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US 11,902,582 B2Granted
Method of coding transform coefficient based on high frequency zeroing and apparatus thereof
AssigneeLG Electronics Inc.
InventorsJungah Choi, Sunmi Yoo, Jin Heo, Ling Li, Jangwon Choi, Seunghwan Kim
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Abstract
An image decoding method performed by a decoding apparatus according to the present disclosure includes receiving a bitstream including residual information; deriving quantized transform coefficients for a current block based on the residual information included in the bitstream; deriving residual samples for the current block based on the quantized transform coefficients; and generating a reconstructed picture based on the residual samples for the current block.
Claims14
A decoding apparatus of decoding an image, comprising:
- a memory;
- and
- at least one processor connected to the memory, the at least one processor configured to:
- derive quantized transform coefficients for a current block based on residual information received from a bitstream;
- derive dequantized transform coefficients for the current block based on the quantized transform coefficient;
- derive residual samples for the current block based on the dequantized transform coefficients;
- and
- generate a reconstructed picture based on the residual samples for the current block,
- wherein the current block includes a low frequency transform coefficient region including at least one non-zero transform coefficient and a region including only zero transform coefficients other than the low frequency transform coefficient region,
- wherein the residual information includes last significant coefficient prefix information on a position of a last non-zero transform coefficient among the transform coefficients for the current block,
- wherein the last significant coefficient prefix information includes column position prefix information and row position prefix information,
- wherein the position of the last non-zero transform coefficient is determined based on prefix codewords related to the last significant coefficient prefix information,
- wherein the prefix codewords include a first codeword for the column position prefix information and a second codeword for the row position prefix information, and
- wherein a maximum value of the last significant coefficient prefix information and a maximum length of the prefix codewords are determined based on a size of the low frequency transform coefficient region.
11 more elements
An encoding apparatus of encoding an image, comprising:
- a memory;
- and
- at least one processor connected to the memory, the at least one processor configured to:
- derive residual samples for a current block;
- derive transform coefficients for the current block based on the residual samples;
- derive quantized transform coefficients based on the transform coefficients for the current block;
- and
- encode residual information related to the quantized transform coefficients,
- wherein the current block includes a low frequency transform coefficient region including at least one non-zero transform coefficient and a region including only zero transform coefficients other than the low frequency transform coefficient region,
- wherein the residual information includes last significant coefficient prefix information on a position of a last non-zero transform coefficient among the transform coefficients for the current block,
- wherein the last significant coefficient prefix information includes column position prefix information and row position prefix information,
- wherein the position of the last non-zero transform coefficient is determined based on prefix codewords related to the last significant coefficient prefix information,
- wherein the prefix codewords include a first codeword for the column position prefix information and a second codeword for the row position prefix information, and
- wherein a maximum value of the last significant coefficient prefix information and a maximum length of the prefix codewords are determined based on a size of the low frequency transform coefficient region.
11 more elements
A non-transitory computer readable storage medium storing a bitstream generated by an encoding apparatus, the encoding apparatus comprising:
- a memory;
- and
- at least one processor connected to the memory, the at least one processor configured to:
- derive residual samples for a current block;
- derive transform coefficients for the current block based on the residual samples;
- derive quantized transform coefficients based on the transform coefficients for the current block;
- and
- encode residual information related to the quantized transform coefficients to generate the bitstream,
- wherein the current block includes a low frequency transform coefficient region including at least one non-zero transform coefficient and a region including only zero transform coefficients other than the low frequency transform coefficient region,
- wherein the residual information includes last significant coefficient prefix information on a position of a last non-zero transform coefficient among the transform coefficients for the current block,
- wherein the last significant coefficient prefix information includes column position prefix information and row position prefix information,
- wherein the position of the last non-zero transform coefficient is determined based on prefix codewords related to the last significant coefficient prefix information,
- wherein the prefix codewords include a first codeword for the column position prefix information and a second codeword for the row position prefix information, and
- wherein a maximum value of the last significant coefficient prefix information and a maximum length of the prefix codewords are determined based on a size of the low frequency transform coefficient region.
11 more elements
Dependencies are inferred from the claim text.