You want to download a youtube video in your android phone of any length or just audio file.One the bug in Youtube app is that it Doesn’t Support high quality Videos to watch popping message like “This video is not available in Your Platform”.But using this method you can download that videos in any resolution and watch it.
1) Go to the Link www.tubemate.net
2) Download the TubeMate apk file and Install it in your Android phone.
3) Now open it.You will see some tips to use it.
4)This app has a awesome inbuilt browser.So Just search the video hat you want to Download.
5)On the video page top you will see a Green Color Download arrow.
6) Click on it choose the video resolution and download it.