Mohammadreza Ramezanpour - Department of Computer Engineering, Mobarakeh Branch, Islamic Azad University, Mobarakeh, Isfahan, Iran
Reihaneh Khorsand - Department of Computer Engineering, Dolatabad Branch, Islamic Azad University, Isfahan, Iran

Intra coding in High efficiency video coding (HEVC) can significantly improve the compression efficiency using 35 intra-prediction modes for 2N×2N (N is an integer number ranging from six to two) luma blocks. To find the luma block with the minimum rate-distortion, it must perform 11932 different rate-distortion cost calculations. Although this approach improves coding efficiency compared to the previous standards such as H.264/AVC, but computational complexity is increased significantly. In this paper, an intra-prediction technique has been described to improve the performance of the HEVC standard by minimizing its computational complexity. The proposed algorithm called prediction unit size decision (PUSD) was introduced to decrease evaluation of block sizes. The simulation results show that the time complexity is decreased by ~36% while the bit-rate is increased by 1.1 kbps, and PSNR is decreased by 0.6 db. Accordingly, the proposed algorithms have negligible effect on the video quality with great saving in the time complexity.

block size decision, HEVC, Intra coding, Temporary direction map, Prediction unit