Moving picture encoding method and motion picture decoding method

摘要

A moving picture coding apparatus includes a motion compensation coding unit for deciding a coding mode for coding a current block to be coded and for generating predictive image data based on the coding mode, and includes a direct mode enable/disable judgment unit for judging whether or not scaling processing can be performed when the coding mode decided by the motion compensation coding unit is a temporal direct mode. When it is judged that the scaling processing cannot be performed, the motion compensation coding unit performs motion compensation either by using another coding mode or without the scaling processing.

主权项

1. A decoding method of using a decoding apparatus for decoding a current block of a current field picture in a temporal direct mode using a motion vector of a decoded field picture, the decoded field picture being located closely in display order to the current field picture in which the current block is included, said decoding method comprising:
obtaining a motion vector of a co-located block included in the decoded field picture, the co-located block being co-located with the current block included in the current field picture to be decoded; judging that scaling of the motion vector of the co-located block cannot be performed when (i) display order information of the decoded field picture that includes the co-located block and (ii) display order information of a reference field picture that is referred to by the co-located block in a decoding process of the co-located block, are identical, and judging that the scaling of the motion vector of the co-located block can be performed when (i) the display order information of the decoded field picture that includes the co-located block and (ii) the display order information of the reference field picture that is referred to by the co-located block, are not identical, the decoded field picture and the reference picture belonging to the same frame as a top field and a bottom field; generating two motion vectors of the current block through the scaling when said judging judges that the scaling can be performed because (i) the display order information of the decoded field picture that includes the co-located block and (ii) the display order information of the reference field picture that is referred to by the co-located block, are not identical, and generating the two motion vectors of the current block by setting one of the two motion vectors to a zero value and another of the two motion vectors to be a predetermined value without the scaling when said judging judges that the scaling cannot be performed because (i) display order information of the decoded field picture that includes the co-located block and (ii) display order information of a reference field picture that is referred to by the co-located block in a decoding process of the co-located block, are identical; and performing motion compensation of the current block using the two motion vectors generated in said generating, wherein, the scaling is performed based on a temporal location relation between the current field picture and the decoded field picture and the reference field picture according to the display order information.