Telefonaktiebolaget LM Ericsson (publ)
Pixel pre-processing and encoding

Abstract:

A pixel pre-processing comprises subsampling a linear color in a first color space to obtain a subsampled linear color in the first color space. A first transfer function is applied to the subsampled linear color the first color space to obtain a subsampled non-linear color in the first color space. A first color transform is applied to the subsampled non-linear color in the first color space to obtain a subsampled first non-linear chroma component value and/or a subsampled second non-linear chroma component value in a second color space. A non-linear luma component value in the second color space is derived for the pixel, which together with the subsampled non-linear chroma component values represent a color the pixel. The pre-processing reduces chroma artifacts that may otherwise occur when chroma subsampling is performed following application of the first transfer function and the first color transform.