Method and apparatus for performing intra-prediction using adaptive filter
Provided is a method and apparatus for performing intra-prediction using an adaptive filter. The method for performing intra-prediction includes the steps of: determining whether or not to apply a first filter for a reference pixel value on the basis of information of a neighboring block of a current block; applying the first filter for the reference pixel value when it is determined to apply the first filter; performing intra-prediction on the current block on the basis of the reference pixel value; determining whether or not to apply a second filter for a prediction value according to each prediction mode of the current block, which is predicted by the intra-prediction performance on the basis of the information of the neighboring block; and applying the second filter for the prediction value according to each prediction mode of the current block when it is determined to apply the second filter.
1. A video decoding method, comprising:
determining whether to apply a first filter to a reference pixel value of a current block based on at least one of an intra prediction mode of the current block and a size of the current block;
deriving a prediction pixel value of the current block using the reference pixel value; and
determining whether to apply a second filter to the prediction pixel value of the current block based on at least one of an intra prediction mode of the current block and a size of the current block, for thereby producing a filtered prediction pixel value,
wherein when the intra prediction mode of the current block is a DC mode, the filtered prediction pixel value is generated by applying a 3-tap filter to an upper-leftmost pixel of the current block among the prediction pixels of the current block and applying a 2-tap filter to remaining uppermost and leftmost pixels except the upper-leftmost pixel among the prediction pixels of the current block.
2. A video encoding method comprising:
encoding information related to whether to apply a first filter to a reference pixel value of a current block and whether to apply a second filter to a prediction pixel value of the current block,
wherein the information is related to at least one of an intra prediction mode of the current block and a size of the current block,
wherein when the intra prediction mode of the current block is a DC mode, as the second filter, a 3-tap filter is applied to an upper-leftmost pixel of the current block among prediction pixels of the current block and a 2-tap filter is applied to remaining uppermost and leftmost pixels except the upper-leftmost pixel among the prediction pixels of the current block, and wherein the upper-leftmost pixel corresponds to a first filter coefficient and the remaining uppermost and leftmost pixels correspond to a second filter coefficient, wherein the second filter coefficient is 1.5 times larger than the first filter coefficient.
3. A non-transitory computer-readable storage medium storing a bitstream, the bitstream comprising:
information related to whether to apply a first filter to a reference pixel value of a current block and whether to apply a second filter to a prediction pixel value of the current block, wherein the information is related to at least one of an intra prediction mode of the current block and a size of the current block,
wherein when the intra prediction mode of the current block is a DC mode, as the second filter, a 3-tap filter is applied to an upper-leftmost pixel of the current block among prediction pixels of the current block and a 2-tap filter is applied to remaining uppermost and leftmost pixels except the upper-leftmost pixel among the prediction pixels of the current block, and
wherein the upper-leftmost pixel corresponds to a first filter coefficient and the remaining uppermost and leftmost pixels correspond to a second filter coefficient, wherein the second filter coefficient is 1.5 times larger than the first filter coefficient.