Adaptive Quad-tree Complexity Control for HEVC

To reduce the computational complexity of High Efficiency Video Coding (HEVC), this paper proposed an adaptive quad-tree complexity control mechanism. The proposed mechanism first defines similar region flag (SRF) to distinguish between similar region and non-similar region. Then, two algorithms, similar region depth range prediction algorithm and non-similar region depth range prediction algorithm, are proposed. The similar region depth range prediction algorithm estimates the feature of similar region based on coding unit (CU) depth of this region. The optimal depth of this region can be predicted. The non-similar region depth range prediction algorithm can skip low probability tree nodes based on depth correlation coefficient (DCC), which is calculated based on scene content change. Experimental results show that the pro-posed mechanism can reduce computational complexity by 28.17% on average with 0.75% Bjøntegaard delta bit rate (BDBR) increase and 0.03dB Bjøntegaard delta peak signal-to-noise rate (BDPSNR) drop under random access (RA) con-figuration. For low delay (LD) configuration, it can reduce complexity by 32.99% with 1.98% BDBR increase and 0.06dB BDPSNR drop penalty. The proposed mechanism is expected to be applied in the real-time environments.