Combined Intra-Prediction for High-Efficiency Video Coding

New activities in the video coding community are focused on the delivery of technologies that will enable economic handling of future visual formats at very high quality. The key characteristic of these new visual systems is the highly efficient compression of such content. In that context this paper presents a novel approach for intra-prediction in video coding based on the combination of spatial closed- and open-loop predictions. This new tool, called Combined Intra-Prediction (CIP), enables better prediction of frame pixels which is desirable for efficient video compression. The proposed tool addresses both the rate-distortion performance enhancement as well as low-complexity requirements that are imposed on codecs for targeted high-resolution content. The novel perspective CIP offers is that of exploiting redundancy not only between neighboring blocks but also within a coding block. While the proposed tool enables yet another way to exploit spatial redundancy within video frames, its main strength is being inexpensive and simple for implementation, which is a crucial requirement for video coding of demanding sources. As shown in this paper, the CIP can be flexibly modeled to support various coding settings, providing a gain of up to 4.5% YUV BD-rate for the video sequences in the challenging High-Efficiency Video Coding Test Model.