Consider the following embed code of this video from Vimeo - Popular video hosting site:
<iframe src="http://player.vimeo.com/video/41321504?title=0&byline=0&portrait=0&color=c8c8c8" width="400" height="300" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>
the video embed url(http://player.vimeo.com/video/41321504) does open, if open directly in new browser window but doesn't contain location of video anywhere in html source code, thereby preventing downloads,i guess this is a feature of flash DRM. But then, a third-party website comes in & was able to give the direct urls to same video
http://av.vimeo.com/42007/964/95995392.mp4?aksessionid=96d0b8ffbb4c0c04b1c6b7f1562de7d5&token=1343971749_85ce464ec3361604fbda75e38e29f4e8
From a programmers standpoint, i was wondering how does it work? how are these video downloaders able to fetch direct url of the videos which are not even present in html source? what is their process if anyone can explain that step-by-step.
They do server-side analysis of the flash object, which will establish a conection to download the video. That connection can easily be captured. That even works in a browser, with Firebug for example: