# US 11,309,910 B2 · Methods and apparatus for unified significance map coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,910 B2 - Document ID: US11309910B2 - Status: Granted - Kind: B2 - Application number: 17/154,283 - Filed: 2021-01-21 - Published: 2021-06-03 - Granted: 2022-04-19 - Earliest claimed: 2010-05-12 - Assignees: InterDigital Madison Patent Holdings, SAS - Applicants: Interdigital Madison Patent Holdings, SAS - Inventors: Xiaoan Lu; Joel Sole; Peng Yin; Qian Xu; Yunfei Zheng - Web page: https://patentgrep.com/patent/US11309910B2 ## CPC - H03M 7/4006: {Conversion to or from arithmetic code} - H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type - H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding - H04N 19/18: the unit being a set of transform coefficients - H04N 19/64: characterised by ordering of coefficients or of bits for transmission - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Methods and apparatus are provided for unified significance map coding. An apparatus includes a video encoder (400) for encoding transform coefficients for at least a portion of a picture. The transform coefficients are obtained using a plurality of transforms. One or more context sharing maps are generated for the transform coefficients based on a unified rule. The one or more context sharing maps are for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms. ## Claims ### Claim 1 An apparatus, comprising: a video encoder (400) for transform coefficients obtained using a plurality of transforms and converted from a two dimensional to a one-dimensional array, wherein one or more context sharing maps are generated for the transform coefficients based on a unified rule for generating the context sharing maps, the one or more context sharing maps for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms, wherein a context is assigned based on transform coefficient position. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the transform coefficients are two-dimensional transform coefficients, and the unified rule specifies mapping the two-dimensional transform coefficients into a one-dimensional array according to a scanning order, and assigning first N coefficients from among the transform coefficients to separate contexts. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the transform coefficients are encoded into a resultant bitstream, multiple rules are used as candidates for the unified rule, and the unified rule is indicated in the resultant bitstream. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the unified rule comprises at least two unified rules that vary based on video sequences to which the transform coefficients correspond, picture resolutions, and quantization parameters. ### Claim 5 A method, comprising: encoding transform coefficients obtained using a plurality of transforms and converted from a two dimensional to a one-dimensional array, wherein one or more context sharing maps are generated for the transform coefficients based on a unified rule for generating the context sharing maps, the one or more context sharing maps for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms, wherein a context is assigned based on transform coefficient position (800, 1000). ### Claim 6 (depends on 5) The method of claim 5, wherein the transform coefficients are two-dimensional transform coefficients, and the unified rule specifies mapping the two-dimensional transform coefficients into a one-dimensional array according to a scanning order, and assigning first N coefficients from among the transform coefficients to separate contexts (820). ### Claim 7 (depends on 6) The method of claim 6, wherein remaining coefficients from among the transform coefficients are assigned to a single context (820). ### Claim 8 (depends on 5) The method of claim 5, wherein the transform coefficients are encoded into a resultant bitstream, multiple rules are used as candidates for the unified rule, and the unified rule is indicated in the resultant bitstream (1020). ### Claim 9 (depends on 5) The method of claim 5, wherein the unified rule comprises at least two unified rules that vary based on video sequences to which the transform coefficients correspond, picture resolutions, and quantization parameters (1020). ### Claim 10 An apparatus, comprising: a video decoder (500) for decoding transform coefficients obtained using a plurality of transforms and converted from a two dimensional to a one-dimensional array, wherein one or more context sharing maps are generated for the transform coefficients based on a unified rule for generating the context sharing maps, the one or more context sharing maps for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms, wherein a context is assigned based on transform coefficient position. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the transform coefficients are two-dimensional transform coefficients, and the unified rule specifies mapping the two-dimensional transform coefficients into a one-dimensional array according to a scanning order, and assigning first N coefficients from among the transform coefficients to separate contexts. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein remaining coefficients from among the transform coefficients are assigned to a single context. ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the transform coefficients are decoded from a bitstream, multiple rules are used as candidates for the unified rule, and the unified rule is determined from the bitstream. ### Claim 14 (depends on 10) The apparatus of claim 10, wherein the unified rule comprises at least two unified rules that vary based on video sequences to which the transform coefficients correspond, picture resolutions, and quantization parameters. ### Claim 15 A method, comprising: decoding transform coefficients for at least a portion of a picture, the transform coefficients obtained using a plurality of transforms and converted from a two dimensional to a one-dimensional array, wherein one or more context sharing maps are generated for the transform coefficients based on a unified rule for generating the context sharing maps, the one or more context sharing maps for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms, wherein a context is assigned based on transform coefficient position (900, 1100). ### Claim 16 (depends on 15) The method of claim 15, wherein the transform coefficients are two-dimensional transform coefficients, and the unified rule specifies mapping the two-dimensional transform coefficients into a one-dimensional array according to a scanning order, and assigning first N coefficients from among the transform coefficients to separate contexts (920). ### Claim 17 (depends on 16) The method of claim 16, wherein remaining coefficients from among the transform coefficients are assigned to a single context (920). ### Claim 18 (depends on 15) The method of claim 15, wherein the transform coefficients are decoded from a bitstream, multiple rules are used as candidates for the unified rule, and the unified rule is determined from the bitstream (1120). ### Claim 19 (depends on 15) The method of claim 15, wherein the unified rule comprises at least two unified rules that vary based on video sequences to which the transform coefficients correspond, picture resolutions, and quantization parameters (1120). ### Claim 20 A non-transitory computer readable storage media having video signal data encoded thereupon, comprising: transform coefficients obtained using a plurality of transforms and converted from a two dimensional to a one-dimensional array, wherein one or more context sharing maps are generated for the transform coefficients based on a unified rule for generating the context sharing maps, the one or more context sharing maps for providing at least one context that is shared among at least some of the transform coefficients obtained from at least two different ones of the plurality of transforms, wherein a context is assigned based on transform coefficient position.