fix for transport streams with no duration

app/common/rational.cpp

@@ -79,6 +79,16 @@ double rational::toDouble() const
     return static_cast<double>(0);
 }
 
+AVRational rational::toAVRational() const
+{
+  AVRational r;
+
+  r.num = static_cast<int>(numer);
+  r.den = static_cast<int>(denom);
+
+  return r;
+}
+
 rational rational::flipped() const
 {
   return rational(denom, numer);

app/common/rational.h

@@ -96,6 +96,8 @@ public:
   //Function: convert to double
   double toDouble() const;
 
+  AVRational toAVRational() const;
+
   // Produce "flipped" version
   rational flipped() const;