DEBUG ACTIVO
URL original: [https://www.youtube.com/watch?v=PFV4gehKsmA]
Largo: 43
Array
(
    [scheme] => https
    [host] => www.youtube.com
    [path] => /watch
    [query] => v=PFV4gehKsmA
)

Video ID detectado: [PFV4gehKsmA]
Pasa el regex? SI