WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/d50f54ef/player_ias.vflset/en_US/base.js
WARNING: [youtube] g9ZATokl1Qg: nsig extraction failed: Some formats may be missing
         n = aJ1A0rzs7yMBrWTbGa ; player = https://www.youtube.com/s/player/d50f54ef/player_ias.vflset/en_US/base.js
WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/d50f54ef/player_ias.vflset/en_US/base.js
WARNING: [youtube] g9ZATokl1Qg: nsig extraction failed: Some formats may be missing
         n = LKKZzamfqAtTja5xZt ; player = https://www.youtube.com/s/player/d50f54ef/player_ias.vflset/en_US/base.js