dash: For first segments, don't choose the lowest bitrate.

For some streams, the lowest bitrate is an audio stream only. We will
fall back to a more appropriate stream after a few chunks.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 73b30f553150be24f2fb523d629fba788d18646b)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/stream_filter/dash/adaptationlogic/AbstractAdaptationLogic.cpp

@@ -34,7 +34,7 @@ using namespace dash::exception;
 
 AbstractAdaptationLogic::AbstractAdaptationLogic    (IMPDManager *mpdManager)
 {
-    this->bpsAvg        = 0;
+    this->bpsAvg        = -1;
     this->bpsLastChunk  = 0;
     this->mpdManager    = mpdManager;
 }

modules/stream_filter/dash/adaptationlogic/AbstractAdaptationLogic.h

@@ -52,7 +52,7 @@ namespace dash
                 long                        getBpsLastChunk         ();
 
             private:
-                long                    bpsAvg;
+                int                     bpsAvg;
                 long                    bpsLastChunk;
                 dash::mpd::IMPDManager  *mpdManager;
         };

modules/stream_filter/dash/http/HTTPConnectionManager.cpp

@@ -161,6 +161,8 @@ void                HTTPConnectionManager::attach                   (IDownloadRa
 }
 void                HTTPConnectionManager::notify                   ()
 {
+    if ( this->bpsAvg <= 0 )
+        return ;
     for(size_t i = 0; i < this->rateObservers.size(); i++)
         this->rateObservers.at(i)->downloadRateChanged(this->bpsAvg, this->bpsLastChunk);
 }

modules/stream_filter/dash/mpd/BasicCMManager.cpp

@@ -91,38 +91,30 @@ Period*                 BasicCMManager::getFirstPeriod          ()
     return periods.at(0);
 }
 
-Representation*         BasicCMManager::getRepresentation       (Period *period, long bitrate)
+Representation*         BasicCMManager::getRepresentation(Period *period, int bitrate )
 {
-    std::vector<Group *> groups = period->getGroups();
+    std::vector<Group *>    groups = period->getGroups();
 
-    Representation  *best       = NULL;
-    int             bestDif  = -1;
+    Representation  *best = NULL;
+    std::cout << "Sarching for best representation with bitrate: " << bitrate << std::endl;
 
     for(size_t i = 0; i < groups.size(); i++)
     {
         std::vector<Representation *> reps = groups.at(i)->getRepresentations();
-        for(size_t j = 0; j < reps.size(); j++)
+        for( size_t j = 0; j < reps.size(); j++ )
         {
             int     currentBitrate = reps.at(j)->getBandwidth();
             assert( currentBitrate != -1 );
-            int     dif = bitrate - currentBitrate;
 
-            if( bestDif == -1 )
+            if ( best == NULL || bitrate == -1 ||
+                 ( currentBitrate > best->getBandwidth() &&
+                   currentBitrate < bitrate ) )
             {
-                bestDif = dif;
-                best = reps.at(j);
-            }
-            else
-            {
-                if ( dif >= 0 && dif < bestDif )
-                {
-                    bestDif = dif;
-                    best = reps.at(j);
-                }
+                std::cout << "Found a better Representation (#" << j << ") in group #" << i << std::endl;
+                best = reps.at( j );
             }
         }
     }
-
     return best;
 }
 Period*                 BasicCMManager::getNextPeriod           (Period *period)

modules/stream_filter/dash/mpd/BasicCMManager.h

@@ -52,7 +52,7 @@ namespace dash
                 Period*                         getNextPeriod( Period *period );
                 Representation*                 getBestRepresentation( Period *period );
                 std::vector<const Segment *>    getSegments( Representation *rep );
-                Representation*                 getRepresentation( Period *period, long bitrate );
+                Representation*                 getRepresentation( Period *period, int bitrate );
                 const MPD*                      getMPD() const;
 
             private:

modules/stream_filter/dash/mpd/IMPDManager.h

@@ -32,7 +32,7 @@ namespace dash
                 virtual Period*                 getNextPeriod           (Period *period)                = 0;
                 virtual Representation*         getBestRepresentation   (Period *period)                = 0;
                 virtual std::vector<const Segment *> getSegments        (Representation *rep)           = 0;
-                virtual Representation*         getRepresentation       (Period *period, long bitrate)  = 0;
+                virtual Representation*         getRepresentation       (Period *period, int bitrate)   = 0;
                 virtual const MPD*              getMPD                  () const = 0;
                 virtual ~IMPDManager(){}
         };