Comcast Digital Transition

Posted in Home Theater, Windows at 9:28 pm by mike

So it seems Comcast 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 all the forums and websites to understand exactly what happens from here.    Futhermore, a couple new news items popped up in the meantime which clarified what Comcast and other cable operators are doing.

So I’m currently running Microsoft Media Center on Vista, and I actually don’t experience all the horrid Vista stories you slash.dot readers may be accustomed to.   That said, there still are a number of quirks, but keeping an eye on thegreenbutton W7 posts, I haven’t been convinced that Windows 7 Media Center is going to be much better.

No More Analog Channels

So as Comcast started turning off the analog channels, I started seeing complaints from Media Center as it could no longer record shows on those channels.    Running a channel scan didn’t pick up any of the new channels, which I thought was odd since I knew the digital broadcasts of the extended basic channels are not encrypted (yet).    It turns out that Comcast sets a privacy flag on those channels which VMC respects and thus doesn’t automatically tune the channel.  (Thanks John) Instead, you have to go through a fairly cumbersome process of adding the channel by hand, editing the listing of the channel to merge it with the old analog channel in the guide, and then edit the sources of the channel and disable the analog signal (which is just static at this point).

For those of you who simply bought a TV with a digital tuner, connected your cable to it and found all the channels you paid for the same way your old analog set worked, that should still work, assuming your TV ignores the privacy flag.   If not, I’m told the digital TV tuners provide a similar mechanism to enter the digital channel number.    Unfortunately, Comcast and the other cable providers have received an FCC waiver to encrypt these channels as well.   So eventually everyone will need to either have a full set-top-box, a DTA converter, or a CableCARD compatible tuner.

So it’s unclear when Comcast will start encrypting those channels.   In order to do so, they will need to either replace or upload new firmware to the DTA’s currently distributed to customers.   Supposedly, these devices are designed to be updated in the field,  but I suspect that’s easier said than done, so we may have the unencrypted channels for some time.    That said, the current situation does allow Basic Cable subscribers to get Extended Basic without paying for it, but to do this you need to be pretty savvy (or read this blog, and who does that?).

Tuning Digital Channels

So how do you find the digital channel numbers for the clear QAM extended basic channels that VMC or your TV won’t scan by default?    Well first there’s the hard way.   It turns the new DTA’s deployed by Comcast have a simple diagnostic mode which will tell you the actual frequency and program number the current channel is broadcasting on.  Once you have the frequency, you can either do some math, or look it up on Wikipedia to find the channel number.

Or, you can simply go to SiliconDust, enter your zip code and find a complete listing there.   Make sure you choose the right line up.   After tuning a couple channel using the first method, going to SiliconDust is simply cheating.     SiliconDust is the maker of the HDHomeRun which is a combined DVR/media server solution.  Unfortunately, the value of this product will be greatly reduced when Comcast starts encrypting the extended basic channels.   It will still be able to record all the local broadcast channels, but that’s going to be a much more limited set than what they have today.   I suppose they can always offer a CableCARD version of the product, but their current customer base is probably going to be very unhappy.

Just Install the Damn CableCARD!

So not only would all these headaches go away if I just picked up a couple CableCARDs from Comcast, but I’d also be able to record a slew of new HD channels my VMC box currently doesn’t see.     The problem here is that the current CableCARD firmware incorrectly adds DRM to all recordings, even when not specified by the broadcaster.   This means everything recorded on the HTPC must stay there.   This means my daughter can’t watch Sesame Street on the laptop while I watch football, which is unacceptable.   The DRM also disables the commercial skip capabilities provided by programs such as ShowAnalyzer.  Futhermore, who has time to actually watch the shows when you’re spending so much time hacking the system?  In any case, the CableLabs OCUR (OpenCable Unidirectional Receiver) spec has finally been updated to remove this requirement.    But in order for this to work, a firmware update from ATI is required for the DCT.  I’m hopeful, but I’ve heard this story before.

Update 06.07.2010

So before ATI killed the card, they did release the firmware update.   I’m now happily running Windows 7 with 2 ATI tuners, both with a CableCARD and no DRM.   I’m happily watching on my laptop and skipping commercials.

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