download YouTube videos using iPhone?

hi vergers,

can i download 1080p HD YouTube videos from my iPhone?

not a playlist manager or a 720p downloader...anyone know a 3rd party app to download 1080p HD videos using iPhone.

i have a way to download removed apps from app store...if you know a removed good app,comment please

my device,

ios 7.1.1 / iPhone 5s / no jailbreak