US Patent 7155472 Fixed-point quantizer for video coding

A quantizer employs a scaled integral inverse ratio division for quantization of an input T by a quantization step Q. The quantizer forms an integral approximation q of 2r/Q by either trunc(2r/Q) or round(2r/Q). A multiplier multiplies the absolute value of T by the q. An adjustment factor is added alternatively to the absolute value of T prior to multiplication or to the product after multiplication. This adjustment factor minimizes errors near transition points in the quantization. This invention is applicable to both trunc(T/Q) and round(T/Q).