I want to create a PHP/Java application that would be able to download videos from youtube.I think there is no direct youtube apis from google.Have any third party apis available? please help me.
You can use third part apps clive, it is a command line tool. Hope it helps you.
You can also use ffmpeg in addition to convert different format from flv or mp4 that you download from youtube.
I was recently able to find this site they provide a REST api for downloading videos, mp3 it seems like it is easy to use