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] gywzwPD8F3E: nsig extraction failed: Some formats may be missing
         n = T8OqKoAHcT-pWFJ8R ; 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] gywzwPD8F3E: nsig extraction failed: Some formats may be missing
         n = 7GZDAomaHQH5k-ZvC ; player = https://www.youtube.com/s/player/e7567ecf/player_ias.vflset/en_US/base.js