DEBUG ACTIVO
URL original: [https://www.youtube.com/watch?v=riJAh_I560U&list=PLlXaxWqGy4-r3SWvz5OrifX1tM0UqQJkL&index=37]
Largo: 92
Array
(
    [scheme] => https
    [host] => www.youtube.com
    [path] => /watch
    [query] => v=riJAh_I560U&list=PLlXaxWqGy4-r3SWvz5OrifX1tM0UqQJkL&index=37
)

Video ID detectado: [riJAh_I560U]
Pasa el regex? SI