[mythtv] [mythtv-commits] Ticket #3541: Backend Crashes When Recording From Mux A In The UK (Freeview / DVB-T)

Allan Stirling Dibblahmythml0015 at pendor.org
Fri Jul 27 08:31:06 UTC 2007

Daniel Kristjansson wrote:
> On Fri, 2007-07-27 at 03:18 +0100, Allan Stirling wrote:
>> MythTV wrote:
>>> #3541: Backend Crashes When Recording From Mux A In The UK (Freeview / DVB-T)
>>> Comment(by danielk):
>>>  Can you try the attached patch?
>>>  A long time ago it was reported to me that the cards with the "Philips
>>>  TDA10046H DVB-T" frontend destroyed the CRC of their PMT tables and so we
>>>  had to turn off error checking and risk crashes in order to support this
>>>  card at all.
>>>  However, a similar report was also filed about "DST DVB-S" cards, which
>>>  I've  now tested myself and it does not exhibit the reported problem, at
>>>  least with drivers produced in the last year. The attached patch turns off
>>>  the "don't check and fly blindly" behavior in MythTV for all cards. If you
>>>  can tune in channels at all with this patch applied, it will take me 5
>>>  minutes to commit a proper fix.
>> AFAIR, this was before we handled packets which (validly) 
>> had no CRC.
> It was, but this was reported to on the PAT & PMT sections.
>> There is nothing that the frontend does that can change the 
>> contents of the packets. The only card that could possibly 
>> do something like this is the 'fully featured' technotrend 
>> cards, which can (again, as far as I know) rewrite the stream.
> What about cards with a CAM? I assumed this was due to a
> faulty implementation of code which removes CA descriptors.
> This would probably be firmware on the card itself; three
> out of the four cards this problem was reported on were DVB-S
> cards. In Europe, DVB-S cards with CAM's are popular to
> receive subscription restricted satellite transmissions.
> -- Daniel

That could well be true. The entire TS (not sure if before 
or after PID filtering) is passed through the CAM. However, 
the FE used still has no effect :(



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