Windows Media: reloaded

by Francois Joseph de Kermadec

Some of you may remember my writing about

a Windows Media Player bug

a few days ago. As you know, it all turned out for the best and I went along my merry way, playing the file my customer had sent me, understanding the look they were after and working on that next commercial of theirs.

There is however, as usual with things Windows Media, a seeming incompatibility between core Mac OS X technologies and the digital rights management system built into the application. This time, it was all about user switching: after switching accounts on my machines and trying to read the file on each of them, for testing purposes, the magic that allowed for the decryption of the content stopped working and I was presented with a very laconic error message, stating that the “Hardware license was inconsistent”.

Very much like last time, a quick look through the web revealed mostly PC-based solutions that were of little interest to me. Also, there seems to be an assumption in forums that anyone asking this question is trying to hack a file and, therefore, one seldom finds answers.

It turns out this is the DRM-version of a corrupted preference file. You see, Windows Media Player, when it connects to the servers using Internet Explorer (which, again, you’ll have to temporarily set as your default browser, a scary thought), downloads a little file containing some kind of key and stores it safely and warmly, ready to be used whenever you request that the file in question be played.

Unfortunately, when you switch between accounts, launch the application and generally attend to your business, that string can get damaged or inaccessible, which causes Windows Media to go bonkers.

Here, the roughness of the application works at our advantage. I spent hours looking for hidden files, software mechanisms, compared the working and the now seemingly faulty versions of the file to no avail. For some reason, nothing DRM-related was where I expected it. It turns out Windows Media Player simply creates a folder called “DRM” in your “/Library/Preferences/” folder and stores its keys there.

Moving this folder out of the Player’s way allowed for the operations to resume smoothly. Windows Media Player looked for the license, didn’t find it, went back to my client’s server, downloaded a fresh copy of the keys and started playing the content again.

Note that this method won’t allow you to really “hack” anything. All it does is convince Windows Media Player to request a fresh copy of the license from the servers. Provided you are allowed to do that, it should allow you to resume the playing of your files that are most likely in perfect working condition.

Amazing how an application that looks for hidden files in the recesses of the Classic folders creates a folder called “DRM” in the most obvious of locations… But hey, that may be the one thing in favor of Windows Media Player: at least it does its shady things in the sunlight!


2005-09-06 12:17:12
I've actually never used it, but my understanding is that it will play most formats.

Maybe in practice it is not all it should be, but I guess it might save dancing with the Dark Side.

2005-09-06 14:06:25

First of all, thank you very much for taking the time to post and share your comments with us! :^)

Yes, MPlayer is indeed supposed to be able to handle many formats. Unfortunately, the DRM-ed files that were the source of so much trouble do rely on some proprietary Microsoft licensing code and, as far as I know, only Windows Media Player itself plays them as of today… :^(


2005-09-06 16:24:10
windows media player DRM - Janus for OS/X
slightly off-topic, i realize:

since you are already up to your elbows in WMP drm, i am wondering if you could do us all a favour and find an explanation of how/why the windows drm (JANUS) is not availible as part of the os/x drm.

thanx alot!

2005-09-09 13:27:52
windows media player DRM - Janus for OS/X
I strongly believe it is for the same reason that you cannot play Windows Media songs on an iPod. Nothing technical preventing it.
2005-12-08 15:57:34
Win Media fix for Mac
Thank you so much for finding this fix for us. I am part of a tech support for a DRM website and you just saved us a lot of time and trouble, by finding this solution! We have been working on it for a couple of months, but had not found a working solution.

Anyway, one point of clarification, if I may. When you say "get the file out of Win Media's way", I am assuming you mean to either delete the key or the whole DRM file each time they want to view a movie. Is this correct?

2005-12-08 16:07:00
Win Media fix for Mac
Hi there!

I am glad this modest blog entry was of interest to you! Thanks for taking the time to post.

By "getting it out of Windows Media's way", I mean moving it outside of its original location which causes it to be "deleted" as far as the application is concerned without actually removing it from the user's hard drive — for example, if it contained keys for another site or movie and were to be put back in place later. This also isn't something you would want to do every time, simply when the mechanism goes awry.

Feel free to email me (the address is in my profile) and I would be glad to provide you with any additional information you may require. I would be glad to assist with the writing of a quick help sheet for your customers as well - on a purely friendly basis, needless to say.


2006-01-11 20:49:50
Out of curiosity...
What websites offer DRM files in Windows Media format that are compatible with the limited version of DRM built into the Mac WMP9?

I have yet to find any. Everything I've ever tried wanted Windows Media Rights Manager v7 or greater.