WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/f3d47b5a/player_ias.vflset/en_US/base.js
WARNING: [youtube] tsF1EwwMTa0: nsig extraction failed: Some formats may be missing
         n = C31I3J5XTiMBBiDAL ; player = https://www.youtube.com/s/player/f3d47b5a/player_ias.vflset/en_US/base.js
WARNING: [youtube] Falling back to generic n function search
         player = https://www.youtube.com/s/player/f3d47b5a/player_ias.vflset/en_US/base.js
WARNING: [youtube] tsF1EwwMTa0: nsig extraction failed: Some formats may be missing
         n = T0p5BbjD1jRa3Coje ; player = https://www.youtube.com/s/player/f3d47b5a/player_ias.vflset/en_US/base.js