Independent uniform prediction mode for screen content video coding

Many of the existing video coding standards in use today were developed primarily using camera-captured content as test material. Today, with the more widespread use of connected devices, there is an increased interest in developing video coding tools that target screen content video. Screen content video is often characterized by having sharp edges, noiseless graphics-generated region, repeated patterns, limited sets of colors, etc. This paper presents an independent uniform prediction (IUP) mode for improving the coding efficiency of screen content video. IUP chooses one color out of a small set of global colors to form a uniform prediction block. Unlike existing palette-based modes, IUP does not have to construct and signal a color index map for every block that is coded. Experimental results using IUP in the HEVC Range Extensions 6.0 framework are presented, along with results using techniques that reduce complexity so that the IUP-based encoder is faster than the reference encoder.