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26 Mar 2011  
dsperber

Windows 7 Pro x64 (1), Win7 Pro X64 (2)
 
 
Why isn't "copy protected" WTV usable after system image restore?

I knew the encryption key used for copy-protected WTV recorded files out of Windows Media Center (Win7 Pro 64-bit), from the 4-tuner Ceton cablecard-enabled hardware, was usable on the currently installed Win7 system only. It would not be possible to view copy-protected WTV programs using WMC or WMP on another machine, or even on this machine after a new Win7 reinstall.

I had thought these WTV files could surely be moved to another location (e.g. to a server) from there originally recorded location, and still be usable. And this certainly seems to be true.

And I'd also thought that in case of disaster if you had to to a "system image restore", that since this was still the "originally installed Win7 OS that had done the recording" that those copy-protected WTV files WOULD still be usable after the system image restore. Well, it turns out that this does NOT appear to be true!!! And I'm puzzled.

I had to do a restore tonight from a system image from last month, as a last-resort only available convenient method (other than reinstall from scratch) to solve a problem I had when I tried to upgrade ATI video drivers and ran into trouble. Everything restored properly, and I then spent the next few hours bringing that restored system current again.

Well, when I got to Windows Media Center, I already knew that there were about 6 WTV recordings from copy-protected channels in my "Recorded TV" folder. I specifically looked there before restoring the system image, and decided I didn't have to worry (or pre-watch them before doing the system image restore) since the encryption key in the restored Win7 would be the same as before. So I'd gone ahead and done the system image restore.

Much to my surprise, all but one of the copy-protected WTV recordings was NOT usable by WMC after the system image restore!!! They all (but one) showed no image in their thumbnail, and they all produced a message from WMC when I tried to play them... indicating that they could not be copied.

Strangely, ONE recording (from SHOHD, which certainly is copy-protected) WAS still usable!!! This was bizarre, since another recording also from SHOHD was NOT usable.

The recordings were from an assortment of cable channels, and here in TWC/LA land EVERY channel is marked "copy-once" except for the the local OTA networks. So I'm not surprised about the copy-protected nature of these WTV files.

However I'm stunned that I could not view them with WMC in the Win7 recovered from a system image restore... or rather, all but one of them was unusable because of copy protection and the encryption key. And, even more mysterious, why was that one particular SHOHD movie NOT similarly lost???


Am I wrong?

Forgetting about the mystery of that one copy-protected file which was usable, shouldn't I have been able to read all those other copy-protected WTV files after my system image restore?
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