Ticket #5754: activeeit-one-in-eight-hours.diff

libs/libmythtv/tv_rec.h

@@ -371 +371 @@
     TuningQueue    tuningRequests;
     TuningRequest  lastTuningRequest;
     QDateTime      eitScanStartTime;
+    QDateTime      eitScanStopTime;
+    uint           activeScanCycleTime;
+    uint           activeScanDuration;
     QWaitCondition triggerEventLoop;
     QWaitCondition triggerEventSleep;
     bool           m_switchingBuffer;

libs/libmythtv/tv_rec.cpp

@@ -890 +890 @@
     // to avoid race condition with it's tuning requests.
     if (HasFlags(kFlagEITScannerRunning))
     {
+        VERBOSE(VB_EIT, LOC + "Stopping EIT Active Scan due to tuning in TVRec::HandleStateChange.");
         scanner->StopActiveScan();
         ClearFlags(kFlagEITScannerRunning);
     }
@@ -1309 +1310 @@
     SetFlags(kFlagRunMainLoop);
     ClearFlags(kFlagExitPlayer | kFlagFinishRecording);
 
+    uint ActiveCycleSleepSecs;
+    bool ScanStopped;
+
+    ScanStopped = true;
+
     eitScanStartTime = QDateTime::currentDateTime();    
     // check whether we should use the EITScanner in this TVRec instance
     if (CardUtil::IsEITCapable(genOpt.cardtype) &&
@@ -1444 +1450 @@
             ClearFlags(kFlagExitPlayer);
         }
 
+
+        // EIT Scanner handling
         if (channel && scanner &&
             QDateTime::currentDateTime() > eitScanStartTime)
         {
@@ -1458 +1466 @@
                         "for all sources on this card.");
                 eitScanStartTime = eitScanStartTime.addYears(1);
             }
+            // Things are good to start Active Scan
+            // We now know that currentDateTime > eitScanStartTime but we don't know if
+            // we have exceeded the eitScanStopTime
             else
             {
+                // Following are control variables for the improved active scan
+                // It stops after a defined period and closes the tuner card,
+                // the idea is to see if it saves some power. There is usually no need
+                // to scan for EIT data continuously.
+        
+                // Set the repeat rate of the active scan to 480 minutes (8 hours)
+                activeScanCycleTime = 480;
+                // It would be wise to schedule an EIT scan shortly before a recording,
+                // to check for re-schedules (To Be Done).
+        
+                // Set the duration of the active scan to 60 minutes (1 hour)
+                activeScanDuration = 60 * 60;
+        
+                eitScanStopTime = eitScanStartTime
+                        .addSecs(activeScanDuration);
+        
+                // Log some information about the settings
+                VERBOSE(VB_EIT, LOC +
+                QString("Improved Active Scan cycle time %1 minutes")
+                .arg(activeScanCycleTime));
+                VERBOSE(VB_EIT, LOC +
+                QString("Improved Active Scan Duration   %1 minutes")
+                .arg(activeScanDuration/60));
+        
+                ScanStopped = false ; 
+
+                // Active Scan is restarted after a recording uses the tuner, so the
+                // relative position of the 'window' moves as recordings are made.
+                // If settings give poor programme guide population, they can be changed
+                // Ideally there could be a control in mythtv-setup where active scan is enabled
+
+                VERBOSE(VB_EIT, LOC + "EIT Active Scan being (re)started.");
                 scanner->StartActiveScan(
                     this, eitTransportTimeout, eitIgnoresSource);
                 SetFlags(kFlagEITScannerRunning);
+                // This next line prevents multiple entries into this 'if' if scan has started
                 eitScanStartTime = QDateTime::currentDateTime().addYears(1);
             }
         }
+        else if (channel && scanner && 
+            (QDateTime::currentDateTime() > eitScanStopTime) && !ScanStopped )
+        {
+            // Now we catch the same conditions but with eitScanStopTime exceeded
+            // and we haven't already been here, ie. ScanStopped is still false
 
+            VERBOSE(VB_EIT, LOC + "Reached Active Scan Duration, ceasing active scan until next cycle. Flushing cache...");
+            scanner->StopActiveScan();
+            ScanStopped = true ; 
+
+            // Now calculate the number of seconds we have to wait to complete the
+            // Active Scan Cycle. This way, the cycle will always be same length.
+            // (Apart from recordings which will extend the cycle)
+            // activeScanCycleTime is in minutes and activeScanDuration is in secs
+            ActiveCycleSleepSecs = activeScanCycleTime * 60 - activeScanDuration;
+            VERBOSE(VB_EIT, LOC +
+                QString("Calculated Active Scan wait time of %1 minutes. Active Scan will resume then.")
+                   .arg(ActiveCycleSleepSecs/60));
+
+            // We have to wait for ActiveCycleSleepSecs. This is easily achieved
+            // by doing nothing until the appropriate time is reached
+            eitScanStartTime = QDateTime::currentDateTime().addSecs(ActiveCycleSleepSecs);
+        }
+
         // We should be no more than a few thousand milliseconds,
         // as the end recording code does not have a trigger...
         // NOTE: If you change anything here, make sure that