Video Download Helper is an exceptional add-on to FF that detects downloadable videos on a webpage automatically, lists the available stats of each, and downloads your selections to the location you set, showing the progress in its own d/l GUI (not the browser's). Its clearly written setup menu lets you fine-tune everything. Resulting files are exactly the same length and quality seen online. NB: VDH respects copyright restrictions of a few sites and keeps the user informed and legal.