Watch Only Once: An End-to-End Video Action Detection Framework Paper (ICCV 2021) Watch Only Once: An End-to-End Video Action Detection Framework Shoufa Chen, Peize Sun, Enze Xie, Chongjian Ge, Jiannan Wu, Lan Ma, Jiajun Shen, and Ping Luo Updates (10/2021) Releasing code. Install Please find installation instructions in INSTALL.md.