Alan Jay Stein

Effective flicker removal from periodic intra frames and accurate flicker measurement

Flicker at periodic Intra-coded frames is a commonly seen video coding artifact, especially in low or medium bit rate coding. In this paper, a novel two-pass scheme is proposed to effectively remove I-frame flicker. The scheme involves a first pass of simplified P-frame coding to derive the no-flicker reference of the current frame, which is then taken as the target frame and coded with small quantization scales in the second pass of actual I-frame coding. Extensive experiment results demonstrate that our scheme successfully removes I-frame flicker, and greatly enhances the overall perceptual quality of coded video. Another contribution of this paper is a novel flicker distortion metric, which is superior than the existing metric, and can accurately measure flicker for any single frame.

Perceptual quality measurement of video frames affected by both packet losses and coding artifacts

This paper addresses the problem of perceptual quality measurement on individual coded video frames with distortions caused by both lossy source coding and lossy transmission. We focus on low bitrate H.264 coded video with error concealment and propagation due to packet losses. Identifying Human Visual System (HVS) masking effect as one of the most important factors affecting the perceptual quality, we investigate its impacts on the two aforementioned artifacts in individual video frames respectively, and then evaluate their corresponding Just-Noticeable-Difference (JND) based perceptual distortions. Finally, we combine the two distortions together and propose a block-wise full-reference quality metric for a single distorted video frame. Our subjective evaluation results show that the proposed metric correlates fairly well with actual subjective quality ratings.

An Unequal Error Protection Framework for DVB-H and Its Application to Video Streaming

In this paper, an unequal error protection (UEP) scheme is proposed for DVB-H based on its link layer forward error correction. The scheme preserves the existing DVB-H protocol stack and maintains its original time diversity. The UEP scheme is further applied to DVB-H video streaming service. The H.264 based temporal scalable coding is employed to facilitate UEP application and provides a set of UEP configurations to accommodate different channel conditions. Experimental results show graceful video quality degradation provided by the proposed framework.