# US 12,604,039 B2 · Sign prediction for block-based video coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,604,039 B2 - Document ID: US12604039B2 - Status: Granted - Kind: B2 - Application number: 18/743,673 - Filed: 2024-06-14 - Published: 2024-12-12 - Granted: 2026-04-14 - Earliest claimed: 2021-08-17 - Assignees: Beijing Dajia Internet Information Technology Co., Ltd. - Applicants: Beijing Dajia Internet Information Technology Co., Ltd. - Inventors: Xiaoyu Xiu; Ning Yan; Yi-Wen Chen; Che-Wei Kuo; Wei Chen; Hong-Jheng Jhu; Han Gao; Xianglin Wang; Bing Yu - Web page: https://patentgrep.com/patent/US12604039B2 ## CPC - H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type - H04N 19/60: using transform coding - H04N 19/124: Quantisation - 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 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence) - H04N 19/147: according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/18: the unit being a set of transform coefficients - H04N 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) - H04N 19/61: in combination with predictive coding - H04N 19/91: Entropy coding, e.g. variable length coding [VLC] or arithmetic coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Implementations of the disclosure provide a video decoding apparatus and method for transform coefficient sign prediction on a video decoder side. The method may include receiving a bitstream including a sequence of sign signaling bits for a set of candidate transform coefficients. The method may further include generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame from a video. The method may also include decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients. The method may additionally include estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the decoded sequence of sign signaling bits. ## Claims ### Claim 1 A video decoding method for sign prediction of transform coefficients, comprising: receiving a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients; generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame; decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients, wherein a context of the one or more contexts used to entropy-encode a sign signaling bit is determined based on a scan position of a candidate transform coefficient corresponding to the sign signaling bit; and estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of decoded sign signaling bits. ### Claim 2 (depends on 1) The video decoding method of claim 1, wherein estimating the original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of sign signaling bits comprises: updating the predicted signs of the candidate transform coefficients according to the correctness indicated by the respective sign signaling bits to determine the original signs of the candidate transform coefficients. ### Claim 3 (depends on 1) The video decoding method of claim 1, wherein decoding the sequence of sign signaling bits comprises: determining a context used to entropy-encode the sign signaling bit based on a magnitude of the candidate transform coefficient corresponding to the sign signaling bit. ### Claim 4 (depends on 3) The video decoding method of claim 3, wherein magnitudes of the candidate transform coefficients fall within a plurality of magnitude segments, wherein a plurality of contexts are assigned to entropy-encode sign signaling bits for transform coefficients belonging to the respective magnitude segments, wherein determining the context used to entropy-encode the sign signaling bit comprises: determining a magnitude segment, among the plurality of magnitude segments, to which the magnitude of the candidate transform coefficient corresponding to the sign signaling bit belongs; and determining the context assigned to the magnitude segment as the context used to entropy-encode the sign signaling bit. ### Claim 5 (depends on 4) The video decoding method of claim 4, wherein every two consecutive magnitude segments, among the plurality of magnitude segments, are separated by a threshold. ### Claim 6 (depends on 3) The video decoding method of claim 3, wherein the bitstream further comprises encoded data of quantized levels of the set of candidate transform coefficients, wherein the video decoding method further comprises: determining the magnitude of the candidate transform coefficient by directly parsing a quantized level of the candidate transform coefficient from the bitstream without dequantization. ### Claim 7 (depends on 3) The video decoding method of claim 3, wherein the bitstream further comprises encoded data of quantized levels of the set of candidate transform coefficients, wherein the video decoding method further comprises: parsing a quantized level of the candidate transform coefficient from the bitstream; determining a quantization index of the candidate transform coefficient based on the quantized level of the candidate transform coefficient and a transition state of the candidate transform coefficient; and determining the magnitude of the candidate transform coefficient based on the quantization index of the candidate transform coefficient. ### Claim 8 (depends on 1) The video decoding method of claim 1, wherein the set of candidate transform coefficients are selected from transform coefficients of the transform block that are reordered according to their magnitudes, wherein the video decoding method further comprises: reordering the set of candidate transform coefficients parsed from the bitstream. ### Claim 9 (depends on 8) The video decoding method of claim 8, wherein the contexts used to entropy-encode the sign signaling bits are determined based on the magnitudes of reordered transform coefficients. ### Claim 10 (depends on 8) The video decoding method of claim 8, wherein the contexts used to entropy-encode the sign signaling bits are determined based on the magnitudes of transform coefficients before the reordering. ### Claim 11 (depends on 1) The video decoding method of claim 1, wherein scan positions of the transform coefficients are classified into a plurality of groups, wherein a plurality of contexts are assigned to entropy-encode sign signaling bits for transform coefficients belonging to the respective groups, wherein the context of the one or more contexts used to entropy-encode a sign signaling bit is determined by: determining a group, among the plurality of groups, to which the scan position of the candidate transform coefficient corresponding to the sign signaling bit belongs; and determining the context assigned to the group as the context used to entropy-encode the sign signaling bit. ### Claim 12 (depends on 1) The video decoding method of claim 1, wherein decoding the sequence of sign signaling bits comprises: determining a context used to entropy-encode the sign signaling bit based on coding mode, a block size or component channel information of the candidate transform coefficient corresponding to the sign signaling bit. ### Claim 13 (depends on 1) The video decoding method of claim 1, wherein the set of transform coefficients in the bitstream are generated by applying a plurality of different transform cores, wherein decoding the sequence of sign signaling bits comprises: determining a context used to entropy-encode the sign signaling bit based on the transform core applied to generate the candidate transform coefficient corresponding to the sign signaling bit. ### Claim 14 (depends on 13) The video decoding method of claim 13, wherein the transform cores comprise a multiple transform selection (MTS) and a low-frequency non-separable transform (LFNST). ### Claim 15 (depends on 1) The video decoding method of claim 1, wherein generating the set of predicted signs for the set of candidate transform coefficients comprises: generating a plurality of candidate hypotheses for the set of candidate transform coefficients; and selecting a hypothesis from the plurality of candidate hypotheses as the set of predicted signs for the set of candidate transform coefficients. ### Claim 16 A video decoding apparatus, comprising: a memory configured to store a bitstream comprising a set of candidate transform coefficients and a sequence of sign signaling bits for the set of candidate transform coefficients; and a processor coupled to the memory and configured to perform operations comprising: receiving a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients; generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame; decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients, wherein a context of the one or more contexts used to entropy-encode a sign signaling bit is determined based on a scan position of a candidate transform coefficient corresponding to the sign signaling bit; and estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of decoded sign signaling bits. ### Claim 17 A non-transitory computer-readable storage medium having stored therein a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients, wherein the bitstream is decodable by performing operations comprising: receiving a bitstream comprising a sequence of sign signaling bits for a set of candidate transform coefficients; generating a set of predicted signs for the set of candidate transform coefficients associated with a transform block of a video frame; decoding the sequence of sign signaling bits based on one or more contexts used to entropy-encode the sequence of sign signaling bits to obtain an indication of correctness of the predicted signs of the respective candidate transform coefficients, wherein a context of the one or more contexts used to entropy-encode a sign signaling bit is determined based on a scan position of a candidate transform coefficient corresponding to the sign signaling bit; and estimating original signs for the set of candidate transform coefficients based on the set of predicted signs and the sequence of decoded sign signaling bits.