Coefficient coding harmonization in HEVC
Coefficient coding for transform units (TUs) during high efficiency video coding (HEVC), and similar standards, toward simplifying design while enhancing efficiency. Elements of the invention include coefficient coding for TUs with up-right diagonal scans being modified, and selectively applying multi-level significance map coding.
1. A coding apparatus, comprising:
one or more processors configured to:
execute, as a condition that diagonal scan is applied to a 4×4 transform block, diagonal scan consisting of diagonal scan of one 4×4 sub-block of the 4×4 transform block, and apply multi-level significance map encoding to the 4×4 transform block; and
execute, as a condition that diagonal scan is applied to an 8×8 transform block, diagonal scan consisting of diagonal scan of four 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 8×8 transform block, and apply the same multi-level significance map encoding to the 4×4 sub-blocks of the 8×8 transform block.
2. The coding apparatus recited in claim 1 , wherein the one or more processors are further configured to execute, as a condition that diagonal scan is applied to a 16×16 transform block, the diagonal scan consisting of diagonal scan of sixteen 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 16×16 transform block to apply the same multi-level significance map encoding to the 4×4 sub-blocks of the 16×16 transform block.
3. The coding apparatus recited in claim 1 , wherein the one or more processors are further configured to execute, as a condition that diagonal scan is applied to a 32×32 transform block, the diagonal scan consisting of diagonal scan of sixty four 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 32×32 transform block to apply the same multi-level significance map encoding to the 4×4 sub-blocks of the 32×32 transform block.
4. A method, comprising:
in a coding apparatus:
executing, as a condition that diagonal scan is applied to a 4×4 transform block, diagonal scan consisting of diagonal scan of one 4×4 sub-block of the 4×4 transform block, and applying multi-level significance map encoding to the 4×4 transform block; and
executing, as a condition that diagonal scan is applied to an 8×8 transform block, diagonal scan consisting of diagonal scan of four 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 8×8 transform block, and applying the same multi-level significance map encoding to the 4×4 sub-blocks of the 8×8 transform block.
5. The method recited in claim 4 , further comprising executing, as a condition that diagonal scan is applied to a 16×16 transform block, the diagonal scan consisting of diagonal scan of sixteen 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 16×16 transform block to apply the same multi-level significance map encoding to the 4×4 sub-blocks of the 16×16 transform block.
6. The method recited in claim 4 , further comprising executing, as a condition that diagonal scan is applied to a 32×32 transform block, the diagonal scan consisting of diagonal scan of sixty four 4×4 sub-blocks and diagonal scan within each of the 4×4 sub-blocks of the 32×32 transform block to apply the same multi-level significance map encoding to the 4×4 sub-blocks of the 32×32 transform block.