but if i have tv id how can i get it's certification

You can get a TV shows certification by calling the /content_ratings method.

also if i use discover in movies i can filter certifications while in tv i cannot?

It's true, TV discover does not have content ratings hooked up. I've created a new ticket to think about this here.

@travisbell was content ratings ever added to TV discover?

Hi @kevinjacob, no, not yet.

@travisbell is this on the Trello Board? I tried to find it so I could vote on it but I could not locate the ticket. Thanks so much for the reply and all your work!

It was not! Here's the link: https://trello.com/c/hmPJ34Hp/85-add-content-ratings-filter-to-tv-discover

Thanks!