mkvparser: Get frame default duration

Track::GetDefaultDuration is implemented as an alternative
to VideoTrack::GetFrameRate which seems to be deprecated.

Change-Id: I2c7a6d56a232125b8632d87eab75b9600c5451e1

mkvparser.cpp

@@ -5580,6 +5580,7 @@ int Track::Info::Copy(Info& dst) const
 
     dst.type = type;
     dst.number = number;
+    dst.defaultDuration = defaultDuration;
     dst.uid = uid;
     dst.lacing = lacing;
     dst.settings = settings;
@@ -5678,6 +5679,10 @@ bool Track::GetLacing() const
     return m_info.lacing;
 }
 
+unsigned long long Track::GetDefaultDuration() const
+{
+    return m_info.defaultDuration;
+}
 
 long Track::GetFirst(const BlockEntry*& pBlockEntry) const
 {
@@ -6579,6 +6584,7 @@ long Tracks::ParseTrackEntry(
     info.type = 0;
     info.number = 0;
     info.uid = 0;
+    info.defaultDuration = 0;
 
     Track::Settings v;
     v.start = -1;
@@ -6693,6 +6699,15 @@ long Tracks::ParseTrackEntry(
             if (status)
                 return status;
         }
+        else if (id == 0x03E383)  //Default Duration
+        {
+            const long long duration = UnserializeUInt(pReader, pos, size);
+
+            if (duration < 0)
+                return E_FILE_FORMAT_INVALID;
+
+            info.defaultDuration = static_cast<unsigned long long>(duration);
+        }
         else if (id == 0x06)  //CodecID
         {
             const long status = UnserializeString(

mkvparser.hpp

@@ -354,6 +354,7 @@ public:
     const char* GetCodecId() const;
     const unsigned char* GetCodecPrivate(size_t&) const;
     bool GetLacing() const;
+    unsigned long long GetDefaultDuration() const;
 
     const BlockEntry* GetEOS() const;
 
@@ -377,6 +378,7 @@ public:
         long type;
         long number;
         unsigned long long uid;
+        unsigned long long defaultDuration;
         char* nameAsUTF8;
         char* language;
         char* codecId;