Adaptive Temporal Scalability of H.264-compliant Video Conferencing in Heterogeneous Mobile Environments

In this paper, we present a multipoint video conferencing system that adapts to heterogeneous members including mobiles. The system is built upon a low complexity scalable extension of our H.264 codec DAVC, and a congestion-aware dynamic adaptation layer. Our temporally scaled video codec DSVC has the same RD performance as the non-scaled version with comparable configuration. We achieve this by QP cascading, i.e., assigning gradually refining quantization parameters to the declining temporal layers. We present and analyse a mobile-compliant version of DSVC at reduced complexity that still admits comparable performance. Finally, we report on early work of dynamic layer tuning. Derived of delay variation measures, senders exploit scalable video layering to adapt the video transmission to varying network conditions. Initial results indicate that video performance remains close to optimal

Compoud media streaming in time

The widespread availability of networked multimedia pontentials embedded in an infrastructure of qualitative superior kind gives rise to new approaches in the areas of teleteaching and internet presentation: The distribution of professionally styled multimedia streams has fallen in the realm of possibility. This paper presents a prototype - both model and runtime environment - of a time directed media system treating any kind of presentational contribution as reusable media object components. The plug-in free runtime system is based on a database and allows for a flexible support of static media types. as well as for easy extensions by streaming media servers. The technique of pluggable subservers is used to include a real-time video codec, based on a fast low complexity wavelet transformation and an highly efficient lossless precoding scheme using ´partitioning, aggregation, and conditional coding (PACC). The JAVA implementation enables real-time video streaming in CIF format on IP connections with low bandwidth (≈ 200kb/s)

Compound Media Straming in Time

The widespread availability of networked multimedia potentials embedded in an infrastructure of qualitative superior kind gives rise to new approaches in the areas of teleteaching and Internet presentation: The distribution of professionally styled multimedia streams has fallen in the realm of possibility. This paper presents a prototype - both model and runtime environment - of a time directed media system treating any kind of presentational contribution as reusable media object components. The plug-in free runtime system is based on a database and allows for a flexible support of static media types as well as for easy extensions by streaming media servers. The technique of pluggable subservers is used to include a real-time video codec, based on a fast low complexity wavelet transformation and an highly efficient lossless precoding scheme using 'partitioning, aggregation, and conditional coding (PACC). The JAVA implementation enables real—time video streaming in CIF format on IP connections with low bandwidth (≈ 200kb/s)

An Environment for Processing Compound Media Streams - Work in progress paper V 2.0 -

With today s widespread availability of networked multimedia potentials embedded in an infrastructure of qualitative superior kind the distribution of professionally styled multimedia streams has fallen in the realm of possibility. This paper presents a prototypic environment - both model and runtime system - for processing composite media streams variably composed of multimedia data objects. The system consists of an intelligent media database, a Web-authoring tool, a time directed presentation stream and is based on a hypermedia data model of reusable object components. The plug-in free runtime system is designed as a pure JAVA implementation. Further educational applications of our architecture are presented, as well