Decoupling enhancements in sample adaptive offset (SAO) for high efficiency video encoder (HEVC)
An encoder/decoder is described using enhanced signaling mechanisms SAO parameters. The various parameters are signaled in various ways according to different embodiments of the invention. In a first embodiment (embodiment A), SAO on/off is decoupled form SAO type coding, with SAO on/off flags being jointly encoded for all color components. The second embodiment (embodiment B), is similar to embodiment A, but modified for application to JCTVC-J0268. In a third embodiment separate signaling is provided for SAO on/off, SAO types BO and EO, and for BO and EO side information (classes or band position). Each of these enhanced SAO signaling mechanisms provide enhanced coding efficiency.
1. An encoding apparatus, comprising:
at least one processor; and
a memory configured to store instructions for execution by the at least one processor, wherein the at least one processor is configured to:
receive a decoded video signal from a deblocking filter;
code a first bin of a binarized Sample Adaptive Offset (SAO) type that indicates one of a Not applied, a Band offset (BO) or an Edge Offset (EO) based on context coding operation, and a remaining bin of the binarized SAO type based on by-pass coding operation;
signal the SAO type to a decoder;
code one of absolute values for the BO or absolute values for the EO, based on the by-pass coding operation and whether the SAO type is one of the BO or the EO;
signal one of the absolute values for the BO or the absolute values for the EO, to the decoder based on whether the SAO type is one of the BO or the EO;
code one of offset signs for the BO and subsequently a BO band or an EO class, based on the by-pass coding operation and whether the SAO type is one of the BO or the EO; and
signal one of the offset signs for the BO and subsequently the BO band or the EO class, to the decoder based on whether the SAO type is one of the BO or the EO.
2. The encoding apparatus of claim 1 , wherein the at least one processor is further configured to:
set, based on the binarized SAO type that indicates the Not applied, a SAO type index equal to 0;
set, based on the binarized SAO type that indicates the BO, the SAO type index equal to 1; and
set, based on the binarized SAO type that indicates the EO, the SAO type index equal to 2.
3. The encoding apparatus of claim 1 , wherein the at least one processor is further configured to
binarize a SAO type based on truncated unary.
4. The encoding apparatus of claim 1 , wherein the at least one processor is further configured to
binarize the EO class based on a fixed length code.
5. An encoding method, comprising:
in an encoding apparatus:
receiving a decoded video signal from a deblocking filter;
coding a first bin of a binarized Sample Adaptive Offset (SAO) type indicating one of a Not applied, a Band offset (BO) or an Edge Offset (EO) based on context coding, and a remaining bin of the binarized SAO type based on by-pass coding;
signaling the SAO type to a decoder;
coding one of absolute values for the BO or absolute values for the EO, based on the by-pass coding and whether the SAO type is one of the BO or the EO;
signaling one of the absolute values for the BO or the absolute values for the EO, to the decoder based on whether the SAO type is one of the BO or the EO;
coding one of offset signs for the BO and subsequently a BO band or an EO class, based on the by-pass coding and whether the SAO type is one of the BO or the EO; and
signaling one of the offset signs for the BO and subsequently the BO band or the EO class, to the decoder based on whether the SAO type is one of the BO or the EO.
6. The encoding method of claim 5 , further comprising:
setting, based on the binarized SAO type indicating the Not applied, a SAO type index equal to 0;
setting, based on the binarized SAO type indicating the BO, the SAO type index equal to 1; and
setting, based on the binarized SAO type indicating the EO, the SAO type index equal to 2.
7. The encoding method of claim 5 , further comprising
binarizing a SAO type based on truncated unary.
8. The encoding method of claim 5 , further comprising
binarizing the EO class based on a fixed length code.
9. The encoding apparatus of claim 1 , wherein:
a SAO syntax comprises the SAO type and side information,
the side information comprises the EO class and the BO band position, and
the SAO type of the SAO syntax and the side information of the SAO syntax are signaled separately.