Add comments about the time range duration

Signed-off-by: Darby Johnston <[email protected]>

Author: darbyjohnston

src/opentime/timeRange.h

@@ -58,7 +58,7 @@ class TimeRange
     /// @brief Returns true if the time range is invalid.
     ///
     /// The time range is considered invalid if either the start time or
-    /// duration is invalid.
+    /// duration is invalid, or if the duration is less than zero.
     bool is_invalid_range() const noexcept
     {
         return _start_time.is_invalid_time() || _duration.is_invalid_time() || _duration.value() < 0.0;
@@ -67,7 +67,8 @@ class TimeRange
     /// @brief Returns true if the time range is valid.
     ///
     /// The time range is considered valid if both the start time and
-    /// duration are valid.
+    /// duration are valid, and the duration is greater than or equal to
+    /// zero.
     bool is_valid_range() const noexcept
     {
         return _start_time.is_valid_time() && _duration.is_valid_time() && _duration.value() >= 0.0;

src/py-opentimelineio/opentime-bindings/opentime_timeRange.cpp

@@ -45,11 +45,11 @@ meaning that :meth:`end_time_inclusive` (last portion of a sample in the time ra
         .def(py::init<double, double, double>(), "start_time"_a, "duration"_a, "rate"_a)
         .def("is_invalid_range", &TimeRange::is_invalid_range, R"docstring(
 Returns true if the time range is invalid. The time range is considered invalid if either the start time or
-duration is invalid.
+duration is invalid, or if the duration is less than zero.
 )docstring")
         .def("is_valid_range", &TimeRange::is_valid_range, R"docstring(
 Returns true if the time range is valid. The time range is considered valid if both the start time and
-duration are valid.
+duration are valid, and the duration is greater than or equal to zero.
 )docstring")
         .def_property_readonly("start_time", &TimeRange::start_time)
         .def_property_readonly("duration", &TimeRange::duration)