Fast HEVC intra mode decision based on dominant edge evaluation and tree structure dependencies

The encoding efficiency of the current version of the High Efficient Video Coding (HEVC) standard is considerably higher than that of previous video coding standards. One contributor to this improvement is the large set of prediction directions used in intra prediction, resulting in better values for the Rate-Distortion (R-D) performance when compared to the H.264/AVC equivalent predictor. However the larger set of prediction directions implies in a much larger computational cost. This work presents an intra mode decision algorithm that reduces this complexity by taking into account the dominant edge orientation of the current and previous tree depth Prediction Units (PU). Experimental results show that the proposed method provides a reduction of up to 34.9% in computational complexity with a small increase in the bit-rate and a negligible reduction in PSNR values.