Quick deciding method for division of HEVC intraframe coding units

Abstract

The invention discloses a quick deciding method for division of HEVC intraframe coding units, which respectively adopts corresponding strategy according to the depth of the CU to decide whether the CU is continuously divided or whether to skip the prediction process of the CU. Brightness variations of each CU in the horizontal, vertical and diagonal directions are computed by using Haar wavelet transform, and the texture complexity of the CU is determined according to the magnitudes of the variations. For the CU with the depth of 0 or 1, if all the brightness variations in the three directions are more than a threshold, the current CU needs to be divided continuously. For such CU, the prediction process based on rate distortion optimization of the current CU is to be skipped and directly divided into the next layer. For the CU with the depth of 2 or 3, if all the brightness variations in the three directions are more than a threshold, the current CU is not divided continuously. According to the method, the statistic characteristics and texture characteristics of the CU division distribution are combined, whether the division of the CU needs to be stopped or continued can be effectively predicted, and thereby a quadtree is effectively pruned and redundant coding nodes are skipped. The computation complexity of intraframe coding of the HEVC coder can be significantly reduced.

Description

technical field [0001] The invention belongs to the technical field of high-performance video coding (High Efficiency Video Coding, HEVC), and relates to a decision-making technology of CU division in intra-frame coding. technical background [0002] In order to produce a better compression effect, the HEVC coding standard adopts the image division method of the quadtree structure. This division method can obtain better compression efficiency than H.264 / AVC, but at the same time, due to the need for each size of coding unit (CodingUnit, CU), prediction unit (PredictionUnit, PU) and transformation unit (TransformUnit, TU ) must be calculated by Rate-Distortion Optimization (RDO) to obtain the optimal division, which greatly increases the computational complexity of the encoder. If the division method of the CU can be predicted in advance, the RDO process can be directly skipped for some nodes in the quadtree or the quadtree can be pruned, which can effectively reduce the com...

AI Technical Summary

Problems solved by technology

However, because this method only uses one feature of variance, the prediction is not accurate enough, which leads to a large loss of video quality after the encoder is accelerated.

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