Not the right place
I agree that there needs to be some kind of "open" standards-based DRM system.
I do not like it. I wish that Hollywood etc. would trust their customers enough to do without it.
They will not. Not yet, anyway. This means we need some way to get rid of the proprietary DRM lock-in.
Flash was bad, but at least it was fairly cross-platform. Most systems had an implementation. It may have been crap (on Linux, for example), but at least it existed.
Silverlight is worse. Not surprising, really, when it's a Microsoft product, but everyone seems to be moving over to it, locking out a huge number of devices. AFAIK, only Windows, MacOS and Symbian(?!) are supported. So, no iPhone, no Android, and definitely no Linux.
Moving on, it is clear that if we must have DRM, we need an "open" standard DRM. A system which can be implemented on anything. It doesn't need to be FOSS, but it needs to be able to interoperate with FOSS, or anything else.
With this in mind, my concern is that web standards are not the right place for it, IMHO. But then again, I disagreed with adoption of H264 as the "standard" HTML5 video format.
I have given this some thought in the past, and I believe that graphics card drivers would be the best place to implement this (one way or another). Come up with an open specification which allows data to be passed to the video card, encrypted, and allow them to decrypt and display. This would be relatively trivial for them to implement (in software for older cards, hardware for new models) and would keep everything secure. It could even be made interoperable with HDCP, so a GFX card hooked up to a HDTV would just stream the content, and the TV does the work. Do the decoding at the furthest point along the line possible. This keeps content providers happy (their content is as protected as possible), and consumers happy (because they can play their content).
It would not keep die-hard FOSS nuts happy, but nothing will in this situation other than abandoning DRM, which isn't going to happen soon.
It would not keep "pirates" happy, but who cares about
On a side note, I agree with others here that having the Pirate Parties join this fight only weakens the case. It's like the South Park episode where they were arguing over the flag (S4 E7 - Chef Goes Nanners).