Video coding method and apparatus
The present invention relates to a method and apparatus for performing encoding and decoding using a variably-sized quantization coefficient group, in quantization coefficient group encoding and decoding of video compression technology.
1. An intra prediction method for video decoding, comprising:
determining an intra prediction mode belonging to an initial directional prediction range for intra prediction of a M×N current block;
determining whether to modify the intra prediction mode from the initial directional prediction range into a modified directional prediction range based on a horizontal length (N) and a vertical length (M) of the M×N current block;
determining the modified intra prediction mode belonging to the modified directional prediction range; and
performing the intra prediction of the M×N current block based on the modified intra prediction mode,
wherein the initial directional prediction range comprises a first prediction range indicating center degrees, a second prediction range indicating higher degrees adjacent to the center degrees and a third prediction range indicating lower degrees adjacent to the center degrees,
wherein the modified directional prediction range is determined to comprise the first prediction range, the second prediction range and a fourth prediction range indicating higher degrees other than the second prediction range, according to the vertical length (M) of the M×N current block, and
wherein the intra prediction of the M×N current block is performed by using a reference region adjacent to the M×N current block, and
wherein the reference region includes a top reference pixel column and a left reference pixel column of the current block.
2. The method of claim 1 , wherein the fourth prediction range is derived based on the third prediction range.
3. The method of claim 2 , wherein the modified directional prediction range is determined to comprise the first prediction range, the third prediction range and a fifth prediction range indicating lower degrees other than the third prediction range, according to the horizontal length (N) of the M×N current block.
4. The method of claim 3 , wherein the fifth prediction range is derived based on the second prediction range.
5. The method of claim 4 , wherein the initial directional prediction range for intra prediction of the M×N current block is determined on the basis of an angle ranging from 45 degrees to 315 degrees.
6. An intra prediction method for video encoding, comprising:
determining an intra prediction mode belonging to an initial directional prediction range for intra prediction of a M×N current block;
determining whether to modify the intra prediction mode from the initial directional prediction range into a modified directional prediction range based on a horizontal length (N) and a vertical length (M) of the M×N current block;
determining the modified intra prediction mode belonging to the modified directional prediction range; and
performing the intra prediction of the M×N current block based on the modified intra prediction mode,
wherein the initial directional prediction range comprises a first prediction range indicating center degrees, a second prediction range indicating higher degrees adjacent to the center degrees and a third prediction range indicating lower degrees adjacent to the center degrees,
wherein the modified directional prediction range is determined to comprise the first prediction range, the second prediction range and a fourth prediction range indicating higher degrees other than the second prediction range, according to the vertical length (M) of the M×N current block, and
wherein the intra prediction of the M×N current block is performed by using a reference region adjacent to the M×N current block, and
wherein the reference region includes a top reference pixel column and a left reference pixel column of the current block.
7. The method of claim 6 , wherein the fourth prediction range is derived based on the third prediction range.
8. The method of claim 7 , wherein the modified directional prediction range is determined to comprise the first prediction range, the third prediction range and a fifth prediction range indicating lower degrees other than the third prediction range according to the horizontal length (N) of the M×N current block.
9. The method of claim 8 , wherein the fifth prediction range is derived based on the second prediction range.
10. The method of claim 9 , wherein the initial directional prediction range for intra prediction of the M×N current block is determined on the basis of an angle ranging from 45 degrees to 315 degrees.
11. A non-transitory computer-readable medium for storing a bitstream associated with a video signal,
wherein the bitstream includes a M×N current block encoded by intra prediction,
wherein the intra prediction of the M×N current block is performed based on a modified intra prediction mode,
wherein the modified intra prediction mode belongs to a modified directional prediction range,
wherein whether to modify an intra prediction mode from an initial directional prediction range into the modified directional prediction range is determined based on a horizontal length (N) and a vertical length (M) of the M×N current block,
wherein the intra prediction mode belongs to the initial directional prediction range,
wherein the initial directional prediction range comprises a first prediction range indicating center degrees, a second prediction range indicating higher degrees adjacent to the center degrees and a third prediction range indicating lower degrees adjacent to the center degrees,
wherein the modified directional prediction range is determined to comprise the first prediction range, the second prediction range and a fourth prediction range indicating higher degrees other than the second prediction range, according to the vertical length (M) of the M×N current block, and
wherein the intra prediction of the M×N current block is performed by using a reference region adjacent to the M×N current block, and
wherein the reference region includes a top reference pixel column and a left reference pixel column of the current block.