arkTube, the ultimate YouTube downloader.

/* Usage */
Use Google's YouTube app and select a video
Select the share button(arrow) on the top right corner and choose arkTube
Use a separate video player and watch the downloaded video
/* Features */
Supports downloading ALL resolutions including 1080p, 1440p, 4K and 8K [1]
Supports downloading audio [1]
Supports downloading playlists [1]
Download accelerator support [1]
Automatically merges thumbnail(artwork), tags and other metadata when downloading audio
Provides option to merge metadata to video downloads [1]
Supports downloading videos as VP9 format [1]
Supports downloading audio as Vorbis / Opus codec [1]
Supports downloading 50fps / 60fps
Supports resuming paused downloads
/* Powerful engine */
arkTube uses one of the most actively developed open-source project in the world : youtube-dl
Supports downloading all options
Optimized downloader for faster downloads
Download without any loss to quality
Consistently updated for best compatiblity
** Video that requires adult authentication or login, marked as hidden from public, is a live-stream may be unsupported.
** VP9 is a new video codec from Google that improves video quality and reduces overall file size. Galaxy S6 and Galaxy Note 5 currently supports VP9.
** 50fps / 60fps with 1440p+ resolution is only provided as VP9.
** If you run into issues, make sure you're running the latest version and contact the developer with the URL of the video.
[1] These features require additional donation package to be installed