Copy mode for static screen content coding with HEVC

Screen content largely consists of static parts, e.g. static background. However, none of the available screen content coding tools fully employs this characteristic. In this paper we present the copy mode, a new coding mode specifically aiming at increased coding efficiency for static screen content. The basic principle of the copy mode is the direct copy of the collocated block from the reference frame. Mean weighted BD-Rate gains of 2.4% are achieved for JCT-VC test sequences compared to SCM-2.0. For sequences containing lots of static background, coding gains as high as 7.6% are observed. The new coding mode is further enhanced by several encoder optimizations, among them an early skip mechanism. Thereby, the encoder runtime complexity is reduced by up to 39%.