Rational: conversion to opentime take framerate

Add a frame rate option to the conversion to opentime rationals as
otio generaly expects rationals to be in the form value/framerate.

Also add a check to make sure the rational is not in the form 0/0
as this can cause errors with OTIO.

app/common/rational.cpp

@@ -103,10 +103,12 @@ AVRational rational::toAVRational() const
 }
 
 #ifdef USE_OTIO
-opentime::RationalTime rational::toRationalTime() const
+opentime::RationalTime rational::toRationalTime(double framerate) const
 {
   // Is this the best way of doing this?
-  return opentime::RationalTime::from_seconds(toDouble());
+  // Olive can store rationals as 0/0 which causes errors in OTIO
+  opentime::RationalTime time = opentime::RationalTime(numer_, denom_ == 0 ? 1 : denom_);
+  return time.rescaled_to(framerate);
 }
 #endif
 

app/common/rational.h

@@ -101,7 +101,8 @@ public:
   AVRational toAVRational() const;
 
 #ifdef USE_OTIO
-  opentime::RationalTime toRationalTime() const;
+  // Convert Olive ratioanls to opentime rationals with the given framerate (defaults to 24)
+  opentime::RationalTime toRationalTime(double framerate = 24) const;
 #endif
 
   // Produce "flipped" version

app/task/project/saveotio/saveotio.cpp

@@ -144,8 +144,8 @@ opentimelineio::v1_0::Track *SaveOTIOTask::SerializeTrack(TrackOutput *track)
     }
     case Block::kGap:
     {
-      otio_block = new opentimelineio::v1_0::Gap(
-            opentimelineio::v1_0::TimeRange(block->in().toRationalTime(), block->length().toRationalTime()),
+      otio_block = new opentimelineio::v1_0::Gap(opentimelineio::v1_0::TimeRange(block->in().toRationalTime(),
+                                          block->length().toRationalTime()),
             block->GetLabel().toStdString()
       );
       break;