A video encoding method of adjusting a range of encoded output data to adjust a bit depth during restoring of encoded samples, and a video decoding method of preventing overflow from occurring in output data in operations of a decoding process. The video decoding method includes parsing and restoring quantized transformation coefficients in units of blocks of an image from a received bitstream, restoring transformation coefficients of a first bit depth or less by performing inverse quantization on the quantized transformation coefficients, and restoring samples of a second bit depth or less by performing one-dimensional (1 D) inverse transformation and inverse scaling on the quantized transformation coefficients.
