Download using Download Helper Add On

Go to Download Helper page ...::Click Here::...
Then Click Add to Firefox (Look at the picture above)

Click that button, show the installation window... Wait a seconds and then click Install


Wait until the installation Finish

If the installation finish, restart your firefox
You can see in the Tools menu the DownloadHelper option


Every you view a video on youtube or other site, Download Helper can detect and give a option to download file in many formats




Click one of that option to download and your download can be started... Wait until the download complete & ENJOY YOUR VIDEO ^^v