Patent ID: 7848426

Claim:
A method of estimating a motion vector of a macroblock of a current frame in a transcoder, the method comprising: (a) determining whether at least one motion vector of the macroblock of the current frame is created with reference to a macroblock of a dropped frame; (b) if the at least one motion vector of the macroblock of the current frame is created with reference to the macroblock of the dropped frame, then estimating the at least one motion vector and the number of at least one reference frame of the macroblock of the current frame by tracing back at least one reference frame until an undropped frame is found, wherein the number of at least one reference frame is determined by considering the number of at least one dropped frame; (c) decomposing a sub-block of a predetermined size into 4×4 blocks, wherein the macroblock is composed of a plurality of sub-blocks; and (d) if the 4×4 blocks overlap a reference frame, searching for an overlapped sub-block of the reference frame and estimating a motion vector of each of the 4×4 blocks based on an overlapping area and motion vector information of the overlapped sub-block of the reference frame, wherein, in the estimating the motion vector of each of the 4×4 blocks, the motion vector of each of the 4×4 blocks is estimated based on an averaged value of motion vectors of sub-block that are overlapped by the each of the 4×4 blocks and an averaged value of overlapping areas of the overlapped sub-blocks of the reference frame.