Processing methods and apparatuses for video data comprise receiving input data associated with a current transform block in a current video picture, determining if a size of the current transform block is a power of 4, determining a normalized quantization or dequantization scaling factor, generating transform coefficient levels by applying a quantization processing to scaled transform coefficients in the current transform block or generating scaled transform coefficients by applying an inverse quantization processing to transform coefficient levels in the current transform block, and encoding or decoding the current transform block. The quantization processing comprises scaling the scaled transform coefficients by the normalized quantization scaling factor and the inverse quantization processing comprises scaling the transform coefficient levels by the normalized dequantization scaling factor.