Fritz Seytter

Manipulation objektbasiert codierter Bilder als Anwendungsbeispiel neuer Videostandards

Dieser Artikel zeigt Moglichkeiten der Weiterverarbeitung von Datenstrukturen, welche im Rahmen des neuen Videocodierstandards MPEG-4 geplant sind. Die Struktur enthalt die Bilddaten segmentiert in semantisch bedeutsame Objekte, auf welche einzeln zugegriffen werden kann. Das fur die Erzeugung der Segmentierung benutzte Wasserscheidenverfahren sowie das Ergebnis der Manipulation der von ihm erkannten Objekte wird vorgestellt.

An efficient multiplex architecture for mobile MPEG-4 systems

This paper describes a multiplex architecture for mobile multimedia applications which has been considered as the underlying multiplex system in the MPEG-4 standardization effort (MPEG-4: Coding of audio-visual objects, standardization project of the ISO/IEC JTC1/SC29/WG11). Multimedia information consists of several different kinds of information which differ widely in their requirements on Quality of Service (QoS). The generic data services in todays mobile networks are not designed to comply with these QoS requirements. On the other hand, future object-based multimedia systems (e.g. MPEG-4) will use a multitude of simultaneous data streams. Many of these will have similar requirements on transmission. The proposed multiplexing architecture consists of two layers. One layer serves to bundle elementary data streams of similar QoS requirements, resulting in a small number of data streams with differing QoS requirements. The other layer serves to provide appropriate error protection for each of these streams and to form a single data stream which can be transmitted over an error prone link. Thus multiplexing overhead is minimized while error protection is adapted to the requirements of the individual elementary streams. It is argued that the lower layers dealing with protection and the error-resilient multiplex of the protected streams should be included in the network in order to avoid the problems of end-to-end error control. The system described can thus help to obtain highly efficient multimedia communication with future mobile networks.

MPEG-4 for broadband communications

This paper presents the future multimedia standard MPEG-4 and discusses its potential use for broadband applications. After an introduction into MPEG-4, scenarios for broadband MPEG-4 sessions are described and some examples are presented. At the same time, the structure of a decoder terminal is explained and the relevant parts from the broadband key issues of the standard are presented in more detail.

Wavelet codec for image sequence coding at very low bit rate with low latency

Wavelet theory provides an alternative approach to traditional DCT-based coding with properties that suggest an advantage over traditional schemes, especially for high compression ratios. This paper presents the design of an image coder for very low bit rates (8..64 kbit/s) which can be used for videophone applications. Apart from the image quality coding delay is an important critical factor. The coder performs a hybrid motion compensation/transform coding approach using a warping motion compensation to completely avoid blocking artifacts. Experiments using standard videophone test sequences show that the obtained image quality is similar to the best available results from DCT coders.