On video source format of screen content compression

This work attempts to quantitatively study the impacts of the different input video source format on the coding efficiency and complexity of the recent High-Efficiency Video Coding (HEVC) based screen content compression. Besides the native RGB color space, YUV color space with 4:4:4 and 4:2:0 chroma sampling are investigated. Decoded videos are all converted to the RGB space to calculate the structural similarity as the subjective distortion estimation, and perform the subjective rating to have the Mean Opinion Score (MOS). Performance is evaluated using the bit rate versus structural similarity (SSIM), and bit rate versus MOS. Experiments have demonstrated approximately 1.3% SSIM loss with 30% bit rate reduction, and 3.4% SSIM loss with 33% bit rate reduction, respectively, when using YUV 4:4:4 and YUV 4:2:0 as input sources versus native RGB input. Similar performance is recorded for MOS versus bit rate. We have also observed 18% and 31% encoding time reduction by using YUV 4:4:4 and YUV 4:2:0 rather than RGB content for popular low-delay scenario.