[linux-dvb] ca question

phil.vid at gmail.com phil.vid at gmail.com
Sat Apr 23 15:33:48 CEST 2005


I'm trying to diagnose a problem with some code in mythtv that prevents an 
encrypted channel being decrypted correctly. I'm using a Nova-S CI with 
Irdeto cam.

What I see is the cam capability request returning a bunch of system IDs. 
Then when the code parses the pmt, it finds 2 system IDs (0x0604, 0x0624) 
out of 3 that match the capabilities of the cam.
When one of the system IDs is used (0x0604) or both in the order 0x0604 then 
0x0624, the decryption fails. When the other is used (0x0624) it succeeds. 
What I dont understand is why decryption would fail if both system ids are 
listed as supported in the cam.
In previous versions of the code, and way back to the original code from 
vdr, it seems that the pmt is parsed and only the first matching system ID 
(0x0624) is used. Thus the decryption would work.

Does anyone have any pointers to any standards that can describe how 
multiple matching system IDs are meant to be handled in a ca_pmt table? I'm 
not sure if this is a standards thing or just irdeto weirdness.


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