Video picture prediction method and apparatus

A video encoder comprising:

• one or more processors;
• and
• a non-transitory computer-readable storage medium coupled to the processors and storing programming for execution by the processors, wherein the programming, when executed by the processors, configures the encoder to carry out operations comprising:
• obtaining a first indicator;
• if a value of the first indicator is equal to a first value,
• obtaining a second indicator, wherein, the second indicator is used to indicate a maximum length of a first candidate motion vector list according to following formula:
• MaxNumSubblockMergeCand=K−K_minus_max_num_subblock_merge_cand, wherein MaxNumSubblockMergeCand represents the maximum length of the first candidate motion vector list, K_minus_max_num_subblock_merge_cand represents the second indicator, and K is a preset non-negative integer, wherein the first candidate motion vector list is constructed for a block to be processed when a subblock merge prediction mode is used for the block;
• and
• encoding the first indicator and second indicator in a bitstream;
• if the value of the first indicator is equal to a second value,
• obtaining a third indicator, wherein, the third indicator is used to indicate the maximum length of the first candidate motion vector list, the second value is different from the first value;
• and encoding the first indicator and third indicator in the bitstream.