Method and device for encoding and decoding image signal
View Patent ↗A method for encoding image signal, according to the present invention, can: encode a partial block coefficient flag indicating whether a coefficient of a current partial block is a non-zero coefficient; encode a first flag indicating whether an absolute value of the coefficient is greater than 1, encode a second flag indicating whether the absolute value of the coefficient is greater than 2; encode the residual coefficients, which have not been encoded, on the basis of the first flag or the second flag in the current partial block; and encode a code for the coefficient of the current partial block.
1. A method for decoding a video signal, comprising:
receiving a bitstream including encoding information of a transform block, the encoding information including a flag indicating whether a current coefficient of the transform block is a non-zero coefficient;
entropy-decoding the flag of the current coefficient by considering previous coefficients; and
decoding the transform block based on the entropy-decoded flag,
wherein entropy-decoding the flag comprises:
calculating a number of non-zero coefficients among the previous coefficients;
deriving probability information relating to the flag of the current coefficient by considering the number of the non-zero coefficients; and
decoding the flag of the current coefficient using the probability information,
wherein the previous coefficients are representative of residual coefficients encoded before the current coefficient according to a scan type,
wherein, when a coordinate of the current coefficient is [x, y], coordinates of the previous coefficients include at least one of [x+2, y], [x, y+2] or [x+1, y+1], and
wherein the scan type is determined based on at least one of transform block related information, intra-prediction related information, or prediction related information.
2. The method of claim 1 , wherein a number of the previous coefficients to be considered for the entropy-decoding of the flag of the current coefficient is greater than 2.
3. The method of claim 1 , wherein all of the previous coefficients to be considered for the entropy-decoding of the flag of the current coefficient belong to only a same transform block as the current coefficient.
4. A method for encoding a video signal, comprising:
obtaining encoding information of a transform block by encoding the transform block; and
generating a bitstream including the encoding information of the transform block,
wherein the encoding information includes a flag of a current coefficient in the transform block, the flag indicating whether the current coefficient is a non-zero coefficient,
wherein obtaining the encoding information comprises entropy-encoding the flag by considering previous coefficients,
wherein entropy-encoding the flag comprises:
calculating a number of non-zero coefficients among the previous coefficients;
deriving probability information relating to the flag of the current coefficient by considering the number of the non-zero coefficients; and
encoding the flag of the current coefficient using the probability information,
wherein the previous coefficients are representative of residual coefficients encoded before the current coefficient according to a scan type,
wherein, when a coordinate of the current coefficient is [x, y], coordinates of the previous coefficients include at least one of [x+2, y], [x, y+2] or [x+1, y+1], and
wherein the scan type is determined based on at least one of transform block related information, intra-prediction related information, or prediction related information.
5. The method of claim 4 , wherein a number of the previous coefficients to be considered for the entropy-decoding of the flag of the current coefficient is greater than 2.
6. The method of claim 4 , wherein all of the previous coefficients to be considered for the entropy-encoding of the flag of the current coefficient belong to only a same transform block as the current coefficient.
7. A non-transitory computer-readable medium for storing data associated with a video signal, comprising:
a data stream stored in the non-transitory computer-readable medium, the data stream comprising encoding information obtained by encoding a transform block,
wherein the encoding information includes a flag indicating whether a current coefficient of the transform block is a non-zero coefficient, and
wherein the flag is entropy-decoded by considering previous coefficients,
wherein entropy-decoding the flag comprises:
calculating a number of non-zero coefficients among the previous coefficients;
deriving probability information relating to the flag of the current coefficient by considering the number of the non-zero coefficients; and
decoding the flag of the current coefficient using the probability information,
wherein the previous coefficients are representative of residual coefficients encoded before the current coefficient according to a scan type,
wherein, when a coordinate of the current coefficient is [x, y], coordinates of the previous coefficients include at least one of [x+2, y], [x, y+2] or [x+1, y+1], and
wherein the scan type is determined based on at least one of transform block related information, intra-prediction related information, or prediction related information.
8. The non-transitory computer-readable medium of claim 7 , wherein a number of the previous coefficients to be considered for the entropy-decoding of the flag of the current coefficient is greater than 2.
9. The non-transitory computer-readable medium of claim 7 , wherein all of the previous coefficients to be considered for the entropy-decoding of the flag of the current coefficient belong to only a same transform block as the current coefficient.