Download musics as playlist

Sometimes, I (and I guess i'm not the only one) want to download severals musics from differents channels/playlist on youtube, and to download them as a playlist (so that it could automatically create a folder for the playlist and automatically enumerate the musics)
So I think there could be a field (somewhere on the top of the window) to name (or rename) the playlist, and the "download" button may purpose "download" or "download as playlist"