Patent ID: 8917766

Claim:
A picture coding apparatus which codes an interlaced moving picture signal, said picture coding apparatus comprising: a non-transitory memory storing computer executable instructions; and a processor which executes the computer executable instructions to perform the steps of: acquiring motion information on motion in a field to be coded for each of a plurality of areas having at least one pixel included in the field to be coded, the plurality of areas including (i) at least one static area having motion equal to or smaller than a first threshold and (ii) at least one non-static area having motion greater than the first threshold; acquiring information indicating a ratio of (i) the number of the static areas in the entirety of the field to be coded to (ii) the number of the areas in the entirety of the field to be coded, based on the motion information for each of the plurality of areas included in the field to be coded, the number of the areas in the entirety of the field to be coded including the number of static areas in the entirety of the field to be coded and the number of the non-static areas in the entirety of the field to be coded; when only one reference field is selected from among fields previously coded, setting the reference field by selectively switching between a top field previously coded and a bottom field previously coded, based on the information indicating the ratio of (i) the number of the static areas in the entirety of the field to be coded to (ii) the number of the areas in the entirety of the field to be coded, the reference field being referred to for the field to be coded; and coding the field to be coded by using the set reference field.