VIDEO ENCODING/DECODING METHOD AND APPARATUS FOR PERFORMING PDPC AND METHOD FOR TRANSMITTING BITSTREAM

1 . An image decoding method performed by an image decoding apparatus, the image decoding method comprising:

generating prediction samples by performing intra prediction on a current chroma block;

determining whether to apply position dependent intra prediction combination (PDPC) to the prediction samples;

generating prediction samples of the current chroma block, by applying PDPC to the prediction samples based on the determination; and

reconstructing the current chroma block based on the prediction samples of the current chroma block,

wherein the determining whether to apply PDPC to the prediction samples comprises determining whether a size of the current chroma block satisfies a predetermined condition,

wherein, based on a size of the current chroma block satisfying a predetermined condition, it is determined to apply PDPC to the prediction samples,

wherein, based on the size of the current chroma block doing not satisfy the predetermined condition, it is determined not to apply PDPC to the prediction samples,

wherein the predetermined condition is that a width of the current chroma block is greater than or equal to 4 and a height of the current chroma block is greater to or equal to 4,

wherein, based on block difference pulse code modulation (BDPCM) being not applied to the current chroma block, and the intra prediction mode of the current chroma block being an angular prediction mode having an index of 18 or less, it is determined to apply PDPC to the prediction samples, and

wherein, based on the intra prediction mode of the current chroma block being an intra planar mode or an intra DC mode, it is determined to apply PDPC to the prediction samples.

2 . The image decoding method of claim 1 ,

wherein, based on a reference sample line being a predetermined reference sample line, it is determined to apply PDPC to the prediction samples, and

wherein, based on the reference sample line being not the predetermined reference sample line, it is determined not to apply PDPC to the prediction samples.

3 . The image decoding method of claim 2 , wherein the predetermined reference sample line is a first reference sample line adjacent to the current chroma block.

4 . An image encoding method performed by an image encoding apparatus, the image encoding method comprising:

generating prediction samples by performing intra prediction on a current chroma block;

determining whether to apply position dependent intra prediction combination (PDPC) to the prediction samples; and

generating prediction samples of the current chroma block, by applying PDPC to the prediction samples based on the determination; and

reconstructing the current chroma block based on the prediction samples of the current chroma block

wherein the determining whether to apply PDPC to the prediction samples comprises determining whether a size of the current chroma block satisfies a predetermined condition,

wherein, based on a size of the current chroma block satisfying a predetermined condition, it is determined to apply PDPC to the prediction samples,

wherein, based on the size of the current chroma block doing not satisfy the predetermined condition, it is determined not to apply PDPC to the prediction samples,

wherein the predetermined condition is that a width of the current chroma block is greater than or equal to 4 and a height of the current chroma block is greater to or equal to 4,

wherein, based on block difference pulse code modulation (BDPCM) being not applied to the current chroma block, and the intra prediction mode of the current chroma block being an angular prediction mode having an index of 18 or less, it is determined to apply PDPC to the prediction samples, and

wherein, based on the intra prediction mode of the current chroma block being an intra planar mode or an intra DC mode, it is determined to apply PDPC to the prediction samples.

5 . The image encoding method of claim 4 ,

wherein, based on a reference sample line being a predetermined reference sample line, it is determined to apply PDPC to the prediction samples, and

wherein, based on the reference sample line being not the predetermined reference sample line, it is determined not to apply PDPC to the prediction samples.

6 . A method of transmitting a bitstream generated by an image encoding method, the image encoding method comprising:

generating prediction samples by performing intra prediction on a current chroma block;

determining whether to apply position dependent intra prediction combination (PDPC) to the prediction samples;

generating prediction samples of the current chroma block, by applying PDPC to the prediction samples based on the determination; and

reconstructing the current chroma block based on the prediction samples of the current chroma block,

wherein the determining whether to apply PDPC to the prediction samples comprises determining whether a size of the current chroma block satisfies a predetermined condition,

wherein, based on a size of the current chroma block satisfying a predetermined condition, it is determined to apply PDPC to the prediction samples,

wherein, based on the size of the current chroma block doing not satisfy the predetermined condition, it is determined not to apply PDPC to the prediction samples,

wherein the predetermined condition is that a width of the current chroma block is greater than or equal to 4 and a height of the current chroma block is greater to or equal to 4,

wherein, based on block difference pulse code modulation (BDPCM) being not applied to the current chroma block, and the intra prediction mode of the current chroma block being an angular prediction mode having an index of 18 or less, it is determined to apply PDPC to the prediction samples, and

wherein, based on the intra prediction mode of the current chroma block being an intra planar mode or an intra DC mode, it is determined to apply PDPC to the prediction samples.

7 . A non-transitory computer-readable recording medium storing a bitstream generated by an image encoding method, the image encoding method comprising:

generating prediction samples by performing intra prediction on a current chroma block;

determining whether to apply position dependent intra prediction combination (PDPC) to the prediction samples;

generating prediction samples of the current chroma block, by applying PDPC to the prediction samples based on the determination;

reconstructing the current chroma block based on the prediction samples of the current chroma block,

wherein the determining whether to apply PDPC to the prediction samples comprises determining whether a size of the current chroma block satisfies a predetermined condition,

wherein, based on a size of the current chroma block satisfying a predetermined condition, it is determined to apply PDPC to the prediction samples,

wherein, based on the size of the current chroma block doing not satisfy the predetermined condition, it is determined not to apply PDPC to the prediction samples,

wherein the predetermined condition is that a width of the current chroma block is greater than or equal to 4 and a height of the current chroma block is greater to or equal to 4,

wherein, based on block difference pulse code modulation (BDPCM) being not applied to the current chroma block, and the intra prediction mode of the current chroma block being an angular prediction mode having an index of 18 or less, it is determined to apply PDPC to the prediction samples, and

wherein, based on the intra prediction mode of the current chroma block being an intra planar mode or an intra DC mode, it is determined to apply PDPC to the prediction samples.