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] G--Vb80efp0: nsig extraction failed: Some formats may be missing
         n = 1bhAK-oj79WKbzAa5 ; 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] G--Vb80efp0: nsig extraction failed: Some formats may be missing
         n = rL6oOQKiYI4zNXNEv ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js