Standard-Compliant Low-Pass Temporal Filter to Reduce the Perceived Flicker Artifact

Abstract

Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Abstract-Flicker is a common video compression-related temporal artifact. It occurs when co-located regions of consecutive frames are not encoded in a consistent manner, especially when Intra frames are periodically inserted at low and medium bit rates. In this paper we propose a flicker reduction method which aims to make the luminance changes between pixels in the same area of consecutive frames less noticeable. To this end, a temporal low-pass filtering is proposed that smooths these luminance changes on a block-by-block basis. The proposed method has some advantages compared to another state-of-the-art methods. It has been designed to be compliant with conventional video coding standards, i.e., to generate a bitstream that is decodable by any standard decoder implementation. The filter strength is estimated on-the-fly to limit the PSNR loss and thus the appearance of a noticeable blurring effect. The proposed method has been implemented on the H.264/AVC reference software and thoroughly assessed in comparison to a couple of state-of-the-art methods. The flicker reduction achieved by the proposed method (calculated using an objective measurement) is notably higher than that of compared methods: 18.78% vs. 5.32% and 31.96% vs. 8.34%, in exchange of some slight losses in terms of coding efficiency. In terms of subjective quality, the proposed method is perceived more than two times better than the compared methods.Index Terms-Flicker artifact, flicker reduction, H.264/AVC, low-pass temporal filtering, motion-guided temporal filtering, onthe-fly filter strength control, standard compliant.

Dynamic Texture Map Based Artifact Reduction For Compressed Videos

“…= exp − (I(x + m, y + n, t + k) − I(x, y, t)) 2 2σ 2 (m, n, k) , (5) where the σ(m, n, k) spread parameter of the Gaussian function adapts the strength of the 3D-fuzzy filters at different activity levels such as smooth or detail areas [2,3].…”

“…The prediction error sometime is large and can cause mosquito artifacts. The authors in [4] and [5] introduce a method of flicker detection and reduction, however this method requires the original frames which are not available at the decoder.…”