diff --git a/MP4/box_avcC.cpp b/MP4/box_avcC.cpp
index 0bcb15eb..354312c7 100644
--- a/MP4/box_avcC.cpp
+++ b/MP4/box_avcC.cpp
@@ -18,11 +18,14 @@ void Box_avcC::SetDataReferenceIndex( uint16_t DataReferenceIndex ) {
   Container->SetPayload((uint32_t)2,Box::uint16_to_uint8( DataReferenceIndex ),6);
 }
 
-void Box_avcC::SetDimensions ( uint16_t Width, uint16_t Height ) {
-  Container->SetPayload((uint32_t)2,Box::uint16_to_uint8( Height ),26);
+void Box_avcC::SetWidth( uint16_t Width ) {
   Container->SetPayload((uint32_t)2,Box::uint16_to_uint8( Width ),24);
 }
 
+void Box_avcC::SetHeight( uint16_t Height ) {
+  Container->SetPayload((uint32_t)2,Box::uint16_to_uint8( Height ),26);
+}
+
 void Box_avcC::SetResolution ( uint32_t Horizontal, uint32_t Vertical ) {
   Container->SetPayload((uint32_t)4,Box::uint32_to_uint8( Vertical ),32);
   Container->SetPayload((uint32_t)4,Box::uint32_to_uint8( Horizontal ),28);
@@ -55,6 +58,7 @@ void Box_avcC::SetReserved( ) {
 }
 
 void Box_avcC::SetDefaults( ) {
+  SetDimensions( );
   SetDepth ( );
   SetFrameCount ( );
   SetResolution ( );
diff --git a/MP4/box_avcC.h b/MP4/box_avcC.h
index 51d7dbd7..ba465832 100644
--- a/MP4/box_avcC.h
+++ b/MP4/box_avcC.h
@@ -7,7 +7,8 @@ class Box_avcC {
     ~Box_avcC();
     Box * GetBox();
     void SetDataReferenceIndex( uint16_t DataReferenceIndex = 0 );
-    void SetDimensions ( uint16_t Width = 0, uint16_t Height = 0);
+    void SetWidth( uint16_t Width = 0 );
+    void SetHeight( uint16_t Height = 0 );
     void SetResolution ( uint32_t Horizontal = 0x00480000, uint32_t Vertical = 0x00480000 );
     void SetFrameCount ( uint16_t FrameCount = 1 );
     void SetCompressorName ( std::string CompressorName = "");
diff --git a/MP4/box_mvhd.h b/MP4/box_mvhd.h
index 28caa169..b84a446d 100644
--- a/MP4/box_mvhd.h
+++ b/MP4/box_mvhd.h
@@ -14,7 +14,7 @@ class Box_mvhd {
     void SetDurationTime( uint32_t TimeUnits = 0 );
     void SetRate( uint32_t Rate = 0x00010000 );
     void SetVolume( uint16_t Volume = 0x0100 );
-    void SetNextTrackID( uint32_t TrackID = 0 );
+    void SetNextTrackID( uint32_t TrackID = 0xFFFFFFFF );
   private:
     void SetReserved();
     void SetDefaults();
diff --git a/MP4/box_tkhd.cpp b/MP4/box_tkhd.cpp
index b274f832..06900356 100644
--- a/MP4/box_tkhd.cpp
+++ b/MP4/box_tkhd.cpp
@@ -70,12 +70,14 @@ void Box_tkhd::SetTrackID( uint32_t TrackID ) {
   Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(TrackID),12);
 }
 
-void Box_tkhd::SetWidth( uint32_t Width ) {
-  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(Width),72);
+void Box_tkhd::SetWidth( uint16_t Width ) {
+  uint32_t ResultWidth = ( Width << 16 );
+  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(ResultWidth),72);
 }
 
-void Box_tkhd::SetHeight( uint32_t Height ) {
-  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(Height),76);
+void Box_tkhd::SetHeight( uint16_t Height ) {
+  uint32_t ResultHeight = ( Height << 16 );
+  Container->SetPayload((uint32_t)4,Box::uint32_to_uint8(ResultHeight),76);
 }
 
 void Box_tkhd::SetDefaults() {
diff --git a/MP4/box_tkhd.h b/MP4/box_tkhd.h
index e326ba16..3a9e2bc4 100644
--- a/MP4/box_tkhd.h
+++ b/MP4/box_tkhd.h
@@ -11,8 +11,8 @@ class Box_tkhd {
     void SetCreationTime( uint32_t TimeStamp = 0 );
     void SetModificationTime( uint32_t TimeStamp = 0 );
     void SetDurationTime( uint32_t TimeUnits = 0 );
-    void SetWidth( uint32_t Width = 0 );
-    void SetHeight( uint32_t Height = 0 );
+    void SetWidth( uint16_t Width = 0 );
+    void SetHeight( uint16_t Height = 0 );
     void SetFlags( bool Bit0 = true, bool Bit1 = true, bool Bit2 = true );
     void SetVersion( uint32_t Version = 0 );
     void SetTrackID( uint32_t TrackID = 0 );
diff --git a/MP4/interface.cpp b/MP4/interface.cpp
index 884ca01a..b67618b5 100644
--- a/MP4/interface.cpp
+++ b/MP4/interface.cpp
@@ -1,6 +1,10 @@
 #include "interface.h"
 
 Interface::Interface() {
+  //Initializing local data
+  Width = 0;
+  Height = 0;
+  //Creating the boxes
   ftyp = new Box_ftyp();
   moov = new Box_moov();
   mvhd = new Box_mvhd();
@@ -36,9 +40,12 @@ Interface::Interface() {
   stco_soun = new Box_stco();
   stsd_soun = new Box_stsd();
   esds_soun = new Box_esds();
+  //Set some values we already know won't change once the boxes have been created
+  SetStaticDefaults();
 }
 
 Interface::~Interface() {
+  //Deleting the boxes if they still exist.
   if( esds_soun ) { delete esds_soun; esds_soun = NULL; }
   if( stsd_soun ) { delete stsd_soun; stsd_soun = NULL; }
   if( stco_soun ) { delete stco_soun; stco_soun = NULL; }
@@ -126,8 +133,9 @@ uint8_t * Interface::GetContents( ) {
   return Result;
 }
 
-
 void Interface::UpdateContents( ) {
+  if( !Width ) { std::cerr << "WARNING: Width not set!\n"; }
+  if( !Height ) { std::cerr << "WARNING: Height not set!\n"; }
   stsd_vide->WriteContent( );
   stco_vide->WriteContent( );
   stsc_vide->WriteContent( );
@@ -152,3 +160,30 @@ void Interface::UpdateContents( ) {
 
   moov->WriteContent( );
 }
+
+bool Interface::AllBoxesExist() {
+  return ( ftyp && moov && mvhd && trak_vide && tkhd_vide && mdia_vide && mdhd_vide && hdlr_vide &&
+  minf_vide && vmhd_vide && dinf_vide && dref_vide && url_vide && stbl_vide && stts_vide && stsc_vide &&
+  stco_vide && stsd_vide && avcC_vide && trak_soun && tkhd_soun && mdia_soun && mdhd_soun && hdlr_soun &&
+  minf_soun && smhd_soun && dinf_soun && dref_soun && url_soun && stbl_soun && stts_soun && stsc_soun &&
+  stco_soun && stsd_soun && esds_soun );
+}
+
+void Interface::SetWidth( uint16_t NewWidth ) {
+  Width = NewWidth;
+  avcC_vide->SetWidth( Width );
+  tkhd_vide->SetWidth( Width );
+}
+
+void Interface::SetHeight( uint16_t NewHeight ) {
+  Height = NewHeight;
+  avcC_vide->SetHeight( Height );
+  tkhd_vide->SetHeight( Height );
+}
+
+void Interface::SetStaticDefaults() {
+//  'vide' = 0x76696465
+  hdlr_vide->SetHandlerType( 0x76696465 );
+//  'soun' = 0x736F756E
+  hdlr_soun->SetHandlerType( 0x736F756E );
+}
diff --git a/MP4/interface.h b/MP4/interface.h
index 0125ddf4..70f6b068 100644
--- a/MP4/interface.h
+++ b/MP4/interface.h
@@ -7,8 +7,15 @@ class Interface {
     void link();
     uint32_t GetContentSize();
     uint8_t * GetContents();
+
+    void SetWidth( uint16_t NewWidth );
+    void SetHeight( uint16_t NewHeight );
   private:
+    void SetStaticDefaults();
     void UpdateContents();
+    bool AllBoxesExist();
+    uint16_t Width;
+    uint16_t Height;
     Box_ftyp * ftyp;
     Box_moov * moov;
     Box_mvhd * mvhd;