Guided Chroma Reconstruction for Screen Content Coding

In professional markets, there is a growing need to incorporate off-the-shelf consumer-level hardware to reduce costs and speed up development. Typically, these hardware components contain hardware-accelerated video encoders, which are limited to the more popular YUV4:2:0 profiles. For screen content coding (SCC) (e.g., desktop sharing, supervisory control and data acquisition applications, etc.), chroma subsampling can produce specific artifacts that are disturbing in high-quality professional applications. Current research on SCC focuses on developing specific screen content profiles and coding tools, which are not likely to be integrated in consumer electronics. In this paper, a method is explored to improve the chroma quality of SCC using YUV4:2:0 codecs. It is possible to recover parts of the chroma component based on the luma component and the subsampling filter that is used at the encoder device. A 1.63-dB peak signal-to-noise ratio-chroma improvement and 0.051 structural similarity-chroma improvement are measured on average for screen content sequences. The proposed method still provides improvements if compression is used.