The invention discloses a method and a device for intra-frame prediction and an intra-frame prediction-based encoding / decoding method and an intra-frame prediction-based encoding / decoding
system. The prediction method comprises the following steps of: determining adjacent blocks of M*N blocks to be predicted, and selecting corresponding Ki
reference sample points from the adjacent blocks according to the length Ki (i is equal to 0, 1, 2,...,(M*N-1)) of a filter at each position i in the blocks to be predicted to form a sample
point set for the intra-frame prediction, wherein ki is equal to 0, 1, 2,..., Ki-1, Ki is a natural number and is more than 1, and M and N are natural numbers; selecting a prediction direction m, and determining the prediction
weighting coefficient Wi (m, k) of each sample point Ci to be predicted in the blocks to be predicted respectively, wherein i is equal to 0, 1, 2,...,(M*N-1); and calculating prediction values of
current sample points to be encoded according to the prediction weighting coefficients Wi (m, k) and the sample
point set for the intra-frame prediction. The prediction method improves the prediction precision of an intra-frame prediction mode, so that the integral encoding performance is improved.