Methods, systems, and non-transitory computer readable storage media are disclosed for two-phase encoding a digital video based on downsampling distortion of the digital video and a constant rate factor transition threshold. For example, the disclosed system can determine a downsampling distortion indicating a measure of distortion resulting from downsampling an input digital video. The disclosed systems can utilize the downsampling distortion to determine a constant rate factor transition threshold for selecting sets of encoding parameters. For example, the disclosed systems can select a first set of encoding parameters below the constant rate factor transition threshold and a second set of encoding parameters at or above the constant rate factor transition threshold. Additionally, the disclosed systems can generate first and second sets of digital video encodings of the input digital video by utilizing the first and second sets of encoding parameters, respectively.

Methods, systems, and non-transitory computer readable storage media are disclosed for two-phase encoding a digital video based on downsampling distortion of the digital video and a constant rate factor transition threshold. For example, the disclosed system can determine a downsampling distortion indicating a measure of distortion resulting from downsampling an input digital video. The disclosed systems can utilize the downsampling distortion to determine a constant rate factor transition threshold for selecting sets of encoding parameters. For example, the disclosed systems can select a first set of encoding parameters below the constant rate factor transition threshold and a second set of encoding parameters at or above the constant rate factor transition threshold. Additionally, the disclosed systems can generate first and second sets of digital video encodings of the input digital video by utilizing the first and second sets of encoding parameters, respectively.

Disclosed herein are methods of providing an image storage service, computer-readable recording mediums, and/or computing devices. The method of providing the image storage service includes selecting image data in a first format, determining an initial compression parameter for converting the selected image data in the first format into a second format, obtaining primary image data in the second format by transcoding the selected image data in the first format based on the initial compression parameter, searching for a desired compression parameter based on whether image quality of the primary image data satisfies a criterion, obtaining final image data in the second format by transcoding the selected image data in the first format based on the desired compression parameter, and storing final image data in the second format in the memory.

Embodiments of the present invention relate to methods and systems for ordering, communicating and applying pixel intra-prediction modes.

In a system for coding high dynamic range (HDR) images using lower-dynamic range (LDR) images, a reshaping function allows for a more efficient distribution of the codewords in the lower dynamic range images for improved compression. A trim pass of the LDR images by a colorist may satisfy a director's intent for a given “look,” but may also result in unpleasant clipping artifacts in the reconstructed HDR images. Given an original forward reshaping function which maps HDR luminance values to LDR pixel values, a processor identifies areas of potential clipping and generates modified forward and backward reshaping functions to reduce the visibility of potential artifacts from the trim pass process while preserving the director's intent.

Image encoding and decoding methods and devices thereof are provided. The encoding method includes: performing downsampling on a first image to obtain a second image; encoding the second image to obtain a second image bit stream, and sending the second image bit stream to a decoding end; processing the second image to obtain a third image having a resolution the same as that of the first image; calculating a difference between the third image and the first image to obtain a first difference image; regulating pixel values of the first difference image to fall within a pre-set range, to obtain a second difference image; and encoding the second difference image to obtain a second difference image bit stream, and sending the second difference image bit stream to the decoding end to enable the decoding end to reconstruct the first image.

Image encoding and decoding methods and devices thereof are provided. The encoding method includes: performing downsampling on a first image to obtain a second image; encoding the second image to obtain a second image bit stream, and sending the second image bit stream to a decoding end; processing the second image to obtain a third image having a resolution the same as that of the first image; calculating a difference between the third image and the first image to obtain a first difference image; regulating pixel values of the first difference image to fall within a pre-set range, to obtain a second difference image; and encoding the second difference image to obtain a second difference image bit stream, and sending the second difference image bit stream to the decoding end to enable the decoding end to reconstruct the first image.

A method of adaptive chroma downsampling is presented. The method comprises converting a source image to a converted image in an output color format, applying a plurality of downsample filters to the converted image and estimating a distortion for each filter chose the filter that produces the minimum distortion. The distortion estimation includes applying an upsample filter, and a pixel is output based on the chosen filter. Methods for closed loop conversions are also presented.

A method of adaptive chroma downsampling is presented. The method comprises converting a source image to a converted image in an output color format, applying a plurality of downsample filters to the converted image and estimating a distortion for each filter chose the filter that produces the minimum distortion. The distortion estimation includes applying an upsample filter, and a pixel is output based on the chosen filter. Methods for closed loop conversions are also presented.

An encoding device evaluates a plurality of processing and/or post-processing algorithms and/or methods to be applied to a video stream, and signals a selected method, algorithm, class or category of methods/algorithms either in an encoded bitstream or as side information related to the encoded bitstream. A decoding device or post-processor utilizes the signaled algorithm or selects an algorithm/method based on the signaled method or algorithm. The selection is based, for example, on availability of the algorithm/method at the decoder/post-processor and/or cost of implementation. The video stream may comprise, for example, downsampled multiplexed stereoscopic images and the selected algorithm may include any of upconversion and/or error correction techniques that contribute to a restoration of the downsampled images.