The present disclosure provides systems and methods for inter prediction process in video data coding. One exemplary method comprises: selecting one of a DMVR process and a BDOF process, based on a video bitstream; and inter predicting an image block based on the selected process. The selection can be made either through explicit signaling, or implicit derivation at the decoder side. According to one exemplary method, selecting the one of the DMVR process and the BDOF process can be performed by selecting the one of the DMVR process and the BDOF process based on: a flag signaled at at least one of a coding unit (CU) level and a coding tree unit (CTU) level, or a merge candidate index associated with an extended merge candidate list.