Method and apparatus for encoding/decoding a high dynamic range picture into a coded bitstream
A method and an apparatus for decoding at least one high dynamic range picture from a coded bitstream and a method and corresponding apparatus for coding the bitstream are disclosed. A standard dynamic range picture is decoded from the coded bitstream, a set of pivot points is decoded from the coded bitstream. The set of pivot points is representative of an adjustment function f adj . A predefined color correction function b p_default is selected. An adjusted color correction function b adj is determined by 1/b adj [γ]=f adj [γ]×(1/b p_default [γ]), where γ is a luminance value. The high dynamic range picture is reconstructed from the decoded standard dynamic range picture and the adjusted color correction function b adj .
1. A method for decoding at least one second dynamic range picture from a coded bitstream, the method comprising:
decoding a first dynamic range picture from the coded bitstream;
decoding a set of pivot points from the coded bitstream, the set of pivot points being representative of an adjustment function f adj ;
selecting a predefined color correction function b p_default ;
determining an adjusted color correction function b adj to adjust the selected predefined color correction function b p_default ;
reconstructing the second dynamic range picture from the decoded first dynamic range picture and the adjusted color correction function b adj , wherein the adjusted color correction function b adj is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.
2. A method for coding at least one second dynamic range picture into a coded bitstream, the method comprising:
decomposing the second dynamic range picture into a first dynamic range picture using at least a pre-processing color correction function b 0 ;
determining a post-processing color correction function b p from the pre-processing color correction function b 0 ;
selecting a predefined color correction function b p_default ;
determining an adjustment function f adj used to adjust the predefined color correction function b p_default and an adjusted color correction function b adj ;
encoding a set of pivot points into the coded bitstream, the set of pivot points being representative of the determined adjustment function f adj ;
encoding the first dynamic range picture into the coded bitstream, wherein the adjusted color correction function b adj is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.
3. The method according to claim 2 , wherein determining the adjustment function f adj used to adjust the predefined color correction function b p_default comprises performing a minimization of an error between 1/b p and 1/b adj .
4. An apparatus for decoding at least a second dynamic range picture from a coded bitstream, comprising a memory and at least one processor configured to:
decoding a first dynamic range picture from the coded; bitstream;
decoding a set of pivot points from the coded bitstream, the set of pivot points being representative of an adjustment function f adj ;
selecting a predefined color correction function b p_default ;
determining an adjusted color correction function b adj to adjust the selected predefined color correction function b p_default ;
reconstructing the second dynamic range picture from the decoded first dynamic range picture and the adjusted color correction function b adj , wherein the adjusted color correction function b adj is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.
5. The apparatus for decoding according to claim 4 , wherein the apparatus for decoding is disposed in an electronic device.
6. The apparatus for decoding according to claim 5 , wherein the electronic device is one of a mobile device, a communication device, a game device, a set top box, a TV set, a tablet, a laptop, a display, and a decoding chip.
7. An apparatus for encoding at least one second dynamic range picture into a coded bitstream, comprising a memory and at least one processor configured to:
decomposing the second dynamic range picture into a first dynamic range picture using at least a pre-processing color correction function b 0 ;
determining a post-processing color correction function b p from the pre-processing color correction function b 0 ;
selecting a predefined color correction function b p_default ;
determining an adjustment function f adj used to adjust the predefined color correction function b p_default and an adjusted color correction function b adj ;
encoding a set of pivot points into the coded bitstream, the set of pivot points being representative of the determined adjustment function f adj ;
encoding the first dynamic range picture into the coded bitstream, wherein the adjusted color correction function b adj is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.
8. The apparatus for encoding according to claim 7 , wherein the apparatus for encoding is disposed in an electronic device.
9. The apparatus for encoding according to claim 8 , wherein the electronic device is one of a mobile device, a communication device, a game device, a tablet, a laptop, a still picture camera, a video camera, an encoding chip, a still picture server, and a video server.
10. The apparatus according to claim 7 , wherein determining the adjustment function f adj used to adjust the predefined color correction function b p_default comprises performing a minimization of an error between 1/b p and 1/b adj .
11. A non-transitory computer-readable storage medium having stored instructions that, when executed by a processor, cause the processor to:
decode a first dynamic range picture from a coded bitstream;
decode a set of pivot points from the coded bitstream, the set of pivot points being representative of an adjustment function f adj ;
select a predefined color correction function b p_default ;
determine an adjusted color correction function b adj to adjust the selected predefined color correction function b p_default ;
reconstruct a second dynamic range picture from the decoded first dynamic range picture and the adjusted color correction function b adj , wherein the adjusted color correction function ha is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.
12. A non-transitory computer-readable storage medium having stored instructions that are operative, when executed by a processor, to cause the processor to:
decompose a second dynamic range picture into a first dynamic range picture using at least a pre-processing color correction function b 0 ;
determine a post-processing color correction function b P from the pre-processing color correction function b 0 ;
select a predefined color correction function b p_default ;
determine an adjustment function f adj used to adjust the predefined color correction function b p_default and an adjusted color correction function b adj ;
encode a set of pivot points into a coded bitstream, the set of pivot points being representative of the determined adjustment function f adj ;
encode the first dynamic range picture into the coded bitstream, wherein the adjusted color correction function b adj is determined by:
1/ b adj [ Y ]= f adj [ Y ]×(1/ b p_default [ Y ]),
where Y is a luminance value.