Method for encoding and decoding image information
The present invention relates to a method for encoding and decoding image information and to an apparatus using same, and the method for encoding the image information, according to the present invention, comprises the steps of: generating a recovery block; applying a deblocking filter to the recovery block; applying a sample adaptive offset (SAO) to the recovery block to which the deblocking filter is applied; and transmitting the image information including information on the SAO which is applied, wherein in the step of transmitting, information for specifying bands that cover a scope of a pixel value, to which a band off set is applied, is transmitted when the band offset is applied during the step of applying the SAO.
1. A video decoding method performed by a video decoder, comprising:
obtaining video information including picture reconstruction information, and offset information from a bitstream;
generating a reconstructed picture based on the picture reconstruction information;
applying a deblocking filtering process to the reconstructed picture; and
applying a sample adaptive offset (SAO) process to a sample of the reconstructed picture based on the offset information after completing the deblocking filtering process,
wherein the offset information includes flag information indicating whether the SAO process is enabled for the sample, and
wherein the offset information includes band information indicating one of 32 bands as a starting band of a band group consisting of n (n is integer) bands, the band group is determined based on the starting band, and an offset corresponding to a band among the n bands is applied to the sample.
2. The method of claim 1 , wherein the offset information includes offset type information for specifying an offset type for the sample, and
wherein the offset type information indicates whether an edge offset is applied to the sample, a band offset is applied to the sample, or the offset SAO process is not applied to the sample.
3. The method of claim 2 , wherein the offset type information indicates that the band offset is applied to the sample, and
wherein the offset is applied to the sample corresponding to the band among the n bands.
4. The method of claim 3 , wherein the band is a predetermined section of pixel value range which the samples can have.
5. The method of claim 3 , wherein the band information includes indicates a last band of the n bands.
6. The method of claim 3 , wherein the offset of the band corresponding to the sample out of the n bands is applied to the sample.
7. The method of claim 2 , wherein the step of obtaining the video information includes obtaining the flag information and the offset type information using different decoding methods.
8. The method of claim 7 , wherein in the step of obtaining the video information,
the flag information is obtained through entropy decoding using an exponential Golomb (Exp-Golomb) method, and
the offset type information is obtained through entropy decoding using a context-adaptive binary arithmetic coding.
9. The method of claim 1 , wherein the flag information includes luma flag information indicating whether the offset can be applied to a luma sample and chroma flag information indicating whether the offset can be applied to a chroma sample.
10. The method of claim 9 , wherein when the luma offset information indicates that the offset can be applied to the luma sample, the second offset type information includes luma offset type information for specifying the offset type for the luma sample, and
chroma offset type information for specifying the offset type for the chroma sample.