- template <class T>
- static DCPTime from_frames (int64_t f, T r) {
- return DCPTime (f * HZ / r);
- }
+/* Specializations for the two allowed explicit conversions */
+
+template<>
+Time<ContentTimeDifferentiator, DCPTimeDifferentiator>::Time (Time<DCPTimeDifferentiator, ContentTimeDifferentiator> d, FrameRateChange f);
+
+template<>
+Time<DCPTimeDifferentiator, ContentTimeDifferentiator>::Time (Time<ContentTimeDifferentiator, DCPTimeDifferentiator> d, FrameRateChange f);
+
+/** Time relative to the start or position of a piece of content in its native frame rate */
+typedef Time<ContentTimeDifferentiator, DCPTimeDifferentiator> ContentTime;
+/** Time relative to the start of the output DCP in its frame rate */
+typedef Time<DCPTimeDifferentiator, ContentTimeDifferentiator> DCPTime;