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] QGFWpTU-k9o: nsig extraction failed: Some formats may be missing
         n = jhu-gEpo8vzpPm5za ; 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] QGFWpTU-k9o: nsig extraction failed: Some formats may be missing
         n = OX4DSoW4GIX5rDW_E ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js