# US 2018/0027255 A1 · Video encoding method and apparatus, and video decoding method and apparatus using interpolation filter on which image characteristic is reflected > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0027255 A1 - Document ID: US20180027255A1 - Status: Published application - Kind: A1 - Application number: 15/524,463 - Filed: 2015-11-04 - Published: 2018-01-25 - Earliest claimed: 2014-11-04 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Elena ALSHINA; Alexander ALSHIN - Web page: https://patentgrep.com/patent/US20180027255A1 ## CPC - H04N 19/52: by predictive encoding - H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) - H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type - H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking - H04N 19/136: Incoming video signal characteristics or properties - H04N 19/137: Motion inside a coding unit, e.g. average field, frame or block difference - H04N 19/182: the unit being a pixel - H04N 19/503: involving temporal prediction (adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109) - H04N 19/523: with sub-pixel accuracy - H04N 19/61: in combination with predictive coding - H04N 19/625: using discrete cosine transform [DCT] - H04N 19/80: Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation (H04N19/635, H04N19/86 take precedence) - H04N 19/176: the region being a block, e.g. a macroblock - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Provided are a video encoding method and apparatus to which an interpolation filter is applied according to characteristics of an image for motion compensation, and a video decoding method and apparatus corresponding thereto. The video encoding method according to various embodiments includes determining a degree of change between neighboring samples of at least one integer pixel unit adjacent to a reference sample of an integer pixel unit of a current sample and the reference sample; determining an interpolation filter among interpolation filters having different frequency passbands and configured to produce reference samples of a sub-pixel unit to predict the current sample, based on the degree of change; determining a predicted sample value of the current sample by using a reference sample of a sub-pixel unit produced by applying the determined interpolation filter; and encoding a residual value between the predicted sample value and a sample value of the current sample. ## Claims ### Claim 1 A video decoding method comprising: determining a degree of change between neighboring samples of at least one integer pixel unit adjacent to a reference sample of an integer pixel unit of a current sample and the reference sample; determining an interpolation filter among interpolation filters for producing reference samples of a sub-pixel unit to predict the current sample, based on the degree of change; determining a predicted sample value of the current sample by using a reference sample of a sub-pixel unit produced by applying the determined interpolation filter to the reference sample and the neighboring samples; and producing a reconstructed sample value of the current sample by using a residual value between the predicted sample value and a sample value of the current sample, wherein the interpolation filters have different frequency passbands. ### Claim 2 (depends on 1) The video decoding method of claim 1, wherein the determining of the interpolation filter based on the degree of change comprises selecting an all-pass interpolation filter for passing all frequency bands when the degree of change is large, and selecting a low-pass interpolation filter for passing low-frequency bands when the degree of change is small. ### Claim 3 (depends on 1) The video decoding method of claim 1, wherein the determining of the degree of change comprises determining the degree of change based on a ratio between low-frequency components and high-frequency components among alternating-current (AC) components between the reference sample and neighboring samples of the integer pixel unit. ### Claim 4 (depends on 3) The video decoding method of claim 3, wherein the determining of the interpolation filter based on the degree of change comprises selecting an all-pass interpolation filter for passing all frequency bands when the high-frequency components are large, and selecting a low-pass interpolation filter for passing low-frequency bands when the low-frequency components are small. ### Claim 5 (depends on 1) The video decoding method of claim 1, wherein the determining of the degree of change comprises performing discrete cosine transformation (DCT) on the reference sample and neighboring samples of the integer pixel unit, and determining the degree of change based on a ratio between low-frequency alternating-current (AC) components and high-frequency AC components among DCT coefficients, wherein the DCT coefficients and DCT size are determined based on a number of taps of the interpolation filter. ### Claim 6 (depends on 1) The video decoding method of claim 1, wherein the interpolation filter is determined for each of at least one level among a reference block, a reference picture, a slice, and a sequence. ### Claim 7 (depends on 1) The video decoding method of claim 1, wherein the reference sample of the integer pixel unit is a sample at a position on a reference block indicated by integer components of a motion vector of a current block including the current sample, and the reference sample of the sub-pixel unit is a sample at a position of a sub-pixel unit adjacent to the reference sample of the integer pixel unit, the position being indicated by a sub-pixel component of the motion vector of the current block. ### Claim 8 A video encoding method comprising: determining a degree of change between neighboring samples of at least one integer pixel unit adjacent to a reference sample of an integer pixel unit of a current sample and the reference sample; determining an interpolation filter among interpolation filters for producing reference samples of a sub-pixel unit to predict the current sample, based on the degree of change; determining a predicted sample value of the current sample by using a reference sample of a sub-pixel unit produced by applying the determined interpolation filter to the reference sample and the neighboring samples; and encoding a residual value between the predicted sample value and a sample value of the current sample, wherein the interpolation filters have different frequency passbands. ### Claim 9 (depends on 8) The video encoding method of claim 8, wherein the determining of the interpolation filter based on the degree of change comprises selecting an all-pass interpolation filter for passing all frequency bands when the degree of change is large, and selecting a low-pass interpolation filter for passing low-frequency bands when the degree of change is small. ### Claim 10 (depends on 8) The video encoding method of claim 8, wherein the determining of the degree of change comprises determining the degree of change based on a ratio between low-frequency components and high-frequency components among alternating-current (AC) components between the reference sample and neighboring samples of the integer pixel unit. ### Claim 11 (depends on 10) The video encoding method of claim 10, wherein the determining of the interpolation filter based on the degree of change comprises selecting an all-pass interpolation filter for passing all frequency bands when the high-frequency components are large, and selecting a low-pass interpolation filter for passing low-frequency bands when the low-frequency components are small. ### Claim 12 (depends on 8) The video encoding method of claim 8, wherein the determining of the degree of change comprises performing discrete cosine transformation (DCT) on the reference sample and neighboring samples of the integer pixel unit, and determining the degree of change based on a ratio between low-frequency alternating-current (AC) components and high-frequency AC components among DCT coefficients, wherein the DCT coefficients and DCT size are determined based on a number of taps of the interpolation filter ### Claim 13 (depends on 8) The video encoding method of claim 8, wherein the interpolation filter is determined for each of at least one level among a reference block, a reference picture, a slice, and a sequence. ### Claim 14 A video decoding apparatus comprising: a reference sample determiner configured to determine a degree of change between neighboring samples of at least one integer pixel unit adjacent to a reference sample of an integer pixel unit of a current sample and the reference sample, and determine an interpolation filter among interpolation filters for producing reference samples of a sub-pixel unit to predict the current sample, based on the degree of change; and a predictor configured to determine a predicted sample value of the current sample by using a reference sample of a sub-pixel unit produced by applying the determined interpolation filter to the reference sample and the neighboring samples, and produce a reconstructed sample value of the current sample by using a residual value between the predicted sample value and a sample value of the current sample, wherein the interpolation filters have different frequency passbands. ### Claim 15 (depends on 1) A non-transitory computer-readable recording medium having recorded thereon a program for performing the video decoding method of claim 1 in a computer.