Image encoding and decoding method and apparatus generating an angular intra prediction mode
Provided is an image decoding method including: generating an intra prediction value of a current sample based on a position of the current sample in a current block and an intra prediction mode of the current block; determining a sample value of at least one filtering reference sample to be filtered and a first weight with respect to the filtering reference sample and a second weight with respect to the intra prediction value of the current sample; generating a filtered prediction sample value of the current sample based on the determined sample value of the filtering reference sample to be filtered, the intra prediction value of the current sample, the first weight with respect to the filtering reference sample, and the second weight with respect to the intra prediction value of the current sample; and generating a prediction block of the current block including the filtered prediction sample value.
1. An image decoding method, comprising:
obtaining an intra prediction sample of a current sample in a current block using a first reference sample corresponding to the current sample, wherein the first reference sample is determined based on a position of the current sample and an intra prediction mode of the current block;
when the intra prediction mode of the current block is a first angular mode with one among upper prediction directions including a upper-right prediction direction, determining a second reference sample from among a plurality of reference samples in a left side of the current block based on the position of the current sample and the first angular mode, determining a second weight for the second reference sample based on a X-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the second reference sample, the intra prediction sample of the current sample, the second weight for the second reference sample and a first weight for the intra prediction sample of the current sample;
when the intra prediction mode of the current block is a second angular mode with one among left prediction directions including a lower-left prediction direction, determining a third reference sample from among a plurality of reference samples in an upper side of the current block based on the position of the current sample and the second angular mode, determining a third weight for the third reference sample based on a Y-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the third reference sample, the intra prediction sample of the current sample, the third weight for the third reference sample and the first weight for the intra prediction sample of the current sample; and
reconstructing the current block using the modified intra prediction sample of the current sample and a residual sample of the current sample,
wherein the current block has at least one of a square shape and a non-square shape.
2. An image encoding method, comprising:
obtaining an intra prediction sample of a current sample in a current block using a first reference sample corresponding to the current sample, wherein the first reference sample is determined based on a position of the current sample and an intra prediction mode of the current block;
when the intra prediction mode of the current block is a first angular mode with one among upper prediction directions including a upper-right prediction direction, determining a second reference sample from among a plurality of reference samples in a left side of the current block based on the position of the current sample and the first angular mode, determining a second weight for the second reference sample based on a X-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the second reference sample, the intra prediction sample of the current sample, the second weight for the second reference sample and a first weight for the intra prediction sample of the current sample;
when the intra prediction mode of the current block is a second angular mode with one among left prediction directions including a lower-left prediction direction, determining a third reference sample from among a plurality of reference samples in an upper side of the current block based on the position of the current sample and the second angular mode, determining a third weight for the third reference sample based on a Y-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the third reference sample, the intra prediction sample of the current sample, the third weight for the third reference sample and the first weight for the intra prediction sample of the current sample; and
encoding the current block using the modified intra prediction sample of the current sample,
wherein the current block has at least one of a square shape and a non-square shape.
3. A non-transitory computer-readable medium for recording a bitstream, the bitstream comprising:
an encoded data of a current block,
wherein the encoded data of the current block is obtained by:
obtaining an intra prediction sample of a current sample in the current block using a first reference sample corresponding to the current sample, wherein the first reference sample is determined based on a position of the current sample and an intra prediction mode of the current block;
when the intra prediction mode of the current block is a first angular mode with one among upper prediction directions including a upper-right prediction direction, determining a second reference sample from among a plurality of reference samples in a left side of the current block based on the position of the current sample and the first angular mode, determining a second weight for the second reference sample based on a X-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the second reference sample, the intra prediction sample of the current sample, the second weight for the second reference sample and a first weight for the intra prediction sample of the current sample;
when the intra prediction mode of the current block is a second angular mode with one among left prediction directions including a lower-left prediction direction, determining a third reference sample from among a plurality of reference samples in an upper side of the current block based on the position of the current sample and the second angular mode, determining a third weight for the third reference sample based on a Y-coordinate of the position of the current sample, and obtaining a modified intra prediction sample of the current sample based on the third reference sample, the intra prediction sample of the current sample, the third weight for the third reference sample and the first weight for the intra prediction sample of the current sample; and
encoding the current block using the modified intra prediction sample of the current sample,
wherein the current block has at least one of a square shape and a non-square shape.