WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] Nh1XuVme6C4: nsig extraction failed: Some formats may be missing
         n = Va7Hp3pHjVS4IwxQk ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js
WARNING: [youtube] Nh1XuVme6C4: nsig extraction failed: Some formats may be missing
         n = 1fF6E48XuZPRkLsgc ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js