I have been using Video DownloadHelper about three years now or so . I'am very pleased with the App which is an Firefox Add-on. It' very is easy to use, it works very good every time I use it to download musics and movies I'd like to listen and watch. The quality of the sounds and pictures it delivers to me is always good. However, if the sources of musics or movies were not recorded in MP3 or MP4, it would not download it and it requires another app to download and change the their format to fit to replay.
Thank you very much for letting us using it for free.