Patent ID: 11949872
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 14:
15. A method for transmitting data for an image information, comprising:
obtaining a bitstream of the image information including luma mapping with chroma scaling (LMCS) related information and residual information, wherein the LMCS related information is generated by determining an intra prediction mode for a current block, generating a prediction luma sample based on the intra prediction mode, generating a mapped prediction luma sample based on the prediction luma sample, and deriving the LMCS related information based on the mapped prediction luma sample, and wherein the residual information is generated by generating a residual luma sample based on the mapped prediction luma sample, and deriving residual information based on the residual luma sample; and
transmitting the data comprising the bitstream of the image information including the LMCS related information and the residual information,
wherein a reconstructed luma sample is generated based on the prediction luma sample,
wherein a piecewise function index is derived based on the LMCS related information, and
wherein a modified reconstructed luma sample is generated based on the reconstructed luma sample and the piecewise function index,
wherein a minimum bin index and a maximum bin index are derived based on the LMCS related information,
wherein for deriving the piecewise function index,
it is determined whether a first mapped value, in a case that the piecewise function index is equal to the minimum bin index, is greater than a value of the reconstructed luma sample;
it is determined whether a second mapped value, in a case that the piecewise function index is equal to maximum bin index−1, is greater than the value of the reconstructed luma sample; and
it is determined whether a third mapped value, in a case that the piecewise function index is equal to maximum bin index, is greater than the value of the reconstructed luma sample based on a determination that the second mapped value, in the case that the piecewise function index is equal to maximum bin index−1, is not greater than the value of the reconstructed luma sample, and

wherein, based on the determination that the second mapped value is not greater than the value of the reconstructed luma sample in the case that the piecewise function index is equal to maximum bin index−1, the piecewise function index is derived as the maximum bin index based on a determination that the third mapped value is greater than the value of the reconstructed luma sample.