Anotace:
From the beginnings of ITU-T H.261 to H.265 (HEVC), each new video coding standard has aimed at halving the bitrate at the same perceptual quality by redundancy and irrelevancy reduction. Each improvement has been explained by comparably small changes in the video coding toolset. This contribution aims at starting the Quality of Experience (QoE) analysis of the accumulated improvements over the last thirty years. Based on an overview of the changes in the coding tools, we analyze the changes in the quantized residual information. Visual comparison and statistical measures are performed and some interpretations are provided towards explaining how irrelevancy reduction may have led to such a huge reduction in bitrate. The interpretation of the results in terms of QoE paves the way towards an understanding of the coding tools in terms of visual quality. It may help in understanding how the irrelevancy reduction has been improved over the decades. Understanding how the differences of the residuals relate to known or yet unknown properties of the human visual system, may enable a closer collaboration between perception research and video compression research.