How to Free Download YouTube HD Video on Mac OS X

Every internet user love watching videos on YouTube.
Until not long ago, YouTube has released high quality MP4 video as an additional feature for its users. It will be really satisfying if those MP4s can be downloaded.

Free Download YouTube HD Video with Safari Browser

We can download youtube HD videos with Activity Monitor now.
Everything that is visible to eyes are downloadable and for Safari web browser, all files can be spotted inside Activity Monitor.
Amongst all of files listed inside, there exists a file linking to the HD Video. To spot and download it, follow these steps.

1.Open YouTube URL to video. Append URL with &fmt=18 to view HD video
2.Show up Activity Monitor (Command-Option-A)
3.Seek for file with largest size and Option-Click it
4.The download should be started with default name video.mp4

Free Download YouTube HD Video with Firefox Browser

For Firefox users, HD YouTube video is downloadable using bookmarklet. Just drop the bookmarklet on Bookmark Bar and click on it when you are opening YouTube page. New link will appear afterwards.

Bookmarklet to Download YouTube HD Here is the bookmarklet: YouTube HD

Drag it to your Bookmarks Bar and it will look like screenshot below.



But for some videos, this bookmarklet doesn't work and the activity monitor trick will be needed.
Feel free to share your feeling on the comment box and point out if I've missed any.