Luma Adjustment for High Dynamic Range Video

In this paper we present a solution to a luminance artifact problem that occurs when conventional non-constant luminance Y'CbCr and 4:2:0 subsampling is combined with the type of highly non-linear transfer functions typically used for High Dynamic Range (HDR) video. These luminance artifacts can be avoided by selecting a luma code value that minimizes the luminance error. Subjectively, the quality improvement is clearly visible even for uncompressed video. Improvements in tPSNR-Y of up to 20 dB have been observed, compared to conventional subsampling. Crucially, no change in the decoder is needed.