Abstract: The present invention is a variable length coding method for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and comprises: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Abstract: A picture coding apparatus includes a motion vector estimation unit and a motion compensation unit. The motion vector estimation unit selects one method for deriving a motion vector of a block to be motion-compensated, depending on a motion vector of a block located in a corner of a decoded macroblock from among a group of blocks that compose the decoded macroblock corresponding to the current macroblock to be coded and determines the motion vector derived by the selected method for derivation to be a candidate of the motion vector of the current macroblock to be coded. The motion compensation unit generates a predictive image of the block to be motion-compensated based on the estimated motion vector.

Abstract: The present invention is a variable length coding method for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and comprises: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Abstract: An image decoding method is provided which includes a time information determination step of determining time information of a current picture, a first reference picture referred to by the current picture and a second reference picture referred to by the current picture; a scaling parameter calculation step of calculating a scaling parameter based on a time distance between the first reference picture and a second reference picture; a weighting coefficient determination step of determining two weighting coefficients based on the scaling parameter; a predictive pixel value generation step of generating a predictive pixel value of the current picture by scaling a pixel value of the first reference picture and a pixel value of the second reference picture using the two weighting coefficients determined in the weighting coefficient determination step; and a decoding step of decoding the current picture using the predictive pixel value.

Abstract: The present invention is a variable length coding method for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and comprises: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Abstract: The present invention is a variable length coding method for coding coefficients in each block which are obtained by performing frequency transformation on picture data of a moving picture per block having a predetermined size, and comprises: a coefficient scanning step of scanning the coefficients in the block in a predetermined order; and a coding step of coding the coefficients scanned in the coefficient scanning step into variable length codes in a predetermined order by switching a plurality of tables to be used for coding. Here, a direction of switching between the tables may be one-directional. Also, the coding may be non-arithmetic coding.

Abstract: In a picture coding method for generating a coded signal corresponding to each picture by coding a plurality of coded signals, a switching picture which is capable of switching a plurality of coded signals and subsequent pictures of the switching picture can refer to only a group of pictures of the same time in the coded signals. More specifically, the case where picture numbers of an adjacent picture of an S picture and the S picture are not continuous is not considered as an error.

Abstract: According to a picture coding method, a coded picture is stored, as a reference picture, into a storage unit; commands indicating correspondence between reference pictures and reference indices for designating reference pictures and coefficients used for generation of predictive images are generated; a reference picture being used when motion compensation is performed on a current block in a current picture to be coded is designated by a reference index; a predictive image is generated by performing linear prediction on a block being obtained by motion estimation within the designated reference picture, by use of a coefficient corresponding to the reference index; a coded image signal including a coded signal obtained by coding a prediction error being a difference between the current block in the current picture to be coded and the predictive image, the commands, the reference index and the coefficient is outputted.

Abstract: A video encoder (70) for coding moving pictures comprising a buffer (16c) with a plurality of memory areas capable of storing frames composed of top fields and bottom fields, a motion estimation unit (19) operable to code, field by field, inputted pictures performing moving estimation and moving compensation by referring, field by field, to the picture data stored in a memory area, a motion compensation unit (16d), a subtractor (11), a transformation unit (13) and a quantization unit (14), a memory management unit (71) operable to manage, frame by frame, a plurality of memory areas, an inverse quantization unit (16a) and inverse discrete cosine transform unit (16b) operable to decode picture data in coded fields and store the picture data in the decoded field in any of the plurality of memory areas under the management by the memory management unit (71).

Abstract: A frame coding unit generates individual picture signal information from a moving picture signal, and outputs a frame code value which is a numeric value to be obtained as a result of coding picture signal information of each frame. A variable length coding unit decomposes the frame code value into unit frame code values which are basic units of coding, converts the unit frame code values into frame code words using only a single code table, and constructs a frame stream by combining the converted frame code words. A multiplexing unit multiplexes a header stream which is constructed through a method equivalent to a conventional method and the frame stream, and constructs a picture coded signal.

Abstract: A coding distortion removal method is provided for removing coding distortion in an area disposed on both sides of a block boundary between a first block and an adjacent second block in a picture having a plurality of blocks, each block being adaptively coded either as a field structure block, comprising only even field pixels or comprising only odd field pixels, or a frame structure block, comprising odd field pixels and even field pixels. The method includes detecting whether the block boundary between the first block and the adjacent second block is a block boundary between a field structure block and a frame structure block, and performing a coding distortion removal process on the first block and the adjacent second block. The coding distortion removal process includes determining whether coding distortion removal is needed, determining the number of pixels to be processed, and removing coding distortion.

Abstract: A moving picture coding apparatus includes a counter unit which counts the number of pictures following an intra coded picture; and a motion estimation unit which compares respectively only reference pictures which are the intra coded picture or the following pictures, selected from among a reference picture Ref1, a reference picture Ref2 and a reference picture Ref3 stored in memories, with a picture signal, and determines the reference picture whose inter picture differential value is smallest.

Abstract: A moving picture coding method for coding a picture with switching between frame coding and field coding adaptively on a block-by-block basis includes: determining the maximum number of reference indices for field coding for specifying fields which are to be referred to at the time of field coding, using the maximum number of reference indices for frame coding for specifying frames which are to be referred to at the time of frame coding; and assigning to fields the reference indices for field coding for specifying fields which are to be referred to at the time of field coding, within a range of the determined maximum number thereof, using the reference indices for frame coding for specifying frames which are to be referred to at the time of frame coding.

Abstract: A moving picture coding apparatus includes a motion estimation unit (101) for performing motion estimation by fixing the one of two reference pictures as a reference picture indicated by an inputted default reference picture number DefRefNo and a variable length coding unit (107) for performing variable length coding on coded residual data ERes, a prediction type PredType, a reference picture number RefNo2 and motion vectors MV1, MV2 on a block-by-block basis, and outputting them as coded moving picture data Str.

Abstract: A frame coding unit generates individual picture signal information from a moving picture signal, and outputs a frame code value which is a numeric value to be obtained as a result of coding picture signal information of each frame. A variable length coding unit decomposes the frame code value into unit frame code values which are basic units of coding, converts the unit frame code values into frame code words using only a single code table, and constructs a frame stream by combining the converted frame code words. A multiplexing unit multiplexes a header stream which is constructed through a method equivalent to a conventional method and the frame stream, and constructs a picture coded signal.

Abstract: A frame coding unit generates individual picture signal information from a moving picture signal, and outputs a frame code value which is a numeric value to be obtained as a result of coding picture signal information of each frame. A variable length coding unit decomposes the frame code value into unit frame code values which are basic units of coding, converts the unit frame code values into frame code words using only a single code table, and constructs a frame stream by combining the converted frame code words. A multiplexing unit multiplexes a header stream which is constructed through a method equivalent to a conventional method the frame stream, and constructs a picture coded signal.

Abstract: An image decoding method is provided which includes a time information determination step of determining time information of a current picture, a first reference picture referred to by the current picture and a second reference picture referred to by the current picture; a scaling parameter calculation step of calculating a scaling parameter based on a time distance between the first reference picture and a second reference picture; a weighting coefficient determination step of determining two weighting coefficients based on the scaling parameter; a predictive pixel value generation step of generating a predictive pixel value of the current picture by scaling a pixel value of the first reference picture and a pixel value of the second reference picture using the two weighting coefficients determined in the weighting coefficient determination step; and a decoding step of decoding the current picture using the predictive pixel value.

Abstract: An image decoding method is provided which includes a time information determination step of determining time information of a current picture, a first reference picture referred to by the current picture and a second reference picture referred to by the current picture; a scaling parameter calculation step of calculating a scaling parameter based on a time distance between the first reference picture and a second reference picture; a weighting coefficient determination step of determining two weighting coefficients based on the scaling parameter; a predictive pixel value generation step of generating a predictive pixel value of the current picture by scaling a pixel value of the first reference picture and a pixel value of the second reference picture using the two weighting coefficients determined in the weighting coefficient determination step; and a decoding step of decoding the current picture using the predictive pixel value.

Abstract: 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.

Abstract: A motion vector coding unit 117 executes processing including a neighboring block specification step (S100) of specifying a neighboring block which is located in the neighborhood of a current block; a judgment step (Steps S102, S104) of judging whether or not the neighboring block has been coded using a motion vector of another block; a prediction step (S106, S108) of deriving a predictive motion vector of the current block using a motion vector calculated from the motion vector of the other block as a motion vector of the neighboring block; and a coding step (S110) of coding the motion vector of the current block using the predictive motion vector.