[mythtv] Handling independent CI devices

Issa Gorissen flop.m at usa.net
Tue Mar 1 22:00:50 UTC 2011

> MythTV has always held the same stance on such devices.  The same code 
> that could be used to support independent hardware CAMs could just as 
> easily support software CAMs.  The only significant use of softcams, and 
> similarly the only significant use of such an interface in MythTV, would 
> be for subscription theft.  While this does mean we can't use devices 
> such as the ones you mention, this was a decision made long ago that we 
> stand by.  The only way we would support such devices would be if access 
> to the CAM were managed by the driver, and we got unencrypted video out 
> of it like as happens with tuners with built in CAMs.

Access to the CAM will always be taken care of by the driver, no question
about this.

The question is, with this kind of device, if you want to get the decrypted
signal from dvr0, you will have to send some commands first to a new file (to
ca0 maybe) to select the tuner you want to decrypt from. Of course, using this
way, you lose the possibility to decrypt for more than 1 tuner at the same

One other way (which Ralph Metzler has already implemented in staging) is to
send the encrypted signal from dvr0 to sec0 and read back the decrypted signal
from sec0. Currently, sec0 doesn't fit, it has to be renamed.

So you see that discussion about this are needed, unless no one wants to
support this device.

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