dash: set minbuffer for stream stability

Signed-off-by: Hugo Beauzée-Luyssen <beauze.h@gmail.com>

modules/stream_filter/dash/adaptationlogic/AbstractAdaptationLogic.cpp

@@ -64,3 +64,7 @@ long AbstractAdaptationLogic::getBpsLastChunk        () const
 {
     return this->bpsLastChunk;
 }
+int AbstractAdaptationLogic::getBufferPercent        () const
+{
+    return this->bufferedPercent;
+}

modules/stream_filter/dash/adaptationlogic/AbstractAdaptationLogic.h

@@ -52,6 +52,7 @@ namespace dash
 
                 long                        getBpsAvg               () const;
                 long                        getBpsLastChunk         () const;
+                int                         getBufferPercent        () const;
 
             private:
                 int                     bpsAvg;

modules/stream_filter/dash/adaptationlogic/RateBasedAdaptationLogic.cpp

@@ -55,6 +55,9 @@ Chunk*  RateBasedAdaptationLogic::getNextChunk() throw(EOFException)
 
     long bitrate = this->getBpsAvg();
 
+    if(this->getBufferPercent() < MINBUFFER)
+        bitrate = 0;
+
     Representation *rep = this->mpdManager->getRepresentation(this->currentPeriod, bitrate, this->width, this->height);
 
     if ( rep == NULL )

modules/stream_filter/dash/adaptationlogic/RateBasedAdaptationLogic.h

@@ -35,6 +35,8 @@
 #include <vlc_common.h>
 #include <vlc_stream.h>
 
+#define MINBUFFER 30
+
 namespace dash
 {
     namespace logic