# US 2023/0421815 A1 · Transformations for signal enhancement coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0421815 A1 - Document ID: US20230421815A1 - Status: Published application - Kind: A1 - Application number: 18/185,978 - Filed: 2023-03-17 - Published: 2023-12-28 - Earliest claimed: 2018-08-03 - Assignees: V-Nova International Limited - Applicants: V-Nova International Limited - Inventors: Guido MEARDI; Ivan DAMNJANOVIC - Web page: https://patentgrep.com/patent/US20230421815A1 ## CPC - H04N 19/61: in combination with predictive coding - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type - H04N 19/124: Quantisation - H04N 19/136: Incoming video signal characteristics or properties - H04N 19/33: in the spatial domain - H04N 19/36: Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability - H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/60: using transform coding - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding - H04N 19/93: Run-length coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Measures are provided to encode a signal. An input frame (102) is received and down-sampled to obtain a down-sampled frame (103). The down-sampled frame (103) is passed to an encoding module (104) which encodes the down-sampled frame (103) to generate an encoded frame (105). A decoded frame is obtained from a decoding module (106) which generates the decoded frame by decoding the encoded frame (105). A set of residual data (113) is generated by taking a difference between the decoded frame and the down-sampled frame (103) and is encoded to generate a set of encoded residual data. The encoding comprises transforming the set of residual data into a transformed set of residual data. The set of encoded residual data is output to a decoder to enable the decoder to reconstruct the input frame. Measures are also provided to decode a signal. ## Claims ### Claim 1 (canceled) ### Claim 2 A method of decoding a signal, the method comprising: receiving an encoded frame and first and second sets of encoded residual data; passing the encoded frame to a decoding module, the decoding module being configured to generate a decoded frame by decoding the encoded frame; decoding the first and second sets of encoded residual data to generate first and second sets of reconstructed residual data, wherein the decoding comprises transforming the first and second sets of encoded residual data into reconstructed first and second sets of residual data respectively; combining the first set of reconstructed residual data with the decoded frame to obtain a combined frame; up-sampling the combined frame to obtain a reference decoded frame; and combining the second set of reconstructed residual data with the reference decoded frame to obtain a reconstructed frame. ### Claim 3 (depends on 2) The method according to claim 2, wherein the decoding module is configured to decode the encoded frame in accordance with a first decoding method in order to generate the decoded frame, and wherein: the decoding of the first set of encoded residual data is performed according to a second decoding method, the second decoding method being different from the first decoding method; and/or the decoding of the second set of encoded residual data is performed according to a third decoding method, the third decoding method being different from the first decoding method. ### Claim 4 (depends on 2) The method according to claim 2, wherein the decoding module is configured to use a block-based coding algorithm. ### Claim 5 (depends on 2) The method according to claim 2, wherein the first set of encoded residual data represents a compression error associated with the decoding module. ### Claim 6 (depends on 2) The method according to claim 2, wherein the second set of encoded residual data represents a reconstruction error. ### Claim 7 (depends on 2) The method according to claim 2, wherein the method is performed in a hierarchical coding system having exactly two hierarchical levels. ### Claim 8 (depends on 7) The method according to claim 7, wherein one of the two hierarchical levels corresponds to a baseline layer and the other one of the two hierarchical levels corresponds to an enhancement layer. ### Claim 9 (depends on 2) The method according to claim 2, wherein the transforming uses a Hadamard-based transform. ### Claim 10 (depends on 2) The method according to claim 2, wherein the transforming uses a 2×2 transform kernel. ### Claim 11 (depends on 2) The method according to claim 2, wherein the transforming of the first set of encoded residual data comprises: selecting a subset of the first set of encoded residual data; and applying a transformation on the subset of the first set of encoded residual data to generate a corresponding subset of the transformed first set of encoded residual data. ### Claim 12 (depends on 11) The method according to claim 11, wherein one of the subset of the transformed first set of encoded residual data is obtained by averaging the subset of the first set of encoded residual data. ### Claim 13 (depends on 2) The method according to claim 2, wherein the transforming of the second set of encoded residual data comprises: selecting a subset of the second set of encoded residual data; and applying a transformation on the subset of the second set of encoded residual data to generate a corresponding subset of the transformed encoded second set of residual data. ### Claim 14 (depends on 13) The method according to claim 13, wherein one of the subset of the transformed second set of encoded residual data is obtained by the difference between: an average of a subset of the encoded frame; and a corresponding element of the combination of the first set of encoded residual data and the encoded frame. ### Claim 15 (depends on 2) The method according to claim 2, wherein the decoding comprises quantizing at least some of the transformed first and second sets of encoded residual data respectively into quantized first and second sets of encoded residual data respectively. ### Claim 16 (depends on 15) The method according to claim 15, wherein the decoding comprises entropy-encoding the quantized first and second sets of encoded residual data respectively into entropy-encoded first and second sets of encoded residual data ### Claim 17 (depends on 2) The method according to claim 2, wherein the signal comprises a video signal and/or an image signal. ### Claim 18 A decoder configured to: receive an encoded frame and first and second sets of encoded residual data; pass the encoded frame to a decoding module, the decoding module being configured to generate a decoded frame by decoding the encoded frame; decode the first and second sets of encoded residual data to generate first and second sets of reconstructed residual data, wherein the decoding comprises transforming the first and second sets of encoded residual data into reconstructed first and second sets of residual data respectively; combine the first set of reconstructed residual data with the decoded frame to obtain a combined frame; up-sample the combined frame to obtain a reference decoded frame; and combine the second set of reconstructed residual data with the reference decoded frame to obtain a reconstructed frame.