Advanced video debanding

Abstract

High efficiency video coding has made it possible to stream video over bandwidth constrained communication networks. Depending on bit rate requirements, a video encoder sacrifices some image de- tails which can then introduce visual artefacts. Due to aggressive encoding a contouring staircase artefact called banding can be ob- served in image regions with very low texture. This paper presents a solution for removing banding artefacts using image filtering and dithering techniques. A new banding index (BI) metric is also pre- sented for quantitatively measuring the amount of banding in an im- age. Using this BI metric, we assess how much banding YouTube video encoding introduces in a video test dataset. There is a de- banding filter in ffmpeg called gradfun . We compare the results of our debanding technique with those of gradfun on the YouTube test dataset.