Method for encoding/decoding image and device thereof
A method for image decoding, according to the present invention, includes the following steps: receiving image information including a plurality of filter coefficients; generating a restored block for a current block on the basis of the image information; and applying an adaptive loop filter to the restored block on the basis of the plurality of filter coefficients. According to the present invention, image encoding efficiency may be improved, and complexity may be reduced.
1. A video decoding apparatus, comprising:
an entropy decoder configured to obtain prediction information for a prediction process and offset information for a sample adaptive offset (SAO) process from a bitstream;
a predictor configured to derive prediction samples based on the prediction information;
an adder configured to generate a reconstructed picture based on the prediction samples; and
a filter configured to apply an in-loop filtering process to the reconstructed picture,
wherein for the in-loop filtering process, the filter applies a deblocking filtering process to the reconstructed picture, and applies the SAO process to a sample in the reconstructed picture on which the deblocking filtering process is completed,
wherein the offset information includes offset type information indicating that a band offset type is applied to the sample,
wherein the offset information includes information on n offset values, and
wherein the offset information includes explicit band information indicating one of 32 bands as a starting band of a band group consisting of n bands, and an offset value corresponding to a band among the n bands is applied to the sample, wherein n is an integer.
2. The video decoding apparatus of claim 1 , wherein the offset is applied to the sample based on the offset information which is transmitted for a largest coding unit to which the sample belongs.
3. The video decoding apparatus of claim 1 , wherein the band is determined as a predetermined sample value range to which the sample belongs.
4. The video decoding apparatus of claim 1 , wherein the n bands are specified as the starting band and following bands according to sample value order,
wherein the offset value is determined based on the band to which the sample belongs.
5. The video decoding apparatus of claim 1 , wherein the n is predetermined as a constant value.
6. The video decoding apparatus of claim 1 , wherein the band information further indicates a last band among the n bands.
7. The video decoding apparatus of claim 1 , wherein the offset type information is obtained by context-adaptive arithmetic coding.
8. A video encoding apparatus, comprising:
a predictor configured to derive prediction samples based on a prediction mode;
an adder configured to generate a reconstructed picture based on the prediction samples;
a filter configured to apply an in-loop filtering process to the reconstructed picture, wherein for the in-loop filtering process, the filter applies a deblocking filtering process to the reconstructed picture, and applies a sample adaptive offset (SAO) process to a sample in the reconstructed picture on which the deblocking filtering process is completed; and
an entropy encoder configured to encode prediction information on the prediction mode and offset information for the SAO process,
wherein the offset information includes offset type information indicating that a band offset type is applied to the sample,
wherein the offset information includes information on n offset values, and
wherein the offset information includes explicit band information indicating one of 32 bands as a starting band of a band group consisting of n bands, and an offset value corresponding to a band among the n bands is applied to the sample, wherein n is an integer.
9. The video encoding apparatus of claim 8 , wherein the offset is applied to the sample based on the offset information which is transmitted for a largest coding unit to which the sample belongs.
10. The video encoding apparatus of claim 8 , wherein the band is determined as a predetermined sample value range to which the sample belongs.
11. The video encoding apparatus of claim 8 , wherein the n bands are specified as the starting band and following bands according to sample value order,
wherein the offset value is determined based on the band to which the sample belongs.
12. The video encoding apparatus of claim 8 , wherein the n is predetermined as a constant value.
13. The video encoding apparatus of claim 8 , wherein the band information further indicates a last band among the n bands.
14. The video encoding apparatus of claim 8 , wherein the offset type information is obtained by context-adaptive arithmetic coding.
15. A non-transitory decoder readable storage medium storing a bitstream comprising a decoder executable program, the decoder executable program, when executed, causing a decoder to perform the following steps:
obtaining prediction information for a prediction process and offset information for a sample adaptive offset (SAO) process from a bitstream;
deriving prediction samples based on the prediction information;
generating a reconstructed picture based on the prediction samples; and
applying an in-loop filtering process to the reconstructed picture,
wherein applying the in-loop filtering process includes applying a deblocking filtering process to the reconstructed picture, and applying the SAO process to a sample in the reconstructed picture on which the deblocking filtering process is completed,
wherein the offset information includes offset type information indicating that a band offset type is applied to the sample,
wherein the offset information includes information on n offset values, and
wherein the offset information includes explicit band information indicating one of 32 bands as a starting band of a band group consisting of n bands, and an offset value corresponding to a band among the n bands is applied to the sample, wherein n is an integer.
16. The non-transitory decoder readable storage medium of claim 15 , wherein the band is determined as a predetermined sample value range to which the sample belongs.
17. The non-transitory decoder readable storage medium of claim 15 , wherein the n bands are specified as the starting band and following bands according to sample value order,
wherein the offset value is determined based on the band to which the sample belongs.
18. The non-transitory decoder readable storage medium of claim 15 , wherein the n is predetermined as a constant value.
19. The non-transitory decoder readable storage medium of claim 15 , wherein the band information further indicates a last band among the n bands.