The aim of this special issue is to provide an overview of state-of-the-art IQA/VQA methods and to address new developments towards various directions. The issue starts with an invited paper that surveys an area of great current research interest, namely NR QA. It is followed by another survey paper, which examines audiovisual QA. The next two papers each propose a novel image quality metric, one based on gradient profiles, and the other on structural similarity. They are followed by a paper on perceptual deblocking. Video quality is the topic of the last two papers, one investigating spatio-temporal interactions in VQA, and the other the impact of visual attention on VQA.