I am just going by what google tells me, so take it with a grain of salt but:
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www.silicondust.com/foru ··· 7#p83737"Also, if you are using embedded graphics of Intel CPU, you can't watch these channels if they are copy protected. Intel graphics drivers do not support copy-protection and H.264 at the same time."
And looking at the next post
"Surprisingly, my new windows 8 laptop with hd4000 ( i7-3517U )-plays the protected h.264 content from cox just fine... windows 7 on the same machine using the latest drivers from intel does not and usually results in a blank (black)..."
So I think the fix ""Fixed protected content playback issues for new Windows 8 Store video players like Netflix*." fixed the issue, but only for Windows 8. However the data is not clear. Would need a dual boot with Windows 7 and 8, same hardware, to really isolate. If nothing else though, its a pretty good hypothesis.