Lossless screen content coding in HEVC based on sample-wise median and edge prediction

The generation of screen content (SC) videos has considerably increased with the popularity of multimedia applications such as video conferencing, remote desktop sharing and remote education. SC videos, as opposed to natural video sequences, are challenging to compress due to the high number of sharp edges. This paper proposes the sample-based angular prediction with median and edge prediction (SAP-ME), a novel intra-prediction method for lossless coding of SC videos. SAP-ME incorporates the advantages of three types of sample-wise intra-prediction; namely, DPCM-based angular intra-prediction, median prediction and edge prediction. By using rate distortion optimization, SAP-ME selects among these three types of predictions to accurately predict directional patterns, smooth regions and sharp edges, with a low computational complexity. Evaluation results on a variety of SC videos show that SAP-ME attains average bit-rate reductions of 16.13% over current HEVC intra-prediction coding for lossless coding.