Prediction refinement with convolution model
A method for deriving and using a cross component model to refine intra- or inter-prediction when encoding or decoding a block of pixels is provided. A video coder receives data for the block of pixels to be encoded or decoded as a current block of a current picture of a video. The video coder generates an initial predictor for the current block based on a reference block. The video coder receives a first set of component samples of pixels within or neighboring the reference block. The video coder receives a second set of component samples of pixels within or neighboring the current block. The video coder derives a model based on the first and second sets of component samples. The video coder applies the derived model to the initial predictor to generate a refined predictor. The video coder decodes or encodes the current block by using the refined predictor.
1 . A video coding method comprising:
receiving data for a block of pixels to be encoded or decoded as a current block of a current picture of a video;
generating an initial predictor for the current block based on a reference block;
receiving a first set of component samples of pixels within or neighboring the reference block;
receiving a second set of component samples of pixels within or neighboring the current block;
deriving a model based on the first and second sets of component samples;
applying the derived model to the initial predictor to generate a refined predictor; and
decoding or encoding the current block by using the refined predictor.
2 . The video coding method of claim 1 , wherein the first set of component samples are neighboring samples of the reference block and the second set of component samples are neighboring samples of the current block.
3 . The video coding method of claim 1 , wherein the first set of component samples are luma samples of the reference block and the second set of component samples are luma samples of the current block.
4 . The video coding method of claim 1 , wherein the first set of component samples are neighboring chroma samples of the reference block and the second set of component samples are neighboring chroma samples of the current block.
5 . The video coding method of claim 1 , wherein the derived model comprises a non-linear term.
6 . The video coding method of claim 1 , wherein the derived model comprises a M×N filter.
7 . The video coding method of claim 1 , wherein a weighted sum of the refined predictor and the initial predictor is used as a final predictor for reconstructing the current block.
8 . The video coding method of claim 7 , wherein a first weight assigned to the initial predictor and a second weight assigned to the refined predictor for generating the weighted sum are determined based on one or more prediction modes used to code one or more neighboring blocks of the current block.
9 . The video coding method of claim 8 , wherein the first weight and the second weight are determined based on a first number of neighboring blocks coded in a first prediction mode and a second number of neighboring blocks coded in a second prediction mode.
10 . The video coding method of claim 1 , wherein deriving the model comprises deriving a plurality of candidate models based on the first and second sets of component samples and selecting one candidate model from the plurality of candidate models.
11 . The video coding method of claim 10 , further comprising receiving an indication from a bitstream or signaling the indication to the bitstream for selecting the candidate model from the plurality of candidate models.
12 . The video coding method of claim 10 , wherein the candidate model is selected implicitly based on a setting for encoding or decoding the current block.
13 . The video coding method of claim 1 , further comprising receiving an indication from a bitstream or signaling the indication to the bitstream for determining whether to use the initial predictor or the refined predictor to encode or decode the current block.
14 . The video coding method of claim 1 , further comprising implicitly determining whether to use the initial predictor or the refined predictor to encode or decode the current block based on a setting for encoding or decoding the current block.
15 . An electronic apparatus comprising:
a video coder circuit configured to perform operations comprising:
receiving data for a block of pixels to be encoded or decoded as a current block of a current picture of a video;
generating an initial predictor for the current block based on a reference block;
receiving a first set of component samples of pixels within or neighboring the reference block;
receiving a second set of component samples of pixels within or neighboring the current block;
deriving a model based on the first and second sets of component samples;
applying the derived model to the initial predictor to generate a refined predictor; and
decoding or encoding the current block by using the refined predictor.
16 . A video coding method comprising:
receiving data for a block of pixels to be encoded or decoded as a current block of a current picture of a video;
generating an initial predictor for the current block based on a reference block;
receiving first and second sets of component samples of pixels within or neighboring the current block or the reference block, wherein at least one of the first and second sets of component samples of pixels is from the reference block;
deriving a model based on the first and second sets of component samples;
applying the derived model based on the initial predictor to generate a refined predictor; and
decoding or encoding the current block by using the refined predictor.
17 . The video coding method of claim 16 , wherein the first set of component samples are luma samples of the reference block and the second set of component samples are chroma samples of the reference block.