Progressive motion vector resolution for HEVC

This paper proposes a progressive motion vector resolution (PMVR) method for High Efficiency Video Coding (HEVC). In the proposed scheme, high motion vector (MV) resolutions, e.g. 1/4 or 1/8 pixel resolution, are employed for MVs near to the motion vector predictor (MVP) and low MV resolutions are employed for MVs far from the MVP. The range of each MV resolution is indicated by a threshold parameter. And a new motion vector difference (MVD) derivation method is designed to encode MVD efficiently. Experimental results show that PMVR with 1/8 pixel motion search can achieve a BD-rate gain up to 16% with almost the same coding time with HM8.0, and for PMVR without 1/8 pixel motion search, up to 6.1% BD-rate gain can be achieved with 9% encoding time saving on average.