A method of decoding a bitstream by an electronic device, the method comprising: determining a block unit from an image frame according to the bitstream; selecting, based on a set flag determined from the bitstream, one of a plurality of candidate groups, wherein each of the plurality of candidate groups includes one or more first merge mode with motion vector difference, MMVD, candidate lists, each candidate list being associated with one MMVD prediction parameter and including a plurality of first MMVD candidate parameters for said one MMVD prediction parameter; determining a plurality of MMVD indications of the block unit according to the bitstream; selecting a plurality of MMVD prediction parameters of the block unit based on the plurality of MMVD indications and the selected candidate group, wherein: one or more of the plurality of MMVD prediction parameters are selected from the plurality of first MMVD candidate parameters in the one or more first MMVD candidate lists of the selected one of the plurality of candidate groups selected based on the set flag, and MMVD prediction parameters other than the one or more of the plurality of MMVD prediction parameters are selected from a plurality of second MMVD candidate parameters in one or more second MMVD candidate lists each of which is different from the one or more first MMVD candidate lists; and reconstructing the block unit based on the plurality of MMVD prediction parameters. determining a block unit from an image frame according to the bitstream; selecting, based on a set flag determined from the bitstream, one of a plurality of candidate groups, wherein each of the plurality of candidate groups includes one or more first merge mode with motion vector difference, MMVD, candidate lists, each candidate list being associated with one MMVD prediction parameter and including a plurality of first MMVD candidate parameters for said one MMVD prediction parameter; determining a plurality of MMVD indications of the block unit according to the bitstream; selecting a plurality of MMVD prediction parameters of the block unit based on the plurality of MMVD indications and the selected candidate group, wherein: one or more of the plurality of MMVD prediction parameters are selected from the plurality of first MMVD candidate parameters in the one or more first MMVD candidate lists of the selected one of the plurality of candidate groups selected based on the set flag, and MMVD prediction parameters other than the one or more of the plurality of MMVD prediction parameters are selected from a plurality of second MMVD candidate parameters in one or more second MMVD candidate lists each of which is different from the one or more first MMVD candidate lists; and one or more of the plurality of MMVD prediction parameters are selected from the plurality of first MMVD candidate parameters in the one or more first MMVD candidate lists of the selected one of the plurality of candidate groups selected based on the set flag, and MMVD prediction parameters other than the one or more of the plurality of MMVD prediction parameters are selected from a plurality of second MMVD candidate parameters in one or more second MMVD candidate lists each of which is different from the one or more first MMVD candidate lists; and reconstructing the block unit based on the plurality of MMVD prediction parameters.