Test Zonal Search based on Region Label (TZSR) for Motion Estimation in HEVC

This paper presents a new complexity Reduction method for the diamond search pattern called TZSR based on region labels in HEVC/H.265 video coding. The solution introduces a new image region structure developed from a simplified version of the blob coloring algorithm (image labeling) to HEVC/H.265 video coding. Regions are either whole or part of image objects and normally span several coding tree blocks that are produced during HEVC encoding. Our method executes a complete Diamond Search (DS) for the first block of each region in order to identify the motion vector direction among eight different directions in DS. The motion estimation (ME) for the rest of the blocks in the region will perform a modified DS where only one direction point for various distances will be tested in order to reduce the code complexity. Experimental results demonstrate that the speedup achieved in our solution surpasses the time spent in our blob coloring algorithm. Furthermore, TZSR achieves an average speedup of 42.61% for low delay (LD) configuration and 52.13% for random access (RA) in the encoding time compared to the original ME algorithm in HEVC reference software (HM-16.7) with overall gains in PSNR (Peak Signal-to-Noise Ratio) and bit rate around 18.67% and 0.1 under LD and 28.37% and 0.74 under RA respectively.