Rob's Musings

So I recently sumbled upon this incredibly useful site, www.videolectures.net.  It's a collection of recored lectures on a large variety of different topics.  Their largest catgeory is computer science, and within CS, the largest number of lectures are on machine learning topics.  However, this is perfect as my current research  deals heavily with applying machine learning techniques and probabalistic models to computer grapics.  I must have already watched at least 7 or 8 hours of lectures from this site.  What's even nicer is the fact that most lectures allow you to download the accompanying slides.  Furthermore, when the video of the lecture is playing, the corresponding slides are shown next to the video, and they update on the webpage as the author changes slides in during the lecture!

Despite my overwhelming happiness with this site, I did have one significant objection.  The videos are all streaming; you cannot download them.  Normally, this wouldn't be that big of a deal.  However, they also ( at least in Firefox under Linux ) lack the ability to seek backward, so if I miss something.... well you get the idea.  I tried to scan the source of the page to find a direct link to the videos, only to find that they are streamed using some media streaming protocol.  In fact, if you open up the page's source and search for ".wmv", you'll likely find something like this:

mms://velblod2.ijs.si/2007/pascal/eccs07_dresden/mertens_stephan/eccs07_mertens_com_01.wmv

What do I do with that?  Well, I can use mplayer to watch it directly from this url, but I still can't seek.  After some searching, I found a solution.

mplayer -dumpstream [URL] -dumpfile [filename]

This will dump the stream to a file so that you can watch it at your leisure, and seek backward and forward as you please.  Unfortunatly, the streaming protocol means that it will take you time equal to the length of the video to actually dump the stream to a file, but once you've acquired it, it's yours forever to watch as you please.  I've found this incredibly useful so far.  Hopefully some of you will also.  I'm contemplating writing a Ruby script to crawl the site and download interesting videos automatically ;).