Microsoft clarifies Windows Vista content protection measures

In a post on the Windows Vista Team blog, Microsoft has clarified a number of points about the content protection measures present in Windows Vista.
Written by Adrian Kingsley-Hughes, Senior Contributing Editor

In a post on the Windows Vista Team blog, Microsoft has clarified a number of points about the content protection measures present in Windows Vista.

The post by Dave Marsh, Lead Program Manager for Video, provides some background to the issues surrounding content protection in Vista and also includes a very interesting FAQ.  The FAQ provides answers to some questions that many people are asking about how Windows Vista will protect premium digital content and how this will affect users and programmers alike.

Here are some of the questions and answers that caught my eye and I think warranted further discussion. 

Do these content protection requirements apply equally to the Consumer Electronics industry supplied player devices such as an HD-DVD or Blu-Ray player?

Generally the requirements are equivalent for all devices.

This means that it's a level playing field and Vista isn't imposing any additional content protection burden on users.  The same issues will be present on Windows and Mac and any consumer electronic devices you have in your home.

When are Windows Vista's content protection features actually used?

Windows Vista's content protection mechanisms are only used when required by the policy associated with the content being played.

So it's not Microsoft or Windows that decides whether content is protected or not, it's the publisher.

Will the playback quality be reduced on some video output types?

Image quality constraints are only active when required by the policy associated with the content being played, and then only apply to that specific content -- not to any other content on the user's desktop.  As a practical matter, image constraint will typically result in content being played at no worse than standard definition television resolution.  In the case of HD optical media formats such as HD-DVD and Blu-Ray, the constraint requirement is 520K pixels per frame (i.e., roughly 960x540), which is still higher than the native resolution of content distributed in the DVD-Video format.

So the downgrade will take HD content down to about 960x540 if you don't have appropriate hardware.  That's quite a drop in quality but still not too bad.  I hope Microsoft and other publishers will offer test content so that users will be able to test their system for compatibility.

Do things such as HFS (Hardware Functionality Scan) affect the ability of the open-source community to write a driver?

No.  HFS uses additional chip characteristics other than those needed to write a driver.  HFS requirements should not prevent the disclosure of all the information needed to write drivers.

So the open source community isn't being affected here (although playing protected content will remain a no-no.

Will the Windows Vista content protection board robustness recommendations increase the cost of graphics cards and reduce the number of build options?

Everything was moving to be integrated on the one chip anyway and this is independent of content protection recommendations.

Content protection doesn't make hardware more expensive.

Will Windows Vista content protection features increase CPU resource consumption?

Yes.  However, the use of additional CPU cycles is inevitable, as the PC provides consumers with additional functionality.  Windows Vista's content protection features were developed to carefully balance the need to provide robust protection from commercial content while still enabling great new experiences such as HD-DVD or Blu-Ray playback.

Ahhh, an interesting sticking point.  The answer here is a little vague and doesn't really address the question as to how much more computing power users are going to need to play protected content compared to unprotected content.  My guess would be that protected content and minimum spec for Windows won't go well together.  However, given the power of modern PCs, I don't think this will be a big issue.

What about S/PDIF audio connections?

Windows Vista does not require S/PDIF to be turned off, but Windows Vista continues to support the ability to turn it off for certain content -- a capability that has been present on the Windows platform for many years.  Additionally, in order to support the requirements of some types of content, Windows Vista supports the ability to constrain the quality of the audio component of that content. 

Will Component (YPbPr) video outputs be disabled by Windows Vista's content protection?

Similar to S/PDIF, Windows Vista does not require component video outputs to be disabled, but rather enables the enforcement of the usage policy set by content owners or service providers, including with respect to output restrictions and image constraint.

Again, this is down to the publishers, not Microsoft.

What is revocation and where is it used?

Renewal and revocation mechanisms are an important part of providing robust protection for commercial audiovisual content.  In the rare event that a revocation is required, Microsoft will work with the affected IHV to ensure that a new driver is made available, ideally in advance of the actual revocation.  Revocation only impacts a graphics driver's ability to receive certain commercial audiovisual content; otherwise, the revoked driver will continue to function normally.

This is interesting indeed.  What this means is that if a driver is found to be lacking in some way relating to content protection (for example, it's been compromised by hackers), Microsoft will try to have a new driver present before the old driver is revoked.  This makes sense as it will stall the number of support calls Microsoft would receive and hassle that users will face.  However, it gives hackers extra time to work - and as we've seen with HD-DVD, it doesn't take long for content to make it onto torrent sites.

Will the 'tilt bit' mechanism cause problems even when the driver is not under attack from a hacker, e.g., when there are voltage spikes?

It is pure speculation to say that things like voltage fluctuations might cause a driver to think it is under attack from a hacker.  It is up to a graphics IHV to determine what they regard as an attack.  Even if such an event did cause playback to stop, the user could just press 'play' again and carry on watching the movie (after the driver has re-initialized, which takes about a second).  Again, it is important to note that this could only occur in the case of watching the highest-grade premium content, such as HD-DVD or Blu-Ray.  In practice I doubt it would ever actually happen.

I was always skeptical about this all along.  Yes, while a voltage spike could theoretically cause a driver to look like it's under attack from a hacker, it's not really all that likely.

Will the video and audio content protection mechanisms affect gaming on the PC?

The Windows Vista content protection features were design for commercial audiovisual content and are typically not used in game applications.  A game author would have to specifically request these features for them to impact game performance.

I really can't see content protection making its way into games any time soon.  The added performance overhead would be too much of an issue, not to mention the fact that content protection would add a whole new layer of system requirements to games.

Read the entire Q&A here.

Thoughts?  Do these measures seem fair to you?  Do you think that they will be effective or will the pirates find a way around the system?

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