Vista Media Center DRM woes

Posted in Home Theater at 3:52 am by mike

So prior to switching to VMC, I was using a Replay 5000 to record TV shows, along with a very cool Java program called DVArchive which would download the TV’s to my PC.   I’d then copy them to a portable drive and watch them on my train ride home using VLC.    I was assuming I could do the same with recordings from VMC, but unfortunately I found that life was not that simple.

CableCARD fun

Now when I started this project, I knew I wanted digital capture cards rather than analog (which the Replay 4000 is using) primary to get better quality.    The high-end digital capture cards are now all CableCARD ready, which I thought I would need to capture a digital signal.   It turns out there are a couple things you should know about CableCARDs:

  1. If you’re not interested in recording HBO or any other premium channels you DO NOT need a CableCARD.   Comcast currently broadcasts about 80 channels in analog signal which the ATI DCT will pick up just fine.    Comcast is currently threating to stop broadcasting these channels and convert everything to digital.   Still waiting for that to happen and see what the DCT can pick up once that’s complete.
  2. Once a CableCARD is installed, ALL RECORDED CONTENT WILL BE ENCRYPTED!   That means that any show recorded through the CableCARD will only play back on the PC which recorded it.   Quite a bummer for the mobile solution.
  3. Comcast charges $8 for the first card, and $3 for the next one, so multiple DCTs in the same box don’t kill you, but it will add up after a couple years…

So currently, I don’t have any CableCARDs installed, I receive 80 analog channels and 15 digital HD channels.  The broadcast format for those channels is called Clear QAM since they are not encrypted. I believe they match what’s freely broadcast in the area.   Unfortunately, there’s more DRM hiding in the mix.

Microsoft’s new WTV Format

It turns out that both analog and digital broadcasts can include a “copy protection bit” which also prevents the recording from being watched on another PC.    Here’s where things get interesting.   This copy protection bit was ignored by VMC until TV Pack 2008 was released.    With this update, files are now recorded in WTV format rather than the DVR-MS format which was previously used (this is the default for Windows 7 MC as well).   So not only are many of the recordings copy protected, but all the slick plugin utilities such as ShowAnalyzer and Comskip only understand the DVR-MS format.   Even though Windows 7 includes a wtv2dvrms converter, and one is available with the DVRMSToolbox, neither will work on copy protected or CableCARD encrypted files.

So far the shows I’ve found to have the copy protection bit have been somewhat random.   House, Southland and Breaking Bad (all from different networks) have been consistently protected, while other HD shows have not.

So what now?

So luckily, I didn’t sell my Replay TV yet, so I can still get all the offline shows I want there.    If Comcast does turn off all analog signals, which they are threating to do, then I’ll need to set up their free DTA with an IR blaster.    I could replicate this same setup on my VMC, but then why have the digital capture cards in the first place?    The interesting question is whether Comcast will encrypt all digital channels when they finally turn off analog or will channels 35-80 be broadcast in Clear QAM?   Check out number 31 on this FAQ which implies they will.   You can see more of my rant on thegreenbutton along with some comments from Fred Von Loman of the EFF.

The bottom line is, no one at Comcast can give a straight answer, so we just won’t know until it happens.   I’m sure I’ll be back ranting at that time.



  1. mike said,

    June 19, 2009 at 9:31 pm

    Very apropos after last night’s posting. From the EFF mailing list

    * Into the DTV Era, With No Broadcast Flag Mandate
    Entertainment industries like to argue that they “need” DRM
    to make works available. And policymakers have eagerly
    adopted this argument. But when the bluff is called, it
    turns out that the DRM wasn’t so necessary after all.

  2. mpsharp.com Blog » Comcast Digital Transition said,

    September 12, 2009 at 9:27 pm

    […] has finally turned off the analog signals for the extended basic channels in San Francisco as I alluded to here.   Since it took over 3 months from the actual announcement, it gave me plenty of time to crawl […]

  3. mpsharp.com Blog » Jumbo Frames, iSCSI and Disabling Nagle said,

    October 29, 2010 at 12:48 pm

    […] to a network drive.    This is part of the DRM associated with CableCARD, which I’ve ranted about before.   It turns out the new ATI BIOS relaxed OCUR standards addressed most my CableCARD concerns.  […]