- frame_rate = node->number_child<int> ("FrameRate");
- channels = node->number_child<int64_t> ("Channels");
- first_audio = node->optional_number_child<double> ("FirstAudio");
+ optional<ContentTime::Type> const f = node->optional_number_child<ContentTime::Type> ("FirstAudio");
+ if (f) {
+ first_audio = ContentTime (f.get ());
+ }