This paper reviews the first NTIRE challenge on quality enhancement of compressed video, with a focus on the proposed methods 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,重点是拟议的方法和结果;在这一挑战中,采用了新的大型多样化视频数据集(LDV),挑战分为三个轨道。第一和第二轨道的目的是加强由欧洲电视广播电视中心在固定的QP上压缩的视频,而第三轨道的目的是加强x265在固定的位速率上压缩的视频。此外,提高第1和第3轨目标的质量以提高忠诚度(PSNR),提高第2轨目标提高概念质量。这三轨完全吸引了482个登记。在测试阶段,12个小组、8个小组和11个小组分别提交了第1、2和3轨的最后结果。拟议方法和解决办法衡量提高视频质量的状况。挑战的主页:https://github.com/RenYang-home/NTIRE21_Venh。