Fast CU Encoding Schemes Based on Merge Mode and Motion Estimation for HEVC Inter Prediction
The emerging video coding standard High Efficiency Video Coding (HEVC) has shown almost 40% bit rate reduction over the state of the art Advanced Video Coding (AVC) standard but at about 40% computational complexity overhead. The main reason for HEVC computational complexity is the inter prediction that accounts for 60% 70% of the whole encoding time. In this paper, we propose several fast coding unit (CU) encoding schemes based on the Merge mode and motion estimation information to reduce the computational complexity caused by the HEVC inter prediction. Firstly, an early Merge mode decision method based on motion estimation (EMD) is proposed for each CU size. Then, a Merge mode based early termination method (MET) is developed to determine the CU size at an early stage. To provide a better balance between computational complexity and coding efficiency, several fast CU encoding schemes are surveyed according to the rate distortion complexity characteristics of EMD and MET methods as a function of CU sizes. These fast CU encoding schemes can be seamlessly incorporated in the existing control structures of the HEVC encoder without limiting its potential parallelization and hardware acceleration. Experimental results demonstrate that the proposed schemes achieve 19% 46% computational complexity reduction over the HEVC test model reference software, HM 16.4, at a cost of 0.2% 2.4% bit rate increases under the random access coding configuration. The respective values under the low delay B coding configuration are 17% 43% and 0.1% 1.2%
KSII Trans. Internet Inf. Syst.