Abstract: Motion estimation of a macro block in inter16×16, inter16×8, and inter8×16 modes is performed and a determination of whether to further perform motion estimation in a P8×8 mode is made. Motion estimation in P8×8 mode is either omitted or performed and one mode is determined according to a rate distortion cost of the respective modes. Spatial prediction encoding may then be performed or omitted based on comparing the rate distortion cost of the one mode with a predetermined value. Accordingly, by selectively omitting variable block motion estimation and spatial prediction encoding which are the most complicated operations in an H.264 encoder, determining an encoding mode is rapidly performed such that encoding speed increases.

Abstract: A transcoding method, medium, and apparatus for transforming a coded video format into another coded video format. The transcoding method includes decoding a bitstream encoded using a first coding method to output data in a pixel domain and motion vector and macroblock information for each of macroblock of the bitstream, and performing motion compensation using the motion vector and macroblock information to encode the data in the pixel domain using a second coding method.

Abstract: A motion vector (MV) search method including: searching for an integer-pixel MV among integer pixels and choosing an integer pixel corresponding to the integer-pixel MV; searching for a half-pixel MV among half pixels around the chosen integer pixel and choosing a half pixel corresponding to the half-pixel MV; and searching, when the half pixel is chosen, for a quarter-pixel MV among only specified quarter pixels disposed between the chosen integer pixel and the chosen half pixel and around the chosen half pixel and choosing a quarter pixel corresponding to the quarter-pixel MV.