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] HCMVxP7Viyg: nsig extraction failed: Some formats may be missing
         n = eT5miDrkRbP3ce6tI ; 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] HCMVxP7Viyg: nsig extraction failed: Some formats may be missing
         n = p9J-F5BstbYTHvGHw ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js