A method of decoding a video through symbol decoding includes parsing symbols of image blocks from a received bitstream; classifying a current symbol into a prefix bit string and a suffix bit string based on a threshold value determined according to a size of a current block; performing arithmetic decoding of the prefix bit string and the suffix bit string by using respective arithmetic decoding methods determined for each of the prefix bit string and the suffix bit string; performing inverse binarization of the prefix bit string and the suffix bit string by using respective binarization methods determined for each of the prefix bit string and the suffix bit string; and restoring the image blocks by performing an inverse transformation operation and a prediction operation on the current block by using the current symbol restored through the arithmetic decoding and the inverse binarization.