A conversion method for converting luminance of a video, including a luminance value in a first luminance range, to be displayed on a display apparatus includes: acquiring a first luminance signal indicating a code value obtained by quantization of the luminance value of the video; and converting the code value indicated by the acquired first luminance signal into a second luminance value determined based on a luminance range of the display apparatus, the second luminance value being compatible with a second luminance range with a maximum value smaller than a maximum value of the first luminance range and larger than 100 nit. This provides the conversion method capable of achieving further improvement.

A method includes encoding target parameters describing characteristics for a target color space for a video picture to be displayed in the target color space and encoding color transform parameters that facilitate remapping the video picture to the target color space. A method includes decoding target parameters describing characteristics for a target color space for a video picture to be displayed in the target color space, decoding color transform parameters that facilitate remapping the video picture to the target color space, remapping the video picture to the target color space utilizing at least one of the decoded color transform parameters, and displaying the remapped video picture in the target color space. The color transform parameters represent at least three successively applied color transforms comprising a first color transform followed by a second color transform followed by a third color transform. Related apparatus for each method are described.

A method includes encoding target parameters describing characteristics for a target color space for a video picture to be displayed in the target color space and encoding color transform parameters that facilitate remapping the video picture to the target color space. A method includes decoding target parameters describing characteristics for a target color space for a video picture to be displayed in the target color space, decoding color transform parameters that facilitate remapping the video picture to the target color space, remapping the video picture to the target color space utilizing at least one of the decoded color transform parameters, and displaying the remapped video picture in the target color space. The color transform parameters represent at least three successively applied color transforms comprising a first color transform followed by a second color transform followed by a third color transform. Related apparatus for each method are described.

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.

[Object] To contribute to the achievement of a workflow in which an HDR video and an SDR video are compatible with each other. [Solving Means] This video signal processing apparatus includes an HDR video generation unit including a first converter unit that performs OOTF conversion on an HDR video by using an exponentiation function for calculating an exponentiation of 1.2, where 100% is 1, to an input signal level of the HDR video having a range from a point of 0%, where an expression range of an input signal level of an SDR video is 100%, to a change point optionally determined within a range of 100% to 500%, and by using a linear function for multiplying an input signal level of the HDR video having a range higher than the change point by a predetermined coefficient to maintain a change rate of a calculation result in a portion of the change point calculated by using the exponentiation function.

A video signal processing method includes obtaining a first linear luminance signal based on a first linear red green blue (RGB) signal corresponding to a video signal, converting the first linear luminance signal into a first non-linear luminance signal, performing a piecewise luminance mapping on the first non-linear luminance signal to obtain a second non-linear luminance signal, converting the second non-linear luminance signal into a second linear luminance signal, calculating a luminance gain between the second linear luminance signal and the first linear luminance signal, and obtaining, based on a product of the luminance gain and the first linear RGB signal, an RGB display signal corresponding to the video signal.

A video signal processing method includes obtaining a first linear luminance signal based on a first linear red green blue (RGB) signal corresponding to a video signal, converting the first linear luminance signal into a first non-linear luminance signal, performing a piecewise luminance mapping on the first non-linear luminance signal to obtain a second non-linear luminance signal, converting the second non-linear luminance signal into a second linear luminance signal, calculating a luminance gain between the second linear luminance signal and the first linear luminance signal, and obtaining, based on a product of the luminance gain and the first linear RGB signal, an RGB display signal corresponding to the video signal.

Techniques for a fast approximation of linear light scaling for inputs of non-linear light values are described. As one example, a computer-implemented method includes receiving a request to downscale a plurality of pixels of a single frame of a video file performing, in response to the request to downscale, a lookup in a lookup table for a first input of a first non-linear light value of luminance for a first pixel of the plurality of pixels and a second input of a second non-linear light value of luminance for a second pixel of the plurality of pixels to generate an output of a third single non-linear light value of luminance for a linear light scaling for the first pixel and the second pixel, generating a scaled frame based at least in part on the third single non-linear light value of luminance for the linear light scaling, receiving a request for a manifest for the video file from a client device, generating the manifest for the client device that identifies a scaled video representation that comprises the scaled frame, and sending the manifest to the client device.

Techniques for a fast approximation of linear light scaling for inputs of non-linear light values are described. As one example, a computer-implemented method includes receiving a request to downscale a plurality of pixels of a single frame of a video file performing, in response to the request to downscale, a lookup in a lookup table for a first input of a first non-linear light value of luminance for a first pixel of the plurality of pixels and a second input of a second non-linear light value of luminance for a second pixel of the plurality of pixels to generate an output of a third single non-linear light value of luminance for a linear light scaling for the first pixel and the second pixel, generating a scaled frame based at least in part on the third single non-linear light value of luminance for the linear light scaling, receiving a request for a manifest for the video file from a client device, generating the manifest for the client device that identifies a scaled video representation that comprises the scaled frame, and sending the manifest to the client device.