# US 11,122,274 B2 · Video encoding apparatus, video decoding apparatus, and video decoding method for performing intra-prediction based on directionality of neighboring block > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,274 B2 - Document ID: US11122274B2 - Status: Granted - Kind: B2 - Application number: 16/407,086 - Filed: 2019-05-08 - Published: 2019-08-29 - Granted: 2021-09-14 - Earliest claimed: 2009-12-30 - Assignees: Ideahub Inc. - Applicants: Ideahub Inc. - Inventors: Je Chang Jeong; Soon Jong Jin; Sang Jun Park; Hyuk Lee - Web page: https://patentgrep.com/patent/US11122274B2 ## CPC - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/11: among a plurality of spatial predictive coding modes - H04N 19/124: Quantisation - H04N 19/152: by measuring the fullness of the transmission buffer - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/197: {including determination of the initial value of an encoding parameter (H04N19/56 takes precedence)} - H04N 19/513: Processing of motion vectors - H04N 19/547: Motion estimation performed in a transform domain - H04N 19/61: in combination with predictive coding - H04N 19/184: the unit being bits, e.g. of the compressed video stream - H04N 19/50: using predictive coding (H04N19/61 takes precedence) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Provided are methods and apparatuses for improving compression efficiency in directional intra-prediction. A video encoding apparatus, which does not need to record intra mode information, includes a mode selector that selects one from among a plurality of intra modes on the basis of a directionality of at least one neighboring block that has already been reconstructed before a current block is reconstructed, an intra predictor that obtains a prediction block of the current block from the at least one neighboring block according to the directionality of the selected mode, and obtains a residual block by subtracting the prediction block from the current block, and a unit for encoding the obtained residual block. ## Claims ### Claim 1 A video decoding method performed by a video decoding apparatus, the method comprising: determining a neighboring intra prediction mode associated with a neighboring block, the neighboring block being adjacent to a current block; determining a current intra prediction mode associated with the current block based on whether the neighboring intra prediction mode associated with the neighboring block has directionality or not; performing intra-prediction based on the current intra prediction mode associated with the current block to generate a prediction block associated with the current block; obtaining transform coefficients; dequantizing the transform coefficients to generate dequantized transform coefficients; transforming the dequantized transform coefficients to generate a residual block associated with the current block; and reconstructing the current block based on the prediction block and the residual block, wherein determining the current intra prediction mode associated with the current block comprises: determining candidate intra prediction modes associated with the current block according to a first set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has no directionality, determining candidate intra prediction modes associated with the current block according to a second set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has directionality, selecting the current intra prediction mode associated with the current block among the candidate intra prediction modes, wherein the second set of two or more mathematical expressions is different from the first set of two or more mathematical expressions, wherein the second set of two or more mathematical expressions use the neighboring intra prediction mode associated with the neighboring block, and the neighboring block includes an upper block adjacent to the current block. ### Claim 2 (depends on 1) The video decoding method of claim 1, wherein an intra prediction mode having no directionality includes a DC mode. ### Claim 3 (depends on 1) The video decoding method of claim 1, wherein selecting the current intra prediction mode associated with the current block among the candidate intra prediction modes comprises: obtaining information for selecting the current intra prediction mode associated with the current block among the candidate intra prediction modes; and selecting the current intra prediction mode associated with the current block among the candidate intra prediction modes based on the obtained information. ### Claim 4 (depends on 1) The video decoding method of claim 1, wherein obtaining the transform coefficients comprises: decoding an input bitstream to obtain the transform coefficients. ### Claim 5 (depends on 4) The video decoding method of claim 4, wherein decoding the input bitstream comprises: losslessly decoding the input bitstream to obtain the transform coefficients. ### Claim 6 (depends on 1) The video decoding method of claim 1, wherein reconstructing the current block comprises: reconstructing the current block by adding the prediction block and the residual block. ### Claim 7 A video encoding method performed by a video encoding apparatus, the method comprising: determining a current intra prediction mode associated with a current block; performing intra-prediction according to the current intra prediction mode associated with the current block to generate a prediction block associated with the current block; determining a neighboring intra prediction mode associated with a neighboring block, the neighboring block being adjacent to the current block; encoding the current intra prediction mode associated with the current block based on whether the neighboring intra prediction mode associated with the neighboring block has directionality or not; obtaining a residual block associated with the current block by using the prediction block and the current block; transforming the residual block to generate transform coefficients; quantizing the transform coefficients to generate quantized transform coefficients; encoding the quantized transform coefficients, wherein the encoding the current intra prediction mode associated with the current block comprises: determining candidate intra prediction modes associated with the current block according to a first set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has no directionality, determining candidate intra prediction modes associated with the current block according to a second set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has directionality, encoding the current intra prediction mode associated with the current block based on the candidate intra prediction modes, wherein the second set of two or more mathematical expressions is different from the first set of two or more mathematical expressions, wherein the second set of two or more mathematical expressions use the neighboring intra prediction mode associated with the neighboring block, and the neighboring block includes an upper block adjacent to the current block. ### Claim 8 (depends on 7) The video encoding method of claim 7, wherein an intra prediction mode having no directionality includes a DC mode. ### Claim 9 (depends on 7) The video encoding method of claim 7, wherein the encoding the current intra prediction mode associated with the current block among the candidate intra prediction modes comprises: identifying the current intra prediction mode associated with the current block among the candidate intra prediction modes; and encoding information for identifying the current intra prediction mode associated with the current block among the candidate intra prediction modes. ### Claim 10 (depends on 7) The video encoding method of claim 7, wherein encoding the quantized transform coefficients comprises: encoding the quantized transform coefficients to generate an input bitstream. ### Claim 11 (depends on 10) The video encoding method of claim 10, wherein encoding the quantized transform coefficients comprises: losslessly encoding the quantized transform coefficients to generate the input bitstream. ### Claim 12 (depends on 7) The video encoding method of claim 7, wherein obtaining the residual block comprises: subtracting the prediction block from the current block to obtain the residual block associated with the current block. ### Claim 13 A method of transmitting a bitstream performed by an image encoding apparatus, the method comprising: determining a current intra prediction mode associated with a current block; performing intra-prediction according to the current intra prediction mode associated with the current block to generate a prediction block associated with the current block; determining a neighboring intra prediction mode associated with a neighboring block, the neighboring block being adjacent to the current block; encoding, into the bitstream, the current intra prediction mode associated with the current block based on whether the neighboring intra prediction mode associated with the neighboring block has directionality or not; obtaining a residual block associated with the current block by using the prediction block and the current block; transforming the residual block to generate transform coefficients; quantizing the transform coefficients to generate quantized transform coefficients; and encoding, into the bitstream, the quantized transform coefficients; and transmitting the bitstream to an image decoding apparatus, wherein the encoding the current intra prediction mode associated with the current block comprises: determining candidate intra prediction modes associated with the current block according to a first set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has no directionality, determining candidate intra prediction modes associated with the current block according to a second set of two or more mathematical expressions, when the neighboring intra prediction mode associated with the neighboring block has directionality, encoding the current intra prediction mode associated with the current block based on the candidate intra prediction modes, wherein the second set of two or more mathematical expressions is different from the first set of two or more mathematical expressions, wherein the second set of two or more mathematical expressions use the neighboring intra prediction mode associated with the neighboring block, and the neighboring block includes an upper block adjacent to the current block.