| 摘要 |
Encoding or decoding images using a palette coding mode in which each block of pixels has an associated palette which gives a correspondence between pixel values and indexes. The blocks of pixels are encoded as a block of indexes using the palette. At the decoder, the method comprises decoding encoded data of two self-contained coding structures having the same hierarchical level, using a palette coding mode. The palette associated with each processed pixel block is predicted from a palette predictor 1215 using prediction information from the bitstream 1200. A palette predictor initializer 1221 associated with a coding structure hierarchically above the two self-contained coding structures is obtained from the bitstream and used to initialize the palette predictor for each self-contained coding structure using the same obtained palette predictor initializer. The initializer may be defined at the picture, sequence or tile level and may be signalled in the picture parameter set (PPS) or the sequence parameter set (SPS). The self contained coding structures should be independently encoded and may be slices. Preferably, a palette predictor is built 1214 from the union of the previous palette and the previous palette predictor. |
