公开(公告)号：US12238344B2

公开(公告)日：2025-02-25

申请号：US18044775

申请日：2021-09-17

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Guan-Ming Su

IPC: H04N19/85 ,  H04N19/136 ,  H04N19/172 ,  H04N19/179

Abstract: In a cloud-based system for encoding high dynamic range (HDR) video, each node receives a video segment and bumper frames. Each segment is subdivided into primary scenes and secondary scenes to derive scene-based forward reshaping functions that minimize the amount of reshaping-related metadata when coding the video segment. When a parent scene of a secondary scene is processed by two or more neighboring nodes, initial forward reshaping functions and trim-pass correction parameters are adjusted using reference tone-mapping functions and updated scene-based trim-pass correction parameters.

公开(公告)号：US20230388555A1

公开(公告)日：2023-11-30

申请号：US18044775

申请日：2021-09-17

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Guan-Ming Su

IPC: H04N19/85 ,  H04N19/179 ,  H04N19/172 ,  H04N19/136

CPC classification number: H04N19/85 ,  H04N19/179 ,  H04N19/172 ,  H04N19/136

Abstract: In a cloud-based system for encoding high dynamic range (HDR) video, each node receives a video segment and bumper frames. Each segment is subdivided into primary scenes and secondary scenes to derive scene-based forward reshaping functions that minimize the amount of reshaping-related metadata when coding the video segment. When a parent scene of a secondary scene is processed by two or more neighboring nodes, initial forward reshaping functions and trim-pass correction parameters are adjusted using reference tone-mapping functions and updated scene-based trim-pass correction parameters.

公开(公告)号：US20190110054A1

公开(公告)日：2019-04-11

申请号：US16087241

申请日：2017-03-22

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Guan-Ming Su ,  Jon Scott Miller ,  Walter J. Husak ,  Yee Jin Lee ,  Harshad Kadu

IPC: H04N19/186 ,  H04N19/187 ,  H04N19/102 ,  H04N1/60 ,  H04N19/44

CPC classification number: H04N19/186 ,  G06T5/008 ,  H04N1/6027 ,  H04N1/6058 ,  H04N1/648 ,  H04N19/102 ,  H04N19/117 ,  H04N19/154 ,  H04N19/176 ,  H04N19/187 ,  H04N19/44 ,  H04N19/80 ,  H04N19/85 ,  H04N2201/3256

Abstract: A tone-mapping function that maps input images of a high dynamic range into reference tone-mapped images of a relatively narrow dynamic range is generated. A luma forward reshaping function is derived, based on first bit depths and second bit depths, for forward reshaping luma codewords of the input images into forward reshaped luma codewords of forward reshaped images approximating the reference tone-mapped images. A chroma forward reshaping mapping is derived for predicting chroma codewords of the forward reshaped images. Backward reshaping metadata that is to be used by recipient devices to generate a luma backward reshaping function and a chroma backward reshaping mapping is transmitted with the forward reshaped images to the recipient devices. Techniques for the joint derivation of forward luma and chroma reshaping functions are also presented.

公开(公告)号：US20250133241A1

公开(公告)日：2025-04-24

申请号：US18688315

申请日：2022-09-08

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Guan-Ming Su ,  Sheng Qu ,  Per Jonas Andreas Klittmark ,  Hariharan Ganapathy Kathirvelu

IPC: H04N19/98 ,  G06T5/90 ,  H04N19/186 ,  H04N19/46

Abstract: Tensor-Product B-splines (TPB) have been shown to improve video quality when used to represent reshaping functions to map reshaped standard dynamic range content into high dynamic range (HDR) content; however, TPB prediction is computationally intensive and may not be supported by legacy devices. Methods and systems for backwards-compatible signaling of TPB-related metadata and a fast TPB prediction method are presented to overcome both of these limitations. Computation overhead for a TPB-based 3D look-up table is reduced by using temporary two-dimensional arrays. A remapping of the most significant bits of a legacy bit-depth parameter allows for backwards compatibility.

公开(公告)号：US12149753B2

公开(公告)日：2024-11-19

申请号：US17920391

申请日：2021-04-21

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Guan-Ming Su ,  Harshad Kadu

IPC: H04N19/98 ,  G06T5/90 ,  H04N19/186 ,  H04N23/741

Abstract: A method, for generating (a) a forward reshaping function for compressing an input high-dynamic range (HDR) image into a reshaped standard-dynamic-range (SDR) image and (b) a backward reshaping function for decompressing the reshaped SDR image into a reconstructed HDR image, includes (i) optimizing the forward reshaping function to minimize a deviation between the reshaped SDR image and an input SDR image corresponding to the input HDR image, (ii) optimizing the backward reshaping function to minimize a deviation between the reconstructed HDR image and the input HDR image, and (iii) until a termination condition is met, applying a correction to the input SDR image and reiterating, based on the input SDR image as corrected, the steps of optimizing the forward and backward reshaping functions.

公开(公告)号：US11388408B2

公开(公告)日：2022-07-12

申请号：US17299743

申请日：2019-11-27

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Qing Song ,  Guan-Ming Su

IPC: H04N19/132 ,  H04N19/182 ,  H04N19/169 ,  H04N19/98

Abstract: Methods and systems for generating an interpolated reshaping function for the efficient coding of high-dynamic range images are provided. The interpolated reshaping function is constructed based on a set of pre-computed basis reshaping functions. Interpolation schemes are derived for pre-computed basis reshaping functions represented as look-up tables, multi-segment polynomials, or matrices of coefficients in a multivariate, multi-regression representation. Encoders and decoders using asymmetric reshaping and interpolated reshaping functions for mobile applications are also presented.

公开(公告)号：US10701375B2

公开(公告)日：2020-06-30

申请号：US16087241

申请日：2017-03-22

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Guan-Ming Su ,  Jon Scott Miller ,  Walter J. Husak ,  Yee Jin Lee ,  Harshad Kadu

IPC: H04N19/186 ,  H04N19/176 ,  G06T5/00 ,  H04N19/80 ,  H04N19/154 ,  H04N19/117 ,  H04N19/102 ,  H04N19/187 ,  H04N19/44 ,  H04N1/60 ,  H04N19/85 ,  H04N1/64

Abstract: A tone-mapping function that maps input images of a high dynamic range into reference tone-mapped images of a relatively narrow dynamic range is generated. A luma forward reshaping function is derived, based on first bit depths and second bit depths, for forward reshaping luma codewords of the input images into forward reshaped luma codewords of forward reshaped images approximating the reference tone-mapped images. A chroma forward reshaping mapping is derived for predicting chroma codewords of the forward reshaped images. Backward reshaping metadata that is to be used by recipient devices to generate a luma backward reshaping function and a chroma backward reshaping mapping is transmitted with the forward reshaped images to the recipient devices. Techniques for the joint derivation of forward luma and chroma reshaping functions are also presented.

公开(公告)号：US12244872B2

公开(公告)日：2025-03-04

申请号：US18252357

申请日：2021-11-10

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Janos Horvath ,  Harshad Kadu ,  Guan-Ming Su

IPC: H04N19/98 ,  H04N19/105 ,  H04N19/186

Abstract: An input image of a first bit depth in an input domain is received. Forward reshaping operations are performed on the input image to generate a forward reshaped image of a second bit depth in a reshaping domain. An image container containing image data derived from the forward reshaped image is encoded into an output video signal of the second bit depth.

公开(公告)号：US12143644B1

公开(公告)日：2024-11-12

申请号：US18684098

申请日：2022-08-14

Applicant: Dolby Laboratories Licensing Corporation

Inventor： Harshad Kadu ,  Guan-Ming Su

IPC: H04N19/85 ,  H04N19/119 ,  H04N19/186

Abstract: Input images are received as input to a multi-node system. The input images are divided into segments assigned to respective nodes of the multi-node system. Primary and secondary scenes are identified in the segments to ensure compliance with minimum and average distance constraints. Scene-level forward reshaping mappings are generated for the scenes by a respective node for an assigned segment. Forward reshaped images in the segment are generated by the node using the forward reshaping mappings and encoded into an output video signal, which enables a recipient device to generate reconstructed images and to render display images derived from the reconstructed images on an image display.

公开(公告)号：US11962760B2

公开(公告)日：2024-04-16

申请号：US17764394

申请日：2020-09-29

Applicant: DOLBY LABORATORIES LICENSING CORPORATION

Inventor： Guan-Ming Su ,  Harshad Kadu ,  Qing Song ,  Neeraj J. Gadgil

IPC: H04N19/105 ,  H04N19/132 ,  H04N19/154 ,  H04N19/196 ,  H04N19/436

CPC classification number: H04N19/105 ,  H04N19/132 ,  H04N19/154 ,  H04N19/196 ,  H04N19/436

Abstract: A set of tensor-product B-Spline (TPB) basis functions is determined. A set of selected TPB prediction parameters to be used with the set of TPB basis functions for generating predicted image data in mapped images from source image data in source images of a source color grade is generated. The set of selected TPB prediction parameters is generated by minimizing differences between the predicted image data in the mapped images and reference image data in reference images of a reference color grade. The reference images correspond to the source images and depict same visual content as depicted by the source images. The set of selected TPB prediction parameters is encoded in a video signal as a part of image metadata along with the source image data in the source images. The mapped images are caused to be reconstructed and rendered with a recipient device of the video signal.