Motion picture encoding device and motion picture decoding device

An apparatus comprising:

• a decoder which decodes, using a generated chrominance motion vector, an encoded motion picture signal composed of a plurality of fields with an inter-field motion compensating prediction to thereby provide a decoded motion picture signal,
• wherein the decoder generates the chrominance motion vector from a luminance motion vector according to a calculation method represented by
• the formula:
• MVCy=MVy/2
• when a reference source field and a reference destination field are both a top field or are both a bottom field,
• the formula:
• MVCy=MVy/2−0.25 when the reference source field is the top field and the reference destination field is the bottom field, and
• the formula:
• MVCy=MVy/2+0.25
• when the reference source field is the bottom field and the reference destination field is the top field, wherein
• MVy implies a luminance motion vector indicating a vertical displacement of one luminance pixel of a field image by the value 1 of a vector component as units,
• MVCy implies a chrominance motion vector indicating a vertical displacement of one chrominance pixel of a field image by the value 1 of a vector component as units, and
• a motion vector is a vector that connects two corresponding pixels between a reference source field and a reference destination field.