Adaptive Coefficients Scanning for Transform Units in HEVC

• Main Authors: Yi-Ching Kuo, 郭乙情
• Other Authors: 楊士萱
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/kzw2c4

碩士 === 國立臺北科技大學 === 資訊工程系研究所 === 100 === High Efficiency Video Coding (HEVC) is a new video-coding standard after H.264/AVC, jointly developed by ISO/IEC and ITU. For the residual coefficients in a transform unit (TU), one of the three scanning orders, diagonal scan, horizontal scan, and vertical scan, will be chosen before entropy coding. The scanning-mode selection algorithm in HEVC is based on the TU size and the mode of intra prediction. We found from experiments that approximately 1.4% reduction in bit rate may be achieved by the optimal mode decision. In this thesis, we first analyze when the selection algorithm of HEVC may not be able to obtain the best scanning order. An adaptive mode-decision method is obtained from the reference blocks, based on the distribution pattern and grouping property of nonzero coefficients. The proposed method may decrease the bit-rate by 0.13% to 0.25% while maintaining the same video quality with almost the same encoding time.