There are several video and audio stream ripper with which you can download videos and audio streams, but most are complicated, or simply down load the video in FLV format.
Have you ever come across the wonderful video and audio stream grabbers, iTube Grabber for Mac OSX. With this tool you can download one click audio and video streams, and automatically convert into various file formats. The program is still in beta testing and is free to try.
The iTube Grabber is very easy to use and works for pretty much all Youtube and Google videos which I've tried. Theoretically, it should also work for other sites, but I have not been tested yet. If you do not find the video you can download it, you can send the URL via email to the developer so he can optimize the filter.
Features:
* Simple GUI with integrated browser
* Grabbing audio and video streams from most pages
* Extended filter stream. For many audio and video streams
* Detects multiple audio and video streams on one page
* Bookmark manager
* Converts automatically downloaded streams (in various formats. Mp4,. Mkv. Wav,. Mp3, etc.)
* HD Videos
* Batch processing of video and audio streams
* Multi-Core Support
* Compatible with OS X 10.5.x and OS X 10.6.x
The iTube Grabber you can just watch videos with the built-in browser and save it with a button. The pages can also be saved as bookmarks for faster access to the page you want to be.
Download iTubeGrabber 
