Cross-component adaptive loop filter for chroma
AssigneeCanon Kabushiki Kaisha
InventorsJonathan TAQUET, Christophe GISQUET, Guillaume LAROCHE, Patrice ONNO
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Abstract
A method of filtering an image is disclosed, the method comprising: receiving filter coefficients and first component sample values corresponding to samples surrounding a reference sample, and inputting said filter coefficients and first component sample values into a cross component filter to produce a cross component filter output; wherein said cross-component filter uses a restricted number of bits to represent said filter coefficients and/or first component sample values to produce said filter output.
Claims21
A method of decoding an image portion encoded using Cross-Component Adaptive Loop Filter (CCALF), the method comprising:
- acquiring filter coefficients and first component sample values corresponding to samples surrounding a reference sample;
- using said filter coefficients and first component sample values for the Cross-Component Adaptive Loop Filter to produce an output of the Cross-Component Adaptive Loop Filter for a second component;
- determining if CCALF is indicated for a given component;
- decoding CCALF coefficients from a bitstream;
- and
- decoding said image portion using said CCALF coefficients,
- wherein said CCALF coefficients are each represented by a fixed number of bits in the bitstream,
- wherein a possible value of each filter coefficient has been restricted to any one of zero and values of powers of two represented by a fixed number of bits, and
- wherein said first component sample value is a sample value at a position at a defined position relative to a reference sample.
A decoder for decoding an image portion encoded using Cross-Component Adaptive Loop Filter (CCALF), the decoder comprising:
- means for determining if CCALF is indicated for a given component;
- means for decoding CCALF coefficients from a bitstream;
- and
- means for decoding said image portion using said CCALF coefficients,
- wherein said CCALF coefficients are each represented by a fixed number of bits in the bitstream,
- wherein a possible value of each filter coefficient has been restricted to any one of zero and values of powers of two represented by a fixed number of bits, and
- wherein said first component sample value is a sample value at a position at a defined position relative to a reference sample.
A non-transitory computer readable storage medium storing a program for causing a computer to execute a method of decoding an image portion encoded using Cross-Component Adaptive Loop Filter (CCALF), the method comprising:
- acquiring filter coefficients and first component sample values corresponding to samples surrounding a reference sample;
- using said filter coefficients and first component sample values for the Cross-Component Adaptive Loop Filter to produce an output of the Cross-Component Adaptive Loop Filter for a second component;
- determining if CCALF is indicated for a given component;
- decoding CCALF coefficients from a bitstream;
- and
- decoding said image portion using said CCALF coefficients,
- wherein said CCALF coefficients are each represented by a fixed number of bits in the bitstream,
- wherein a possible value of each filter coefficient has been restricted to any one of zero and values of powers of two represented by a fixed number of bits, and
- wherein said first component sample value is a sample value at a position at a defined position relative to a reference sample.
Dependencies are inferred from the claim text.