If you ever found yourself repeatedly starting and stopping an online video clip because it wouldn't buffer fast enough or felt that Flash was slowing your browser down to a crawl, you should try Video DownloadHelper for Firefox.
Video DownloadHelper is a free add-on, and it has been around for years. With almost six million downloads and over 3,000 reviews giving it an average of over four stars, this is one of the best ways to download videos off YouTube, Vimeo, and a slew of other video-hosting websites.
When you first install Video DownloadHelper, it takes you to an "installation successful" page. This is one of the more disappointing parts of the user experience: The page features sketchy-looking banners offering a "free scan for hidden PC errors" and a large button leading to a ranked list of video sites, many of which are adult-oriented. In other words, the best thing you can do as soon as Firefox restarts after the installation is close that tab and pretend it was never there. Just as you wouldn't judge a book by its cover, try not to judge Video DownloadHelper by its website.
What that success page should really contain is a quick tutorial showing how to use Video DownloadHelper. This is not trivial: Video DownloadHelper used to have a menu item, as well as an optional button in the status bar. The menu item is still there, but the menu itself has been hidden in recent Firefox versions, leaving only an orange Firefox button at the top-left corner of the window. The status bar has also been axed, replaced with an "add-on bar" that is hidden by default. This makes getting to Video DownloadHelper tricky at first.
The secret is to go to a webpage with a video, start playing the video, and right-click anywhere on the screen. You should now see a DownloadHelper entry in the context menu, featuring lots of options. This has a sub-menu labeled Media, only visible once you start playing the video, which lets you easily download the current video to disk. If you're on YouTube, you even get to pick what quality you'd like to download. The DownloadHelper menu also lets you access a rich Preferences dialog, but the add-on works just fine with the default settings.
Downloads are done via the browser's built-in download dialog. Once you begin a download, you can close the video's tab--the download happens in the background, no Flash involved. The video files you get can be played with any modern media player, such as VLC or SPlayer. Even with the same resolution, watching a video file locally feels better: You can play and pause using your keyboard's media keys, there's no buffering involved, and you don't have to read the comments.
Video DownloadHelper is a valuable tool, especially if you're on a slow connection. It takes a little bit of getting used to, but if you enjoy watching videos online, it can certainly add to the experience.