US 10,477,223 B2 · Coding of significance maps and transform coefficient blocks

Abstract

A higher coding efficiency for coding a significance map indicating positions of significant transform coefficients within a transform coefficient block is achieved by the scan order by which the sequentially extracted syntax elements indicating, for associated positions within the transform coefficient block, as to whether at the respective position a significant or insignificant transform coefficient is situated, are sequentially associated to the positions of the transform coefficient block, among the positions of the transform coefficient block depends on the positions of the significant transform coefficients indicated by previously associated syntax elements. Alternatively, the first-type elements may be context-adaptively entropy decoded using contexts which are individually selected for each of the syntax elements dependent on a number of significant transform coefficients in a neighborhood of the respective syntax element, indicated as being significant by any of the preceding syntax elements.

Claims30

Dependent claims

An apparatus for decoding transform coefficient blocks encoded in a data stream, comprising:

a decoder configured to extract, from the data stream, a last significant syntax element by entropy decoding, the last significant syntax element associated with a respective position within a corresponding transform coefficient block, indicating information regarding a transform coefficient at the respective position as being the last significant transform coefficient according to a scan order in the corresponding transform coefficient block;
and
an associator configured to associate the last significant syntax element with a respective position of the corresponding transform coefficient block in the scan order,
wherein the decoder is configured to use, in entropy decoding a current last significant syntax element, a context for the current last significant syntax element associated with a current transform coefficient block, wherein the context is selected based on at least the position of the current last significant syntax element within the current transform coefficient block, information related to at least one corner coordinate of the current transform coefficient block, and a color plane type associated with the current transform coefficient block.

1 more element

A non-transitory computer-readable medium for storing data associated with a video, comprising:

a data stream stored in the non-transitory computer-readable medium, the data stream comprising information related to transform coefficient blocks including a last significant syntax element, the last significant syntax element associated with a respective position within a corresponding transform coefficient block, indicating information regarding a transform coefficient at the respective position as being the last significant transform coefficient according to a scan order in the corresponding transform coefficient block,
wherein a current last significant syntax element is encoded into the data stream in the scan order using entropy encoding based on a context for the current last significant syntax element associated with a current transform coefficient block,
wherein the context is selected based on at least the position of the current last significant syntax element within the current transform coefficient block, information related to at least one corner coordinate of the current transform coefficient block, and a color plane type associated with the current transform coefficient block.

Dependencies are inferred from the claim text.

Coding of significance maps and transform coefficient blocks

Life of this patent

Coding of significance maps and transform coefficient blocks

Life of this patent

Abstract

Claims30