Abstract: The H.266 video codec takes several improvements in each coding step, and the overall effect of many measures does result in a doubling of the coding efficiency compared to HEVC. In this paper, several video sequences with different dynamic conditions (*.yuv) are compressed and decompressed using the H.266 codec, and the differences in coding efficiency and time loss after video compression are investigated by varying the quantization parameters (QP) values at different bit rates. Experiments show that for lower bit rates and near the bit rate commonly used for 4K video (20Mbps), there is a significant advantage in both bit rate savings and video quality, but at very large bit rates, both perform nearly identically. Calculations of the time multiplier and bitrate savings reveal a wide range of results for each video sequence, suggesting that coding complexity and coding performance are highly dependent on the selected video sequence itself. h.266 improves significantly for more complex video sequences, with a significant increase in coding complexity, up to 100x at some bitrates. h.266 also poses a significant hardware arithmetic H.266 also poses a significant challenge to hardware arithmetic, which will need to be further optimised in the future.