Miloš Liška

High-definition multimedia for multiparty low-latency interactive communication

We describe a high-quality collaborative environment that uses High-Definition (HD) video to achieve near realistic perception of a remote site. The capture part, consisting of a HD camera, Centaurus HD-SDI capture card, and UltraGrid software, produces a 1.5 Gbps UDP data stream of uncompressed HD video that is transferred over a 10GE network interface to the high-speed IP network. The HD video stream displaying uses either a software-based solution with color depth down-sampling and field de-interlacing, or another Centaurus card. Data distribution to individual participants of the videoconference is achieved using a user-controlled UDP packet reflector based on the Active Element idea. The viability of this system has been demonstrated at the iGrid 2005 conference for a three-way high quality videoconference among sites in the Czech Republic, Louisiana, and California.

Distributed and collaborative visualization of large data sets using high-speed networks

We describe an architecture for distributed collaborative visualization that integrates video conferencing, distributed data management and grid technologies as well as tangible interaction devices for visualization. High-speed, low-latency optical networks support high-quality collaborative interaction and remote visualization of large data.

Multimedia support for individualized learning

Multimedia play growing role in learning. It is possible to use multimedia support not only for demonstrations during the lectures but also to create multimedia material for learning as record of the lecture. Recording lectures and providing recorded material both on-line and off-line is a way to solve otherwise contradictory requirements: how to substantially increase the number of students while keeping the number of teachers and their load constant or even decreasing. Design and implementation of a system for supporting individualized learning process in both synchronous and asynchronous manner are discussed as well as practical experiences with this system. Important role in learning process plays information accessibility and this feature is achieved by the indexing of the lecture record.

Stereoscopic Video over IP Networks

Transfers of high-quality multimedia content pose new demands on capacity and services provided by the contemporary high-speed computer networks. Transfer of stereoscopic video is a specific example, as it needs synchronization between two separate data streams. We have set up a stereoscopic video capture system and studied synchronization of two separate digital video format streams sent over packet networks. We have adapted application tools to support the synchronization and used an active element working as a synchronizing UDP packet reflector to explicitly synchronize the streams if they are desynchronized in the network. We have experimentally studied the quality of achievable synchronization and the relationship between the amount of desynchronization and the additional latency overhead posed by buffering of the data on the synchronizing reflector. The results prove our assumption that even high-quality DV streams can be successfully synchronized using the simple packet reflector running on common IA32-based computer

Special Media Transmissions: The Technology and Applications

The talk will showcase the technology developed by CESNET for very high quality, low-latency media transmissions over high-speed networks and its applications in various fields including medicine, arts, broadcasting and cinematography, sports or education. The talk covers different aspects and demands of such applications and how they can be implemented using a commodity hardware and the UltraGrid software for low latency and high-quality media network transmissions. Complex applications of high-quality media transmissions over dynamic network infrastructures may easily become very hard to be configured, deployed and orchestrated manually. The talk will also showcase the CoUniverse middleware developed by CESNET and the Masaryk University designed for building real-time user-empowered applications based on media transmissions. The solution based on the CoUniverse middleware is also able to interface with the SDN networks and orchestrate its own network paths optimized with respect to the quality of the transmitted media in the SDN environments.