Abstract: In one embodiment, the method includes obtaining reference picture information, and determining at least one reference picture of the current image block from a plurality of pictures stored in a reference buffer based on the reference picture information. The reference picture information indicates a reference picture type of the reference picture. The reference picture type is based on temporal distance between a current picture including the current image block and the reference picture. At least one motion vector of the current image block is obtained according to the reference picture type. This obtaining step includes obtaining a motion vector of a co-located image block, and generating the motion vector of the current image block based on the motion vector of the co-located image block and the reference picture type. The current image block is decoded by motion-estimating the current image block using the motion vector of current image block.

Abstract: In one embodiment, the method includes obtaining reference picture information, and determining a first reference picture of the bi-predictive image block. The first reference picture has a co-located image block with respect to the bi-predictive image block. A second reference picture is determined based on a motion vector of the co-located image block. At least one motion vector of the bi-predictive image block is obtained according to the motion vector of the co-located image block and the reference picture type of at least one of the first reference picture and the second reference picture. The reference picture information indicates reference picture types of reference pictures, and the reference picture type being based on temporal distance between a current picture including the bi-predictive image block and the reference picture. The bi-predictive image block is decoded by motion-estimating the bi-predictive image block using the motion vector of the bi-predictive image block.

Abstract: In one embodiment, the method includes obtaining reference picture information, and determining at least one reference picture of the current image block from the reference picture information. The reference picture information indicates a reference picture type of the reference picture. The reference picture type is based on temporal distance between a current picture including the current image block and the reference picture. At least one motion vector of the current image block is obtained according to the reference picture type. This obtaining step includes obtaining a motion vector of a co-located image block, and generating the motion vector of the current image block based on the motion vector of the co-located image block and the reference picture type. The current image block is decoded by motion-estimating the current image block using the motion vector of current image block.

Abstract: In one embodiment, the method includes obtaining first and second motion vectors and a reference picture index of blocks other than the current block. The other blocks neighbor the current block. First and second motion vectors of the current block are determined using the first and second motion vectors of the other blocks. This determining includes applying a median operation to the first motion vectors of the other blocks and applying a median operation to the second motion vectors of the other blocks. A reference picture index of the current block is determined using the reference picture indices of the other blocks.

Abstract: In one embodiment, the apparatus includes a decoder. The decoder is configured to obtain first and second motion vectors and a reference picture index of a block other than the current block. The decoder is configured to determine first and second motion vectors of the current block using the first and second motion vectors of the other block such that the first motion vector of the current block has a same direction as the first motion vector of the other block and the second motion vector of the current block has a same direction as the second motion vector of the other block. The decoder is further configured to determine a reference picture index of the current block using the reference picture index of the other block, and to determine a direction of a reference picture for the current block based on the determined reference picture index.

Abstract: In one embodiment, the apparatus includes a decoder. The decoder is configured to obtain first and second motion vectors of a block other than the current block. The other block neighbors the current block at one of a left, top and top right position. The decoder is configured to determine first and second motion vectors of the current block using the first and second motion vectors of the other block such that the first motion vector of the current block has a same direction as the first motion vector of the other block and the second motion vector of the current block has a same direction as the second motion vector of the other block.

Abstract: In one embodiment, the method includes selecting a list 1 motion vector of the co-located block in a first list 1 reference picture as the motion vector for deriving list 0 and list 1 motion vectors of the bi-predictive block, if the co-located block only has the list 1 motion vector. The first list 1 reference picture is a type of reference picture permitted to be located temporally before or after a current picture, and the selected list 1 motion vector points to a second list 1 reference picture which is a reference picture of the first list 1 reference picture. The current picture includes the bi-predictive block. At least one motion vector of the bi-predictive block is derived by applying a bit operation to the selected motion vector.

Abstract: In one embodiment, the method includes obtaining first and second motion vectors and a reference picture index of a block other than the current block. First and second motion vectors of the current block are determined using the first and second motion vectors of the other block such that the first motion vector of the current block has a same direction as the first motion vector of the other block and the second motion vector of the current block has a same direction as the second motion vector of the other block. A reference picture index of the current block is determined using the reference picture index of the other block, and a direction of a reference picture for the current block is determined based on the determined reference picture index.

Abstract: In one embodiment, the method includes obtaining first and second motion vectors of a block other than the current block. The other block neighbors the current block at one of a left, top and top right position. First and second motion vectors of the current block are determined using the first and second motion vectors of the other block such that the first motion vector of the current block has a same direction as the first motion vector of the other block and the second motion vector of the current block has a same direction as the second motion vector of the other block.

Abstract: In one embodiment, the method includes obtaining a reference picture list including multiple reference pictures, and determining an initial reference picture index of the multiple reference pictures in the reference picture list based on display order information for the multiple reference pictures. The reference picture index numbers increase for reference pictures having a decreasing display order with respect to a picture including the macroblock and the reference picture numbers increase for reference pictures having an increasing display order with respect to the picture including the macroblock. The reference picture index numbers of the reference pictures having a decreasing display order are less than the reference picture index numbers of the reference pictures having an increasing display order. The initial reference picture index is selectively modified to produce a determined reference picture index based on the macroblock level of the macroblock.

Abstract: In one embodiment, the method includes obtaining a reference picture list including multiple reference pictures, and determining an initial reference picture index of the multiple reference pictures in the reference picture list based on display order information for the multiple reference pictures. The reference picture index numbers increase for reference pictures having a decreasing display order with respect to a picture including the macroblock, and the reference picture numbers increase for reference pictures having an increasing display order with respect to the picture including the macroblock. The reference picture index numbers of the reference pictures having a decreasing display order are greater than the reference picture index numbers of the reference pictures having an increasing display order. The initial reference picture index is selectively modified to produce a determined reference picture index based on the macroblock level of the macroblock.

Abstract: In one embodiment, the method includes selecting one motion vector of the co-located block in a first reference picture as the motion vector for deriving the motion vector of the bi-predictive block. A first temporal distance is derived from a difference between a current picture and a first reference picture. The current picture includes the bi-predictive block. A second temporal distance is derived from a difference between the first reference picture and a second reference picture. The selected motion vector is scaled based on the first and second temporal distances, and the motion vector of the bi-predictive block is derived based on the scaled motion vector.

Abstract: In one embodiment, the apparatus includes a decoder. The decoder is configured to obtain first and second motion vectors and a reference picture index of blocks other than the current block. The other blocks neighbor the current block. The decoder is configured to determine first and second motion vectors of the current block using the first and second motion vectors of the other blocks. This determination includes applying a median operation to the first motion vectors of the other blocks and applying a median operation to the second motion vectors of the other blocks. The decoder is further configured to determine a reference picture index of the current block using the reference picture indices of the other blocks.

Abstract: In one embodiment, the apparatus includes a decoder. The decoder is configured to obtain at least one motion vector of a block other than the current block, and the other block is associated with at least one reference picture indicated by a reference index for a set of multiple reference pictures. The decoder is configured to obtain a difference between picture output order information of the picture to be decoded and picture output order information of the at least one reference picture, and is configured to predict the motion vector for the current block using said at least one motion vector, based on the obtained difference.

Abstract: In one embodiment, the method includes selecting a list0 motion vector of a co-located image block in a reference picture for the bi-predictive image block as a motion vector for deriving motion vectors of the bi-predictive image block regardless of whether the co-located block includes a list1 motion vector. At least one motion vector of the bi-predictive block is derived by applying a bit operation to the selected motion vector.

Abstract: In one embodiment, the method includes obtaining a reference picture list including multiple reference pictures, and determining an initial reference picture index of the multiple reference pictures in the reference picture list based on display order information for the multiple reference pictures. The initial reference picture index is selectively modified to produce a determined reference picture index based on the macroblock level of the macroblock. The determined reference picture index is the initial reference picture index if the macroblock level of the macroblock is a frame, and the determined reference picture index is the initial reference picture index divided by 2 if the macroblock level of the macroblock is a field. The macroblock is decoded by selecting at least one reference picture from the reference picture list using the determined reference picture index.

Abstract: In one embodiment, the method includes selecting the list 1 motion vector of the co-located block in a first list 1 reference picture as the motion vector for deriving list 0 and list 1 motion vectors of the bi-predictive block, if the co-located block only has the list 1 motion vector. The first list 1 reference picture is a type of reference picture permitted to be located temporally before or after a current picture, and the selected list 1 motion vector points to a second list 1 reference picture which is a reference picture of the first list 1 reference picture. Also, the current picture includes the bi-predictive block. The selected motion vector is scaled based on a temporal distance between the current picture and the first list 1 reference picture, and the motion vector of the bi-predictive block is derived based on the scaled motion vector.

Abstract: In one embodiment, the method includes selecting the list0 motion vector of the co-located image block for the bi-predictive image block as a motion vector for deriving motion vectors of the bi-predictive image block regardless of whether the co-located block includes a list1 motion vector. The selected motion vector of the co-located block in the reference picture is scaled based on a temporal distance between a current picture and the reference picture. The current picture includes the bi-predictive block. The motion vector of the bi-predictive block is derived based on the scaled motion vector of the co-located block.

Abstract: In one embodiment, the method includes selecting the list0 motion vector of the co-located image block for the bi-predictive image block as a motion vector for deriving motion vectors of the bi-predictive image block if the co-located image block has a list1 and a list0 motion vector. At least one motion vector of the bi-predictive block is derived by applying a bit operation to the selected motion vector.

Abstract: In one embodiment, the method includes selecting a list0 motion vector of the co-located image block in the reference picture for the bi-predictive image block as a motion vector for deriving motion vectors of the bi-predictive image block if the co-located image block has a list1 and a list0 motion vector; and scaling the selected motion vector of the co-located block in the reference picture based on a temporal distance between a current picture including the bi-predictive block and the reference picture. The motion vector of the bi-predictive block is derived based on the scaled motion vector of the co-located block.