Ein Beitrag zur Pixel-basierten Verteilten Videocodierung: Seiteninformationsgenerierung, WZ-Codierung und flexible Decodierung

The transmission of audiovisual media is one of the major tasks of communications engineering. Broadcasting (television and radio) is a typical application scenario. In modern digital transmission systems conventional video coding methods are used. Those coding methods are very suitable for the broadcasting scenario, due to their low decoding complexity. New application scenarios such as video encoding on mobile devices pose new challenges. Mobile devices are very limited in computing capability. Thus the demand for low complexity video encoders is born. The distributed video coding theory provides methods to design video communication systems with very low encoding complexity. This thesis is a contribution to the distributed video coding. It is focused on very low encoding complexity, increased rate distortion performance and improved decoding flexibility. The very low encoding complexity is ensured by following the pixeldomain coding approach. One major contributions relates to the side information improvement by temporal interpolation. Major problems such as very fast and inhomogeneous motion as well as occlusions and revelation are considered. Local image features are incorporated to get a rough and robust estimation of the motion in a video sequence. Furthermore, the rate distortion performance is strongly influenced by the WynerZiv coding. It is implemented using the powerful turbo coding approach. The coding efficiency is particularly improved by modifying the turbo decoding process for nonuniform sources. At least, the feedback channel is a major drawback of distributed video coding systems compared to conventional systems. Many application scenarios do not support a feedback channel. Flexible decoding is proposed, which is one step in the solution of the feedback channel problem. It provides a higher degree of freedom for the decoder, which can handle the received data in a more flexible way. Finally, the evaluation of the developed methods shows equal performance compared to conventional video coding (e.g. H.264intra), for sequences with moderate motion.