HEVC intra partitioning and mode decision using histograms of oriented gradients

A constant need for higher encoding efficiency is fulfilled by the newest video coding standard H.265/HEVC. It was designed to support higher resolution video like FullHD and 4K, but the cost brought by the improved coding efficiency is a major increase in computational complexity. This paper proposes a new algorithm for intra mode decision in HEVC, targeting real-time video processing. Our method achieves a considerable complexity reduction in intra prediction. It reaches the optimal coding-unit size and angular mode decision with a pre-processing step designed to evaluate the texture. Using an adjusted histogram of oriented gradients, the algorithm selects the best choice in CU size and computes an estimate for the dominant edges. Testing performed on two test video sequences showed significantly lower encoding times for the same quality, compared to the original reference software.