I Heard that IDM Users or another Downloader users can't grab VEVO's videos in Youtube or Videos downloaded without audio, so i have the solution.A  tiny App that named  "Youtube-dl"

For Ubuntu and Fedora Users just simply install "youtube-dl" package
For Windows and OSX Users 
Download In Youtube-dl in Youtube-dl Download Page 
Move it into apps directory 
Windows :  C:\WINDOWS\

OSX : Open terminal and type

sudo curl https://yt-dl.org/downloads/2013.09.20.1/youtube-dl -o /usr/local/bin/youtube-dl

sudo chmod a+x /usr/local/bin/youtube-dl

youtube-dl -U

The Last Line is to Update the application to the latest update

 Syntax to Download  Video

youtube-dl [Video URL]

When You can't download videos because of encryption just simply update the Apps

with Syntax 

youtube-dl -U

It Support downloading videos from

• YouTube.com.
• YouTube.com playlists (playlist URLs in "view_play_list" form).
• YouTube.com searches, using the special keyword "ytsearch" as a form of URL, as in "ytsearch:cute kittens". Do not forget the quotes if you want to include spaces in your search. Other variants are "ytsearchN" to download more than the first result, with N being a number, and "ytsearchall".
• YouTube.com user videos, using user page URLs or the specifc "ytuser" keyword.
• metacafe.com.
• Google Video.
• Google Video searches ("gvsearch" keyword).
• Photobucket videos.
• Yahoo! screen.
• Yahoo! screen searches ("yvsearch" keyword).
• Dailymotion.
• DepositFiles.
• blip.tv.
• vimeo.
• myvideo.de.
• The Daily Show / Colbert Nation.
• The Escapist.
• CollegeHumor.
• arte.tv.
• Soundcloud.
• xvideos.
• infoq.
• mixcloud.
• Stanford Open Content.
• Youku.
• MTV.
• XNXX.
• Google Plus.
• A generic downloader that works in some sites.

Screenshots