Last coefficient coding for adaptive transform based video compression
AssigneeInterDigital VC Holdings, Inc.
InventorsSebastien Lasserre, Saurabh Puri, Patrick Le Callet
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Abstract
Coding of the last coded coefficient position is performed by basing the coding of the y coordinate of the position of the last coded coefficient on knowledge of the size of the partial transform used to generate a block of coefficients from a block of video pixels. This enables a context adaptive coding of the last coded coefficient parameter to be performed much more efficiently.
Claims20
A method for encoding, comprising:
- applying a partial transform to a block of image values to obtain a block of transform coefficients;
- and
- entropy encoding the block of transform coefficients,
- wherein the entropy encoding of the block of transform coefficients comprises entropy encoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy encoding of the syntax element depending on a size of the partial transform.
An apparatus for encoding comprising electronic circuitry configured to:
- apply a partial transform to a block of image values to obtain a block of transform coefficients;
- and
- entropy encode the block of transform coefficients,
- wherein the entropy encoding of the block of transform coefficients comprises entropy encoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy encoding of the syntax element depending on a size of the partial transform.
A method for decoding, comprising:
- entropy decoding a block of transform coefficients obtained by applying a partial transform to an input block of image values, wherein the entropy decoding of the block of transform coefficients comprises entropy decoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy decoding of the syntax element depending on a size of the partial transform;
- and
- inverse transforming the block of transform coefficients using the partial transform to obtain an output block of image values.
An apparatus for decoding comprising electronic circuitry configured to:
- entropy decode a block of transform coefficients obtained by applying a partial transform to an input block of image values, wherein the entropy decoding of the block of transform coefficients comprises entropy decoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy decoding of the syntax element depending on a size of the partial transform;
- and
- inverse transform the block of transform coefficients using the partial transform to obtain an output block of image values.
A non-transitory computer-readable storage medium storing program code instructions operative, when executed by a processor, to cause the processor to:
- apply an entropy decoding on a block of transform coefficients obtained by applying a partial transform to an input block of image values, wherein the entropy decoding of the block of transform coefficients comprises entropy decoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy decoding of the syntax element depending on a size of the partial transform;
- and
- inverse transform the block of transform coefficients using the partial transform to obtain an output block of image values.
A non-transitory computer-readable storage medium storing program code instructions operative, when executed by a processor, to cause the processor to:
- apply a partial transform to a block of image values to obtain a block of transform coefficients;
- and
- apply an entropy encoding to the block of transform coefficients,
- wherein the entropy encoding of the block of transform coefficients comprises entropy encoding a syntax element representing a coordinate of a position of a last coded transform coefficient in the block of transform coefficients, the entropy encoding of the syntax element depending on a size of the partial transform.
Dependencies are inferred from the claim text.