Adaptive Motion Vector Resolution in AVS3 Standard

This paper introduces an inter prediction technique, adaptive motion vector resolution and its extension, both of which have been adopted in the Baseline Profile of the AVS3 standard. In the previous video coding standard AVS2, the motion vector resolution is fixed to be quarter-pixel for motion vector difference coding. The adaptive motion vector resolution method allows the motion vector difference of a coding unit to be coded in various resolutions to reduce the bits coded for motion vector difference. To further improve the coding efficiency, an extended motion vector resolution scheme is developed by binding motion vector resolutions and history-based motion vector prediction candidates together according to a carefully designed rule. It is reported that the adaptive motion vector resolution method together with the extended motion vector resolution scheme achieves 4.1% BD-rate reduction on average in random access configuration on the latest AVS3 reference software.