If you need a service to download and convert videos, the best option is Y2Mate. Here is the link to this youtube to mp3 converter . I had to look for such a site to work on video projects, and when on some forum a guy told me about Y2Mate, it just saved me! It is very convenient and fast, which is especially important when you work with a large volume of files. Now I only use it, and I recommend it to you too!