1. Description and Lookup of Media-Stream Adaptation Services Andreas Schorr, Franz Hauck Dept. of Distributed Systems, University of Ulm, Germany andreas.schorr@uni-ulm.de Andreas Kassler Dept. of Computer Science, Karlstad University, Sweden

2. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 2 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

3. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 3 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 required  Streaming applications require adaptation in real-time Multimedia Stream Adaptation Services – Introduction to Stream Adaptation Services (MSAS)

4. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 4 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)

5. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 5 Multimedia-Stream Adaptation Node (MSAN) Multimedia Stream Adaptation Services - Introduction to Stream Adaptation Services (MSAS) codec: MPEG-2 codec: H.263 Receiver A codec: MPEG-4 Receiver B GPRS-Network Video Server MSAN

6. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 6 Heterogeneous Broadcast Services Multimedia Stream Adaptation Services - Introduction to Stream Adaptation Services (MSAS) Broadcast Server MPEG-2 6 Mbps MPEG-2 6 Mbps MPEG-4 1 Mbps MPEG-4 1 Mbps MPEG-4 384 kbps MSAN 2 H.263 64 kbps H.264 48 kbps H.263 64 kbps MSAN 3 WLAN UMTS GPRS DVB-T M-JPEG 128 kbps AD HOC MSAN 1

7. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 7 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) Multimedia Stream Adaptation Services - Introduction to Stream Adaptation Services (MSAS)

8. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 8 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 Multimedia Stream Adaptation Services - Introduction to Stream Adaptation Services (MSAS)

9. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 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. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 10 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

11. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 11 Daidalos service discovery architecture Multimedia Stream Adaptation Services – Dynamic Discovery of MSAS SLP + RDF Service Discovery Server MEGACO MSANClient RDQL, SPARQL Service Invocation Service Registration Service Query Service Description

12. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 12 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

13. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 13 High-level Properties of an MSAN Multimedia Stream Adaptation Services – Description of MSAS with RDF http://example.org/MSAN1 msas:gBSD-supported _:1 msas:contact-info-set true^^xsd:boolean msas:ued-supported _:2 msas:proto-trans-ops _:3 msas:media-adapt-ops _:4 msas:error-cor-ops _:5 msas:mix-ops _:6 msas:rate-control-schemes _:7 msas:rtp-profiles _:8 msas:out-multiplicities msas:MSAN 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-List rdf:type msas:rtp-payload-formats

14. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 14 MSAN Contact Information Multimedia Stream Adaptation Services – Description of MSAS with RDF _:1 _:9 _:10 contact-info 123.45.57.89 2944 megaco sig-proto port contact-address tcp transp-layer transp-layer-proto _:12 sip:a@b.c sip sig-proto udp _:11 5060 port tcp transp-layer-proto contact-address transp-layer _:13 session-desc-formats sdp sdpng sdpng++ session-desc-format

15. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 15

16. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 16 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 Multimedia Stream Adaptation Services – Description of MSAS with RDF

17. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 17 Sample SPARQL Query PREFIX msas: 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 ; msas:out-format ; msas:delay ?delay. ?delay msas:content-dependent false ; msas:time-value ?delayvalue. FILTER (?delayvalue < 100). } ORDER BY ?delayvalue LIMIT 4 Multimedia Stream Adaptation Services – Description of MSAS with RDF

18. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 18 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 Multimedia Stream Adaptation Services – Description of MSAS with RDF

19. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 19 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. 29.09.2006 Andreas Schorr, Dept. of Distributed Systems, University of Ulm 20 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