This paper reviews the first NTIRE challenge on quality enhancement of compressed video, with focus on proposed solutions and results. In this challenge, the new Large-scale Diverse Video (LDV) dataset is employed. The challenge has three tracks. Tracks 1 and 2 aim at enhancing the videos compressed by HEVC at a fixed QP, while Track 3 is designed for enhancing the videos compressed by x265 at a fixed bit-rate. Besides, the quality enhancement of Tracks 1 and 3 targets at improving the fidelity (PSNR), and Track 2 targets at enhancing the perceptual quality. The three tracks totally attract 482 registrations. In the test phase, 12 teams, 8 teams and 11 teams submitted the final results of Tracks 1, 2 and 3, respectively. The proposed methods and solutions gauge the state-of-the-art of video quality enhancement. The homepage of the challenge: https://github.com/RenYang-home/NTIRE21_VEnh

翻译：本文回顾了国家电视广播电视网在提高压缩视频质量方面的第一个挑战,重点是拟议的解决方案和结果;在这一挑战中,采用了新的大型多样化视频数据集(LDV),挑战有三条轨道:第一和第二轨道的目的是加强在固定的QP上由HEVC压缩的视频,而第三轨道的目的是加强在固定的位速率上由x265压缩的视频;此外,提高第1和第3轨目标的质量,提高忠实度(PSNR),提高第2轨目标的质量,提高概念质量。三轨完全吸引了482个注册。在测试阶段,12个团队、8个团队和11个团队分别提交了第1、2和3轨的最后结果。建议的方法和解决方案用来衡量提高视频质量的状态。挑战的主页:https://github.com/REnYang-home/NTIRE21_Venh。