A decoding apparatus has an arithmetic decoder and a controller. A counter logic of the controller generates a first statistics result according to a first syntax element decoding result. A control logic of the controller instructs the arithmetic decoder to perform a first scan procedure at least once to generate the first syntax element decoding result of transform coefficients of a transform coefficient block, controls a repetition number of a second scan procedure based at least partly on the first statistics result, and instructs the arithmetic decoder to perform the second scan procedure at least once to generate a second syntax element decoding result of the transform coefficients. The first scan procedure decodes a first coded syntax element of one transform coefficient when performed by the arithmetic decoder once. The second scan procedure decodes a second coded syntax element of one transform coefficient when performed by the arithmetic decoder once.