Abstract: A method, medium, and apparatus predicting direct mode motion of a multi-angle moving picture on a temporal and spatial basis. The method may include locating a block to which a co-located block of a block for which coding is sought makes reference with a motion vector, calculating a forward motion vector and a backward motion vector by making reference to pictures of an adjacent camera that exists in a direction parallel to a direction corresponding to the motion vector when a reference picture is not taken by the same camera as the picture to which the block for which coding is sought belongs, and calculating forward and backward reference blocks of the block for which coding is sought by applying weights to the calculated motion vectors. Therefore, the moving picture can be coded/decoded by locating motion vectors of previous and subsequent pictures without predicting motion, reducing calculation and performance time.

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.