1. A method of decoding a video using an intra-prediction at a video decoding apparatus, comprising: reconstructing information on an intra-prediction mode of a current block to be decoded from a bitstream, wherein the current block is a square block; reconstructing transform block information from the bitstream and reconstructing transform coefficients corresponding to each of one or more transform blocks divided in a quad tree structure from the current block; and reconstructing the current block based on the information on the intra-prediction mode and the reconstructed transform coefficients of the transform blocks, wherein the reconstructing of the transform block information comprises: reconstructing a split transform flag indicating whether a block corresponding thereto is divided into four equal-sized square blocks of a low layer in the quad tree structure; reconstructing a first chroma coded block flag and a second chroma coded block flag of the corresponding block, irrespectively of whether or not the split transform flag indicates that the corresponding block is divided, wherein: the first second chroma coded block flag indicates whether a first chrominance component of the corresponding block has at least one non-zero transform coefficient, and the second chroma coded block flag indicates whether a second chrominance component of the corresponding block has at least one non-zero transform coefficient; and when the split transform flag indicates that the corresponding block is not further divided, reconstructing a luma coded block flag indicating whether a luminance component of the corresponding block has at least one non-zero transform coefficient and identifying the corresponding block which is not further divided as one of the transform blocks, wherein, when the split transform flag indicates that the corresponding block is further divided, the luma coded block flag of the corresponding block is not reconstructed from the bitstream.