Serve InfiniTV 4 tuner on Linux and decrypt on Windows?

[rickatnight11]

I currently have a PCI-E InfiniTV 4 tuner installed in my Windows 7 HTPC with Verizon Fios TV. I have 2 of the tuners assigned locally, and two tuners are assigned to another Windows 7 HTPC in another room. It's working well with Windows Media Center on both machines, but it's annoying needing to keep the main HTPC powered on at all times. I already have a few Linux servers running 24/7 that I could "host" the card from, and allocate 2 tuners per HTPC.

My question comes down to the encrypted channels. I know only Windows Media Center can decrypt the encrypted channels, which is why I'm not running MythTV on Linux on the HTPCs. I believe this limitation is solely in the software (WMC has the decryption keys), so would it be possible for the InfiniTV to be physically installed on a Linux machine (with the tuners shared over the network), and still maintain channel decryption support on the 2 Windows Media Center clients?

[The Mac]

There are no linux drivers.

[rickatnight11]

There are no linux drivers.

Yes, there are:

http://cetoncorp.com/infinitv_support/linux_drivers/

[barnabas1969]

Rick, you are correct about the drivers. I've never tried using an InfiniTV tuner in Linux. I would guess that in order to do what you want, you would need to figure out how to bridge the NIC in your Linux system so that it routes traffic to the InfiniTV tuner (which appears to the OS as another network interface). Then, you'd need to figure out how to configure your Media Center PC's so that they use the tuner in your Linux system.

[rickatnight11]

Rick, you are correct about the drivers. I've never tried using an InfiniTV tuner in Linux. I would guess that in order to do what you want, you would need to figure out how to bridge the NIC in your Linux system so that it routes traffic to the InfiniTV tuner (which appears to the OS as another network interface). Then, you'd need to figure out how to configure your Media Center PC's so that they use the tuner in your Linux system.

Configuring the network bridge in Linux won't be an issue. I suspect configuring WMC on the clients will work the same way it always has with auto-discovery. What I'm interested to know is if I'll have a problem with copy-protected channels. I believe that the decryption is done at the very end of the process via software, so I think I'll be fine, but I was hoping someone had tried before me.

[barnabas1969]

If you can figure out how to configure the network bridge, and how to configure the clients, then the encryption/decryption should work the same as if you installed the tuner in a Windows Home Server as several people have done in the past. The tuner performs the encryption and then sends the encrypted data over TCP/IP. As long as the data gets to Media Center, then PlayReady should decrypt it (assuming that you have run the Digital Cable Advisor and setup PlayReady).

[rickatnight11]

If you can figure out how to configure the network bridge, and how to configure the clients, then the encryption/decryption should work the same as if you installed the tuner in a Windows Home Server as several people have done in the past. The tuner performs the encryption and then sends the encrypted data over TCP/IP. As long as the data gets to Media Center, then PlayReady should decrypt it (assuming that you have run the Digital Cable Advisor and setup PlayReady).

Exactly what I wanted to hear. I'll give it a shot.

Another question...does the tuner actually perform the encryption? That seems odd and easy to bypass (perhaps by flashing another firmware that doesn't encrypt anything.) I would think the channels come encrypted from the provider (Verizon in this case), and the tuner just converts the signal on the coax to a usable or encrypted MPEG stream, which the is up to the software client to handle.

[barnabas1969]

As I understand it, the CableCARD decrypts the data coming from the cable company. The tuner then re-encrypts it using an encryption method that can be decrypted by PlayReady. PlayReady decrypts it, and then encrypts it again before writing it to disk.

That's why the tuner is a system-on-chip and is only accessible as a network interface. All the encryption stuff happens inside the SOC. I know that Ceton has put out some firmware that doesn't do the encryption part... but they only released it to individuals who had an open support ticket with Ceton that required a capture of the un-encrypted data stream in order for Ceton to resolve the issue.

I suppose it might be possible for an enterprising individual to reverse-engineer the firmware, but I would imagine that the firmware images are also encrypted, and are only decrypted by the SOC at the hardware layer. Otherwise, it would be fairly easy for someone to modify the firmware so that the encryption step is skipped. This is similar to PlayReady... if it was easy to reverse-engineer, someone would have already done it.