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A history of Comcast and MythTV
Posted on 10-23-2011 23:03:28 UTC | Updated on 01-21-2012 21:15:58 UTC
Section: /software/mythtv/ | Permanent Link

I have recently upgraded my Mythbuntu 8.04 install to Mythbuntu 10.04, I am successfully using the new HDHomeRun Prime digital network tuner to record all of my shows. But the road to this new clean install was long and hard. I wanted to reflect on the years of trying to use a DVR like MythTV with my local cable provider Comcast. I will post a second article after this one with my notes on the actual install and configuration.

The good old analog days

When I first starting using MythTV (mid 2000's) I had 2 analog Hauppauge PVR-150 cards. They were hooked directly into the cable lines and the MythTV machine could easily change the channels and record TV shows. It was super simple setup thanks to Comcast just providing an analog feed that worked with any cable ready TV on the market. This worked flawlessly for a few years but with everything starting to move to digital it was time for a new tuner.

The good old digital days

I did some research at the time and read many great reviews about a tuner you could use over an Ethernet network. It was called the Silicondust HDHomeRun. This little box had 2 tuners and could record the digital channels Comcast supported and on top of that it could record HDTV. I was sold. I bought the unit and hooked it up. It worked great! I could get almost all of the channels Comcast provided using a clear unencrypted (QAM-256) digital stream. Along with this I could keep my 2 analog tuners since the analog signals worked right alongside the digital signals. Life was good and then just a few years ago everything started to crumble.

The bad old digital days

Comcast decided that all of their analog stations were taking up way to much of their available bandwidth. You see 1 analog channel = ~20 SD digital channels or ~3-4 HD channels (using QAM-256). Obviously that is a huge bandwidth savings so Comcast decreed that all customers will now be required to use a cable box or cable card with all of their devices. They implemented their plan of shutting down most of the analog channels and reclaiming them for digital channels. Customers were offered 2 basic digital boxes for free and then you have to pay for the rest.

This move by Comcast did not sound so bad since most new digital TV's supported clear (unencrypted) QAM-256. My HDHomeRun was the same way. It was already recording all of the digital shows using QAM-256. This would mean that I would have to get rid of my 2 analog tuner cards and possibly just buy another HDHomeRun. That would eliminate the cards and cables going to my MythTV machine and put all my tuners on the network. I could live with that. Onward and upwards as they say. Comcast decided to not mention one major detail.

They were also going to encrypt all of their digital channels during this big switchover. That means a cable box will be required (for decryption) for all TV's regardless. That one small douche bag move (that was not even necessary to keep all the devices working) broke all of the TV's and cable devices like the HDHomeRun. They could have just moved the channels to digital and given out boxes to people with old analog TV's. The newer digital TV's and devices would have kept working fine and would not have needed a box. Now any device requires a box to get anything more than the local TV stations. The only reason they did not encrypt those as well was because the FCC mandated they were not allowed to do it. I'm sure they would have done it if the law permitted it.

Quick shaming of Comcast and Verizon

I will take a quick moment here to say shame on you Comcast. You could have gone digital and saved your bandwidth like you needed to and left it at that. Now you stick it to your customers by requiring boxes. Yes, you give a few away for free but it is one more thing that is now required but not needed. But I just can't shame you. Verizon does the exact same thing (I checked). Comcast could have set themselves apart from Verizon (they did it first) and kept clear QAM for most of their digital channels but they took the low road. I was disappointed to say the least but I stayed the course. Now I will have to use their boxes and exploit the "Analog Hole".

The bad old analog days

As ridiculous as all of that seems, recording with MythTV would have to be done with the analog PVR-150 cards again. But not in the same way it was done before. Since cable boxes are required to decrypt the signals now the new setup would require 2 cable boxes, 2 analog cards, and a IR blaster to change the channel with a script. Luckily, MythTV was versatile enough to handle this setup (hooray MythTV!). This is the setup I had up until a few weeks ago. It was an ugly conglomeration of wires and not the most reliable setup. I have hated this setup for that past few years, but I had very few choices if I wanted to record most cable channels with MythTV.

The bright new digital days

My goal for the upgrade was to get rid of my cable boxes, IR blasters, PVR-150 analog cards and go to an all digital setup. The only way to get rid of this mess would be to use a device that would allow me to record all of my extended digital cable channels without using the ugly cable box. I had read that SiliconDust (the company that makes the HDHomeRun) had a new product coming to market in 2011. It was another network tuner like the HDHomeRun (that I love so much) but this one would use CableCARD. Using a CableCARD would allow it to tune in and decrypt all of the digital channels like the days of yore. Best of all it would have 3 tuners and be able to be accessed over the network. This new savior of a device is called the HDHomeRun Prime and it was just released at the end of July.

Now your thinking, Comcast offering a CableCARD that actually makes their customers lives easier? Haha, yea right! They would never do that without being forced to. Remember, who forced them to keep local channels unencrypted. That's right it was the FCC. Guess who required them make available CableCARDs? If you answered the FCC your right again. In the "Plug and Play" proceedings, the FCC required all cable companies to make available CableCARDs, which enables anyone to offer an alternative to set-top boxes. Read more about this here. This ability of anyone being able to make a cable box paved the way for the HDHomeRun Prime.

Introducing the HDHomeRun Prime

The HDHomeRun Prime is a device hooks into your network that allows you to view your cable channels from any device that has software client written for it. MythTV happens to be a client that can read and record the digital streams from the Prime. I purchased the HDHomeRun Prime about a month ago and hooked it up to my network. I got a CableCARD from Comcast and plugged it into the Prime. I called the number to activate it and got it activated successfully. But for some reason I could only see local channels.

The first run in with digital copy protection

Any time I tried tuning in any station other than a local station the channel showed that the CCI Protection flag was set to "Copy Once". CCI stands for Copy Control Information. It has flags set in it's digital stream that allows the content provider to tell the device what it is allowed to do with the content. This is where the FCC caved into Hollywood and allowed them put Digital Rights Management (DRM) "features" into the CableCARD. My channels were showing it was set to "Copy Once" (0x02). This means the content is allowed to be copied only to the device receiving the stream and it must be encrypted with a unique key so the recording device is the only one that can play the stream. Tivo and Windows Media Center can record these streams but most software can not. Unless you get a blessing from the maker of CableCARDs (CableLabs) then you will not be able to see this stream. Very few front-end applications have been approved for use with CableCARD tuners using the copy once flag and MythTV is not one of them.

From everything I read about Comcast and Verizon they set the copy freely flag in most areas of the country. Many people have even said it is a corporate policy of Comcast to set the copy freely flag. I was perplexed by why this flag was showing up. I hit the SiliconDust forums and found out the answer. After the cable card is activated you have to speak to tier 2 support to get them to send a "hit" to your cable card. A "hit" is like a major reset and clear of your cable card. Even though the card is activated it will not start working until this hit is done. Tier 1 support does not know about this. All they try to do is keep re-activating your cable card. After tier 2 sent the hit to my cable card I could see all of the channels I subscribe to. Checking the CCI flag after the fix it did not say "Copy Freely" as I expected, it said CCI Protection "unrestricted". That works for me. I did just say I could see all of my channels. I lied. I later found out I could not view all of them.

The second run in with copy protection

After getting that cleared up I noticed that my local HD PBS station and my local HD CBS affiliate would not tune in with the Prime. Upon further inspection of the logs I found a line that said "auth=unknown cci=none cgms=protected-rcd". Both channels said this when tuned it. All other local HD channels were fine. This new copy protection that is being sent is the Copy Generation Management System. It is copy protection for analog signals (there is digital version as well) and if this flag is set the Prime must obey it because it has to obey the CableCARD standard. The description of this issue is described best by SiliconDust employee Jason replying to a Verizon user on the forum with the same issues as me:

The network enables the redistribution control "broadcast flag" on some content. The CableCARD standards require that OCUR devices enforce copy protection when this flag is set and no CCI value is set by the card (CCI overrides all other forms of copy protection). Verizon doesn't set CCI on clear QAM channels, so that can result in it getting blocked. Yes, this is a pointless requirement since any tuner that doesn't support CableCARD will completely ignore the flag and do whatever you want with clear QAM channels, but the HDHomeRun PRIME and other OCUR tuners are nonetheless required to play by the rules. We plan to submit a request to CableLabs to have this requirement changed. One workaround might be to contact Verizon and see if they can start sending CCI data for that one channel just to override the broadcast flag.

So this issue is something Comcast is doing and I have not bothered with it further (UPDATE 11-19-2011: A firmware update for the Prime has cleared up this "redistribution control flag" issue. I can now see my local HD PBS channel.). Why you ask? Well, if you read what Jason said above clear QAM devices ignore this crappy flag as they do not have to abide by CableLabs certification. The 2 stations I'm having an issue with are sent by Comcast as clear QAM. My older HDHomeRun just reads the clear QAM and shows the station just fine. Now your thinking, why can't the Prime see the clear QAM station and just show it. The issue with that is when the CableCARD is in the Prime it has to obey CableLabs restrictions so if there is a copy protection flag it can not show the station. If the card is not in the Prime it would tune in the clear QAM signal just fine. But it is not allowed to tune in both at the same time. I might revisit this issue at a later time but for now I can live with it.

Finally a working MythTV

After getting all of that worked out I can now see all of the stations from my MythTV machine. It is happily recording all of the shows on my schedule. I'm using version 24.1 + fixes and it is fantastic. I could not be happier with it.

Reflection

After going through all of these issues I will say that I hate copy protection (DRM) even more than I did before. It does nothing but hassle the people that actually pay for content and hinders their ability to use it in the way they seem fit. One of my favorite people that write about these things is Corey Doctorow. Check out this lecture he gave in 2004. It really sums up why DRM does not work and why it is bad business. The honest user is the one who pays the price by being put through long phone calls to support, annoying workarounds, and limited use just to use the product they legitimately purchased. Fred von Lohmann had a quote that I have remembered to this day when Apple was using DRM on their music "No one wakes up and says, 'Hey, I want to do less with my music today," he said. "And that's what DRM does - allows you to do less and less with content.". That brilliant quote just about sums it up. DRM lets us do less and less with the content we buy. Apple figured out that DRM does not work. I wish other corporations would figure it out as well. And they wonder why people turn to "pirating" content...

Reddit!

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