Method for encoding and decoding images based on constrained offset compensation and loop filter, and apparatus therefor

Abstract

Provided are a method and apparatus for encoding and decoding images based on constrained offset compensation and a loop filter. The image decoding apparatus: receives, from an encoder, a first indicator indicating whether a sequence, a picture, a frame, a slice, a coding unit (CU), a prediction unit (PU), and/or a transform unit (TU) supports constrained offset compensation; receives, from the encoder, a second indicator indicating whether constrained sample adaptive offset (SAO) compensation or an adaptive loop filter (ALF) is applied; receives a parameter from the encoder; and applies the SAO compensation or the ALF to pixels of a restored image on the basis of the second indicator and the parameter.

The invention claimed is: 
     
       1. A method for decoding a video, the method comprising:
 receiving a first constrained offset compensation indicator and a second constrained offset compensation indicator from an encoding apparatus, wherein the first constrained offset compensation indicator indicates whether constrained offset compensation across tile boundaries can be applied or not, and the second constrained offset compensation indicator indicates whether constrained offset compensation across slice boundaries can be applied or not; 
 receiving a sample adaptive offset (SAO) compensation indicator from the encoding apparatus, wherein the SAO compensation indicator indicates whether to perform SAO compensation; 
 receiving a SAO parameter from the encoding apparatus when the SAO compensation indicator indicates performing SAO compensation; and 
 performing SAO compensation, using the SAO compensation indicator and the SAO parameter, on a sample across tile when the first constrained offset compensation indicator indicates that constrained offset compensation across tile boundaries are not applied and across slice when the second constrained offset compensation indicator indicates that constrained offset compensation across slice boundaries are not applied, 
 wherein the performing SAO compensation comprises determining an offset category for the SAO compensation based on the first constrained offset compensation indicator, the second constrained offset compensation indicator, and encoding parameters of a target block of the SAO compensation, and at least one of neighboring blocks of the target block upon an edge offset being applied to an offset compensation target sample within the target block. 
 
     
     
       2. The method of  claim 1 , wherein the first constrained offset compensation indicator and the second constrained offset compensation indicator are included in a sequence parameter set (SPS), a picture parameter set (PPS), or a slice header within a bit stream. 
     
     
       3. The method of  claim 1 , wherein the SAO compensation indicator is included in a sequence parameter set (SPS), a picture parameter set (PPS), or slice header within a bit stream. 
     
     
       4. The method of  claim 1 , wherein the SAO parameter comprises an offset type, an offset kind, an offset value, or an offset sign. 
     
     
       5. The method of  claim 1 , wherein the SAO compensation indicator is received with respect to each of a luma component and chroma component. 
     
     
       6. An apparatus for decoding video, the apparatus comprising:
 a decoder to receive and decode a first constrained offset compensation indicator indicating whether a tile supports constrained offset compensation, a second constrained offset compensation indicator indicating whether a slice supports constrained offset compensation, a sample adaptive offset (SAO) compensation indicator indicating whether to preform SAO compensation, and a SAO parameter from an encoding apparatus; and 
 a filter unit to perform SAO compensation on a target sample of a target block of reconstructed video based on the SAO compensation indicator and the SAO parameter, 
 wherein the filter unit determines an offset category for the SAO compensation based on the first constrained offset compensation indicator, the second constrained offset compensation indicator, and encoding parameters of the target block of the SAO compensation, and at least one of neighboring blocks of the target block upon an edge offset being applied to an offset compensation target sample within the target block. 
 
     
     
       7. The apparatus of  claim 6 , wherein the first constrained offset compensation indicator and the second constrained offset compensation indicator are included in a sequence parameter set (SPS), a picture parameter set (PPS), or a slice header within a bit stream. 
     
     
       8. The apparatus of  claim 6 , wherein the SAO compensation indicator is included in a sequence parameter set (SPS), a picture parameter set (PPS), or a slice header within a bit stream. 
     
     
       9. The apparatus of  claim 6 , wherein the SAO parameter comprises an offset type, an offset kind, and offset value, or and offset sign. 
     
     
       10. The apparatus of  claim 6 , wherein the SAO compensation indicator is received with respect to each of a luma component and chroma component.