In conventional video coding schemes such as H.264/AVC, prediction value p is obtained for the original pixel value x via inter/intra prediction and the prediction residue d = (x - p) is calculated prior to orthogonal transform and quantization. Encoding the prediction residue is nothing but ignoring the variety of distribution Pr(d\p) with respect to p, that is, using Pr(d) as a whole instead. Because H(d\p) les H(d), coding d using Pr(d) is not a good idea. For example, when p = 255, the prediction residue is always less than or equal to zero (i.e., d les 0) because 0 < x < 255 (for 8-bit case). Conventional prediction residue coding methods do not take this boundary into account and therefore involve coding inefficiency.
['Seishi Takamura', 'Yoshiyuki Yashima']
On Performance Evaluation of Predictive Coding Using a Residue-Free Approach