Now retuning if the received transponder's SDT doesn't contain the expected values for NID and TID

CONTRIBUTORS

@@ -285,6 +285,7 @@ Uwe Scheffler <linux_dvb@uni.de>
  for reporting a black screen while a "Recording started" message is displayed
  for reporting a problem with the lock on the Channels list in cDisplayChannel still
  being held when Flush() was called
+ for reporting a problem with failed tuning in SCR systems
 
 Matjaz Thaler <matjaz.thaler@guest.arnes.si>
  for improving AC3 decoding when replaying DVDs
@@ -3586,6 +3587,8 @@ Helmut Binder <cco@aon.at>
  for fixing updating the checksum in the CA table after mapping EMM PIDs for MTD
  for fixing a compiler warning in ExchangeChars()
  for suggesting to add __attribute__((packed)) to tIndexPes and tIndexTs
+ for helping with the implementation of retuning if the received transponder's SDT
+ doesn't contain the expected values for NID and TID
 
 Ulrich Eckhardt <uli@uli-eckhardt.de>
  for reporting a problem with shutdown after user inactivity in case a plugin is

HISTORY

@@ -9420,8 +9420,11 @@ Video Disk Recorder Revision History
 - Fixed handling the S2SatelliteDeliverySystemDescriptor for transponders broadcasting
   in "backwards compatibility mode" according to ETSI EN 300 468 (thanks to Onur Sentürk).
 
-2020-04-11:
+2020-05-04:
 
 - Fixed moving channels between number groups in SVDRP's MOVC command and the Channels
   menu, in case a channel is moved to a higher number and into a numbered group
   (reported by Manuel Reimer).
+- Now retuning if the received transponder's SDT doesn't contain the expected values
+  for NID and TID (thanks to Uwe Scheffler for reporting a problem with failed tuning
+  in SCR systems, and Helmut Binder for helping with the implementation).

device.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: device.h 4.13 2019/05/28 14:47:09 kls Exp $
+ * $Id: device.h 4.14 2020/05/04 08:50:20 kls Exp $
  */
 
 #ifndef __DEVICE_H
@@ -450,6 +450,8 @@ public:
        ///< Attaches the given filter to this device.
   void Detach(cFilter *Filter);
        ///< Detaches the given filter from this device.
+  const cSdtFilter *SdtFilter(void) const { return sdtFilter; }
+  cSectionHandler *SectionHandler(void) const { return sectionHandler; }
 
 // Common Interface facilities:
 

dvbdevice.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: dvbdevice.c 4.21 2019/05/28 14:40:49 kls Exp $
+ * $Id: dvbdevice.c 4.22 2020/05/04 08:50:20 kls Exp $
  */
 
 #include "dvbdevice.h"
@@ -1701,6 +1701,7 @@ void cDvbTuner::Action(void)
                      }
                   }
                tunerStatus = tsTuned;
+               device->SectionHandler()->SetStatus(true); // may have been turned off when retuning
                Timer.Set(tuneTimeout + (scr ? rand() % SCR_RANDOM_TIMEOUT : 0));
                if (positioner)
                   continue;
@@ -1733,6 +1734,14 @@ void cDvbTuner::Action(void)
                      isyslog("frontend %d/%d regained lock on channel %d (%s), tp %d", adapter, frontend, channel.Number(), channel.Name(), channel.Transponder());
                      LostLock = false;
                      }
+                  if (device->SdtFilter()->TransponderWrong()) {
+                     isyslog("frontend %d/%d is not receiving transponder %d for channel %d (%s) - retuning", adapter, frontend, channel.Transponder(), channel.Number(), channel.Name());
+                     device->SectionHandler()->SetStatus(false);
+                     tunerStatus = tsSet;
+                     lastDiseqc = NULL;
+                     lastSource = 0;
+                     continue;
+                     }
                   tunerStatus = tsLocked;
                   locked.Broadcast();
                   lastTimeoutReport = 0;

sdt.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: sdt.c 4.5 2015/08/02 11:33:23 kls Exp $
+ * $Id: sdt.c 4.6 2020/05/04 08:50:20 kls Exp $
  */
 
 #include "sdt.h"
@@ -23,8 +23,13 @@ static bool DebugSdt = false;
 cSdtFilter::cSdtFilter(cPatFilter *PatFilter)
 {
   source = cSource::stNone;
+  lastSource = cSource::stNone;
+  lastTransponder = 0;
+  lastNid = 0;
+  lastTid = 0;
   patFilter = PatFilter;
-  Set(0x11, 0x42);  // SDT
+  transponderState = tsUnknown;
+  Set(0x11, 0x42);  // SDT actual TS
 }
 
 void cSdtFilter::SetStatus(bool On)
@@ -34,6 +39,7 @@ void cSdtFilter::SetStatus(bool On)
   sectionSyncer.Reset();
   if (!On)
      source = cSource::stNone;
+  transponderState = tsUnknown;
 }
 
 void cSdtFilter::Trigger(int Source)
@@ -45,11 +51,37 @@ void cSdtFilter::Trigger(int Source)
 void cSdtFilter::Process(u_short Pid, u_char Tid, const u_char *Data, int Length)
 {
   cMutexLock MutexLock(&mutex);
-  if (!(source && Transponder()))
-     return;
   SI::SDT sdt(Data, false);
   if (!sdt.CheckCRCAndParse())
      return;
+  if (transponderState == tsUnknown) {
+     // The transponder can be verified with any section, no sync required:
+     int Nid = sdt.getOriginalNetworkId();
+     int Tid = sdt.getTransportStreamId();
+     if (Source() != lastSource || !ISTRANSPONDER(Transponder(), lastTransponder)) {
+        // We expect a change in NID/TID:
+        if (Nid && Tid && Nid == lastNid && Tid == lastTid) {
+           transponderState = tsWrong;
+           dsyslog("SDT: channel %d NID/TID (%d/%d) not found, got %d/%d", Channel()->Number(), Channel()->Nid(), Channel()->Tid(), Nid, Tid);
+           return;
+           }
+        }
+     // NID/TID is acceptable:
+     lastSource = Source();
+     lastTransponder = Transponder();
+     lastNid = Nid;
+     lastTid = Tid;
+     if (Nid == Channel()->Nid() && Tid == Channel()->Tid()) {
+        // NID/TID correspond with the channel data:
+        transponderState = tsVerified;
+        }
+     else {
+        // NID/TID differ from the channel data, but we accept it, since this *is* the data for this transponder:
+        transponderState = tsAccepted;
+        }
+     }
+  if (!(source && Transponder()))
+     return;
   if (!sectionSyncer.Sync(sdt.getVersionNumber(), sdt.getSectionNumber(), sdt.getLastSectionNumber()))
      return;
   cStateKey StateKey;

sdt.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: sdt.h 3.1 2014/03/10 14:40:54 kls Exp $
+ * $Id: sdt.h 4.1 2020/05/04 08:50:20 kls Exp $
  */
 
 #ifndef __SDT_H
@@ -15,16 +15,24 @@
 
 class cSdtFilter : public cFilter {
 private:
+  enum eTransponderState { tsUnknown, tsWrong, tsAccepted, tsVerified };
   cMutex mutex;
   cSectionSyncer sectionSyncer;
   int source;
+  int lastSource;
+  int lastTransponder;
+  int lastNid;
+  int lastTid;
   cPatFilter *patFilter;
+  enum eTransponderState transponderState;
 protected:
   virtual void Process(u_short Pid, u_char Tid, const u_char *Data, int Length);
 public:
   cSdtFilter(cPatFilter *PatFilter);
   virtual void SetStatus(bool On);
   void Trigger(int Source);
+  bool TransponderVerified(void) const { return transponderState == tsVerified; } // returns true if the expected NIT/TID have been received in the SDT
+  bool TransponderWrong(void) const { return transponderState == tsWrong; } // returns true if an expected change of NIT/TID has not happened
   };
 
 #endif //__SDT_H