Abstract: Methods and systems for image denoising when displaying high-dynamic-range images are described. Given an input image in a first dynamic range, and an input backward reshaping function mapping codewords from the first dynamic range to a second dynamic range, wherein the second dynamic range is equal or higher than the first dynamic range, statistical data based on the input image and the input backward reshaping function are generated to estimate the risk of noise artifacts in a target image in the second dynamic range generated by applying the input backward reshaping function to the input image. Using a measure of the variance in codeword bins in histograms of consecutive input frames (denoted as temporal histogram variance), a modified backward reshaping function is generated, which when applied to the input image to generate the target image eliminates or reduces noise artifacts in the target image.

Abstract: Methods and systems for reducing banding artifacts when displaying high-dynamic-range images are described. Given an input image in a first dynamic range, and an input backward reshaping function mapping codewords from the first dynamic range to a second dynamic range, wherein the second dynamic range is equal or higher than the first dynamic range, statistical data based on the input image and the input backward reshaping function are generated to estimate the risk of banding artifacts in a target image in the second dynamic range generated by applying the input backward reshaping function to the input image. Separate banding alleviation algorithms are applied in the darks and highlights parts of the first dynamic range to generate a modified backward reshaping function, which when applied to the input image to generate the target image eliminates or reduces banding in the target image.

Abstract: A standard dynamic range (SDR) image is received. Composer metadata is generated for mapping the SDR image to an enhanced dynamic range (EDR) image. The composer metadata specifies a backward reshaping mapping that is generated from SDR-EDR image pairs in a training database. The SDR-EDR image pairs comprise SDR images that do not include the SDR image and EDR images that corresponds to the SDR images. The SDR image and the composer metadata are encoded in an output SDR video signal. An EDR display operating with a receiver of the output SDR video signal is caused to render an EDR display image. The EDR display image is derived from a composed EDR image composed from the SDR image based on the composer metadata.

Abstract: A standard dynamic range (SDR) image and a reference backward reshaping mapping are received. The reference backward reshaping mapping comprises a reference luma backward reshaping mapping. A color preservation mapping function is used with inputs generated from the SDR image and the reference backward reshaping mapping to determine luminance increase for SDR luma histogram bins generated based on luma codewords in the SDR image. A modified backward reshaping mapping is generated and comprises a modified luma backward reshaping mapping generated from the reference backward reshaping function based on the luminance increase for the SDR luma histogram bins. The SDR image and the modified backward reshaping mapping are encoded into an SDR video signal.

Abstract: In some embodiments, an encoder device is disclosed to receive an input video stream containing images in a first dynamic range including a first image. The device receives a second image representing the first image. The device obtains statistical data for the first and the second images. The device determines, at a first time delay, a scene cut data from the input video stream and storing the scene cut data in a first sliding window. The device determines, at a second time delay, a first smoothing mapping function based on a second sliding window and the determined scene cut data. The device determines, at a third time delay, a second smoothing mapping function based on a third sliding window and the determined scene cut data. The device generates, at the third time delay, a composer metadata for the first image based on the first and second smoothing mapping functions.

Abstract: Given a standard-dynamic range (SDR) video input, techniques for generating and compressing composer metadata describing inverse luma and chroma reshaping functions are described. Given the SDR input, the composer metadata allow a decoder to generate a corresponding output in high-dynamic range. Three techniques are proposed: a static, sequence-based, architecture, a two-stage, scene-based, distributed solution with a centralized post-processing method, and a single-stage distributed solution using overlapped segments. Techniques to reduce the amount of transmitted composer metadata are also described.

Abstract: Sequence-level parameters are generated for an image frame sequence including sequence-level indicators for indicating metadata types present for each image frame in the sequence of image frames. Frame-present parameters are generated for a specific image frame in the sequence including frame-present indicators corresponding to the metadata types as indicated in the sequence-level parameters. The frame-present indicators identify first metadata types for which metadata parameter values are to be encoded in a coded bitstream as metadata payloads. The image frame sequence, the sequence-level parameters, the frame-present parameters and the metadata payloads are encoded in the coded bitstream. A recipient device can generate, from the specific image frame based partly on the metadata parameter values determined for the first metadata types, a target display image for a target display.

Abstract: A standard dynamic range (SDR) image and a reference backward reshaping mapping are received. The reference backward reshaping mapping comprises a reference luma backward reshaping mapping. A color preservation mapping function is used with inputs generated from the SDR image and the reference backward reshaping mapping to determine luminance increase for SDR luma histogram bins generated based on luma codewords in the SDR image. A modified backward reshaping mapping is generated and comprises a modified luma backward reshaping mapping generated from the reference backward reshaping function based on the luminance increase for the SDR luma histogram bins. The SDR image and the modified backward reshaping mapping are encoded into an SDR video signal.

Abstract: Given a standard-dynamic range (SDR) video input, techniques for generating and compressing composer metadata describing inverse luma and chroma reshaping functions are described. Given the SDR input, the composer metadata allow a decoder to generate a corresponding output in high-dynamic range. Three techniques are proposed: a static, sequence-based, architecture, a two-stage, scene-based, distributed solution with a centralized post-processing method, and a single-stage distributed solution using overlapped segments. Techniques to reduce the amount of transmitted composer metadata are also described.