[mythtv] CAM Issue?

Daniel Kristjansson danielk at cuymedia.net
Fri Aug 25 13:54:28 UTC 2006

On Fri, 2006-08-25 at 09:38 +0100, Stuart Auchterlonie wrote:
> On Fri, Aug 25, 2006 at 04:38:01PM +1000, Dave Oxley wrote:
> > I have a problem getting my DVB-S working with Austar here in Australia.
> > I can view an FTA channel, but cannot view non-FTA channels on the same
> > multiplex. I have attached a log with record,channel,siparser where I
> > initially recorded from TVSN (A FTA channel) and then recorded from CNBC
> > (A non-FTA channel). I get picture and sound from TVSN, but on CNBC I
> > just get a black screen with a blue square in the bottom right hand corner.
> > This may or may not be a bug?!?! I really don't know and can't find
> > information on configuring DVB-S and diseqc within MythTV, but I've
> > attached the necessary records from my db.
> From what I can see the CA information streams aren't passed through
> to the output PMT, and then tv_rec refuses to record the encrypted
> stream.
> either
> a) the CA streams need to be passed through to the output PMT
> b) the streams need decrypting before being send to the recorder.
> Which one is the correct behaviour?

They need decrypting before being sent to the recorder.
What is supposed to happen is that when we get the input
PMT or CAT table and it tells us that something is
encrypted we send the CA info to the MythTV CAM module
which does the CAM magic. Meanwhile we strip any CA info
from the output PMT and ignore all encrypted streams.
Once the CAM kicks in it rewrites the flags on the
encrypted streams to tell the recorder it is safe to look
at those PIDs.

MythTV will refuse to record an encrypted stream if you
have "Free to air channels only" checked in the DVB Options
in mythtv-setups Input Connections pane for the input you
are using for this recording. It sounds like that might
be the case. Otherwise this might be a bug. None of the
regular devs use CAM so it might be a while before anyone
fixes a CAM bug, but they should still get tickets.

-- Daniel

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