| 摘要 |
Video encoding comprising dividing an image into blocks and, for the current block, generating a residual block, selecting first direction N which determines a predictor of each sample in the residual block, calculating the difference between each residual block sample and its predictor, and for at least some block samples, calculating differences between the samples and a second predictor based on a second direction M. The resulting differential residual block is entropy encoded. Preferably the predictor modes can be horizontal or vertical. Preferably, the calculation of secondary differences is inhibited for larger block sizes and is not applied in intra-coded blocks. The primary N and secondary M directions may be derived from other block parameters or signalled in the bitstream. In one embodiment, secondary directions are only calculated for samples at which no differences are calculated in the first direction. In particular, if the primary direction is horizontal, this applies to the first column. This video encoding method is related to Differential Pulse Code Modulation (DPCM). A decoding method is also claimed. |
