Description and Lookup of Media-Stream Adaptation Services

1
Description and Lookup of Media-Stream Adaptation
Services

• Andreas Schorr, Franz Hauck
• Dept. of Distributed Systems, University of Ulm,
  Germany
• andreas.schorr_at_uni-ulm.de
• Andreas Kassler
• Dept. of Computer Science, Karlstad University,
  Sweden

2
Outline of this Talk
Multimedia Stream Adaptation Services

• Introduction to Multimedia-Stream Adaptation
  Services (MSAS)
• Dynamic Discovery of MSAS
• Description of MSAS with RDF
• Conclusion / Outlook

3
Motivation
Multimedia Stream Adaptation Services
Introduction to Stream Adaptation Services (MSAS)

• Multimedia-streaming over IP is widely used today
  (VoIP, Video Conferences, VoD, Audio/Video-Broadca
  st)
• 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 required
• Streaming applications require adaptation in
  real-time

4
Location of Adaptation Services
Multimedia Stream Adaptation Services -
Introduction to Stream Adaptation Services (MSAS)

• 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

5
Multimedia-Stream Adaptation Node (MSAN)
Multimedia Stream Adaptation Services -
Introduction to Stream Adaptation Services (MSAS)
MSAN
codec H.263
codec MPEG-2
Receiver A
Video Server
6
Heterogeneous Broadcast Services
Multimedia Stream Adaptation Services -
Introduction to Stream Adaptation Services (MSAS)
WLAN
DVB-T
AD HOC
MPEG-4 1 Mbps
MSAN 2
MPEG-4 1 Mbps
Broadcast Server
M-JPEG 128 kbps
MPEG-4 384 kbps
MPEG-2 6 Mbps
MSAN 1
MPEG-2 6 Mbps
UMTS
MSAN 3
H.263 64 kbps
H.264 48 kbps
GPRS
H.263 64 kbps
7
Types of Adaptation Services
Multimedia Stream Adaptation Services -
Introduction to Stream Adaptation Services (MSAS)

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

• 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

9
Outline of this Talk
Multimedia Stream Adaptation Services

• Introduction to Stream Adaptation Services (MSAS)
• Dynamic Discovery of MSAS
• Description of MSAS with RDF
• Conclusion / Outlook

10
Dynamic Service Discovery of Multimedia-Stream
Adaptation Services
Multimedia Stream Adaptation Services Dynamic
Discovery of MSAS

• 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

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Daidalos service discovery architecture
Multimedia Stream Adaptation Services Dynamic
Discovery of MSAS
Service Invocation
MSAN
Client
MEGACO
Service Description
SLP RDF
RDQL, SPARQL
Service Discovery Server
Service Registration
Service Query
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Outline of this Talk
Multimedia Stream Adaptation Services

• Introduction to Stream Adaptation Services (MSAS)
• Dynamic Discovery of MSAS
• Description of MSAS with RDF
• Conclusion / Outlook

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High-level Properties of an MSAN
Multimedia Stream Adaptation Services
Description of MSAS with RDF
rdftype
truexsdboolean
_1
msasContact-List
msascontact-info-set
rdftype
msasgBSD-supported
_2
msasMedia-Adapt-Ops-List
msasmedia-adapt-ops
truexsdboolean
rdftype
_3
msasProto-Trans-Ops-List
msasproto-trans-ops
msasued-supported
rdftype
msaserror-cor-ops
_4
msasError-Corr-Ops-List
http//example.org/MSAN1
rdftype
_5
msasmix-ops
msasMix-Ops-List
rdftype
rdftype
msasrate-control-schemes
_6
msasRate-Control-Scheme-List
msasMSAN
rdftype
msasrtp-profiles
_7
msasRTP-Profile-List
rdftype
_8
msasOut-Multiplicity-List
msasout-multiplicities
rdftype
msasrtp-payload-formats
msasRTP-Format-List
_0
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MSAN Contact Information
Multimedia Stream Adaptation Services
Description of MSAS with RDF
sipa_at_b.c
contact-address
5060
sig-proto
_9
sip
port
tcp
transp-layer
transp-layer-proto
_11
contact-info
udp
transp-layer-proto
session-desc-formats
session-desc-format
sdp
_1
_13
session-desc-format
sdpng
session-desc-formats
session-desc-format
contact-info
sdpng
123.45.57.89
contact-address
sig-proto
_10
megaco
2944
port
transp-layer
tcp
_12
transp-layer-proto
15
(No Transcript)
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Sample Query
Multimedia Stream Adaptation Services
Description of MSAS with RDF

• 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
Multimedia Stream Adaptation Services
Description of MSAS with RDF

• PREFIX msas lthttp//mqos.de/ns/msas-schema-v1.rdf
  gt
• SELECT ?address ?port ?delayvalue
• WHERE ?msan msascontact-info-set ?cis .
• ?cis msascontact-info ?ci .
• ?ci msassig-proto msasmegaco
• msascontact-address ?address
• msastransp-layer ?transp .
• ?transp msasport ?port .
• ?msan msasmedia-adapt-ops ?ops .
• ?ops msasmedia-adapt-op ?op .
• ?op msasin-format lturnmpegmpeg7csVisu
  alCodingFormatCS20012.1gt
• msasout-format lturnmpegmpeg7csVis
  ualCodingFormatCS20013.1gt
• msasdelay ?delay .
• ?delay msascontent-dependent false
• msastime-value ?delayvalue .
• FILTER (?delayvalue lt 100) .
• ORDER BY ?delayvalue
• LIMIT 4

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Result Set
Multimedia Stream Adaptation Services
Description of MSAS with RDF

• 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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Outline of this Talk
Multimedia Stream Adaptation Services

• Introduction to Stream Adaptation Services (MSAS)
• Dynamic Discovery of MSAS
• Description of MSAS with RDF
• Conclusion / Outlook

20
Summary
Multimedia Stream Adaptation Services Summary

• Dynamic discovery of Adaptation Services
• RDF Schema for the Description of Media-Stream
  Adaptation Services (http//mqos.de/ns/msas-schem
  a-v1.rdf)
• Decoupling of Service Discovery Protocol (SLP)
  and Service Description (RDF)
• Integrated into the Daidalos Service Discovery
  Architecture (http//www.ist-daidalos.org)