Method and apparatus for transition encoding in video coding and decoding

摘要

The invention is related to video coding and decoding. More precisely, the present invention is dedicated to a coding method investigated in the scope of screen content coding, called palette mode. It particularly concerns the encoding of level values based on the use of patterns to predict the level value in order to avoid their transmission. It has been devised to avoid the transmission of level value when the value may be predicted based on the neighbourhood of the pixel to encode. This neighbourhood is matched against memorized pattern so as to predict the level value due to the repetitive occurrence of these patterns. It proposes to save a pattern table in addition to the palette table. This pattern table is constructed symmetrically by the encoder and the decoder and allows to retrieve some predicted level value and to avoid their transmission.

主权项

1. A method for decoding a block of indexes used for decoding a coding unit of an image according to a palette, each index being related to one of the pixels forming the coding unit, the palette comprising a set of indexes associated to pixel values, wherein the method comprises:
storing at least one pattern constituted by the indexes of at least one neighbour of an index of the block of indexes, said pattern being associated with at least one prediction index corresponding to an index expected at a location in the neighbourhood of the pattern; identifying for a current index to be decoded in the block of indexes a stored pattern corresponding to the neighbourhood of the current index; and decoding the index of the current index by reference to the stored pattern.