Media Synchronization – perception and performance

Graduation (external) project TNO ICT – NCS/PPQ 2010

Title: TNOMedia Synchronization – perception and performance
Contact: TNO: Dr. Ir. M.O. van Deventer, R.Kooij, UT: Dr. Ir. G. Karagiannis (
Start: To be decided, preferably early 2010
Location: TNO, Brassersplein 2, Delft



IPTV offers a new range of TV services. This includes interactive services which involve the TV watcher with the programs, or enable mutual communication between watchers. The TNO-developed service ConnecTV is an example of an interactive TV service, where multiple users are "watching apart together" the same content at different TV sets, while communicating with each other using text, speech and/or video communication.

Synchronicity is a problem, as the "watching apart together" experience is already spoiled if the playout time differs less than a second, whereas delay differences of multiple seconds are likely to occur. TNO has a working ConnecTV implementation. However, user perception of synchronization errors has never been investigated, nor is it known what synchronization performance realistic implementations can achieve.

Project description

The graduate student should design and perform user tests to determine requirements on synchronicity, both in static (users watching apart together) and dynamic (users joining or leaving the group) cases.

Next, the graduate student should make an analysis of realistic network scenarios to design synchronization algorithms and to validate their performance, which should be verified with simulations.

We are looking for:

A graduate student with a beta background (Electronic Engineering, Computer Science or similar). Feeling for perception, user test design, performance analysis and - simulation is required. Experience with technical implementations of video technologies are desired, but not essential.

TNO is offering:

An interesting external assignment (at TNO), carried out in a stimulating environment, possibly resulting in a publication.

Candidates can contact: Georgios Karagiannis (




F. Boronat, J. Lloret, M. García, “Multimedia group and inter-stream synchronization techniques: A comparative study”, Elsevier Information Systems 34 (2009), pp. 108–131

Overview of synchronization technologies

Toshiro Nunome; Shuji Tasaka, "An Application–Level QoS Comparison of Inter–Destination Synchronization Schemes for Continuous Media Multicasting", IEICE transactions on communications, ISSN 0916-8516, Vol. 87 (2004), No. 10, pp. 3057-3067 (11).

Validation of inter-destination media synchronization technologies

ETSI TS 181 016: “Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Service Layer Requirements to integrate NGN services and IPTV”.

Search for "synchronization" to find the relevant use cases and requirements on inter-destination media synchronization

ETSI TS 182 027: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IPTV Architecture; IPTV functions supported by the IMS subsystem".

Search for "synchronization" to find the relevant architecture and procedures on inter-destination media synchronization

ETSI TS 183 063: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IMS-based IPTV stage 3 specification".

Search for "synchronization" to find the relevant protocol definition for inter-destination media synchronization

IETF: SIP: Session Initiation Protocol,

Session initiation protocol (SIP), that is used by TS 183 063 to initiate IPTV sessions and synchronization sessions

IETF: RTP: A Transport Protocol for Real-Time Applications,

Real-time transport protocol (RTP) and especially Real-time transport control protocol(RTCP), that is used by TS 183 063 to exchange synchronization status information and synchronization settings instructions. (RTP transports audio and video, RTCP achieves lip-sync between audio and video, TS 183 063 reuses RTCP for inter-destination media synchronization)

IETF: RTP Control Protocol Extended Reports (RTCP XR),

Solution to extend RCTP, which is used by TS 183 063 to convey additional parameters for synchronization.


Good introductions about IMS, IPTV,SIP and RTCP.