A survey of hybrid MC/DPCM/DCT video coding distortions

The motion-compensated hybrid DCT/DPCM algorithm has been successfully adopted in various video coding standards, such as H.261, H.263, MPEG-1 and MPEG-2. However, its robustness is challenged in the face of an inadequate bit allocation, either globally for the whole video sequence, or locally as a result of an inappropriate distribution of the available bits. In either of these situations, the trade-off between quality and the availability of bits results in a deterioration in the quality of the decoded video sequence, both in terms of the loss of information and the introduction of coding artifacts. These distortions are an important factor in the fields of filtering, codec design, and the search for objective psychovisual-based quality metrics; therefore, this paper presents a comprehensive analysis and classification of the numerous coding artifacts which are introduced into the reconstructed video sequence through the use of the hybrid MC/DPCM/DCT video coding algorithm. Artifacts which have already been briefly described in the literature, such as the blocking effect, ringing, the mosquito effect, MC mismatch, blurring, and color bleeding, will be comprehensively analyzed. Additionally, we will present artifacts with unique properties which have not been previously identified in the literature. (C) 1998 Elsevier Science B.V. All rights reserved.