) and Service Description (RDF)

• Integrated into the Daidalos Service Discovery Architecture (http://www.ist-daidalos.org)

Multimedia Stream Adaptation Services – Summary

Description and Lookup of Media-Stream Adaptation Services

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