Intra-prediction-based encoding and decoding method, apparatus and filter

An intra-prediction-based encoding apparatus, comprising:

• acquiring module, to acquire reconstructed pixels adjacent to a to-be-predicted prediction block;
• prediction module, to determine corresponding reconstructed pixels adjacent to the to-be-predicted prediction block among the reconstructed pixels as reference pixels for filtering, based on prediction modes of the to-be-predicted prediction block;
• if a first type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block are used as reference pixels for filtering;
• if a second type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• if a third type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block and a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• the first type of prediction modes include modes 18-34, the filter degenerates into a two-tap filter, which is expressed as Formula (3):
• P(x,y)=(f(x)·T(−1,y)+(64−f(x))·T(x,y)+32)>>6 Formula (3);
• the second type of prediction modes includes modes 2-17, the filter degenerates into a two-tap filter, which is expressed as Formula (2):
• P(x,y)=f(y)·T(x,−1)+(64−f(y))·T(x,y)+32)>>6 Formula (2);
• and the third type of prediction modes includes the DC mode and the planar mode, the filter is a three-tap filter, which is expressed as Formula (1):
• P(x,y)=f(x)·T(−1,y)+f(y)·T(x,−1)+(64−f(x)−f(y))·T(x,y)+32)>>6 Formula (1);
• wherein P(x, y) is a new pixel value of the to-be-predicted prediction block;
• T(x, y) is an interim prediction value of the to-be-predicted prediction block;
• T(−1, y) is a reference pixel value to the left of the to-be-predicted prediction block;
• T(x, −1) is a reference pixel value above the to-be-predicted prediction block;
• x and y are coordinates in the predicted block to be predicted;
• x=0 denotes the first column of the to-be-predicted prediction block;
• y=0 denotes the first row of the to-be-predicted prediction block;
• M denotes the width of the to-be-predicted prediction block;
• N denotes the height of the to-be-predicted prediction block;
• f(x) denotes a filter coefficient of T(−1, y);
• f(y) denotes a filter coefficient of T(x, −1);
• based on the reference pixels, use a filter corresponding to the prediction modes of the to-be-predicted prediction block to filter interim prediction values of the to-be-predicted prediction block, to obtain new pixel values of the to-be-predicted prediction block, wherein the interim prediction values are obtained based on other intra prediction methods;
• the filter coefficients are expressed as Formulas (4) and (5):
• f(x)=FS[M][x] Formula (4)
• f(y)=FS[N][y] Formula (5)
• wherein FS are filter coefficients;
• perform a CLIP operation on the new pixel values of the to-be-predicted prediction block, to obtain a first prediction value of the to-be-predicted prediction block.

An intra-prediction-based decoding method, comprising:

• acquiring reconstructed pixels adjacent to a to-be-predicted prediction block;
• determining corresponding reconstructed pixels adjacent to the to-be-predicted prediction block among the reconstructed pixels as reference pixels for filtering, based on prediction modes of the to-be-predicted prediction block;
• if a first type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block are used as reference pixels for filtering;
• if a second type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• if a third type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block and a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• the first type of prediction modes include modes 18-34, the filter degenerates into a two-tap filter, which is expressed as Formula (3):
• P(x,y)=(f(x)·T(−1,y)+(64−f(x))·T(x,y)+32)>>6 Formula (3);
• the second type of prediction modes includes modes 2-17, the filter degenerates into a two-tap filter, which is expressed as Formula (2):
• P(x,y)=(f(y)·T(x,−1)+(64−f(y))·T(x,y)+32)>>6 Formula (2);
• and the third type of prediction modes includes the DC mode and the planar mode, the filter is a three-tap filter, which is expressed as Formula (1):
• P(x,y)=(f(x)·T(−1,y)+f(y)·T(x,−1)+(64−f(x)−f(y))·T(x,y)+32)>>6 Formula (1);
• wherein P(x, y) is a new pixel value of the to-be-predicted prediction block;
• T(x, y) is an interim prediction value of the to-be-predicted prediction block;
• T(−1, y) is a reference pixel value to the left of the to-be-predicted prediction block;
• T(x, −1) is a reference pixel value above the to-be-predicted prediction block;
• x and y are coordinates in the predicted block to be predicted;
• x=0 denotes the first column of the to-be-predicted prediction block;
• y=0 denotes the first row of the to-be-predicted prediction block;
• M denotes the width of the to-be-predicted prediction block;
• N denotes the height of the to-be-predicted prediction block;
• f(x) denotes a filter coefficient of T(−1, y);
• f(y) denotes a filter coefficient of T(x, −1);
• based on the reference pixels, using a filter corresponding to the prediction modes of the to-be-predicted prediction block to filter interim prediction values of the to-be-predicted prediction block, to obtain new pixel values of the to-be-predicted prediction block;
• the filter coefficients are expressed as Formulas (4) and (5):
• f(x)=FS[M][x] Formula (4)
• f(y)=FS[N][y] Formula (5)
• wherein FS are filter coefficients;
• performing a CLIP operation on the new pixel values of the to-be-predicted prediction block to obtain a reconstructed coding block.

An intra-prediction-based decoding apparatus, comprising:

• acquiring module, to acquire reconstructed pixels adjacent to a to-be-predicted prediction block;
• prediction module, to determine corresponding reconstructed pixels adjacent to the to-be-predicted prediction block among the reconstructed pixels as reference pixels for filtering, based on prediction modes of the to-be-predicted prediction block;
• if a first type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block are used as reference pixels for filtering;
• if a second type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• if a third type of prediction modes are used for intra prediction to predict the to-be-predicted prediction block, a column of reconstructed pixels to the left of the to-be-predicted prediction block and a row of reconstructed pixels above the to-be-predicted prediction block are used as reference pixels for filtering;
• the first type of prediction modes include modes 18-34, the filter degenerates into a two-tap filter, which is expressed as Formula (3):
• P(x,y)=f(x)·T(−1,y)+(64−f(x))·T(x,y)+32)>>6 Formula (3);
• the second type of prediction modes includes modes 2-17, the filter degenerates into a two-tap filter, which is expressed as Formula (2):
• P(x,y)=f(y)·T(x,−1)+(64−f(y))·T(x,y)+32)>>6 Formula (2);
• and the third type of prediction modes includes the DC mode and the planar mode, the filter is a three-tap filter, which is expressed as Formula (1):
• P(x,y)=f(x)·T(−1,y)+f(y)·T(x,−1)+(64−f(x)−f(y))·T(x,y)+32)>>6 Formula (1);
• wherein P(x, y) is a new pixel value of the to-be-predicted prediction block;
• T(x, y) is an interim prediction value of the to-be-predicted prediction block;
• T(−1, y) is a reference pixel value to the left of the to-be-predicted prediction block;
• T(x, −1) is a reference pixel value above the to-be-predicted prediction block;
• x and y are coordinates in the predicted block to be predicted;
• x=0 denotes the first column of the to-be-predicted prediction block;
• y=0 denotes the first row of the to-be-predicted prediction block;
• M denotes the width of the to-be-predicted prediction block;
• N denotes the height of the to-be-predicted prediction block;
• f(x) denotes a filter coefficient of T(−1, y);
• f(y) denotes a filter coefficient of T(x, −1);
• based on the reference pixels, use a filter corresponding to the prediction modes of the to-be-predicted prediction block to filter interim prediction values of the to-be-predicted prediction block, to obtain new pixel values of the to-be-predicted prediction block;
• the filter coefficients are expressed as Formulas (4) and (5):
• f(x)=FS[M][x] Formula(4)
• f(y)=FS[N][y] Formula(5)
• wherein FS are filter coefficients;
• perform a CLIP operation on the new pixel values of the to-be-predicted prediction block to obtain a reconstructed coding block.