represent the signal with fewer bits in video encoding quantization is the step that introduces loss so that a balance between bitrate and reconstruction quality can be established h 264 avc employs a scalar quantizer whose step size is controlled by a quantization parameter h 264 avc codecs combine transform scaling and quantization into a single step a 4 u00d7 4 input residual x is transformed into unscaled coefficients y subsequently each element of y is scaled and quantized scaled and quantized coefficients of the 4 u00d7 4 block are then reorganized into a 16 u00d7 1 array in zig zag order and sent to the entropy coder at the decoder side the process is reversed for rescaling and inverse transformation a received coefficients block is pre scaled with element wise multiplication and inverse transformed to obtain the residual the entropy coder takes the syntax elements such as the mode information and the quantized coefficients and represents them efficiently in the bitstream h 264 avc employs two different encoders in order to achieve this context adaptive variable length coding cavlc and context adaptive binary arithmetic coding cabac variable length coding assigns short codewords to elements which appear with a high.