[mythtv-commits] Ticket #8645: Change the way myth "decides" if a program is encrypted

[MythTV]

#8645: Change the way myth "decides" if a program is encrypted
--------------------------+-------------------------------------------------
 Reporter:  anonymous     |       Owner:  janne     
     Type:  defect        |      Status:  new       
 Priority:  minor         |   Milestone:  unknown   
Component:  MythTV - DVB  |     Version:  Trunk Head
 Severity:  medium        |     Mlocked:  0         
--------------------------+-------------------------------------------------
 I have a whole sat lineup, with almost only pay channels, BUT there is one
 clear channel that mythtv, most of the time, tries to descramble whereas
 it is clear, which does not work.
 The reason is this code in mpegtables.cpp

 /** \fn ProgramMapTable::IsEncrypted(void) const
  *  \brief Returns true iff PMT contains CA descriptor.
  */
 bool ProgramMapTable::IsEncrypted(void) const
 {
     bool encrypted = IsProgramEncrypted();

     for (uint i = 0; !encrypted && i < StreamCount(); i++)
         encrypted |= IsStreamEncrypted(i);

     return encrypted;
 }

 It happens in my case that the PMT of the free program is detected by myth
 as:

 2010-07-09 14:06:41.024 CreatePMTSingleProgram()
 2010-07-09 14:06:41.024 PMT in input stream
 2010-07-09 14:06:41.024 Program Map Table ver(16) pid(0x509) pnum(9069)
 len(213)

  Stream #0 pid(0xa9) type(video-mpeg2  0x2)
  Stream #1 pid(0x74) type(audio-mp2-layer[1,2,3]  0x4)
   ISO-639 Language: code(fra) canonical(fre) eng(French)
  Stream #2 pid(0x35) type(private-data  0x6)
   Teletext Descriptor (0x56) length(5)
  Stream #3 pid(0xda) type(unknown  0xc0)
   Unknown(198) Descriptor (0xc6) length(5)
   Unknown(194) Descriptor (0xc2) length(40)
  Stream #4 pid(0x119) type(unknown  0xc0)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #5 pid(0x4e2) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #6 pid(0x153) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #7 pid(0x4e3) type(unknown  0xc6)
  Stream #8 pid(0xcf) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
   Conditional Access: sid(0x100) pid(0x708) data_size(13)
   Conditional Access: sid(0x100) pid(0x16a8) data_size(13)
  Stream #9 pid(0xce) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)

 So this is flagged as being encrypted as at least one stream is (the one
 before the last one). But if you compare with a PMT of a real pay channel
 like this one:
 2010-07-09 15:23:44.986 Program Map Table ver(28) pid(0x514) pnum(9100)
 len(295)

  Stream #0 pid(0xb4) type(video-mpeg2  0x2)
   Conditional Access: sid(0x100) pid(0x6a4) data_size(28)
  Stream #1 pid(0x9e) type(audio-mp2-layer[1,2,3]  0x4)
   ISO-639 Language: code(fra) canonical(fre) eng(French)
   Conditional Access: sid(0x100) pid(0x6a4) data_size(28)
  Stream #2 pid(0xda) type(unknown  0xc0)
   Unknown(198) Descriptor (0xc6) length(5)
   Unknown(194) Descriptor (0xc2) length(40)
  Stream #3 pid(0x119) type(unknown  0xc0)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #4 pid(0x4e2) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #5 pid(0x153) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #6 pid(0xce) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #7 pid(0x155) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #8 pid(0x159) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
  Stream #9 pid(0x4e3) type(unknown  0xc6)
  Stream #10 pid(0xcf) type(unknown  0xc1)
   Unknown(194) Descriptor (0xc2) length(8)
   Conditional Access: sid(0x100) pid(0x708) data_size(28)

 you can see that here the audio and video streams contain a ca descriptor.
 So the fix I propose would be to only test the presence of ca descriptors
 in audio or video streams only, which is what really matters.
 I cant propose a patch as my system is too fragile right now, but it is a
 matter of adding isaudio and isvideo calls in the loop.
 HTH

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Ticket URL: <http://svn.mythtv.org/trac/ticket/8645>
MythTV <http://www.mythtv.org/>
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