diff --git a/MP4/box.cpp b/MP4/box.cpp
index 55f6408c..93a55575 100644
--- a/MP4/box.cpp
+++ b/MP4/box.cpp
@@ -94,6 +94,12 @@ uint8_t * Box::uint16_to_uint8( uint16_t data ) {
   return temp;
 }
 
+uint8_t * Box::uint8_to_uint8( uint8_t data ) {
+   uint8_t * temp = new uint8_t[1];
+   temp[0] = data;
+   return temp;
+}
+
 BoxHeader Box::GetHeader( ) {
   return header;
 }
diff --git a/MP4/box.h b/MP4/box.h
index 772bbb82..67b73dc2 100644
--- a/MP4/box.h
+++ b/MP4/box.h
@@ -24,6 +24,7 @@ class Box {
 
     static uint8_t * uint32_to_uint8( uint32_t data );
     static uint8_t * uint16_to_uint8( uint16_t data );
+    static uint8_t * uint8_to_uint8( uint8_t data );
     BoxHeader GetHeader( );
     void ResetPayload( );
   private:
diff --git a/MP4/box_asrt.cpp b/MP4/box_asrt.cpp
new file mode 100644
index 00000000..32a43661
--- /dev/null
+++ b/MP4/box_asrt.cpp
@@ -0,0 +1,57 @@
+#include "box_asrt.h"
+
+Box_asrt::Box_asrt( ) {
+  Container = new Box( 0x61737274 );
+}
+
+Box_asrt::~Box_asrt() {
+  delete Container;
+}
+
+Box * Box_asrt::GetBox() {
+  return Container;
+}
+
+void Box_asrt::SetUpdate( bool Update ) {
+  isUpdate = Update;
+}
+
+void Box_asrt::AddQualityEntry( std::string Quality, uint32_t Offset ) {
+  if(Offset >= QualitySegmentUrlModifiers.size()) {
+    QualitySegmentUrlModifiers.resize(Offset+1);
+  }
+  QualitySegmentUrlModifiers[Offset] = Quality;
+}
+
+void Box_asrt::AddSegmentRunEntry( uint32_t FirstSegment, uint32_t FragmentsPerSegment, uint32_t Offset ) {
+  if( Offset >= SegmentRunEntryTable.size() ) {
+    SegmentRunEntryTable.resize(Offset+1);
+  }
+  SegmentRunEntryTable[Offset].FirstSegment = FirstSegment;
+  SegmentRunEntryTable[Offset].FragmentsPerSegment = FragmentsPerSegment;
+}
+
+void Box_asrt::SetDefaults( ) {
+  SetUpdate( );
+}
+
+void Box_asrt::WriteContent( ) {
+  std::string serializedQualities = "";
+  Container->ResetPayload( );
+
+  for( uint32_t i = 0; i < Qualities.size(); i++ ) {
+    serializedQualities.append(Qualities[i].QualityModifier.c_str());
+    serializedQualities += '\0';
+  }
+
+  uint32_t OffsetSegmentRunEntryCount = 8 + serializedQualities.size();
+  
+  for( uint32_t i = 0; i < SegmentRunEntryTable.size(); i ++ ) {
+    Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(SegmentRunEntryTable[i].FragmentsPerSegment),(8*i)+OffsetSegmentRunEntryCount+8);
+    Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(SegmentRunEntryTable[i].FirstSegment),(8*i)+OffsetSegmentRunEntryCount+4);
+  }
+  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(SegmentRunEntryTable.size()),OffsetSegmentRunEntryCount);  
+  Container->SetPayload((uint32_t)serializedQualities.size(),(uint8_t*)serializedQualities.c_str(),5);
+  Container->SetPayload((uint32_t)1,Box::uint8_to_uint8(QualitySegmentUrlModifiers.size()),4);
+  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8((isUpdate ? 1 : 0)));
+}
diff --git a/MP4/box_asrt.h b/MP4/box_asrt.h
new file mode 100644
index 00000000..f5b78e9b
--- /dev/null
+++ b/MP4/box_asrt.h
@@ -0,0 +1,25 @@
+#include "box.h"
+#include <string>
+#include <vector>
+
+struct asrt_segmentrunentry {
+  uint32_t FirstSegment;
+  uint32_t FragmentsPerSegment;
+};//abst_qualityentry
+
+class Box_asrt {
+  public:
+    Box_asrt( );
+    ~Box_asrt();
+    Box * GetBox();
+    void SetUpdate( bool Update = false );
+    void AddQualityEntry( std::string Quality = "", uint32_t Offset = 0 );
+    void AddSegmentRunEntry( uint32_t FirstSegment = 0, uint32_t FragmentsPerSegment = 100, uint32_t Offset = 0 );
+    void WriteContent( );
+  private:
+    void SetDefaults( );
+    bool isUpdate;
+    std::vector<std::string> QualitySegmentUrlModifiers;
+    std::vector<asrt_segmentrunentry> SegmentRunEntryTable;
+    Box * Container;
+};//Box_ftyp Class