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] dL14M35kNw8: nsig extraction failed: Some formats may be missing
         n = BtgEGTXCQf9cG-sUV ; 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] dL14M35kNw8: nsig extraction failed: Some formats may be missing
         n = yrD479PhYP2ICPVRH ; player = https://www.youtube.com/s/player/f3d47b5a/player_ias.vflset/en_US/base.js