Patent ID: 7983339
Filing Date: 2011-07-19
Classification: H04N

Abstract:
1. Method for coding a sequence of pictures arranged in groups of pictures, wherein each group of pictures GOP comprises pictures of different picture types including a P picture type, and wherein a picture comprises multiple picture entities, said method comprising the steps: calculating a backward motion vector field of a picture k−s and/or a forward motion vector field of a picture k+p, corresponding to a motion estimation for entities of picture k−s with respect to a following picture k and/or of picture k+p with respect to a previous picture k, respectively, s and p being non zero natural integers; calculating a rate of use of entities of picture k for a backward predictive coding of picture k−s, according to the number of vectors of backward motion vector field of picture k−s pointing to the entity of picture k or in its near surroundings, and/or calculating a rate of use of entities of picture k for a forward predictive coding of picture k+p, according to the number of vectors of forward motion vector field of picture k+p pointing to the entity of picture k or in its near surroundings; calculating, for a predictive coding and/or for a future coding, a rate of use for picture k, according to the rates of use assigned to the entities of said picture k; performing the above steps for other pictures of said picture sequence; defining picture classes depending on whether the future rate of use is noticeably greater than the past rate of use, or is in the same order as the past rate of use, or is noticeably lower than the past rate of use, and classifying the pictures correspondingly; determining ranges of pictures constituted by a predefined minimum number of successive pictures of same class; organizing a GOP by imposing reference pictures of type P at the extremes of determined ranges.