HEVC's intra mode process expedited using Histogram of Oriented Gradients

The brute-force behavior of High Efficiency Video Coding (HEVC) is the biggest hurdle in the communication of multimedia content. Therefore, two novel methods will be presented here to expedite the intra mode decision process of HEVC. In the first algorithm, the feasibility of Histogram of Oriented Gradients (HOG) for early intra mode decision is presented by using statistical evidence. Then, HOG of the current block and 35 intra predictions are obtained. The intra-prediction that gives the least sum of absolute difference (SAD) with the HOG of the current block is selected as the termination point. In the second algorithm, the difference between the Hardmard-cost of intra modes is modeled to achieve fast intra mode decision. The proposed algorithms accelerated the encoding process of the HEVC by 5% and 35.57%, while their Bjontegaard Delta Bit Rate (BD-BR) is 1.09% and 1.61%, respectively.