Sample adaptive offset (SAO) parameter signaling
Techniques for signaling of sample adaptive offset (SAO) information that may reduce the coding rate for signaling such information in the compressed bit stream are provided. More specifically, techniques are provided that allow SAO information common to two or more of the color components to be signaled using one or more syntax elements (flags or indicators) representative of the common information. These techniques reduce the need to signal SAO information separately for each color component.
1. A method for edge offset sample adaptive offset (SAO) parameter signaling in a video encoder, the method comprising:
determining, for a coding unit (CU) of a reconstructed picture, edge offset SAO parameters for Cb and Cr components of the CU;
including a flag in a compressed video bit stream indicating the Y component is not SAO filtered;
including flags in the compressed video bit stream indicating which of the Cb, and Cr components are edge offset SAO filtered; and
including SAO information for the CU in the compressed video bit stream, wherein the SAO information comprises a combined flag signaling at least two components share SAO parameters.
2. The method of claim 1 , wherein the SAO information further comprises SAO parameters, the SAO parameters comprising a filter type and a plurality of offsets, and the combined flag signals that the SAO parameters are to be used for two of the three components.
3. The method of claim 1 , wherein the combined flag is a combined merge flag signaling that SAO parameters of one or more components of an upper neighboring CU are to be used for corresponding one or more components of the CU.
4. The method of claim 1 , wherein the combined flag is a combined merge flag signaling that SAO parameters of the components of an upper neighboring CU are to be used for corresponding components of the CU.
5. The method of claim 1 , wherein the combined flag is a combined merge flag signaling that SAO parameters of one or more components of a left neighboring CU are to be used for corresponding one or more components of the CU.
6. The method of claim 1 , wherein the combined flag is a combined merge flag signaling that SAO parameters of the components of a left neighboring CU are to be used for corresponding components of the CU.
7. A method for edge offset sample adaptive offset (SAO) filtering in a video decoder, the method comprising:
extracting a first flag from a compressed video bit stream, the first flag indicating edge offset SAO filtering of a Y component of a CU is not enabled for the CU;
extracting a second flag from the compressed video bit stream indicating whether or not edge offset SAO filtering of a Cb component of the CU is enabled;
extracting a third flag from the compressed video bit stream indicating whether or not edge offset SAO filtering of a Cr component of the CU is enabled; and
applying edge offset SAO filtering to the Cb and Cr components based on the second flag and the third flag.